NISTIR 8146

Interlaboratory Analytical 

Comparison Study of Fatty Acid 

Concentrations in Human SerumResults for Exercise 03: 

QA16FASER03 

Michele M. Schantz 

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http://dx.doi.org/10.6028/NIST.IR.8146 
 

 

 

 

 

 

 

NISTIR 8146 

Interlaboratory Analytical 

Comparison Study of Fatty Acid 

Concentrations in Human SerumResults for Exercise 03: 

QA16FASER03 

Michele M. Schantz 

Chemical Sciences Division 

Material Measurement Laboratory 

This publication is available free of charge from: 

http://dx.doi.org/10.6028/NIST.IR.8146 

September 2016 

U.S. Department of Commerce 

Penny Pritzker, Secretary 

National Institute of Standards and Technology 

Willie May, Under Secretary of Commerce for Standards and Technology and Director 
 

 

 

 

 

 

ABSTRACT 

The National Institute of Standards and Technology (NIST), at the request of the National 

Institute of Health’s (NIH’s) Office of Dietary Supplements (ODS) and in conjunction with the 

Centers for Disease Control and Prevention (CDC), initiated a third interlaboratory analytical 

comparison study of fatty acid concentrations in human serum in 2016. Three unknown serum 

samples were distributed along with Standard Reference Material (SRM) 1950 Metabolites in 

Frozen Human Plasma as the control sample. This is a performance-based program so 

participating laboratories were requested to use the analytical procedures that they typically use 

in their laboratories for these analyses and report data for those fatty acids that they typically 

quantify. The results from the third exercise are reported along with a summary of the analytical 

methods used by each laboratory. 

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Background 

The National Institute of Standards and Technology (NIST) currently offers three quality 

assurance programs (QAPs) for the determination of micronutrients, vitamin D metabolites, and 

fatty acids in serum and plasma matrices, the Micronutrients Measurement QAP (MMQAP), the 

Vitamin D QAP (VitDQAP), and the Fatty Acid QAP (FAQAP), respectively. Given the 

similarity in the operations of these programs, NIST has consolidated the three programs into 

one larger program, the NIST Clinical Quality Assurance Program, or ClinQAP 

(http://www.nist.gov/mml/csd/clinqap.cfm). The primary goals of the ClinQAP are to support 

the comparability of clinical measurements through the MMQAP, VitDQAP, and the FAQAP 

and to monitor and support the emerging measurement needs of the clinical community. 

The first exercise of the FAQAP was conducted in 2012 with 11 laboratories returning data for 

the content of individual fatty acids in Standard Reference Material (SRM) 2378 Fatty Acids in 

Frozen Human Serum (a candidate material at that time) along with SRM 1950 Metabolites in 

Frozen Human Plasma which was distributed as the control sample. Candidate SRM 2378 

consists of three serum materials collected from: donors who have not taken fish or flaxseed oil 

supplements for one month prior to collection; donors who have taken flaxseed oil supplements 

for a minimum of one month prior to collection; and donors who have taken fish oil supplements 

for a minimum of one month prior to collection. SRM 1950 is designed to represent “normal” 

human plasma. Plasma was obtained from 100 individuals (equal number of men and women in 

a narrow age range (40 to 50 years) who had undergone an overnight fast prior to blood draw. 

The results from the first exercise were published in NIST Internal Report (NISTIR) 7953. [1] 

The second exercise of the FAQAP was conducted in 2015 with 14 laboratories returning data 

for the content of individual fatty acids in three serum samples, that had been originally collected 

for use in the MMQAP, and in each of the three levels of SRM 2378 (as control samples). The 

results from the second exercise were published in NISTIR 8086 [2]. 

Overview of Exercise 03: QA16FASER03 

For the third FAQAP exercise, the intercomparison materials were three serum samples 

previously used in the VitDQAP studies. [3] The samples used were: 

SRM 972a Level 2 relabeled as FAQAP Unk 004 (black label) 

VitDQAP Sample I relabeled as FAQAP Unk 005 (red label) 

VitDQAP Sample II relabeled as FAQAP Unk 006 (green label) 

In addition, participants were requested to run SRM 1950 as the control material. The 

laboratories were provided with three vials of each unknown material, each vial contained 

approximately 1 mL of serum, and were requested to do triplicate measurements of each 

unknown sample using their laboratory's and/or program's analytical protocols for the 

concentrations of the fatty acids currently being determined in their laboratory. In addition, they 

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were requested to analyze one subsample of the control material, SRM 1950. A target list of 

fatty acids was provided; however, participants did not need to quantify all of these compounds 

and could add additional compounds when reporting data. They were requested to report results, 

using three significant figures, in units of either μg/g or μmol/L (μM) and to provide brief 

descriptions of their cleanup and analytical procedures. 

Reported Results 

Thirteen laboratories returned data and were assigned numerical identification codes in order of 

receipt of data with the exception of the NIST laboratory, which is Lab 1 in this exercise. The 

fatty acids included in the study are listed in Table 1 with the suggested list of fatty acids at the 

top of the table and the additional fatty acids reported listed below. For the total (esterified and 

free) fatty acids, the laboratory mean values, standard deviations, and relative standard 

deviations are shown in Tables 2, 4, and 6 in μg/g for unknowns 004, 005, and 006, respectively, 

and in Tables 3, 5, and 7 in μM for unknowns 004, 005, and 006, respectively. The laboratory 

values reported for the control sample, SRM 1950, are summarized in Tables 8 and 9 in μg/g and 

in μM, respectively. The summary statistics (median, number of laboratories reporting, and 

lowest and highest value reported) are given in Table 10 for the total fatty acids. 

This is the first study in which the laboratories were also given the option of reporting data for 

the free fatty acids in the serum samples. Only one laboratory (Lab 12) did so, however. Their 

data for the free fatty acids are shown in Table 11, and the % of free to total fatty acid based only 

on that laboratory’s data are shown in Table 12. 

Summaries of the methods used and notes submitted by each laboratory are in Appendix A, and 

charts of the mean numerical results reported by each laboratory for each analyte in the exercise 

materials are in Appendix B. 

Discussion 

NIST contacted over 40 laboratories in early 2016 regarding participation in the third 

interlaboratory analytical comparison study of fatty acid concentrations in human serum. Of the 

laboratories contacted, 15, including NIST, replied with interest in participating in this study. As 

stated above, laboratories were also given the option of reporting free fatty acids along with total 

fatty acids for the samples received. Of the 15 laboratories requesting samples, four (4) said that 

they were interested in quantifying the free fatty acids in addition to the total fatty acids and two 

(2) were interested in quantifying the free fatty acids. Only one of those laboratories, designated 

as Lab 12 in this study, reported data for the free fatty acids. 

Samples were sent on dry ice between March 14 and 21, 2016. The deadline for submission of 

data to NIST was June 1, 2016. All but two laboratories returned data by June 30, 2016. One of 

the remaining laboratories reported that they would not be sending in data because they had 

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problems with the hydrolysis step resulting in low results on the control material. The last 

laboratory did not respond to requests for a status report on their analyses. 

After submitting data, one of the laboratories (designated as Lab 11 in this study) asked that their 

data be removed from the data summary. Their results were 5 to 10 times higher than expected 

based on the SRM 1950 values. They stated that their method is semi-quantitative, reported as 

normalized area percents. They have had success with the method for foods but speculate that 

the residue mass from the serum and plasma samples is composed of more than fatty acids thus 

overestimating the concentrations of each fatty acid. 

Another laboratory (designated as Lab 13 in this study) provided a recalculated set of data on 

July 12. The recalculated data set has been incorporated into this report. The laboratory did not 

report what the recalculation involved. 

An alphabetical list of laboratories that returned data is given in Appendix C. Note that the 

numerical codes in the following tables and figures are based on the receipt of the data and 

therefore do not follow the order in Appendix C. 

Laboratories were requested to submit data for the fatty acids that they typically monitor in 

similar samples (Table 1) for three subsamples of each unknown sample received and one 

subsample of SRM 1950 in units of either μg/g or μM along with the density of each sample. 

Summaries of the results submitted by each laboratory are presented in Tables 2 through 7 as the 

means, standard deviations, and relative standard deviations for the three values submitted for 

each unknown sample in both μg/g and μM. Three (3) laboratories reported the data in μg/g, 

and nine (9) laboratories reported the data in μM. The conversions between the units reported 

and the alternate units were calculated using the densities provided by each laboratory except for 

labs 1, 2, 5, 7, and 13. These laboratories did not report a density so the density was assumed to 

be 1 g/mL for the conversion. The densities reported by the remaining laboratories are shown in 

the tables and range from 0.954 g/mL to 1.09 g/mL. Summaries of the results from each 

participant for the analysis of one subsample of SRM 1950 are presented in tables 8 and 9 in 

μg/g and μM, respectively, along with the certified and reference values for the fatty acids. 

As shown in Tables 2 through 7, the relative standard deviations (RSDs) for each participating 

laboratory for the analyses of three subsamples for each unknown serum sample are generally < 

10 %. Lab 13 had a few analytes, particularly in unknown 004, with higher RSDs as well as high 

RSDs (> 90 %) for C22:1n9 in unknown 005 and unknown 006. The higher RSDs for C22:1n9 

came from reporting one or more 0 values for the subsamples. 

Several laboratories reported data for additional fatty acids. These fatty acids are included at the 

bottom of Table 1 and summarized at the bottom of Tables 2 through 9. 

The data in terms of μM are plotted by analyte in each material in Appendix B. Each data point 

is the mean and associated standard deviation of the data reported by the laboratory of the 

indicated analyte in the indicated sample. The medians calculated from the data received for the 

fatty acid in each unknown sample are summarized in Table 10 and included on each chart for 

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the unknown samples. The charts for SRM 1950 include the certified or reference values for 

comparison purposes. 

The relative expanded uncertainty for the medians ranged from 9 % to 66 % for unknown 004, 

from 7 % to > 300 % for unknown 005, and < 1 % to > 200 % for unknown 006. The high 

relative uncertainties for C22:1n9 in unknown 005 and 006 are due to a limited number of 

laboratories reporting data (n=4), and one of those laboratories (Lab 13) appearing to be an 

outlier. As mentioned above, this is also the compound for which Lab 13 reported several 0 

values resulting in high RSDs for their data. In general, the agreement among the laboratories 

was best in all of the samples for those fatty acids at highest concentrations, particularly C16:0, 

C18:0, C18:1n9, and C18:2n6. 

Examples of the comparison of the median values and associated uncertainties are shown below 

for 10 of the fatty acids quantified in this study. 

0 

500 

1000 

1500 

2000 

2500 

3000 

3500 

4000 

C16:0 C18:0 C18:1n9 C18:2n6 C20:4n6 

μM 

Comparison of Median Values across Samples 

(error bars are the uncertainty of the median values) 

unk 04 unk 05 unk 06 1950 

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0 

20 

40 

60 

80 

100 

120 

140 

160 

180 

200 

C18:3n3 C20:5n3 C22:5n3 C22:5n6 C22:6n3 

μM 

Comparison of Median Values across Samples 

(error bars are the uncertainty of the median values) 

unk 04 unk 05 unk 06 1950 

The concentrations of the individual fatty acids in the four (4) samples quantified in this study 

were similar with the uncertainty of the median values overlapping for most of the fatty acids 

with the exception of C20:5n3 being highest in unknown 006. It is interesting to note that the 

agreement among the laboratories was best for the majority of the fatty acids in unknown 006. 

In the past exercises [1,2], there were some trends across all fatty acids in the samples with a 

particular laboratory reporting high data or low data. In this exercise, that does not appear to be 

the case. The laboratories reporting the highest or lowest data tend to vary from fatty acid to 

fatty acid within the samples, however, tend to be consistent across samples. Using C20:4n6 as 

an example, Lab 2 reported the lowest values for unknown 004, unknown 005, and SRM 1950 

and the second lowest value for unknown 006; whereas Lab 7 reported the highest value for all 

of the samples. These results could be obtained by incomplete extraction (low), coelution with 

other fatty acids or matrix components on the analytical column used (high), misidentification of 

the chromatographic peaks (low or high), or from some other method variations such as 

inaccurate calibration. 

The methods used by each laboratory are summarized in Appendix A with the procedures for the 

total fatty acids in Table A-1, Lab 12’s procedures for the free fatty acids in Table A-2, the 

calibration information in Table A-3, and notes submitted by laboratories in Table A-4. For the 

laboratories reporting an hydrolysis method, they used both acid and base, and the extraction 

methods were typically liquid-liquid. Most laboratories used gas chromatography (GC) with 

either flame ionization detection (FID) or mass spectrometry (MS) following a derivatization. 

The derivatizing reagants used by each laboratory are summarized in Appendix A. The 

exception being lab 7, which used a liquid chromatography (LC)/ MS/MS method. They, 

however, reported data for only three fatty acids, C20:4n6, C20:5n3, and C22:6n3. 

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For the GC analyses, the columns used ranged in polarity from relatively non-polar (5% phenyl 

methylpolysiloxane phase) to relatively polar (cyanopropyl phase). For the calibration 

information (Table A-3), labs 1, 2, 7, 8, 9, 10 used a linear regression, labs 3, 4, and 12 used a 

quadratic regression, and lab 6 used a mix of linear and quadratic regression tailored by analyte. 

Lab 5 only reported the limits of their calibration range, and labs 11 and 13 did not report 

calibration information. Combining the method information with the trends in the data reported 

does not lead to obvious explanations of the variations noted in the data submitted by individual 

laboratories. 

Lab 12 reported data for the free fatty acids (Table 11) in addition to the total fatty acids. Using 

only lab 12’s data, the relative amount of free to total for each fatty acid in the four samples has 

been calculated and is summarized in Table 12. The free fatty acids are from < 1% to 34 % of 

the total fatty acids with most in the 2 % to 10 % range. Hopefully, more laboratories will report 

data for free fatty acids in future intercomparison exercises. 

The data from this exercise can be used to assess the comparability across a limited number of 

laboratories (see Appendix C). The data do not indicate specific method biases but do indicate 

the need for such intercomparisons and for the use of control materials to increase the 

comparability of data across laboratories. 

Acknowledgments 

The financial support for this intercomparison exercise was provided by the National Institutes of 

Health (NIH), Office of Dietary Supplements (ODS). Technical coordination was provided by 

Joseph M. Betz of NIH-ODS. 

The time and effort of the analysts and management of the participating laboratories are 

gratefully acknowledged. 

Disclaimer 

Certain commercial equipment, instruments, or materials are identified in this report to specify 

adequately the experimental procedure. Such identification does not imply recommendation or 

endorsement by the National Institute of Standards and Technology, nor does it imply that the 

materials or equipment identified are the best available for the purpose. 

References 

1.	 Schantz M.M. Powers C,D., and Schleicher, R Interlaboratory Analytical Comparison 

Study of Total Fatty Acid Concentrations in Human Serum: Results for Exercise 01: 

QA12FASER01, NISTIR 7953, Gaithersburg, MD (2013). 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
2.	 Schantz, M.M. Interlaboratory Analytical Comparison Study of Fatty Acid 

Concentrations in Human Serum: Results for Exercise 02: QA15FASER02, NISTIR 

8086, Gaithersburg, MD (2015). 

3.	 Bedner, M., Lippa, K.A., Tai, S. S.-C. An assessment of 25-hydroxyvitamin D 

measurements in comparability studies conducted by the Viatamin D Metabolites Quality 

Assurance Program, Clinica Chimica Acta 426 (2013) 6-11. 

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Table 1. Fatty Acids Included in Study 

Code Common Name mol wt (g/mol) 

C14:0 Myristic acid 228.38 

C14:1n5 Myristoleic acid 226.38 

C16:0 Palmitic acid 256.43 

C16:1n7 Palmitoleic acid 254.43 

C18:0 Stearic acid 284.48 

C18:1n7 cis-Vaccenic acid 282.48 

C18:1n9 Oleic acid 282.48 

C18:2n6 Linoleic acid 280.48 

C18:3n3 alpha-Linolenic acid 278.48 

C18:3n6 gamma-Linolenic acid 278.48 

C20:0 Arachidic acid 312.54 

C20:1n9 11-Eicosenoic acid 310.54 

C20:2n6 11,14-Eicosadienoic acid 308.53 

C20:3n6 homo-gamma-Linolenic acid 306.53 

C20:4n6 Arachidonic acid 304.52 

C20:5n3 Eicosapentaenoic acid 302.52 

C22:0 Docosanoic acid 340.59 

C22:1n9 Docosenoic acid 338.59 

C22:4n6 Docosatetraenoic acid 332.57 

C22:5n3 Docosapentaenoic acid 330.57 

C22:5n6 Docosapentaenoic acid 330.57 

C22:6n3 Docosahexaenoic acid 328.57 

C24:0 Lignoceric acid 368.64 

C24:1n9 Nervonic acid 366.63 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 Caprylic acid 144.26 

C10:0 Decanoic acid 172.3 

C10:1n1 9-Decenoic acid 170.3 

C12:0 Lauric acid 200.34 

C12:1n1 11-Dodecenoic acid 198.34 

C12:1n7 cis-5-dodecenoic 198.34 

C14:2 224.38 

C15:0 Pentadecanoic acid 242.42 

C16:1n7t Palmitelaidic acid 254.43 

C16:1n9 254.43 

C16:2 252.43 

C17:0 Margaric acid 270.46 

C17:1n9 10-Heptadecenoic acid 268.46 

9c,11t-C18:2n6 Rumenic acid 280.48 

C18:4n3 Stearidonic acid 276.48 

C19:0 Nonadecanoic acid 298.54 

C20:3n3 11,14,17-Eicosatrienoic acid 306.53 

C20:3n9 5,8,11-Eicosatrienoic acid (Mead acid) 306.53 

C20:4n3 Arachidonic acid (Omega 3) 304.53 

C21:0 Heneicosanoic acid 326.58 

C22:2n6 Docosadienoic acid 336.59 

C23:0 Tricosanoic acid 354.62 

C26:0 Hexacosanoic acid 396.68 

C26:1 394.68 

PhA Phytanic acid 312.54 

PrA Pristanic acid 298.5 

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Table 2. Interlaboratory data received for total fatty acids in Unknown 004 (μg/g) 

Lab 1 Lab 2a Lab 3 Lab 4a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 35.3 1.5 4.17% 44.4 1.9 4.19% 34.9 0.5 1.52% 33.1 0.7 2.15% 

C14:1n5 <10 4.75 0.23 4.76% Not analyzed 3.18 0.06 1.75% 

C16:0 828 63 7.61% 777 30 3.84% 740 43 5.79% 771 21 2.77% 

C16:1n7 73.1 5.2 7.05% 74.3 4.2 5.72% 72.3 2.5 3.40% 84.9 1.4 1.69% 

C18:0 178 16 8.83% 261 12 4.68% 207 1 0.28% 208 7 3.26% 

C18:1n7 51.2 4.8 9.45% 83.0 4.5 5.47% 45.5 0.3 0.55% 70.4 1.4 1.99% 

C18:1n9 672 40 5.89% 622 33 5.27% 639 10 1.59% 666 14 2.06% 

C18:2n6 1024 79 7.72% 817 32 3.97% 973 21 2.11% 991 27 2.73% 

C18:3n3 27.8 1.3 4.62% 23.0 0.6 2.79% 24.6 0.4 1.65% 24.1 0.3 1.05% 

C18:3n6 15.5 0.8 5.00% 15.3 0.7 4.81% 15.1 0.6 4.14% 14.8 0.3 2.27% 

C20:0 <10 10.2 0.5 4.68% Not analyzed 7.16 0.13 1.79% 

C20:1n9 <10 Not analyzed Not analyzed Not analyzed 

C20:2n6 Not analyzed Not analyzed Not analyzed Not analyzed 

C20:3n6 Not analyzed 39.2 2.5 6.25% 50.2 0.5 0.98% 58.6 0.4 0.63% 

C20:4n6 240 6 2.44% 173 7 4.02% 210 2 0.99% 224 5 2.22% 

C20:5n3 20.3 0.6 3.18% 16.7 0.9 5.52% 17.5 0.3 1.75% 17.9 0.8 4.26% 

C22:0 <10 24.0 1.0 4.33% 15.9 0.3 1.66% 19.9 0.6 3.17% 

C22:1n9 <10 3.61 0.20 5.41% NA 3.38 0.11 3.29% 

C22:4n6 Not analyzed 9.31 0.58 6.19% 7.18 0.14 1.98% 10.43 0.36 3.49% 

C22:5n3 16.1 1.2 7.15% 15.0 0.7 4.59% 14.1 0.4 2.68% 14.6 0.6 3.76% 

C22:5n6 Not analyzed 8.26 0.66 8.00% Not analyzed 5.67 0.19 3.41% 

C22:6n3 53.0 3.0 5.65% 45.3 4.1 9.05% 44.2 0.5 1.14% 46.6 2.2 4.79% 

C24:0 <20 21.4 1.0 4.56% 13.9 0.4 2.91% 20.7 0.8 3.93% 

C24:1n9 <20 31.5 1.5 4.65% 20.0 0.4 1.80% 26.2 1.1 4.27% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 1.12 0.04 3.18% 

C10:0 1.07 0.02 2.31% 

C10:1n1 1.07 0.06 5.62% 

C12:0 4.23 0.09 2.13% 

C12:1n1 1.02 0.06 5.49% 

C12:1n7 0.920 0.054 5.85% 

C14:2 0.317 0.020 6.23% 

C15:0 5.41 0.15 2.80% 

C16:1n-7t 

C16:1n9 12.9 0.4 2.81% 

C16:2 1.67 0.02 1.36% 

C17:0 6.79 0.19 2.74% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 

C19:0 0.691 0.055 7.90% 

C 20:3n-3 

C20:3n9 4.91 0.09 1.82% 

C20:4n3 

C21:0 0.605 0.030 4.94% 

C 22:2n-6 

C23:0 13.8 1.1 8.21% 

C26:0 0.204 0.008 3.92% 

C26:1 0.171 0.004 2.33% 

PhA 0.363 0.005 1.32% 

PrA 0.064 0.002 2.71% 

density (g/mL) Not analyzed Not analyzed 1.06 0.01 0.55% 0.992 0.001 0.10% 

a

 Reported as μM 

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Table 2 (cont.). Interlaboratory data received for total fatty acids in Unknown 004 (μg/g) 

Lab 5a Lab 6a Lab 7a Lab 8 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 38.7 1.1 2.91% 38.6 1.0 2.54% Not analyzed 46.2 3.9 8.33% 

C14:1n5 2.52 0.04 1.67% Not analyzed Not analyzed 

C16:0 780 17 2.15% 845 19 2.23% Not analyzed 1050 73 6.93% 

C16:1n7 62.6 1.9 3.11% 78.6 2.7 3.50% Not analyzed 97.5 7.0 7.14% 

C18:0 206 5 2.65% 183 2 1.14% Not analyzed 277 20 7.23% 

C18:1n7 44.2 2.3 5.29% Not analyzed Not analyzed 

C18:1n9 625 13 2.02% 677 28 4.10% Not analyzed 861 59 6.85% 

C18:2n6 977 19 1.94% 1029 39 3.78% Not analyzed 1084 78 7.21% 

C18:3n3 23.2 0.5 1.98% 28.8 1.2 4.09% Not analyzed 35.9 3.0 8.31% 

C18:3n6 16.3 0.8 4.98% Not analyzed Not analyzed 

C20:0 6.60 0.18 2.79% Not analyzed Not analyzed 

C20:1n9 5.57 0.35 6.27% Not analyzed 9.41 0.94 9.99% 

C20:2n6 5.96 0.89 14.89% 7.77 0.36 4.59% Not analyzed Not analyzed 

C20:3n6 52.4 1.7 3.32% Not analyzed 68.4 4.9 7.22% 

C20:4n6 205 5 2.40% 239 6 2.65% 858 41 4.83% 317 16 5.18% 

C20:5n3 15.4 0.5 3.07% 19.4 0.1 0.36% 27.4 1.7 6.07% 28.7 3.6 12.44% 

C22:0 22.6 0.1 0.37% Not analyzed Not analyzed 

C22:1n9 Not analyzed Not analyzed 

C22:4n6 8.93 0.21 2.36% Not analyzed 11.2 1.2 10.43% 

C22:5n3 18.5 1.2 6.28% 16.8 0.8 4.81% Not analyzed 18.5 1.2 6.61% 

C22:5n6 7.32 0.08 1.05% Not analyzed Not analyzed 

C22:6n3 37.6 1.8 4.84% 53.4 2.7 5.10% 70.2 0.8 1.18% 18.5 1.2 6.61% 

C24:0 20.3 0.5 2.51% Not analyzed Not analyzed 

C24:1n9 31.4 0.8 2.50% Not analyzed Not analyzed 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 

C10:1n1 

C12:0 

C12:1n1 

C12:1n7 

C14:2 

C15:0 5.99 0.22 3.70% 

C16:1n-7t 

C16:1n9 

C16:2 

C17:0 8.22 0.16 1.89% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 1.10 0.05 4.30% 

C19:0 

C 20:3n-3 

C20:3n9 2.34 0.09 4.02% 

C20:4n3 

C21:0 

C 22:2n-6 

C23:0 10.3 0.2 1.89% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) Not analyzed 0.963 0.003 0.32% Not analyzed 1.03 0.01 1.12% 

a

 Reported as μM 

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Table 2 (cont.). Interlaboratory data received for total fatty acids in Unknown 004 (μg/g) 

Lab 9a Lab 10a Lab 12a Lab 13a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 35.4 0.3 0.96% 32.5 0.6 1.78% 62.2 1.8 2.89% 24.2 2.1 8.54% 

C14:1n5 3.41 0.02 0.65% 1.81 0.04 2.41% 3.93 0.06 1.52% 1.77 0.19 10.87% 

C16:0 794 0.3 0.04% 670 2 0.37% 767 36 4.68% 719 15 2.13% 

C16:1n7 74.2 0.3 0.37% 67.1 0.3 0.44% 65.5 2.8 4.31% 105.1 4.7 4.51% 

C18:0 193 3 1.64% 196 2 0.78% 193 11 5.76% 185 3 1.80% 

C18:1n7 47.8 0.3 0.59% 48.1 0.7 1.47% 45.4 2.2 4.75% 78.7 3.1 3.97% 

C18:1n9 636 2 0.33% 600 8 1.38% 685 32 4.61% 407 10 2.50% 

C18:2n6 1006 3 0.33% 877 2 0.26% 1106 55 4.93% 776 6 0.75% 

C18:3n3 23.3 0.2 0.72% 21.6 0.2 0.73% 18.1 0.6 3.58% 15.9 1.9 12.21% 

C18:3n6 15.1 0.2 1.08% 13.2 0.1 0.98% 18.6 0.6 3.45% Not analyzed 

C20:0 6.98 0.12 1.74% 4.81 0.20 4.24% 4.49 0.19 4.27% 4.02 0.85 21.07% 

C20:1n9 Not analyzed 5.04 0.21 4.13% 10.29 0.63 6.15% 3.18 0.95 29.90% 

C20:2n6 7.35 0.14 1.91% 7.28 0.12 1.71% 7.57 0.11 1.48% 6.41 1.49 23.29% 

C20:3n6 51.2 0.6 1.17% 45.8 0.4 0.97% 31.5 2.3 7.28% 47.8 5.0 10.51% 

C20:4n6 213 0 0.21% 193 1 0.39% 170 13 7.47% 205 12 6.07% 

C20:5n3 17.1 0.1 0.61% 15.7 0.1 0.58% 10.81 0.19 1.76% 33.3 4.0 11.90% 

C22:0 20.9 0.2 1.11% 12.79 0.42 3.24% 3.23 0.21 6.58% 9.97 1.26 12.68% 

C22:1n9 Not analyzed 3.02 0.23 7.65% Not analyzed 4.81 8.33 173.21% 

C22:4n6 7.29 0.12 1.64% 6.77 0.23 3.33% 7.00 0.51 7.26% 11.69 2.00 17.12% 

C22:5n3 14.33 0.26 1.84% 6.05 0.20 3.37% 17.5 0.9 4.87% 18.0 3.4 19.03% 

C22:5n6 6.01 0.06 1.04% 13.23 0.13 0.99% 7.20 0.24 3.37% 4.08 0.56 13.73% 

C22:6n3 46.2 0.6 1.24% 40.6 0.7 1.78% 30.5 2.8 9.19% 40.8 7.4 18.15% 

C24:0 18.8 0.2 0.82% 11.31 0.47 4.14% 1.75 0.04 2.16% 8.22 2.35 28.57% 

C24:1n9 25.7 0.1 0.53% 16.1 0.4 2.66% 4.52 0.56 12.28% 15.19 3.75 24.70% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 1.19 0.16 13.48% 

C10:1n1 

C12:0 3.53 0.55 15.64% 97.1 2.5 2.58% 

C12:1n1 0.601 0.126 20.91% 

C12:1n7 

C14:2 

C15:0 6.89 0.13 1.95% 7.67 0.26 3.45% 

C16:1n-7t 21.9 0.5 2.20% 

C16:1n9 

C16:2 

C17:0 7.45 0.09 1.14% 7.39 0.16 2.10% 16.0 1.2 7.32% 

C17:1n9 6.18 0.41 6.72% 

9c,11t-CLA 6.14 0.16 2.68% 

C18:4n-3 1.03 0.15 14.90% 

C19:0 3.82 0.31 8.15% 

C 20:3n-3 0.750 0.121 16.09% 3.53 0.27 7.64% 

C20:3n9 2.93 0.15 5.06% 

C20:4n3 1.82 0.06 3.45% 

C21:0 2.07 0.19 9.00% 

C 22:2n-6 0.635 0.195 30.75% 4.05 0.17 4.31% 

C23:0 5.79 0.17 2.90% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) 1.02 0.01 1.13% 1.04 0.01 0.58% 1.03 0.00 0.00% Not analyzed 

a

 Reported as μM 

12
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 3. Interlaboratory data received for total fatty acids in Unknown 004 (μM) 

Lab 1a Lab 2 Lab 3a Lab 4 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 155 6 4.17% 194 8 4.19% 161 2 1.52% 144 3 2.15% 

C14:1n5 21.0 1.0 4.76% Not analyzed 13.9 0.2 1.75% 

C16:0 3228 246 7.61% 3031 116 3.84% 3048 177 5.79% 2983 83 2.77% 

C16:1n7 287 20 7.05% 292 17 5.72% 300 10 3.40% 331 6 1.69% 

C18:0 626 55 8.83% 916 43 4.68% 768 2 0.28% 725 24 3.26% 

C18:1n7 181 17 9.45% 294 16 5.47% 170 1 0.55% 247 5 1.99% 

C18:1n9 2378 140 5.89% 2202 116 5.27% 2390 38 1.59% 2339 48 2.06% 

C18:2n6 3652 282 7.72% 2914 116 3.97% 3664 77 2.11% 3504 96 2.73% 

C18:3n3 100 5 4.62% 82.7 2.3 2.79% 93 2 1.65% 86.0 0.9 1.05% 

C18:3n6 55.7 2.8 5.00% 55.0 2.6 4.81% 57.3 2.4 4.14% 52.8 1.2 2.27% 

C20:0 32.7 1.5 4.68% Not analyzed 22.7 0.4 1.79% 

C20:1n9 Not analyzed Not analyzed Not analyzed 

C20:2n6 Not analyzed Not analyzed Not analyzed Not analyzed 

C20:3n6 Not analyzed 128 8 6.25% 173 2 0.98% 190 1 0.63% 

C20:4n6 789 19 2.44% 567 23 4.02% 728 7 0.99% 730 16 2.22% 

C20:5n3 67.1 2.1 3.18% 55.3 3.1 5.52% 61.0 1.1 1.75% 58.6 2.5 4.26% 

C22:0 70.6 3.1 4.33% 49.3 0.8 1.66% 58.0 1.8 3.17% 

C22:1n9 10.7 0.6 5.41% Not analyzed 9.89 0.33 3.29% 

C22:4n6 Not analyzed 28.0 1.7 6.19% 22.8 0.5 1.98% 31.1 1.1 3.49% 

C22:5n3 48.7 3.5 7.15% 45.3 2.1 4.59% 45.2 1.2 2.68% 43.9 1.7 3.76% 

C22:5n6 Not analyzed 25.0 2.0 8.00% Not analyzed 17.0 0.6 3.41% 

C22:6n3 161 9 5.65% 138 12 9.05% 142 2 1.14% 141 7 4.79% 

C24:0 58.0 2.6 4.56% 39.8 1.2 2.91% 55.7 2.2 3.93% 

C24:1n9 86.0 4.0 4.65% 57.6 1.0 1.80% 71.0 3.0 4.27% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 7.72 0.25 3.18% 

C10:0 6.15 0.14 2.31% 

C10:1n1 6.26 0.35 5.62% 

C12:0 20.9 0.4 2.13% 

C12:1n1 5.11 0.28 5.49% 

C12:1n7 4.60 0.27 5.85% 

C14:2 1.40 0.09 6.23% 

C15:0 22.1 0.6 2.80% 

C16:1n-7t 

C16:1n9 50.2 1.4 2.81% 

C16:2 6.57 0.09 1.36% 

C17:0 24.9 0.7 2.74% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 

C19:0 2.30 0.18 7.90% 

C 20:3n-3 

C20:3n9 15.9 0.3 1.82% 

C20:4n3 

C21:0 1.84 0.09 4.94% 

C 22:2n-6 

C23:0 38.6 3.2 8.21% 

C26:0 0.510 0.020 3.92% 

C26:1 0.430 0.010 2.33% 

PhA 1.15 0.02 1.32% 

PrA 0.213 0.006 2.71% 

density (g/mL) Not analyzed Not analyzed 1.06 0.01 0.55% 0.992 0.001 0.10% 

a

 Reported as μg/g 

13
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 3 (cont). Interlaboratory data received for total fatty acids in Unknown 004 (μM) 

Lab 5 Lab 6 Lab 7 Lab 8a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 169 5 2.91% 163 4 2.54% Not analyzed 208 17 8.33% 

C14:1n5 10.7 0.2 1.67% Not analyzed Not analyzed 

C16:0 3042 65 2.15% 3171 71 2.23% Not analyzed 4202 291 6.93% 

C16:1n7 246 8 3.11% 297 10 3.50% Not analyzed 393 28 7.14% 

C18:0 723 19 2.65% 620 7 1.14% Not analyzed 998 72 7.23% 

C18:1n7 151 8 5.29% Not analyzed Not analyzed 

C18:1n9 2212 45 2.02% 2306 95 4.10% Not analyzed 3128 214 6.85% 

C18:2n6 3484 68 1.94% 3531 134 3.78% Not analyzed 3969 286 7.21% 

C18:3n3 83.3 1.6 1.98% 99.5 4.1 4.09% Not analyzed 132 11 8.31% 

C18:3n6 56.5 2.8 4.98% Not analyzed Not analyzed 

C20:0 20.3 0.6 2.79% Not analyzed Not analyzed 

C20:1n9 17.3 1.1 6.27% Not analyzed 31.1 3.1 9.99% 

C20:2n6 19.1 2.8 14.89% 24.2 1.1 4.59% Not analyzed Not analyzed 

C20:3n6 164 5 3.32% Not analyzed 229 17 7.22% 

C20:4n6 675 16 2.40% 756 20 2.65% 2818 136 4.83% 1070 55 5.18% 

C20:5n3 51.0 1.6 3.07% 61.7 0.2 0.36% 90.6 5.5 6.07% 97 12 12.44% 

C22:0 63.9 0.2 0.37% Not analyzed Not analyzed 

C22:1n9 Not analyzed Not analyzed 

C22:4n6 25.8 0.6 2.36% Not analyzed 34.5 3.6 10.43% 

C22:5n3 55.9 3.5 6.28% 48.8 2.3 4.81% Not analyzed 57.5 3.8 6.61% 

C22:5n6 21.3 0.2 1.05% Not analyzed Not analyzed 

C22:6n3 115 6 4.84% 156 8 5.10% 214 3 1.18% 57.9 3.8 6.61% 

C24:0 53.1 1.3 2.51% Not analyzed Not analyzed 

C24:1n9 82.4 2.1 2.50% Not analyzed Not analyzed 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 

C10:1n1 

C12:0 

C12:1n1 

C12:1n7 

C14:2 

C15:0 23.8 0.9 3.70% 

C16:1n-7t 

C16:1n9 

C16:2 

C17:0 29.2 0.6 1.89% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 3.82 0.16 4.30% 

C19:0 

C 20:3n-3 

C20:3n9 7.36 0.30 4.02% 

C20:4n3 

C21:0 

C 22:2n-6 

C23:0 28.0 0.5 1.89% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) Not analyzed 0.963 0.003 0.32% Not analyzed 1.03 0.01 1.12% 

a

 Reported as μg/g 

14
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 3 (cont). Interlaboratory data received for total fatty acids in Unknown 004 (μM) 

Lab 9 Lab 10 Lab 12 Lab 13 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 159 2 1.31% 148 3 1.78% 279 8 2.89% 106 9 8.54% 

C14:1n5 15.4 0.2 1.30% 8.31 0.20 2.41% 17.8 0.3 1.52% 7.80 0.85 10.87% 

C16:0 3170 35 1.09% 2715 10 0.37% 3065 144 4.68% 2802 60 2.13% 

C16:1n7 298 3 1.02% 274 1 0.44% 264 11 4.31% 413 19 4.51% 

C18:0 694 12 1.72% 716 6 0.78% 694 40 5.76% 650 12 1.80% 

C18:1n7 173 2 1.16% 177 3 1.47% 165 8 4.75% 279 11 3.97% 

C18:1n9 2303 21 0.90% 2205 30 1.38% 2486 115 4.61% 1440 36 2.50% 

C18:2n6 3670 36 0.98% 3247 8 0.26% 4040 199 4.93% 2766 21 0.75% 

C18:3n3 85.6 1.4 1.66% 80.6 0.6 0.73% 66.7 2.4 3.58% 57.2 7.0 12.21% 

C18:3n6 55.6 0.7 1.20% 49.1 0.5 0.98% 68.5 2.4 3.45% Not analyzed 

C20:0 22.9 0.5 2.02% 16.0 0.7 4.24% 14.7 0.6 4.27% 12.88 2.71 21.07% 

C20:1n9 Not analyzed 16.9 0.7 4.13% 34.0 2.1 6.15% 10.19 3.05 29.90% 

C20:2n6 24.4 0.5 1.94% 24.5 0.4 1.71% 25.1 0.4 1.48% 20.51 4.78 23.29% 

C20:3n6 171 3 1.55% 155 1 0.97% 105 8 7.28% 156 16 10.51% 

C20:4n6 717 9 1.30% 660 3 0.39% 571 43 7.47% 672 41 6.07% 

C20:5n3 57.7 0.6 0.95% 54.1 0.3 0.58% 36.6 0.6 1.76% 110.1 13.1 11.90% 

C22:0 62.9 1.0 1.63% 39.0 1.3 3.24% 9.73 0.64 6.58% 29.3 3.7 12.68% 

C22:1n9 Not analyzed 9.26 0.71 7.65% Not analyzed 14.20 24.60 173.21% 

C22:4n6 22.4 0.5 2.29% 21.1 0.7 3.33% 21.6 1.6 7.26% 35.1 6.0 17.12% 

C22:5n3 44.4 1.2 2.61% 19.0 0.6 3.37% 54.2 2.6 4.87% 54.4 10.3 19.03% 

C22:5n6 18.6 0.2 0.93% 41.6 0.4 0.99% 22.3 0.8 3.37% 12.35 1.70 13.73% 

C22:6n3 144 3 2.08% 128 2 1.78% 95.2 8.7 9.19% 124.0 22.5 18.15% 

C24:0 52.2 1.0 1.94% 31.9 1.3 4.14% 4.87 0.10 2.16% 22.3 6.4 28.57% 

C24:1n9 71.7 1.0 1.42% 45.6 1.2 2.66% 12.6 1.6 12.28% 41.4 10.2 24.70% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 7.19 0.97 13.48% 

C10:1n1 

C12:0 18.3 2.9 15.64% 497 13 2.58% 

C12:1n1 3.15 0.66 20.91% 

C12:1n7 

C14:2 

C15:0 29.1 0.6 1.95% 31.6 1.1 3.45% 

C16:1n-7t 88.1 1.9 2.20% 

C16:1n9 

C16:2 

C17:0 28.6 0.3 1.14% 28.0 0.6 2.10% 59.1 4.3 7.32% 

C17:1n9 23.6 1.6 6.72% 

9c,11t-CLA 22.4 0.6 2.68% 

C18:4n-3 3.81 0.57 14.90% 

C19:0 13.1 1.1 8.15% 

C 20:3n-3 2.54 0.41 16.09% 11.8 0.9 7.64% 

C20:3n9 9.94 0.50 5.06% 

C20:4n3 6.10 0.21 3.45% 

C21:0 6.51 0.59 9.00% 

C 22:2n-6 1.96 0.60 30.75% 12.3 0.5 4.31% 

C23:0 17.0 0.5 2.90% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) 1.02 0.01 1.13% 1.04 0.01 0.58% 1.03 0.00 0.00% Not analyzed 

a

 Reported as μg/g 

15
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 4. Interlaboratory data received for total fatty acids in Unknown 005 (μg/g) 

Lab 1 Lab 2a Lab 3 Lab 4a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 25.0 1.1 4.25% 29.5 0.8 2.80% 23.1 0.2 0.90% 22.4 0.9 4.12% 

C14:1n5 <10 2.57 0.13 5.09% Not analyzed 1.79 0.05 2.83% 

C16:0 621 22 3.58% 620 16 2.58% 608 6 0.99% 625 40 6.47% 

C16:1n7 47.5 2.9 6.02% 43.2 1.7 3.92% 46.0 0.7 1.52% 53.7 2.3 4.28% 

C18:0 167 7 3.99% 243 6 2.48% 199 3 1.53% 207 14 6.76% 

C18:1n7 29.3 2.6 8.89% 56.4 1.8 3.26% 34.5 0.7 1.90% 41.7 1.6 3.72% 

C18:1n9 582 44 7.55% 505 9 1.70% 519 5 1.02% 549 32 5.75% 

C18:2n6 905 3 0.36% 726 7 0.97% 903 8 0.88% 935 56 5.96% 

C18:3n3 23.9 1.3 5.25% 18.6 0.7 3.77% 21.6 0.3 1.49% 21.4 1.3 6.24% 

C18:3n6 13.9 0.6 4.35% 14.5 0.7 5.09% 13.4 0.1 0.86% 15.7 1.0 6.14% 

C20:0 <10 9.90 0.18 1.82% Not analyzed 7.54 0.29 3.85% 

C20:1n9 <10 Not analyzed Not analyzed Not analyzed 

C20:2n6 Not analyzed Not analyzed Not analyzed Not analyzed 

C20:3n6 Not analyzed 37.4 0.9 2.46% 47.5 1.4 2.97% 55.1 3.5 6.37% 

C20:4n6 247 4 1.53% 168 8 4.49% 223 4 1.86% 240 13 5.47% 

C20:5n3 26.0 1.1 4.24% 20.4 0.9 4.54% 23.1 0.2 1.00% 24.7 1.8 7.28% 

C22:0 <10 24.3 0.5 2.25% 16.9 0.8 4.47% 21.2 0.6 2.78% 

C22:1n9 <10 1.69 0.00 0.00% Not analyzed 2.72 0.04 1.32% 

C22:4n6 Not analyzed 7.32 0.33 4.55% 6.16 0.12 1.90% 9.09 0.61 6.74% 

C22:5n3 16.6 0.4 2.65% 14.5 0.6 3.94% 14.9 0.1 0.67% 15.7 1.1 7.06% 

C22:5n6 Not analyzed 5.73 0.38 6.66% Not analyzed 4.24 0.23 5.38% 

C22:6n3 61.5 3.7 6.05% 48.3 3.1 6.49% 51.9 0.4 0.80% 54.9 5.3 9.60% 

C24:0 <20 23.2 0.6 2.75% 16.1 0.6 3.98% 24.1 1.6 6.71% 

C24:1n9 <20 28.4 0.2 0.75% 18.9 1.3 6.88% 25.6 1.7 6.58% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 0.968 0.061 6.33% 

C10:0 1.00 0.02 1.81% 

C10:1n1 1.01 0.01 1.25% 

C12:0 2.48 0.05 2.01% 

C12:1n1 0.843 0.035 4.19% 

C12:1n7 0.737 0.029 3.91% 

C14:2 0.305 0.021 6.92% 

C15:0 5.45 0.29 5.30% 

C16:1n-7t 

C16:1n9 11.8 0.5 3.90% 

C16:2 1.09 0.07 6.52% 

C17:0 6.66 0.40 6.01% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 

C19:0 0.750 0.050 6.70% 

C 20:3n-3 

C20:3n9 5.74 0.56 9.83% 

C20:4n3 

C21:0 0.597 0.064 10.67% 

C 22:2n-6 

C23:0 14.5 1.1 7.62% 

C26:0 0.227 0.016 7.13% 

C26:1 0.190 0.014 7.37% 

PhA 0.439 0.022 5.04% 

PrA 0.063 0.003 4.76% 

density (g/mL) Not analyzed Not analyzed 1.05 0.01 1.10% 0.989 0.004 0.38% 

a

 Reported as μM 

16
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 4 (cont). Interlaboratory data received for total fatty acids in Unknown 005 (μg/g) 

Lab 5a Lab 6a Lab 7a Lab 8 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 25.4 0.3 1.01% 25.3 0.4 1.45% Not analyzed 24.6 0.3 1.28% 

C14:1n5 1.38 0.04 3.25% Not analyzed Not analyzed 

C16:0 615 2 0.32% 679 7 1.07% Not analyzed 768 10 1.31% 

C16:1n7 33.8 0.6 1.78% 50.3 0.4 0.77% Not analyzed 52.5 0.8 1.48% 

C18:0 199 1 0.56% 179 3 1.41% Not analyzed 248 2 0.73% 

C18:1n7 34.6 0.4 1.28% Not analyzed Not analyzed 

C18:1n9 509 2 0.34% 572 0 0.08% Not analyzed 586 4 0.70% 

C18:2n6 912 2 0.25% 992 6 0.61% Not analyzed 918 16 1.71% 

C18:3n3 20.2 0.1 0.54% 25.2 0.1 0.41% Not analyzed 26.8 0.3 1.21% 

C18:3n6 14.69 0.23 1.59% Not analyzed Not analyzed 

C20:0 6.52 0.18 2.74% Not analyzed Not analyzed 

C20:1n9 4.91 0.05 0.98% Not analyzed 7.30 0.08 1.15% 

C20:2n6 6.10 0.19 3.12% 6.93 0.10 1.48% Not analyzed Not analyzed 

C20:3n6 48.5 0.6 1.30% Not analyzed 60.4 0.4 0.65% 

C20:4n6 220 1 0.52% 256 2 0.59% 831 42 5.10% 307 5 1.71% 

C20:5n3 21.6 0.2 0.86% 26.09 0.36 1.40% 25.0 0.9 3.58% 32.3 0.5 1.54% 

C22:0 23.9 0.2 0.87% Not analyzed Not analyzed 

C22:1n9 Not analyzed Not analyzed 

C22:4n6 7.26 0.26 3.64% Not analyzed 8.68 0.20 2.28% 

C22:5n3 18.2 0.4 2.42% 17.40 0.70 4.02% Not analyzed 18.1 0.5 2.74% 

C22:5n6 5.41 0.12 2.19% Not analyzed Not analyzed 

C22:6n3 46.1 1.1 2.37% 66.2 2.9 4.43% 72.9 2.0 2.70% 62.6 1.7 2.64% 

C24:0 22.6 0.9 4.08% Not analyzed Not analyzed 

C24:1n9 28.9 0.3 0.99% Not analyzed Not analyzed 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 

C10:1n1 

C12:0 

C12:1n1 

C12:1n7 

C14:2 

C15:0 6.11 0.10 1.56% 

C16:1n-7t 

C16:1n9 

C16:2 

C17:0 8.19 0.21 2.62% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 0.963 0.047 4.86% 

C19:0 

C 20:3n-3 

C20:3n9 2.49 0.11 4.28% 

C20:4n3 

C21:0 

C 22:2n-6 

C23:0 10.9 0.2 1.46% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) Not analyzed 0.967 0.002 0.18% Not analyzed 1.04 0.01 0.56% 

a

 Reported as μM 

17
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 4 (cont). Interlaboratory data received for total fatty acids in Unknown 005 (μg/g) 

Lab 9a Lab 10a Lab 12a Lab 13a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 23.2 0.5 2.01% 21.4 0.1 0.40% 51.4 2.8 5.46% 19.8 1.0 4.99% 

C14:1n5 1.78 0.09 4.95% 0.875 0.108 12.37% 2.96 0.09 2.95% 1.22 0.21 17.15% 

C16:0 621 3 0.52% 532 3 0.54% 594 31 5.30% 650 13 2.00% 

C16:1n7 45.8 0.4 0.81% 41.7 0.3 0.64% 37.6 1.3 3.44% 79.5 1.3 1.57% 

C18:0 188 1 0.34% 183 1 0.61% 182 6 3.28% 201 2 1.22% 

C18:1n7 36.0 0.2 0.66% 35.7 0.4 1.11% 34.0 1.9 5.48% 62.3 1.1 1.75% 

C18:1n9 509 4 0.78% 477 4 0.76% 523 30 5.70% 367 4 1.20% 

C18:2n6 917 7 0.79% 805 5 0.62% 979 55 5.63% 789 1 0.12% 

C18:3n3 19.9 0.3 1.71% 18.3 0.3 1.65% 15.3 0.5 3.14% 20.1 0.9 4.63% 

C18:3n6 13.1 0.2 1.08% 11.5 0.1 1.27% 16.3 0.7 4.19% Not analyzed 

C20:0 6.99 0.02 0.31% 4.79 0.04 0.75% 4.30 0.09 2.08% 4.70 0.69 14.70% 

C20:1n9 Not analyzed 4.30 0.06 1.51% 9.95 0.06 0.57% 3.39 0.40 11.82% 

C20:2n6 6.55 0.09 1.45% 6.55 0.07 1.08% 7.13 0.20 2.82% 7.62 0.74 9.66% 

C20:3n6 48.0 0.2 0.46% 43.1 0.4 0.84% 29.2 6.8 23.33% 64.4 4.5 7.04% 

C20:4n6 222 2 0.84% 202 2 0.86% 165 5 2.73% 255 7 2.80% 

C20:5n3 22.4 0.2 0.89% 20.4 0.4 1.84% 13.9 0.3 1.90% 53.6 4.8 8.97% 

C22:0 22.1 0.1 0.43% 13.67 0.55 4.01% 3.17 0.04 1.11% 14.07 0.84 5.98% 

C22:1n9 Not analyzed 1.45 0.17 11.49% Not analyzed 14.72 14.65 99.57% 

C22:4n6 6.22 0.08 1.35% 5.26 0.24 4.55% 6.48 0.15 2.35% 13.53 1.98 14.61% 

C22:5n3 14.9 0.0 0.17% 4.17 0.49 11.70% 18.7 1.8 9.56% 28.5 2.6 9.22% 

C22:5n6 4.37 0.09 2.10% 13.16 0.02 0.13% 5.97 0.12 1.94% 4.44 0.42 9.56% 

C22:6n3 52.7 0.1 0.21% 46.6 0.1 0.31% 30.3 2.3 7.61% 61.4 6.0 9.77% 

C24:0 21.8 0.6 2.89% 13.30 0.58 4.33% 1.74 0.09 5.06% 11.50 0.47 4.12% 

C24:1n9 24.4 0.6 2.62% 15.77 1.00 6.31% 4.52 0.31 6.94% 17.94 1.11 6.18% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 1.49 0.38 25.70% 

C10:1n1 

C12:0 1.51 0.37 24.69% 96.5 10.3 10.67% 

C12:1n1 0.575 0.145 25.23% 

C12:1n7 

C14:2 

C15:0 6.83 0.26 3.77% 9.13 0.55 6.08% 

C16:1n-7t 18.4 1.0 5.41% 

C16:1n9 

C16:2 

C17:0 7.11 0.08 1.17% 6.91 0.18 2.63% 18.7 0.5 2.79% 

C17:1n9 4.90 0.19 3.95% 

9c,11t-CLA 5.56 0.03 0.53% 

C18:4n-3 0.614 0.217 35.37% 

C19:0 3.81 0.04 1.12% 

C 20:3n-3 0.502 0.121 24.17% 3.44 0.26 7.53% 

C20:3n9 3.06 0.15 4.76% 

C20:4n3 1.81 0.14 7.67% 

C21:0 2.07 0.01 0.54% 

C 22:2n-6 0.600 0.201 33.43% 4.06 0.28 6.81% 

C23:0 6.05 0.21 3.55% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) 1.03 0.01 0.56% 1.09 0.01 0.68% 1.03 0.00 0.00% Not analyzed 

a

 Reported as μM 

18
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 5. Interlaboratory data received for total fatty acids in Unknown 005 (μM) 

Lab 1a Lab 2 Lab 3a Lab 4 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 109 5 4.25% 129 4 2.80% 106 1 0.86% 97.2 4.0 4.17% 

C14:1n5 11.3 0.6 5.09% Not analyzed 7.80 0.22 2.83% 

C16:0 2423 87 3.58% 2419 62 2.58% 2495 25 0.99% 2411 156 6.47% 

C16:1n7 187 11 6.02% 170 7 3.92% 190 3 1.52% 209 9 4.28% 

C18:0 586 23 3.99% 855 21 2.48% 737 11 1.53% 721 49 6.76% 

C18:1n7 104 9 8.89% 200 7 3.26% 128 2 1.90% 146 5 3.72% 

C18:1n9 2059 155 7.55% 1789 30 1.70% 1932 20 1.02% 1924 111 5.75% 

C18:2n6 3228 11 0.36% 2587 25 0.97% 3386 30 0.88% 3297 197 5.96% 

C18:3n3 85.9 4.5 5.25% 66.7 2.5 3.77% 81.7 1.2 1.49% 76.1 4.7 6.24% 

C18:3n6 50.0 2.2 4.35% 52.0 2.6 5.09% 50.7 0.4 0.86% 55.7 3.4 6.14% 

C20:0 31.7 0.6 1.82% Not analyzed 23.9 0.9 3.85% 

C20:1n9 Not analyzed Not analyzed Not analyzed 

C20:2n6 Not analyzed Not analyzed Not analyzed Not analyzed 

C20:3n6 Not analyzed 122 3 2.46% 163 5 2.97% 178 11 6.37% 

C20:4n6 812 12 1.53% 553 25 4.49% 771 14 1.86% 779 43 5.47% 

C20:5n3 86.1 3.6 4.24% 67.3 3.1 4.54% 80 1 1.00% 80.6 5.9 7.28% 

C22:0 71.3 1.6 2.25% 52.2 2.3 4.47% 61.5 1.7 2.78% 

C22:1n9 5.00 0.00 0.00% Not analyzed 7.96 0.11 1.32% 

C22:4n6 Not analyzed 22.0 1.0 4.55% 19.5 0.4 1.90% 27.0 1.8 6.74% 

C22:5n3 50.3 1.3 2.65% 44.0 1.7 3.94% 47.4 0.3 0.67% 47.0 3.3 7.06% 

C22:5n6 Not analyzed 17.3 1.2 6.66% Not analyzed 12.7 0.7 5.38% 

C22:6n3 187 11 6.05% 147 10 6.49% 166 1 0.80% 165 16 9.60% 

C24:0 63.0 1.7 2.75% 46.0 1.8 3.98% 64.8 4.3 6.71% 

C24:1n9 77.3 0.6 0.75% 54.2 3.7 6.88% 69.0 4.5 6.58% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 6.64 0.42 6.33% 

C10:0 5.76 0.10 1.81% 

C10:1n1 5.88 0.07 1.25% 

C12:0 12.3 0.2 2.01% 

C12:1n1 4.20 0.18 4.19% 

C12:1n7 3.68 0.14 3.91% 

C14:2 1.34 0.09 6.92% 

C15:0 22.3 1.2 5.30% 

C16:1n-7t 

C16:1n9 46.0 1.8 3.90% 

C16:2 4.27 0.28 6.52% 

C17:0 24.4 1.5 6.01% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 

C19:0 2.49 0.17 6.70% 

C 20:3n-3 

C20:3n9 18.5 1.8 9.83% 

C20:4n3 

C21:0 1.81 0.19 10.67% 

C 22:2n-6 

C23:0 40.6 3.1 7.62% 

C26:0 0.567 0.040 7.13% 

C26:1 0.477 0.035 7.37% 

PhA 1.39 0.07 5.04% 

PrA 0.210 0.010 4.76% 

density (g/mL) Not analyzed Not analyzed 1.05 0.01 1.10% 0.989 0.004 0.38% a Reported as μg/g 

19
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 5 (cont). Interlaboratory data received for total fatty acids in Unknown 005 (μM) 

Lab 5 Lab 6 Lab 7 Lab 8a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 111 1 1.01% 107 2 1.50% Not analyzed 112 1 1.24% 

C14:1n5 5.89 0.19 3.25% Not analyzed Not analyzed 

C16:0 2399 8 0.32% 2558 27 1.07% Not analyzed 3104 41 1.31% 

C16:1n7 133 2 1.78% 191 1 0.77% Not analyzed 214 3 1.48% 

C18:0 700 4 0.56% 608 9 1.41% Not analyzed 905 7 0.73% 

C18:1n7 118 2 1.28% Not analyzed Not analyzed 

C18:1n9 1803 6 0.34% 1958 2 0.08% Not analyzed 2149 15 0.70% 

C18:2n6 3253 8 0.25% 3419 21 0.61% Not analyzed 3394 58 1.71% 

C18:3n3 72.5 0.4 0.54% 87.3 0.4 0.41% Not analyzed 100 1 1.21% 

C18:3n6 51.0 0.8 1.59% Not analyzed Not analyzed 

C20:0 20.2 0.6 2.74% Not analyzed Not analyzed 

C20:1n9 15.3 0.1 0.98% Not analyzed 24.4 0.3 1.15% 

C20:2n6 19.5 0.6 3.12% 21.7 0.3 1.48% Not analyzed Not analyzed 

C20:3n6 153 2 1.30% Not analyzed 204 1 0.65% 

C20:4n6 723 4 0.52% 814 5 0.59% 2727 139 5.10% 1046 18 1.71% 

C20:5n3 71.4 0.6 0.86% 83.4 1.2 1.40% 82.6 3.0 3.58% 111 2 1.54% 

C22:0 67.8 0.6 0.87% Not analyzed Not analyzed 

C22:1n9 Not analyzed Not analyzed 

C22:4n6 21.1 0.8 3.64% Not analyzed 27.1 0.6 2.28% 

C22:5n3 55.0 1.3 2.42% 50.9 2.0 4.02% Not analyzed 56.7 1.6 2.74% 

C22:5n6 15.8 0.3 2.19% Not analyzed Not analyzed 

C22:6n3 140 3 2.37% 195 9 4.43% 222 6 2.70% 198 5 2.64% 

C24:0 59.3 2.4 4.08% Not analyzed Not analyzed 

C24:1n9 76.1 0.8 0.99% Not analyzed Not analyzed 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 

C10:1n1 

C12:0 

C12:1n1 

C12:1n7 

C14:2 

C15:0 24.4 0.4 1.56% 

C16:1n-7t 

C16:1n9 

C16:2 

C17:0 29.3 0.8 2.62% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 3.37 0.16 4.86% 

C19:0 

C 20:3n-3 

C20:3n9 7.86 0.34 4.28% 

C20:4n3 

C21:0 

C 22:2n-6 

C23:0 29.6 0.4 1.46% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) Not analyzed 0.967 0.002 0.18% Not analyzed 1.04 0.01 0.56% 

a Reported as μg/g 

20
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 5 (cont). Interlaboratory data received for total fatty acids in Unknown 005 (μM) 

Lab 9 Lab 10 Lab 12 Lab 13 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 104 2 1.46% 103 0 0.37% 231 12 5.33% 86.9 4.3 4.99% 

C14:1n5 8.09 0.36 4.39% 4.22 0.52 12.37% 13.4 0.4 2.95% 5.39 0.92 17.15% 

C16:0 2487 12 0.46% 2264 12 0.54% 2375 126 5.30% 2535 51 2.00% 

C16:1n7 185 2 0.94% 179 1 0.64% 151 5 3.44% 312 5 1.57% 

C18:0 678 6 0.90% 701 4 0.61% 657 22 3.28% 707 9 1.22% 

C18:1n7 131 2 1.17% 138 2 1.11% 123 7 5.48% 220 4 1.75% 

C18:1n9 1850 10 0.54% 1843 14 0.76% 1896 108 5.70% 1297 16 1.20% 

C18:2n6 3357 15 0.46% 3132 19 0.62% 3577 201 5.63% 2813 3 0.12% 

C18:3n3 73.3 1.2 1.57% 71.8 1.2 1.65% 56.3 1.8 3.14% 72.0 3.3 4.63% 

C18:3n6 48.4 0.9 1.84% 45.0 0.6 1.27% 59.9 2.5 4.19% Not analyzed 

C20:0 23.0 0.1 0.25% 16.7 0.1 0.75% 14.1 0.3 2.08% 15.0 2.2 14.70% 

C20:1n9 Not analyzed 15.1 0.2 1.51% 32.9 0.2 0.57% 10.9 1.3 11.82% 

C20:2n6 21.8 0.4 2.00% 23.2 0.3 1.08% 23.7 0.7 2.82% 24.4 2.4 9.66% 

C20:3n6 161 2 0.95% 154 1 0.84% 97.5 22.8 23.33% 210 15 7.04% 

C20:4n6 750 3 0.35% 724 6 0.86% 555 15 2.73% 838 23 2.80% 

C20:5n3 76.1 1.0 1.26% 73.7 1.4 1.84% 47.2 0.9 1.90% 177 16 8.97% 

C22:0 66.5 0.3 0.40% 43.8 1.8 4.01% 9.54 0.11 1.11% 41.3 2.5 5.98% 

C22:1n9 Not analyzed 4.67 0.54 11.49% Not analyzed 43.5 43.3 99.57% 

C22:4n6 19.2 0.4 1.88% 17.3 0.8 4.55% 20.0 0.5 2.35% 40.7 5.9 14.61% 

C22:5n3 46.1 0.2 0.45% 13.8 1.6 11.70% 57.9 5.5 9.56% 86.2 8.0 9.22% 

C22:5n6 13.6 0.4 2.59% 43.5 0.1 0.13% 18.5 0.4 1.94% 13.4 1.3 9.56% 

C22:6n3 165 1 0.35% 155 0 0.31% 94.7 7.2 7.61% 187 18 9.77% 

C24:0 60.7 2.1 3.44% 39.4 1.7 4.33% 4.84 0.24 5.06% 31.2 1.3 4.12% 

C24:1n9 68.3 2.2 3.17% 47.0 3.0 6.31% 12.6 0.9 6.94% 48.9 3.0 6.18% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 9.43 2.42 25.70% 

C10:1n1 

C12:0 8.21 2.03 24.69% 494 53 10.67% 

C12:1n1 3.17 0.80 25.23% 

C12:1n7 

C14:2 

C15:0 28.9 1.1 3.77% 37.7 2.3 6.08% 

C16:1n-7t 73.9 4.0 5.41% 

C16:1n9 

C16:2 

C17:0 28.7 0.3 1.17% 26.2 0.7 2.63% 69.3 1.9 2.79% 

C17:1n9 18.7 0.7 3.95% 

9c,11t-CLA 20.3 0.1 0.53% 

C18:4n-3 2.28 0.81 35.37% 

C19:0 13.1 0.1 1.12% 

C 20:3n-3 1.79 0.43 24.17% 11.5 0.9 7.53% 

C20:3n9 10.9 0.5 4.76% 

C20:4n3 6.10 0.47 7.67% 

C21:0 6.48 0.03 0.54% 

C 22:2n-6 1.95 0.65 33.43% 12.4 0.8 6.81% 

C23:0 18.6 0.7 3.55% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) 1.03 0.01 0.56% 1.09 0.01 0.68% 1.03 0.00 0.00% Not analyzed 

a Reported as μg/g 

21
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 6. Interlaboratory data received for total fatty acids in Unknown 006 (μg/g) 

Lab 1 Lab 2a Lab 3 Lab 4a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 31.7 1.5 4.69% 36.8 1.0 2.85% 29.0 0.3 0.87% 27.6 0.4 1.57% 

C14:1n5 <10 3.47 0.13 3.77% NA 2.23 0.10 4.38% 

C16:0 709 13 1.88% 666 27 4.10% 637 13 2.00% 646 8 1.16% 

C16:1n7 51.2 4.7 9.09% 48.9 1.6 3.25% 50.3 1.0 2.03% 57.6 0.7 1.23% 

C18:0 182 16 8.88% 259 8 3.05% 212 3 1.42% 207 3 1.40% 

C18:1n7 37.0 1.6 4.29% 57.4 1.7 2.96% 35.6 0.6 1.55% 42.3 2.3 5.48% 

C18:1n9 537 42 7.80% 513 11 2.22% 534 3 0.60% 548 7 1.34% 

C18:2n6 993 28 2.80% 781 18 2.28% 989 8 0.77% 973 13 1.36% 

C18:3n3 24.2 1.0 4.24% 20.0 1.4 6.88% 21.1 0.3 1.45% 20.4 0.2 1.01% 

C18:3n6 13.2 0.6 4.42% 14.0 0.4 3.03% 13.5 0.6 4.12% 13.2 0.2 1.71% 

C20:0 <10 11.0 0.4 3.27% Not analyzed 8.29 0.08 1.01% 

C20:1n9 <10 Not analyzed Not analyzed Not analyzed 

C20:2n6 Not analyzed Not analyzed Not analyzed Not analyzed 

C20:3n6 Not analyzed 34.1 1.7 5.11% 40.5 0.6 1.36% 45.5 0.7 1.49% 

C20:4n6 205 17 8.35% 151 2 1.53% 194 7 3.38% 198 3 1.51% 

C20:5n3 40.6 2.9 7.25% 34.2 0.6 1.77% 37.9 0.6 1.69% 37.2 0.4 1.10% 

C22:0 <10 25.0 1.0 4.09% 17.1 0.7 3.99% 21.4 0.4 2.08% 

C22:1n9 <10 1.81 0.20 10.83% NA 2.91 0.07 2.51% 

C22:4n6 Not analyzed 6.54 0.38 5.87% 5.38 0.28 5.16% 7.09 0.08 1.19% 

C22:5n3 15.2 1.3 8.40% 14.2 1.1 8.06% 14.4 0.4 2.43% 13.87 0.15 1.11% 

C22:5n6 ND 5.07 0.19 3.77% NA 3.33 0.06 1.79% 

C22:6n3 68.2 5.7 8.29% 54.1 0.9 1.75% 56.1 0.4 0.64% 53.8 0.8 1.43% 

C24:0 <20 23.1 0.9 3.69% 15.5 0.4 2.58% 22.9 0.3 1.21% 

C24:1n9 <20 34.7 1.5 4.27% 24.7 1.6 6.28% 32.1 0.6 1.81% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 1.05 0.05 4.34% 

C10:0 1.15 0.02 1.46% 

C10:1n1 1.02 0.02 2.37% 

C12:0 3.67 0.06 1.65% 

C12:1n1 0.906 0.020 2.26% 

C12:1n7 0.816 0.013 1.55% 

C14:2 0.298 0.022 7.42% 

C15:0 4.23 0.06 1.46% 

C16:1n-7t 

C16:1n9 10.4 0.2 1.55% 

C16:2 1.21 0.03 2.14% 

C17:0 6.00 0.06 1.01% 

C17:0 

C17:1n9 

9c,11t-CLA 

C18:4n-3 0.684 0.010 1.43% 

C19:0 

C 20:3n-3 4.19 0.14 3.26% 

C20:3n9 

C20:4n3 0.531 0.013 2.37% 

C21:0 

C 22:2n-6 

C23:0 14.7 0.1 0.95% 

C26:0 0.225 0.002 1.04% 

C26:1 0.243 0.006 2.53% 

PhA 0.433 0.007 1.53% 

PrA 0.108 0.002 1.63% 

density (g/mL) Not analyzed Not analyzed 1.03 0.01 1.01% 0.979 0.002 0.21% 

a

 Reported as μM 

22
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 6 (cont). Interlaboratory data received for total fatty acids in Unknown 006 (μg/g) 

Lab 5a Lab 6a Lab 7a Lab 8 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 32.8 0.2 0.54% 32.1 0.6 1.76% Not analyzed 32.7 0.5 1.47% 

C14:1n5 1.84 0.03 1.53% Not analyzed NA 

C16:0 671 8 1.19% 719 13 1.84% Not analyzed 806 11 1.36% 

C16:1n7 40.0 1.1 2.80% 55.3 1.7 3.08% Not analyzed 58.3 0.7 1.17% 

C18:0 214 3 1.26% 190 1 0.42% Not analyzed 258 4 1.62% 

C18:1n7 35.8 1.6 4.55% Not analyzed NA 

C18:1n9 529 5 0.89% 575 20 3.44% Not analyzed 577 6 1.09% 

C18:2n6 1013 8 0.82% 1062 44 4.14% Not analyzed 945 8 0.88% 

C18:3n3 20.1 0.2 1.09% 24.7 0.7 2.98% Not analyzed 26.2 0.3 1.11% 

C18:3n6 14.4 0.6 3.91% Not analyzed NA 

C20:0 7.28 0.15 2.08% Not analyzed NA 

C20:1n9 3.98 0.16 3.92% Not analyzed 6.54 0.06 0.86% 

C20:2n6 5.63 0.17 2.94% 5.97 0.07 1.24% Not analyzed NA 

C20:3n6 43.1 1.1 2.50% Not analyzed 51.4 0.8 1.47% 

C20:4n6 194 1 0.66% 217 6 2.66% 585 21 3.60% 250 4 1.68% 

C20:5n3 35.5 0.2 0.65% 41.3 1.6 3.83% 39.9 2.4 6.01% 49.1 0.8 1.62% 

C22:0 24.1 0.3 1.12% Not analyzed NA 

C22:1n9 Not analyzed NA 

C22:4n6 6.07 0.30 4.99% Not analyzed 7.31 0.78 10.73% 

C22:5n3 18.7 0.3 1.50% 16.2 0.4 2.68% Not analyzed 17.3 0.4 2.27% 

C22:5n6 4.30 0.12 2.80% Not analyzed NA 

C22:6n3 51.1 0.9 1.78% 69.5 1.7 2.39% 80.5 5.2 6.41% 66.7 1.1 1.60% 

C24:0 22.1 0.5 2.46% Not analyzed NA 

C24:1n9 35.9 0.6 1.73% Not analyzed NA 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 

C10:1n1 

C12:0 

C12:1n1 

C12:1n7 

C14:2 

C15:0 4.69 0.12 2.54% 

C16:1n-7t 

C16:1n9 

C16:2 

C17:0 7.46 0.17 2.28% 

C17:0 

C17:1n9 

9c,11t-CLA 1.18 0.04 3.44% 

C18:4n-3 

C19:0 

C 20:3n-3 1.90 0.02 0.98% 

C20:3n9 

C20:4n3 

C21:0 

C 22:2n-6 

C23:0 11.2 0.2 1.36% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) Not analyzed 0.954 0.001 0.13% Not analyzed 1.03 0 0.00% 

a

 Reported as μM 

23
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 6 (cont). Interlaboratory data received for total fatty acids in Unknown 006 (μg/g) 

Lab 9a Lab 10a Lab 12a Lab 13a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 29.2 0.1 0.40% 26.7 0.2 0.65% 58.7 4.5 7.69% 24.4 1.1 4.57% 

C14:1n5 2.38 0.05 1.90% 1.35 0.14 10.13% 3.65 0.62 17.02% 1.71 0.21 12.52% 

C16:0 661 4 0.57% 561 2 0.29% 652 48 7.37% 665 28 4.17% 

C16:1n7 50.6 0.1 0.28% 44.9 0.2 0.36% 44.3 3.7 8.40% 85.0 2.4 2.85% 

C18:0 196 3 1.35% 193 1 0.63% 191 15 7.98% 202 4 2.17% 

C18:1n7 37.1 0.1 0.14% 35.6 0.1 0.30% 38.4 2.1 5.43% 63.8 0.8 1.20% 

C18:1n9 518 3 0.49% 485 1 0.20% 548 37 6.80% 356 7 1.87% 

C18:2n6 995 5 0.49% 872 1 0.08% 1113 87 7.83% 821 8 1.03% 

C18:3n3 20.2 0.3 1.65% 18.1 0.1 0.59% 16.2 1.3 8.26% 16.7 0.6 3.56% 

C18:3n6 13.2 0.2 1.58% 11.3 0.1 0.72% 17.8 1.1 6.05% Not analyzed 

C20:0 7.84 0.10 1.30% 5.23 0.35 6.65% 4.70 0.48 10.11% 4.83 1.22 25.24% 

C20:1n9 Not analyzed 3.84 0.14 3.74% 9.96 1.03 10.31% 3.18 0.43 13.37% 

C20:2n6 5.85 0.03 0.58% 5.92 0.15 2.61% 6.66 0.55 8.19% 7.17 0.73 10.14% 

C20:3n6 40.8 0.3 0.79% 37.1 0.1 0.37% 23.6 2.3 9.92% 59.1 3.0 5.09% 

C20:4n6 189 1 0.66% 173 0 0.10% 127.1 9.6 7.52% 215 15 7.03% 

C20:5n3 36.3 0.2 0.43% 33.2 0.1 0.32% 23.7 2.6 11.10% 65.3 1.0 1.58% 

C22:0 22.1 0.3 1.21% 13.6 0.6 4.11% 3.69 0.37 10.03% 12.9 2.2 16.85% 

C22:1n9 Not analyzed 1.71 0.16 9.54% Not analyzed 11.2 10.2 90.29% 

C22:4n6 5.19 0.09 1.72% 4.50 0.20 4.47% 6.00 1.11 18.51% 11.6 0.8 6.74% 

C22:5n3 14.04 0.17 1.19% 3.69 0.31 8.32% 19.9 1.9 9.55% 24.5 2.1 8.40% 

C22:5n6 3.69 0.08 2.17% 12.6 0.3 2.42% 6.23 0.49 7.92% 3.42 0.16 4.57% 

C22:6n3 57.1 0.4 0.61% 50.0 0.1 0.18% 35.6 7.3 20.42% 59.2 2.8 4.64% 

C24:0 20.8 0.3 1.51% 12.2 0.6 5.32% 2.15 0.19 8.63% 10.5 2.3 22.35% 

C24:1n9 30.9 0.6 1.85% 19.1 0.9 4.97% 5.26 0.97 18.47% 21.1 5.9 28.10% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 1.65 0.40 24.08% 

C10:1n1 

C12:0 2.48 0.41 16.58% 103 7 7.09% 

C12:1n1 0.875 0.256 29.25% 

C12:1n7 

C14:2 

C15:0 6.16 0.24 3.86% 6.97 0.31 4.48% 

C16:1n-7t 18.6 0.9 5.10% 

C16:1n9 

C16:2 

C17:0 6.58 0.05 0.79% 6.93 0.52 7.46% 15.7 1.1 6.74% 

C17:0 5.27 0.44 8.29% 

C17:1n9 

9c,11t-CLA 1.42 0.20 13.98% 

C18:4n-3 4.11 0.47 11.38% 

C19:0 0.550 0.066 12.03% 3.61 0.47 12.94% 

C 20:3n-3 2.48 0.10 4.04% 

C20:3n9 1.46 0.33 22.50% 

C20:4n3 2.10 0.22 10.26% 

C21:0 0.464 0.194 41.93% 4.60 0.52 11.23% 

C 22:2n-6 0.478 0.200 41.93% 4.74 0.53 11.23% 

C23:0 5.70 0.39 6.89% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) 1.02 0.01 0.57% 1.09 0.00 0.40% 1.03 0.00 0.00% Not analyzed 

a

 Reported as μM 

24
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 7. Interlaboratory data received for total fatty acids in Unknown 006 (μM) 

Lab 1a Lab 2 Lab 3a Lab 4 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 139 7 4.69% 161 5 2.85% 130 1 0.87% 118 2 1.57% 

C14:1n5 15.3 0.6 3.77% Not analyzed 9.63 0.42 4.38% 

C16:0 2766 52 1.88% 2599 107 4.10% 2553 51 2.00% 2466 29 1.16% 

C16:1n7 201 18 9.09% 192 6 3.25% 203 4 2.03% 222 3 1.23% 

C18:0 641 57 8.88% 911 28 3.05% 766 11 1.42% 713 10 1.40% 

C18:1n7 131 6 4.29% 203 6 2.96% 130 2 1.55% 147 8 5.48% 

C18:1n9 1902 148 7.80% 1817 40 2.22% 1945 12 0.60% 1901 25 1.34% 

C18:2n6 3539 99 2.80% 2783 64 2.28% 3627 28 0.77% 3397 46 1.36% 

C18:3n3 86.8 3.7 4.24% 71.7 4.9 6.88% 78.0 1.1 1.45% 71.7 0.7 1.01% 

C18:3n6 47.5 2.1 4.42% 50.3 1.5 3.03% 49.9 2.1 4.12% 46.6 0.8 1.71% 

C20:0 35.3 1.2 3.27% Not analyzed 26.0 0.3 1.01% 

C20:1n9 Not analyzed Not analyzed Not analyzed 

C20:2n6 Not analyzed Not analyzed Not analyzed Not analyzed 

C20:3n6 Not analyzed 111 6 5.11% 136 2 1.36% 145 2 1.49% 

C20:4n6 672 56 8.35% 494 8 1.53% 655 22 3.38% 637 10 1.51% 

C20:5n3 134 10 7.25% 113 2 1.77% 129 2 1.69% 121 1 1.10% 

C22:0 73.5 3.0 4.09% 51.5 2.1 3.99% 61.6 1.3 2.08% 

C22:1n9 5.33 0.58 10.83% Not analyzed 8.41 0.21 2.51% 

C22:4n6 Not analyzed 19.7 1.2 5.87% 16.6 0.9 5.16% 20.9 0.2 1.19% 

C22:5n3 46.0 3.9 8.40% 43.0 3.5 8.06% 44.9 1.1 2.43% 41.1 0.5 1.11% 

C22:5n6 Not analyzed 15.3 0.6 3.77% Not analyzed 9.86 0.18 1.79% 

C22:6n3 207 17 8.29% 165 3 1.75% 176 1 0.64% 160 2 1.43% 

C24:0 62.7 2.3 3.69% 43.2 1.1 2.58% 60.8 0.7 1.21% 

C24:1n9 94.7 4.0 4.27% 69 4 6.28% 85.9 1.6 1.81% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 7.16 0.31 4.34% 

C10:0 6.55 0.10 1.46% 

C10:1n1 5.87 0.14 2.37% 

C12:0 17.9 0.3 1.65% 

C12:1n1 4.47 0.10 2.26% 

C12:1n7 4.03 0.06 1.55% 

C14:2 1.30 0.10 7.42% 

C15:0 17.1 0.3 1.46% 

C16:1n-7t 

C16:1n9 40.2 0.6 1.55% 

C16:2 4.68 0.10 2.14% 

C17:0 21.7 0.2 1.01% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 

C19:0 2.24 0.03 1.43% 

C 20:3n-3 

C20:3n9 13.4 0.4 3.26% 

C20:4n3 

C21:0 1.71 0.04 2.37% 

C 22:2n-6 

C23:0 40.6 0.4 0.95% 

C26:0 0.557 0.006 1.04% 

C26:1 0.603 0.015 2.53% 

PhA 1.36 0.02 1.53% 

PrA 0.353 0.006 1.63% 

density (g/mL) Not analyzed Not analyzed 1.03 0.01 1.01% 0.979 0.002 0.21% 

a

 Reported as μg/g 

25
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 7 (cont). Interlaboratory data received for total fatty acids in Unknown 006 (μM) 

Lab 5 Lab 6 Lab 7 Lab 8a 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 143 1 0.54% 134 2 1.76% Not analyzed 147 2 1.47% 

C14:1n5 7.74 0.12 1.53% Not analyzed Not analyzed 

C16:0 2616 31 1.19% 2675 49 1.84% Not analyzed 3237 44 1.36% 

C16:1n7 157 4 2.80% 207 6 3.08% Not analyzed 236 3 1.17% 

C18:0 752 9 1.26% 638 3 0.42% Not analyzed 933 15 1.62% 

C18:1n7 121 5 4.55% Not analyzed Not analyzed 

C18:1n9 1872 17 0.89% 1944 67 3.44% Not analyzed 2103 23 1.09% 

C18:2n6 3610 29 0.82% 3615 150 4.14% Not analyzed 3472 31 0.88% 

C18:3n3 72.3 0.8 1.09% 84.8 2.5 2.98% Not analyzed 97 1 1.11% 

C18:3n6 49.3 1.9 3.91% Not analyzed Not analyzed 

C20:0 22.2 0.5 2.08% Not analyzed Not analyzed 

C20:1n9 12.2 0.5 3.92% Not analyzed 21.7 0.2 0.86% 

C20:2n6 18.0 0.5 2.94% 18.5 0.2 1.24% Not analyzed Not analyzed 

C20:3n6 134 3 2.50% Not analyzed 173 3 1.47% 

C20:4n6 636 4 0.66% 679 18 2.66% 1920 69 3.60% 846 14 1.68% 

C20:5n3 117 1 0.65% 130 5 3.83% 132 8 6.01% 167 3 1.62% 

C22:0 67.6 0.8 1.12% Not analyzed Not analyzed 

C22:1n9 Not analyzed Not analyzed 

C22:4n6 17.4 0.9 4.99% Not analyzed 22.7 2.4 10.73% 

C22:5n3 56.7 0.9 1.50% 46.8 1.3 2.68% Not analyzed 53.9 1.2 2.27% 

C22:5n6 12.4 0.3 2.80% Not analyzed Not analyzed 

C22:6n3 156 3 1.78% 202 5 2.39% 245 16 6.41% 209 3 1.60% 

C24:0 57.2 1.4 2.46% Not analyzed Not analyzed 

C24:1n9 93.5 1.6 1.73% Not analyzed Not analyzed 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 

C10:1n1 

C12:0 

C12:1n1 

C12:1n7 

C14:2 

C15:0 18.5 0.5 2.54% 

C16:1n-7t 

C16:1n9 

C16:2 

C17:0 26.3 0.6 2.28% 

C17:1n9 

9c,11t-CLA 

C18:4n-3 4.06 0.14 3.44% 

C19:0 

C 20:3n-3 

C20:3n9 5.92 0.06 0.98% 

C20:4n3 

C21:0 

C 22:2n-6 

C23:0 30.1 0.4 1.36% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) Not analyzed 0.954 0.001 0.13% Not analyzed 1.03 0.00 0.00% 

a

 Reported as μg/g 

26
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 7 (cont). Interlaboratory data received for total fatty acids in Unknown 006 (μM) 

Lab 9 Lab 10 Lab 12 Lab 13 

Code mean stdev rsd mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 130 1 0.77% 127 1 0.65% 264 20 7.69% 107 5 4.57% 

C14:1n5 10.7 0.2 1.43% 6.50 0.66 10.13% 16.5 2.8 17.02% 7.57 0.95 12.52% 

C16:0 2620 0 0.00% 2382 7 0.29% 2608 192 7.37% 2593 108 4.17% 

C16:1n7 202 1 0.50% 192 1 0.36% 179 15 8.40% 334 10 2.85% 

C18:0 702 9 1.21% 741 5 0.63% 689 55 7.98% 711 15 2.17% 

C18:1n7 134 1 0.43% 137 0 0.30% 139 8 5.43% 226 3 1.20% 

C18:1n9 1863 6 0.31% 1870 4 0.20% 1989 135 6.80% 1260 24 1.87% 

C18:2n6 3607 12 0.32% 3389 3 0.08% 4066 318 7.83% 2926 30 1.03% 

C18:3n3 73.7 1.0 1.34% 70.9 0.4 0.59% 59.7 4.9 8.26% 59.9 2.1 3.56% 

C18:3n6 48.3 0.5 1.04% 44.4 0.3 0.72% 65.4 4.0 6.05% Not analyzed 

C20:0 25.5 0.3 1.18% 18.2 1.2 6.65% 15.4 1.6 10.11% 15.44 3.90 25.24% 

C20:1n9 Not analyzed 13.5 0.5 3.74% 32.9 3.4 10.31% 10.24 1.37 13.37% 

C20:2n6 19.3 0.1 0.60% 20.9 0.5 2.61% 22.1 1.8 8.19% 23.2 2.4 10.14% 

C20:3n6 135 2 1.13% 132 0 0.37% 78.8 7.8 9.92% 193 10 5.09% 

C20:4n6 630 3 0.40% 619 1 0.10% 428 32 7.52% 707 50 7.03% 

C20:5n3 122 1 0.82% 120 0 0.32% 80.2 8.9 11.10% 216 3 1.58% 

C22:0 66.1 0.8 1.14% 43.4 1.8 4.11% 11.1 1.1 10.03% 37.7 6.4 16.85% 

C22:1n9 Not analyzed 5.49 0.52 9.54% Not analyzed 33.2 30.0 90.29% 

C22:4n6 15.9 0.4 2.21% 14.8 0.7 4.47% 18.5 3.4 18.51% 34.9 2.4 6.74% 

C22:5n3 43.2 0.7 1.54% 12.2 1.0 8.32% 61.6 5.9 9.55% 74.2 6.2 8.40% 

C22:5n6 11.3 0.3 2.70% 41.5 1.0 2.42% 19.3 1.5 7.92% 10.33 0.47 4.57% 

C22:6n3 177 1 0.65% 166 0 0.18% 111 23 20.42% 180 8 4.64% 

C24:0 57.5 0.9 1.50% 36.1 1.9 5.32% 5.97 0.52 8.63% 28.5 6.4 22.35% 

C24:1n9 85.7 1.6 1.82% 56.7 2.8 4.97% 14.7 2.7 18.47% 57.5 16.2 28.10% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 

C10:0 10.5 2.5 24.08% 

C10:1n1 

C12:0 13.5 2.2 16.58% 524 37 7.09% 

C12:1n1 4.81 1.41 29.25% 

C12:1n7 

C14:2 

C15:0 26.1 1.0 3.86% 28.7 1.3 4.48% 

C16:1n-7t 75.0 3.8 5.10% 

C16:1n9 

C16:2 

C17:0 26.5 0.2 0.79% 26.3 2.0 7.46% 58.1 3.9 6.74% 

C17:1n9 20.1 1.7 8.29% 

9c,11t-CLA 21.0 2.0 9.44% 

C18:4n-3 5.27 0.74 13.98% 

C19:0 14.1 1.6 11.38% 

C 20:3n-3 1.96 0.24 12.03% 12.1 1.6 12.94% 

C20:3n9 8.83 0.36 4.04% 

C20:4n3 4.90 1.10 22.50% 

C21:0 7.06 0.72 10.26% 

C 22:2n-6 1.55 0.65 41.93% 14.4 1.6 11.23% 

C23:0 17.5 1.2 6.89% 

C26:0 

C26:1 

PhA 

PrA 

density (g/mL) 1.02 0.01 0.57% 1.09 0.00 0.40% 1.03 0.00 0.00% Not analyzed 

a

 Reported as μg/g 

27
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 8. Interlaboratory data received for total fatty acids in SRM 1950 (μg/g) 

Code COAa Lab 1 Lab 2b Lab 3 Lab 4b Lab 5b Lab 6b Lab 7b Lab 8 Lab 9b Lab 10b Lab 12b Lab 13b 

C14:0 17.9 ± 3.8 20.9 28.8 22.2 23.1 26.1 25.1 NA 27.0 22.5 20.1 62.2 21.8 

C14:1n5 1.57 ± 0.03 <10 3.17 NA 2.34 1.82 NA NA 2.21 1.29 3.93 1.57 

C16:0 594 ± 19 595 595 581 639 623 643 NA 786 594 504 767 683 

C16:1n7 53.5 ± 6.4 57.4 58.8 62.1 81.9 55.8 70.5 NA 75.9 63.7 59.0 65.5 133 

C18:0 179 ± 12 185 218 179 201 191 163 NA 235 167 166 193 199 

C18:1n7 37.7 ± 0.9 47.3 70.6 37.6 85.5 36.2 NA NA 39.7 45.1 45.4 99.0 

C18:1n9 447 ± 43 468 480 485 550 511 528 NA 601 470 456 685 365 

C18:2n6 780 ± 39 742 646 769 862 822 851 NA 836 780 690 1106 751 

C18:3n3 14.9 ± 1.0 14.6 12.8 13.7 15.2 14.7 16.4 NA 18.6 13.0 12.3 18.1 19.6 

C18:3n6 10.9 ± 2.3 11.1 13.1 14.2 15.2 15.1 NA NA 13.8 12.09 18.6 NA 

C20:0 5.5 ± 0.2 <10 8.13 NA 6.07 5.14 NA NA 5.57 3.80 4.49 3.86 

C20:1n9 3.5 ± 0.1 <10 NA NA NA 3.30 NA 6.12 NA 3.02 10.29 NA 

C20:2n6 5.7 ± 0.2 NA NA NA NA 5.15 5.64 NA NA 5.32 5.34 7.57 NA 

C20:3n6 41.8 ± 1.1 NA 32.5 39.4 50.2 41.1 NA 53.2 40.1 36.6 31.5 40.6 

C20:4n6 293 ± 54 295 150 200 229 214 228 336 255 198 182 170 232 

C20:5n3 11.4 ± 0.1 11.6 10.6 12.3 13.7 12.1 13.5 11.6 17.0 11.56 10.63 10.81 34.0 

C22:0 15.9 ± 1.5 <10 19.2 13.6 17.6 18.3 NA NA 17.1 10.65 3.23 11.79 

C22:1n9 1.1 ± 0.4 <10 2.03 NA 2.43 0.0 NA NA NA 0.058 NA 26.7 

C22:4n6 8.3 ± 0.2 NA 8.98 7.92 12.50 9.17 NA 10.2 7.80 6.95 7.00 15.30 

C22:5n3 12.5 ± 0.2 12.2 11.6 12.6 14.25 15.2 14.32 NA 15.5 12.34 5.22 17.5 19.4 

C22:5n6 6.3 ± 0.1 NA 7.60 NA 6.06 6.94 NA NA 5.73 10.90 7.20 4.65 

C22:6n3 37.9 ± 6.8 37.8 28.9 30.9 36.8 29.5 39.4 39.1 39.2 32.3 27.9 30.5 38.4 

C24:0 16.8 ± 0.9 <20 17.3 11.9 19.0 16.7 NA NA 15.62 9.09 1.75 7.83 

C24:1n9 25.6 ± 1.2 <20 26.0 18.2 26.2 26.5 NA NA 22.1 13.87 4.52 14.81 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 0.772 

C10:0 0.729 1.03 

C10:1n1 0.974 

C12:0 1.86 ± 0.11 2.47 1.69 103 

C12:1n1 0.903 0.492 

C12:1n7 0.804 

C14:2 0.271 

C15:0 1.08 ± 0.01 3.71 3.78 5.33 6.39 

C16:1n-7t 18.2 

C16:1n9 10.2 

C16:2 1.41 

C17:0 4.7 ± 0.2 5.84 6.60 5.55 5.95 13.9 

C17:1n9 5.46 

9c,11t-CLA 5.79 

C18:4n-3 0.860 0.674 

C19:0 0.676 3.59 

C 20:3n-3 0.455 3.47 

C20:3n9 5.64 2.56 3.07 

C20:4n3 1.49 

C21:0 0.492 1.94 

C 22:2n-6 0.000 0.501 4.07 

C23:0 11.952 7.45 3.77 

C26:0 0.182 

C26:1 0.209 

PhA 0.231 

PrA 0.042 

density (g/mL) NAc NAc NAc 1.04 1.00 NAc 0.948 NAc 1.03 1.01 1.07 1.03 NAc 

a

 Certified (bold) and reference values from the Certificate of Analysis (COA) for SRM 1950 

b

 Reported as μM 

c

 NA = not analyzed 

28
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 9. Interlaboratory data received for total fatty acids in SRM 1950 (μM) 

Code COAa Lab 1b Lab 2 Lab 3b Lab 4 Lab 5 Lab 6 Lab 7 Lab 8b Lab 9 Lab 10 Lab 12 Lab 13 

C14:0 80.1 ± 17.0 91.4 126 101 101 114 104 NA 122 99.3 94.5 279 95.3 

C14:1n5 7.1 ± 0.1 14.0 NA 10.4 7.62 NA NA 9.84 6.13 17.8 6.93 

C16:0 2364 ± 77 2320 2319 2356 2498 2428 2377 NA 3158 2340 2110 3065 2664 

C16:1n7 215 ± 26 225 231 254 323 219 263 NA 307 253 249 264 523 

C18:0 644 ± 41 650 768 654 709 671 544 NA 850 592 625 694 701 

C18:1n7 136 ± 3 167 250 138 303 122 NA NA 142 171 165 351 

C18:1n9 1614 ± 154 1657 1699 1786 1950 1810 1771 NA 2192 1680 1732 2486 1291 

C18:2n6 2838 ± 143 2645 2302 2851 3078 2931 2877 NA 3072 2810 2639 4040 2678 

C18:3n3 54.6 ± 3.6 52.4 46.0 51.2 54.8 52.8 55.9 NA 68.9 47.3 47.5 66.7 70.4 

C18:3n6 39.9 ± 8.5 39.9 47.0 53.0 54.6 51.5 NA NA 49.9 46.6 68.5 NA 

C20:0 18.0 ± 0.5 26.0 NA 19.5 15.6 NA NA 18.0 13.1 14.7 12.33 

C20:1n9 11.5 ± 0.5 NA NA 10.1 NA 20.3 NA 10.4 34.0 5.24 

C20:2n6 18.8 ± 0.6 NA NA NA 16.7 17.3 NA NA 17.4 18.6 25.1 13.61 

C20:3n6 139 ± 4 NA 106 134 164 127 NA 179 132 128 105 132.3 

C20:4n6 984 ± 180 969 493 683 754 703 709 1103 864 657 640 571 762 

C20:5n3 38.6 ± 0.5 38.3 35.0 42.3 45.4 40.1 42.2 38.3 57.8 38.6 37.7 36.6 112.5 

C22:0 47.8 ± 4.6 56.5 41.5 51.8 51.0 NA NA 50.8 33.6 9.73 34.6 

C22:1n9 3.4 ± 1.3 6.00 NA 7.20 NA NA NA 0.183 NA 78.9 

C22:4n6 25.5 ± 0.6 NA 27.0 24.8 37.7 26.1 NA 31.6 23.7 22.4 21.6 46.0 

C22:5n3 38.5 ± 0.7 37.0 35.0 39.6 43.2 45.9 41.1 NA 48.4 37.7 16.9 54.2 58.8 

C22:5n6 19.5 ± 0.4 NA 23.0 NA 18.4 19.9 NA NA 17.5 35.4 22.3 14.05 

C22:6n3 118 ± 21 115 88.0 98 112 89.8 114 119 123 99.4 91.1 95.2 117.0 

C24:0 46.6 ± 2.6 47.0 33.6 51.6 42.8 NA NA 42.8 26.5 4.87 21.2 

C24:1n9 71.3 ± 3.2 71.0 51.6 71.5 68.6 NA NA 60.8 40.6 12.6 40.4 

List any additional information such as known coelutions or results for additional fatty acids below: 

C8:0 5.36 

C10:0 4.24 6.42 

C10:1n1 5.73 

C12:0 9.47 ± 0.57 12.4 9.06 527 

C12:1n1 4.56 2.66 

C12:1n7 4.06 

C14:2 1.21 

C15:0 4.56 ± 0.04 15.4 14.8 22.5 25.7 

C16:1n-7t 73.1 

C16:1n9 40.2 

C16:2 5.6 

C17:0 17.6 ± 0.7 21.6 23.1 22.0 22.6 37.6 

C17:1n9 20.8 

9c,11t-CLA 21.3 

C18:4n-3 2.95 2.50 

C19:0 2.27 12.3 

C 20:3n-3 1.59 11.6 

C20:3n9 18.4 7.92 10.7 

C20:4n3 4.98 

C21:0 1.51 6.09 

C 22:2n-6 1.60 12.4 

C23:0 33.8 19.9 11.4 

C26:0 0.460 

C26:1 0.530 

PhA 0.740 

PrA 0.140 

density (g/mL) NAc NAc NAc 1.04 1.00 NAc 0.948 NAc 1.03 1.01 1.07 1.03 NAc 

a

 Certified (bold) and reference values from the Certificate of Analysis (COA) for SRM 1950 

b

 Reported as μg/g 

c

 NA = not analyzed 

29
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 10. Summary statistics for total fatty acids (μM) 

Unknown 004 

Code median unc rel unc na lowest value highest value 

C14:0 161 33 20.7% 11 106 Lab 13 279 Lab 12 

C14:1n5 13.9 4.7 33.4% 7 7.80 Lab 13 21.0 Lab 2 

C16:0 3048 291 9.6% 11 2715 Lab 10 4202 Lab 8 

C16:1n7 297 39 13.1% 11 246 Lab 5 413 Lab 13 

C18:0 716 89 12.4% 11 620 Lab 6 998 Lab 8 

C18:1n7 177 45 25.4% 9 151 Lab 6 294 Lab 2 

C18:1n9 2306 292 12.7% 11 1440 Lab 13 3128 Lab 8 

C18:2n6 3531 296 8.4% 11 2766 Lab 13 4040 Lab 12 

C18:3n3 85.6 14.6 17.1% 11 57.2 Lab 13 132 Lab 8 

C18:3n6 55.7 4.9 8.8% 8 49.1 Lab 10 68.5 Lab 12 

C20:0 20.3 6.3 31.2% 7 12.9 Lab 13 32.7 Lab 2 

C20:1n9 17.3 11.4 65.9% 5 10.2 Lab 13 34.0 Lab 12 

C20:2n6 24.3 2.6 10.6% 6 19.1 Lab 5 25.1 Lab 12 

C20:3n6 164 29 17.8% 9 105 Lab 12 229 Lab 8 

C20:4n6 722 447 61.8% 12 567 Lab 2 2818 Lab 7 

C20:5n3 59.8 15.4 25.8% 12 36.6 Lab 12 110 Lab 13 

C22:0 53.7 18.2 34.0% 8 9.73 Lab 12 70.6 Lab 2 

C22:1n9 10.3 2.8 26.9% 4 9.26 Lab 10 14.2 Lab 13 

C22:4n6 25.8 4.6 17.8% 9 21.1 Lab 10 35.1 Lab 13 

C22:5n3 48.7 7.9 16.3% 11 19.0 Lab 10 57.5 Lab 8 

C22:5n6 21.3 8.8 41.3% 7 12.3 Lab 13 41.6 Lab 10 

C22:6n3 139 27 19.5% 12 57.9 Lab 8 214 Lab 7 

C24:0 46.0 16.7 36.4% 8 4.87 Lab 12 58.0 Lab 2 

C24:1n9 64.3 21.7 33.7% 8 12.6 Lab 12 86.0 Lab 2 

List any additional information such as known coelutions or results for additional fatty acids below: 

C15:0 26.5 5.6 21.1% 4 22.1 Lab 4 31.6 Lab 13 

C17:0 28.6 15.8 55.2% 5 24.9 Lab 4 59.1 Lab 13 

density (g/mL) 1.03 0.03 2.9% 7 0.963 Lab 6 1.06 Lab 3 

a

 n is number of laboratories reporting a value. 

30
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table 10 (cont). Summary statistics for total fatty acids (μM) 

Unknown 005 

Code median unc rel unc na lowest value highest value 

C14:0 107 29 27.3% 11 86.9 Lab 13 231 Lab 12 

C14:1n5 7.80 3.14 40.2% 7 4.22 Lab 10 13.4 Lab 12 

C16:0 2423 164 6.8% 11 2264 Lab 10 3104 Lab 8 

C16:1n7 187 35 18.6% 11 133 Lab 5 312 Lab 13 

C18:0 701 71 10.2% 11 586 Lab 1 905 Lab 8 

C18:1n7 131 32 24.8% 9 104 Lab 1 220 Lab 13 

C18:1n9 1896 163 8.6% 11 1297 Lab 13 2149 Lab 8 

C18:2n6 3297 216 6.6% 11 2587 Lab 2 3577 Lab 12 

C18:3n3 73.3 8.8 12.0% 11 56.2 Lab 12 100 Lab 8 

C18:3n6 50.9 4.0 7.9% 8 45.0 Lab 10 60.0 Lab 12 

C20:0 20.2 5.8 28.8% 7 14.1 Lab 12 31.7 Lab 2 

C20:1n9 15.3 9.9 64.7% 5 10.9 Lab 13 32.9 Lab 12 

C20:2n6 22.5 1.8 7.9% 6 19.5 Lab 5 24.4 Lab 13 

C20:3n6 161 30 18.6% 9 97.5 Lab 12 210 Lab 13 

C20:4n6 775 420 54.2% 12 553 Lab 2 2727 Lab 7 

C20:5n3 80.4 23.1 28.8% 12 47.2 Lab 12 177 Lab 13 

C22:0 56.9 18.0 31.7% 8 9.54 Lab 12 71.3 Lab 2 

C22:1n9 6.48 23.6 363.8% 4 4.67 Lab 10 43.5 Lab 13 

C22:4n6 21.1 6.0 28.4% 9 17.3 Lab 10 40.7 Lab 13 

C22:5n3 50.3 12.7 25.2% 11 13.8 Lab 10 86.2 Lab 13 

C22:5n6 15.8 10.3 65.1% 7 12.7 Lab 4 43.5 Lab 10 

C22:6n3 166 24 14.4% 12 94.7 Lab 12 222 Lab 7 

C24:0 52.7 18.3 34.7% 8 4.84 Lab 12 64.8 Lab 4 

C24:1n9 61.3 18.9 30.8% 8 12.6 Lab 12 77.3 Lab 2 

List any additional information such as known coelutions or results for additional fatty acids below: 

C15:0 26.6 8.5 32.1% 4 22.3 Lab 4 37.7 Lab 13 

C17:0 28.7 21.2 73.9% 5 24.4 Lab 4 69.3 Lab 13 

density (g/mL) 1.03 0.04 3.9% 7 0.967 Lab 6 1.09 Lab 10 

a

 n is number of laboratories reporting a value. 

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Table 10 (cont). Summary statistics for total fatty acids (μM) 

Unknown 006 

Code median unc rel unc na lowest value highest value 

C14:0 134 10 7.3% 11 107 Lab 13 264 Lab 12 

C14:1n5 9.63 3.8 40.0% 7 6.50 Lab 10 16.5 Lab 12 

C16:0 2608 11 0.4% 11 2382 Lab 10 3237 Lab 8 

C16:1n7 202 9 4.5% 11 157 Lab 5 334 Lab 13 

C18:0 713 10 1.3% 11 638 Lab 6 933 Lab 8 

C18:1n7 137 8 6.1% 9 121 Lab 6 226 Lab 13 

C18:1n9 1901 13 0.7% 11 1260 Lab 13 2103 Lab 8 

C18:2n6 3539 17 0.5% 11 2783 Lab 2 4066 Lab 12 

C18:3n3 72.3 3.3 4.6% 11 59.7 Lab 12 97.0 Lab 8 

C18:3n6 48.8 2.4 5.0% 8 44.4 Lab 10 65.4 Lab 12 

C20:0 22.2 4.2 18.7% 7 15.4 Lab 12 & 13 35.3 Lab 2 

C20:1n9 13.5 6.7 49.5% 5 10.2 Lab 13 32.9 Lab 12 

C20:2n6 20.1 1.2 6.2% 6 12.0 Lab 5 23.2 Lab 13 

C20:3n6 135 8 5.7% 9 78.8 Lab 12 193 Lab 13 

C20:4n6 646 43 6.7% 12 428 Lab 12 1920 Lab 7 

C20:5n3 125 8 6.2% 12 80.2 Lab 12 216 Lab 13 

C22:0 56.5 7.8 13.8% 8 11.1 Lab 12 73.5 Lab 2 

C22:1n9 6.95 14.6 209.9% 4 5.33 Lab 2 33.2 Lab 13 

C22:4n6 18.5 4.0 21.4% 9 14.8 Lab 10 34.9 Lab 13 

C22:5n3 46.0 11.0 24.0% 11 12.2 Lab 10 74.2 Lab 13 

C22:5n6 12.4 8.9 72.1% 7 9.86 Lab 4 41.5 Lab 10 

C22:6n3 176 7 3.8% 12 111 Lab 12 245 Lab 7 

C24:0 50.2 8.2 16.4% 8 5.97 Lab 12 62.7 Lab 2 

C24:1n9 77.5 8.9 11.5% 8 14.7 Lab 12 94.7 Lab 2 

List any additional information such as known coelutions or results for additional fatty acids below: 

C15:0 22.3 3.4 15.5% 4 17.1 Lab 4 28.7 Lab 13 

C17:0 26.3 8.0 30.3% 5 21.7 Lab 4 58.1 Lab 13 

density (g/mL) 1.03 0.11 10.7% 7 0.954 Lab 6 1.09 Lab 10 

a

 n is number of laboratories reporting a value. 

32
 

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Table 10 (cont). Summary statistics for total fatty acids (μM) 

SRM 1950 

Code median unc rel unc na lowest value highest value 

C14:0 101 41 39.9% 11 91.4 Lab 1 279 Lab 12 

C14:1n5 9.84 4.0 40.4% 7 6.13 Lab 10 17.8 Lab 12 

C16:0 2377 245 10.3% 11 2110 Lab 10 3158 Lab 8 

C16:1n7 254 65 25.4% 11 219 Lab 5 523 Lab 13 

C18:0 671 63 9.3% 11 544 Lab 6 850 Lab 8 

C18:1n7 167 67 40.2% 9 122 Lab 6 351 Lab 13 

C18:1n9 1771 232 13.1% 11 1291 Lab 13 2486 Lab 12 

C18:2n6 2851 330 11.6% 11 2302 Lab 2 4040 Lab 12 

C18:3n3 52.8 6.7 12.7% 11 46.0 Lab 2 70.4 Lab 13 

C18:3n6 50.7 7.3 14.5% 8 46.4 Lab 10 68.5 Lab 12 

C20:0 15.6 4.4 28.5% 7 12.3 Lab 13 26.0 Lab 2 

C20:1n9 10.4 12.8 122.6% 5 5.24 Lab 13 34.0 Lab 12 

C20:2n6 17.4 3.9 22.5% 6 13.6 Lab 13 25.1 Lab 12 

C20:3n6 132 20 15.2% 9 105 Lab 12 179 Lab 8 

C20:4n6 706 122 17.2% 12 493 Lab 2 1103 Lab 7 

C20:5n3 39.4 15.5 39.3% 12 35.0 Lab 2 113 Lab 13 

C22:0 46.2 13.5 29.2% 8 9.73 Lab 12 56.5 Lab 2 

C22:1n9 6.60 46.7 707.0% 4 0.182 Lab 10 78.9 Lab 13 

C22:4n6 26.1 6.8 25.9% 9 21.9 Lab 12 46.0 Lab 13 

C22:5n3 41.1 8.3 20.2% 11 16.9 Lab 10 58.8 Lab 13 

C22:5n6 19.9 6.4 32.4% 7 14.1 Lab 13 35.4 Lab 10 

C22:6n3 106 9 8.7% 12 88.0 Lab 2 123 Lab 8 

C24:0 38.2 13.8 36.1% 8 4.87 Lab 12 51.6 Lab 4 

C24:1n9 56.2 18.0 32.0% 8 12.6 Lab 12 71.5 Lab 4 

List any additional information such as known coelutions or results for additional fatty acids below: 

C15:0 18.9 6.7 35.5% 4 14.8 Lab 6 25.7 Lab 13 

C17:0 22.6 7.6 33.8% 5 21.6 Lab 4 37.6 Lab 13 

density (g/mL) 1.03 0.04 3.9% 7 0.948 Lab 6 1.07 Lab 10 

a

 n is number of laboratories reporting a value. 

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Table 11. Laboratory 12's data for free fatty acids (μM) 

Unknown 004 (n=3) Unknown 005 (n=3) Unknown 006 (n=3) SRM 1950 (n=1) 

mean stdev rsd mean stdev rsd mean stdev rsd 

C14:0 12.84 0.95 7.41% 9.17 0.70 7.64% 9.83 0.62 6.29% 7.96 

C14:1n5 2.38 0.21 8.74% 1.83 0.20 11.15% 1.74 0.18 10.21% 1.60 

C16:0 125.35 12.41 9.90% 86.98 8.53 9.81% 88.71 4.61 5.20% 80.42 

C16:1n7 15.02 1.65 10.98% 7.60 0.66 8.65% 8.18 0.26 3.22% 10.38 

C18:0 42.22 2.44 5.78% 37.43 3.61 9.65% 37.67 1.53 4.05% 30.65 

C18:1n7 7.68 0.62 8.03% 4.79 0.32 6.59% 5.00 0.21 4.23% 5.55 

C18:1n9 138.26 11.83 8.56% 100.25 7.25 7.23% 95.47 1.63 1.71% 86.75 

C18:2n6 77.85 6.43 8.26% 54.97 4.41 8.02% 57.81 2.45 4.23% 47.89 

C18:3n3 6.81 0.51 7.50% 5.17 0.46 8.85% 4.75 0.21 4.34% 4.19 

C18:3n6 1.00 0.03 2.59% 7.83 12.38 158.25% 0.73 0.04 5.00% 0.70 

C20:0 1.25 0.02 1.85% 1.21 0.12 9.75% 1.28 0.06 4.31% 1.46 

C20:1n9 2.04 0.04 1.89% 1.76 0.02 0.89% 1.73 0.04 2.42% 1.91 

C20:2n6 1.51 0.05 3.45% 1.36 0.08 5.98% 1.28 0.13 9.86% 1.34 

C20:3n6 15.41 0.85 5.50% 13.48 2.07 15.33% 16.46 1.37 8.33% 10.61 

C20:4n6 14.65 0.80 5.44% 15.50 2.52 16.25% 13.23 1.21 9.15% 10.71 

C20:5n3 0.37 0.01 3.37% 0.34 0.01 2.95% 0.35 0.02 4.91% 0.31 

C22:0 0.62 0.01 1.53% 0.57 0.03 5.22% 0.60 0.01 2.44% 0.53 

C22:1n9 Not analyzed (NA) NA NA NA 

C22:4n6 1.06 0.08 7.14% 0.91 0.04 4.76% 0.99 0.11 11.52% 1.11 

C22:5n3 1.19 0.07 6.00% 1.19 0.04 2.95% 1.20 0.08 6.58% 0.97 

C22:5n6 1.03 0.06 5.90% 0.91 0.10 10.61% 0.89 0.04 4.56% 0.93 

C22:6n3 1.51 0.06 4.21% 1.79 0.57 31.68% 2.78 0.26 9.20% 0.81 

C24:0 0.48 0.03 6.71% 0.42 0.03 6.10% 0.61 0.08 13.70% 0.43 

C24:1n9 0.92 0.12 13.20% 0.76 0.07 8.69% 0.98 0.22 22.79% 0.85 

List any additional information such as known coelutions or results for additional fatty acids below: 

C12:0 5.80 0.14 2.41% 4.23 0.26 6.18% 4.90 0.64 13.08% 3.79 

C15:0 2.19 0.14 6.63% 1.96 0.19 9.63% 2.08 0.10 4.77% 1.54 

C16:1n7t 3.00 0.31 10.49% 2.27 0.18 8.04% 3.77 2.08 55.20% 2.10 

C17:0 2.12 0.12 5.72% 1.89 0.12 6.36% 1.84 0.05 2.59% 1.60 

C17:1n9 1.43 0.07 4.54% 1.18 0.09 7.67% 1.08 0.04 3.33% 1.21 

9c,11t-CLA 2.06 0.07 3.23% 1.79 0.06 3.11% 1.77 0.06 3.38% 2.01 

C18:4n3 0.24 0.16 64.90% 0.25 0.15 60.06% 0.31 0.05 15.88% 0.09 

C19:0 0.75 0.03 3.69% 0.65 0.02 2.70% 0.69 0.02 2.56% 0.63 

C20:3n3 0.77 0.05 6.54% 0.66 0.01 1.96% 0.73 0.08 10.87% 0.64 

C20:4n3 0.98 0.01 1.46% 0.96 0.09 9.66% 1.67 0.16 9.89% 0.66 

C21:0 0.41 0.07 17.98% 0.36 0.03 9.35% 0.47 0.15 31.37% 0.36 

C22:2n6 0.76 0.05 6.76% 0.70 0.01 1.54% 0.69 0.01 1.28% 0.81 

C22:1n9 (Docosenoic acid) was used as a surrogate. 

34
 

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Table 12. % of free to total fatty acids based on Laboratory 12's data 

Unknown 004 Unknown 005 Unknown 006 SRM 1950 

C14:0 4.60% 3.98% 3.73% 2.85% 

C14:1n5 13.34% 13.66% 10.55% 8.99% 

C16:0 4.09% 3.66% 3.40% 2.62% 

C16:1n7 5.69% 5.02% 4.58% 3.93% 

C18:0 6.09% 5.70% 5.47% 4.42% 

C18:1n7 4.66% 3.88% 3.59% 3.36% 

C18:1n9 5.56% 5.29% 4.80% 3.49% 

C18:2n6 1.93% 1.54% 1.42% 1.19% 

C18:3n3 10.22% 9.18% 7.97% 6.28% 

C18:3n6 1.47% 13.06% 1.12% 1.02% 

C20:0 8.51% 8.57% 8.33% 9.88% 

C20:1n9 5.99% 5.34% 5.26% 5.61% 

C20:2n6 6.01% 5.73% 5.81% 5.33% 

C20:3n6 14.64% 13.82% 20.88% 10.08% 

C20:4n6 2.57% 2.79% 3.09% 1.87% 

C20:5n3 1.02% 0.71% 0.43% 0.85% 

C22:0 6.35% 5.93% 5.44% 5.41% 

C22:1n9 Not analyzed 

C22:4n6 4.90% 4.58% 5.35% 5.15% 

C22:5n3 2.19% 2.05% 1.94% 1.78% 

C22:5n6 4.61% 4.90% 4.61% 4.17% 

C22:6n3 1.59% 1.89% 2.51% 0.85% 

C24:0 9.85% 8.58% 10.14% 8.85% 

C24:1n9 7.29% 5.99% 6.64% 6.69% 

List any additional information such as known coelutions or results for additional fatty acids below: 

C12:0 1.17% 0.86% 0.93% 0.72% 

C15:0 7.50% 6.77% 8.00% 6.82% 

C16:1n7t 3.40% 3.06% 5.02% 2.88% 

C17:0 7.56% 7.21% 7.00% 7.09% 

C17:1n9 6.08% 6.33% 5.37% 5.83% 

9c,11t-CLA 9.18% 8.81% 8.41% 9.44% 

C18:4n3 6.27% 11.12% 5.92% 3.53% 

C19:0 5.70% 4.99% 4.90% 5.15% 

C20:3n3 6.56% 5.69% 6.07% 5.47% 

C20:4n3 16.04% 15.76% 34.01% 13.29% 

C21:0 6.31% 5.59% 6.68% 5.84% 

C22:2n6 6.18% 5.64% 4.75% 6.51% 

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Appendix A. 

Methods reported by the participating laboratories 

Table A-1. Procedures used 

Table A-2. Calibration information 

Table A-3. Additional notes provided by laboratories 

36
 

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Table A-1 Procedures used for total fatty acids 

Lab # 1 2 3 4 5 

Reporting date 5/9/2016 5/18/2016 5/23/2016 5/25/2016 5/31/2016 

Volume of sample extracted (mL): 0.50 0.05 0.20 0.10 0.02 

Mass of samples extracted (g) (average of 3): 

FAQAP unk004 0.49 not recorded 0.211 0.10 

FAQAP unk005 0.52 not recorded 0.210 0.10 

FAQAP unk006 0.48 not recorded 0.206 0.10 

Mass of samples extracted (g) : 

SRM 1950 0.51 not recorded 0.208 0.10 

Analytical method reference, if available 

Sánchez-Ávila N, Mata-Granados JM, 

Ruiz-Jiménez J, Luque de Castro MD, J 

Chromatog A 1216 (2009) 6864-6872 

Lagerstedt SA, Hinrichs DR, Batt SM, 

Magera MJ, Rinaldo P, McConnell JP. 

(2001) Quantitative determination of 

plasma C8-C26 total fatty acids for the 

biochemical diagnosis of nutritional 

and metabolic disorders. Mol Genet 

Metab,.73:38-45. 

Lagerstedt SA, Hinrichs DR, Batt SM, 

Magera MJ, Rinaldo P, McConnell JP. 

Quantitative determination of plasma 

C8-C26 total fatty acids for the 

biochemical diagnosis of nutritional 

and metabolic disorders. Mol Genet 

Metab 2001;73:38-45 

Bagga D, Capone S, Wang HJ, Heber 

D, Lill M, Chap L, Glasphy JA. J Nat 

Cancer Ins 1997; 89:1123-1131. 

Analytical method used: 

Hydrolysis method 

0.4 M KOH methanol followed by 1 M 

H2SO4 methanol Acid and Base Hydrolysis Acetic acid with Methanol 

Acid hydrolysis followed by basic 

hydrolysis and re-acidification 

Add sample to 1ml methanol:benzene 

(4:1). Add 100 ul acetyl chloride. Heat 

for 60 minutes at 100 C. 

Extraction method Liquid-liquid Liquid Liquid Extraction (LLE) Liquid/Liquid Extraction liquid-liquid 

Extraction solvent hexane with 40 mg/g BHT Hexane Hexane Hexane 

Extraction time vortex 30 s each time 2 min 

14 per batch; each batch about 8 hours 

for extraction 20 min on rotary mixer 

Extraction - other details 

Hexane extraction performed 2x 

following base addition and 2x 

following acid addition 

Extraction solvent evaporated, samples 

derivatized then reconstituted in 

hexane + 0.5N HCl 

Cool sample to room T and add 4 ml of 

potassium carbonate (6%). Centerifuge 

and inject supernatant into GC. 

Sample extract cleanup method none Hexane LLE from derivatizing reagent None 

Centrifugation of samples and removal 

of supernatant for injection 

Derivitization reagent acidic methanol pentafluorobenzylbromide 

Methyl ester is formed from the 

methanol 

2,3,4,5,6-Pentaflourobenzyl bromide 

(10% solution in acetonitrile) 

Analytical instrument GC-FID 

6890N/5973N Gas 

Chromatograph/Mass Spectrometer Agilent MSD 5973N, Agilent GC 6890N 

Agilent 6890 GC/5975C CI MSD in 

negative ion mode 

Agilent Technologies 5890A gas 

chromatograph 

Column phase 

crossbonded polyethylene glycol 

(FAMEWAX, Restek) 5% phenyl-95% methylpolysiloxane DB-23 DB-5MS 

SP2380 stabilized phase fused silica 

capillary column (Sigma-Aldrich) 

Column length, m 30 20 60 30m + 10m guard 30 

Column i.d., mm 0.32 0.18 0.25 0.25 0.32 

Column film thickness, μm 0.25 0.18 0.15 0.25 0.20 

Injection method (split, splitless, etc) split split and splitless Split 

Split and splitless injections for 

different fatty acids split injection 

Method of quantitation: 

ES = external standards (Y/N) N N Y Y 

Number of ES used 0 37 compounds at 6 levels each 12

 IS = internal standards (Y/N) yes Y Y Y 

Number of IS used 2 13 4 13 in one solution 

IS added PRIOR to extraction of sample yes Y Y Y 

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Table A-1 Continued 

Lab # 6 7 8 9 10 

Reporting date 5/31/2016 06/01/2016 6/1/2016 6/1/2016 6/1/2016 

Volume of sample extracted (mL): 0.10 0.0031 0.10 0.10 0.05 

Mass of samples extracted (g) (average of 3): 

FAQAP unk004 0.096 0.103 0.10 0.052 

FAQAP unk005 0.097 0.104 0.10 0.055 

FAQAP unk006 0.095 0.103 0.10 0.054 

Mass of samples extracted (g) : 

SRM 1950 0.095 0.103 0.10 0.054 

Analytical method reference, if available 

Lagertedt S, Hinrichs D, Batt S, Magera 

M, Rinaldo P, McConnell J. 

Quantitative Determination of Plasma 

C8-C26 Total Fatty Acids for the 

Biochemical Diagnosis of Nutritional 

and Metabolic Disorders. Mol Genet & 

Metab 2001; 73: 38-45. 

Analytical method used: 

Hydrolysis method Acid/Base 

Acidic and alkaline hydrolysis using 

10% 6N HCl in acetonitrile and 10% 

10N NaOH in MeOH 

Extraction method Liquid-liquid Liquid extraction Liquid-liquid Extraction Liquid-liquid extraction Modified Folch 

Extraction solvent hexane 0.001% BHT in Methanol Chloroform-Methanol (2:1) Hexanes 3mL 2:1 chloroform:methanol 

Extraction time 20-30 minutes per extraction At 300 rpm for 15 Minutes 3 min 15 minutes 24 hours in 2:1 chloroform:methanol 

Extraction - other details 

triple extraction via automated liquid 

handler Follow by 90% Acetonitrile samples extracted 3x 

Addition of 500uL sodium phosphate 

buffer, vortex, centrifuge, double 

extraction of organic phase 

Sample extract cleanup method Speedvac 

Solvent evaporated and samples 

derivatized Hexane/water 

Derivitization reagent PFBBr - pentafluorobenzyl bromide 

METH-PREP II, Grace Davision 

Discovery Sciences pentafluorobenzyl-bromide 14% boron trifluoride in methanol 

Analytical instrument GC/MS LC-MS/MS Agilent 7890A GC, 5975C MSD Agilent 7890/5975B GC-MS Varian 3900 GC-FID 

Column phase 

90% biscyanopropyl/10% 

phenylcyanopropyl polysiloxane C18 

Non bonded, Poly ( 

80%biscyanopropyl/20%cyanopropyl 

phenyl siloxane) phase Select-FAME DB-FFAP 

Column length, m 60 0.005 30 200 15 

Column i.d., mm 0.25 2.1 0.25 0.25 0.10 

Column film thickness, μm 0.2 3 0.20 0.25 0.10 

Injection method (split, splitless, etc) split splitless split 20:1 50:1 split ratio 

Method of quantitation: 

ES = external standards (Y/N) N Y N N Y 

Number of ES used 3 28

 IS = internal standards (Y/N) Y Y Y Y Y 

Number of IS used 17 1 2 16 1 

IS added PRIOR to extraction of sample Y Y Y Y Y 

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Table A-1 Continued 

Lab # 11 12 13 

Reporting date 6/8/2016 6/23/2016 6/29/2016 

Volume of sample extracted (mL): 0.15 0.05 0.20 

Mass of samples extracted (g) (average of 3): 

FAQAP unk004 0.152 0.21 

FAQAP unk005 0.153 0.21 

FAQAP unk006 0.148 0.21 

Mass of samples extracted (g) : 

SRM 1950 0.152 0.21 

Analytical method reference, if available: Liu et al 2010 

Analytical method used: 

Hydrolysis method Acid-catalyzed transesterification 

0.5M dry methanolic sodium methoxide 

(as part of derivatization) 

Extraction method Organic Phase with Vortexing 

Based on F. Smedes, Analyst, 1999,124, 

1711-1718 Solvent extraction 

Extraction solvent 3:2 Hexane-Isopropanol 

0.41mL 2-propanol, 0.52mL 

cyclohexane, 0.57mL 0.1M ammonium 

acetate Hexane:2-proponol (3:2, v/v) 

Extraction time 10 minutes 6 minutes 

Extraction - other details 

Transfer cyclohexane fraction and reextract with added 0.57mL cyclohexane 

Sample extract cleanup method 

One wash in Hexane/dd-water and 

wash in dd-water 

Evaporate to dryness and reconstitute 

in 1:1 methanol/toluene 

Derivitization reagent 4% Sulfuric Acid in Methanol

 0.5M dry methanolic sodium 

methoxide, 60oC 60 min, +0.1mL 3N 

Methanolic HCl, 60o

C 30 min, 

neutralize, extract with 0.4mL hexanes 

Analytical instrument 

Hewlett-Packard Model (now Agilent) 

GC 6890 FID gas chromatograph with 

7673 Autosampler injector 

Agilent 6890 Plus+ GC, 5973N MSD, 

7683 Injector, DB-225ms column Thermo Trace GC-DSQ system 

Column phase 

fused silica capillary cis/trans column 

SP2560 

(50%-Cyanopropylphenyl)­

dimethylpolysiloxane 

Rxi-5MS-coated 

5%diphenyl/95%dimethyl polysiloxane 

capillary column 

Column length, m 100 30 30.00 

Column i.d., mm 0.25 0.25 0.25 

Column film thickness, μm 0.20 0.25 0.25 

Injection method (split, splitless, etc) splitless splitless splitless 

Method of quantitation: 

ES = external standards (Y/N) 

Y (NOTE: Used for identification not 

quantification) N N 

Number of ES used 43 0

 IS = internal standards (Y/N) N Y Y 

Number of IS used N/A 1 Methyl tridecanoate 

IS added PRIOR to extraction of sample (Y/N) Y Y 

39
 

____________________________________________________________________________________________

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
 

Table A-2 Procedures used for free fatty acids 

Lab # 12 

Reporting date 6/23/2016 

Volume of sample extracted (mL): 0.05 

Mass of samples extracted (g) (average of 3): 

FAQAP unk004 

FAQAP unk005 

FAQAP unk006 

Mass of samples extracted (g) : 

SRM 1950 

Analytical method reference, if available: 

Analytical method used: 

Extraction method 

Based on F. Smedes, Analyst, 1999,124, 

1711-1718 

Extraction solvent 

0.41mL 2-propanol, 0.52mL 

cyclohexane, 0.57mL 0.1M ammonium 

acetate 

Extraction time 6 minutes 

Extraction - other details 

Transfer cyclohexane fraction and reextract with added 0.57mL cyclohexane 

Sample extract cleanup method 

Evaporate to dryness and reconstitute 

in 1:1 methanol/toluene 

Derivitization reagent 

2M Tri(methylsilyl)diazomethane (in 

hexanes) 

Analytical instrument 

Agilent 6890 Plus+ GC, 5973N MSD, 

7683 Injector, DB-225ms column 

Column phase 

(50%-Cyanopropylphenyl)­

dimethylpolysiloxane 

Column length, m 30 

Column i.d., mm 0.25 

Column film thickness, μm 0.25 

Injection method (split, splitless, etc) splitless 

Method of quantitation: 

ES = external standards (Y/N) N 

Number of ES used 0

 IS = internal standards (Y/N) Y 

Number of IS used 1 

IS added PRIOR to extraction of sample Y 

40 

____________________________________________________________________________________________

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table A-3 Calibration information 

Lab Fatty Acid 

Code Fatty Acid Name Lowest std (μmol/L) 

Highest std 

(μmol/L) 

LOD 

(μmol/L) 

LOQ 

(μmol/L) Curve Type Weighting IS used for quantitation 

1 C14:0 Myristic acid used response factors based on three independently prepared calibration solutoins Myristic-d27 

C14:1n5 Myristoleic acid used response factors based on three independently prepared calibration solutoins Myristic-d27 

C16:0 Palmitic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C16:1n7 Palmitoleic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C18:0 Stearic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C18:1n7 cis-Vaccenic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C18:1n9 Oleic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C18:2n6 Linoleic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C18:3n3 alpha-Linolenic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C18:3n6 gamma-Linolenic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C20:0 Arachidic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C20:1n9 11-Eicosenoic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C20:4n6 Arachidonic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C20:5n3 Eicosapentaenoic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C22:0 Docosanoic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C22:1n9 Docosenoic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C22:5n3 Docosapentaenoic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C22:6n3 Docosahexaenoic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C24:0 Lignoceric acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

C24:1n9 Nervonic acid used response factors based on three independently prepared calibration solutoins Palmitic-d31 

2 C14:0 Myristic acid 12.5 150 0.3 3000 Linear None Myristic acid-d3 

C14:1n5 Myristoleic acid 1.25 15 0.013 300 Linear None Pentadecanoic acid-d4 

C16:0 Palmitic acid 25 300 2.81 6000 Linear None Palmitic-d3 

C16:1n7 Palmitoleic acid 12.5 150 0.045 3000 Linear None Myristic acid-d3 

C18:0 Stearic acid 25 300 3.719 6000 Linear None Stearic acid-d3 

C18:1n7 cis-Vaccenic acid 25 300 0.089 6000 Linear None Stearic acid-d4 

C18:1n9 Oleic acid 25 300 0.21 6000 Linear None Stearic acid-d5 

C18:2n6 Linoleic acid 25 300 0.15 6000 Linear None Stearic acid-d6 

C18:3n3 alpha-Linolenic acid 12.5 150 0.009 3000 Linear None Arachidic acid-d3 

C18:3n6 gamma-Linolenic acid 12.5 150 0.009 3000 Linear None Arachidic acid-d3 

C20:0 Arachidic acid 12.5 150 0.25 3000 Linear None Arachidic acid-d3 

C20:3n6 homo-gamma-Linolenic acid 0.625 7.5 0.004 150 Linear None Docosanoic acid-d4 

C20:4n6 Arachidonic acid 12.5 150 0.021 3000 Linear None Arachidic acid-d3 

C20:5n3 Eicosapentaenoic acid 12.5 150 0.019 3000 Linear None Arachidic acid-d3 

C22:0 Docosanoic acid 0.625 7.5 0.036 150 Linear None Docosanoic acid-d4 

C22:4n6 Docosatetraenoic acid 0.625 7.5 0.002 150 Linear None Docosanoic acid-d4 

C22:5n3 Docosapentaenoic acid 0.625 7.5 0.021 150 Linear None Docosanoic acid-d4 

C22:5n6 Docosapentaenoic acid 0.625 7.5 0.021 150 Linear None Docosanoic acid-d4 

C22:6n3 Docosahexaenoic acid 12.5 150 0.03 3000 Linear None Arachidic acid-d3 

C24:0 Lignoceric acid 0.625 7.5 0.029 150 Linear None Tetracosanoic acid-d4 

C24:1n9 Nervonic acid 0.625 7.5 0.004 150 Linear None Tetracosanoic acid-d4 

3 C14:0 myristic 12.7 845 0.963 13.1 quadratic 1/x Methyl Tridecenoate 

C16:0 palmitic 111 7430 29 234 quadratic 1/x Methyl trans-Heptadecenoate 

C16:1 palmitoleic 11.4 757 3.69 23.6 quadratic 1/x Methyl Tridecenoate 

C18:0 stearic 100 6700 6.22 105 quadratic 1/x Methyl trans-Heptadecenoate 

C18:1n7 vaccenic 10.2 682 2.8 21.2 quadratic 1/x Methyl Heneicosanoate 

C18:1n9 oleic 102 6790 36.3 212 quadratic 1/x Methyl trans-Heptadecenoate 

C18:2n6 linoleic 103 6840 26 214 quadratic 1/x Methyl trans-Heptadecenoate 

C18:3n3 alpha-linolenic 10.4 691 0.718 10.8 quadratic 1/x Methyl Heneicosanoate 

C18:3n6 gamma-linolenic 10.4 690 0.682 10.8 quadratic 1/x Methyl Heneicosanoate 

C20:3n6 homo-gamma-linolenic 9.41 628 2.19 19.6 quadratic 1/x Methyl Heneicosanoate 

C20:4n6 arachidonic 93.5 6230 5.12 98.5 quadratic 1/x Methyl trans-Heptadecenoate 

C20:5n3 eicosapentaenoic 9.53 635 0.794 9.92 quadratic 1/x Methyl Tricosenoate 

C22:0 docosanoic 8.5 566 0.382 8.81 quadratic 1/x Methyl Tricosenoate 

C22:4n6 docosatetraenoic 8.67 578 0.481 9.02 quadratic 1/x Methyl Tricosenoate 

C22:5n3 docosapentaenoic 8.72 581 0.424 9.08 quadratic 1/x Methyl Tricosenoate 

C22:6n3 docosahexaenoic 8.79 586 1.46 18.3 quadratic 1/x Methyl Tricosenoate 

C24:0 lignoceric 7.83 522 0.353 8.14 quadratic 1/x Methyl Tricosenoate 

C24:1n9 nervonic 7.87 525 0.409 8.18 quadratic 1/x Methyl Tricosenoate 

41
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table A-3 (cont) Calibration information 

Lab Fatty Acid 

Code Fatty Acid Name Lowest std 

(μmol/L) 

Highest std 

(μmol/L) 

LOD 

(μmol/L) 

LOQ 

(μmol/L) Curve Type Weighting IS used for quantitation 

4 C8:0 Octanoic acid 14 120 quadratic equal C8:0 D3 

C10:0 Decanoic acid 13 110 quadratic equal C10:0 D3 

C10:1 9-Decenoic acid 16 120 quadratic equal C10:0 D3 

C12:0 Lauric acid 12 101 quadratic equal C12:0 D3 

C12:1w1 11-Dodecenoic acid 13 108 quadratic equal C12:0 D3 

C12:1w7 cis-5-Dodecenoic acid 14 115 quadratic equal C12:0 D3 

C14:0 Myristic acid 44 365 quadratic equal C14:0 D3 

C14:1 Myristoleic acid 14 115 quadratic equal C15:0 D3 

C15:0 Pentadecanoic acid 23 190 quadratic equal C15:0 D3 

C16:0 Palmitic acid 468 3900 quadratic equal C16:0 D3 

C16:1w7 Palmitoleic acid 127 1058 quadratic equal C14:0 D3 

C17:0 Heptadecanoic acid 22 180 quadratic equal C15:0 D3 

C18:0 Stearic acid 89 745 quadratic equal C18:0 D3 

C18:1w7 Vaccenic acid 241 2010 quadratic equal C18:0 D3 

C18:1w9 Oleic acid 600 5000 quadratic equal C18:0 D3 

C18:2w6 Linoleic acid 474 3950 quadratic equal C18:0 D3 

C18:3w3 a-linolenic acid 55 460 quadratic equal C18:0 D3 

C18:3w6 g-linolenic acid 60 500 quadratic equal C18:0 D3 

C19:0 Nonadecanoic acid 5 43 quadratic equal C22:0 D3 

C20:0 Arachidic acid 115 960 quadratic equal C20:0 D3 

C20:3w6 Eicosatrienoic acid (w6) (Homo-g- linolenic acid) 13 112 quadratic equal C22:0 D3 

C20:3w9 5,8,11-Eicosatrienoic acid (MEAD) 7 55 quadratic equal C22:0 D3 

C20:4w6 Arachidonic acid 121 1000 quadratic equal C20:0 D3 

C20:5w3 Eicosapentaenoic acid (w3) 78 650 quadratic equal C20:0 D3 

C21:0 Heneicosanoic acid 11 95 quadratic equal C22:0 D3 

C22:0 Docosanoic acid (Behenic acid) 14 115 quadratic equal C22:0 D3 

C22:1w9 Erucic acid (w9) 9 72 quadratic equal C22:0 D3 

C22:4w6 Docosatetraenoic acid (w6) 6 46 quadratic equal C22:0 D3 

C22:5w3 Docosapentaenoic acid (w3) 25 210 quadratic equal C22:0 D3 

C22:5w6 Docosapentaenoic acid 6 50 quadratic equal C22:0 D3 

C22:6w3 Docosahexaenoic acid (w3) 13 108 quadratic equal C22:0 D3 

C23:0 Tricosanoic acid 12 97 quadratic equal C24:0 D4 

C24:0 Tetracosanoic acid 6 51 quadratic equal C24:0 D4 

C24:1w9 Nervonic acid (w9) 23 195 quadratic equal C24:0 D4 

C26:0 Hexacosanoic acid 1.4 11.3 quadratic equal C26:0 D4 

PhA Phytanic acid 2.6 21.7 quadratic equal PhA D3 

PrA Pristanic acid 0.25 2.05 quadratic equal PrA D3 

5 C14:0 Myristic acid 56.8 909.9 

C14:1n5 Myristoleic acid NA NA 

C16:0 Palmitic acid 151.7 2428.3 

C16:1n7 Palmitoleic acid 51.9 832.4 

C18:0 Stearic acid 91.7 1467.9 

C18:1n7 cis-Vaccenic acid NA NA 

C18:1n9 Oleic acid 92.4 1479 

C18:2n6 Linoleic acid 46.7 749.1 

C18:3n3 alpha-Linolenic acid 47 750.5 

C18:3n6 gamma-Linolenic acid NA NA 

C20:0 Arachidic acid NA NA 

C20:1n9 11-Eicosenoic acid NA NA 

C20:2n6 11,14-Eicosadienoic acid 21.1 337.4 

C20:3n6 homo-gamma-Linolenic acid NA NA 

C20:4n6 Arachidonic acid 39.7 654.1 

C20:5n3 Eicosapentaenoic acid 36.2 580.70 

C22:0 Docosanoic acid NA NA 

C22:1n9 Docosenoic acid NA NA 

C22:4n6 Docosatetraenoic acid NA NA 

C22:5n3 Docosapentaenoic acid 39.9 636.7 

C22:5n6 Docosapentaenoic acid NA NA 

C22:6n3 Docosahexaenoic acid 39.6 632.8 

C24:0 Lignoceric acid NA NA 

C24:1n9 Nervonic acid NA NA 

42
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table A-3 (cont) Calibration information 

Lab Fatty Acid 

Code Fatty Acid Name Lowest std (μmol/L) 

Highest std 

(μmol/L) 

LOD 

(μmol/L) 

LOQ 

(μmol/L) Curve Type Weighting IS used for quantitation 

6 C18:3n3 alpha-Linolenic acid 6.53 653 1.54 not available linear 1/x2 alpha -Linolenic-d14 

C20:0 Arachidic acid 0.90 89.5 0.82 not available linear 1/x2 Arachidic-d39 

C20:4n6 Arachidonic acid 23.4 2337 7.34 not available linear 1/x2 Arachidonic-d8 

C10:0 Capric acid 0.44 43.9 1.59 not available quadratic 1/x2 Capric-d3 

C22:0 Docosanoic acid 1.83 183 0.68 not available linear 1/x2 Docosanoic-d4 

C22:6n3 Docosahexaenoic acid 7.88 788 1.84 not available linear 1/x2 Docosahexaenoic-d5 

C22:5n3 Docosapentaenoic n-3 acid 2.49 249 0.55 not available linear 1/x2 Docosahexaenoic-d5 

C22:5n6 Docosapentaenoic n-6 acid 1.59 159 0.24 not available linear 1/x2 Docosahexaenoic-d5 

C22:4n6 Docosatetraenoic acid 1.48 148 0.31 not available quadratic 1/x2 Docosahexaenoic-d5 

C20:2n6 11,14-Eicosadienoic acid 0.98 97.7 0.31 not available quadratic 1/x2 Arachidic-d39 

C20:1n9 11-Eicosenoic acid 1.00 100 0.87 not available quadratic 1/x2 Arachidic-d39 

C20:5n3 Eicosapentaenoic acid 7.15 715 0.79 not available quadratic 1/x2 Eicosapentaenoic-d5 

C20:3n9 5Z, 8Z, 11Z-Eicosatrienoic acid 0.64 64.3 0.39 not available quadratic 1/x2 Arachidic-d39 

C18:3n6 gamma-Linolenic acid 2.93 293 0.42 not available linear 1/x2 alpha -Linolenic-d14 

C20:3n6 homo-gamma-Linolenic acid 4.62 462 1.14 not available quadratic 1/x2 alpha -Linolenic-d14 

C12:0 Lauric acid 2.33 233 2.33 not available quadratic 1/x2 Lauric-d3 

C24:0 Lignoceric acid 1.47 147 1.09 not available linear 1/x2 Tetracosanoic-d4 

C18:2n6 Linoleic acid 82.7 8274 22.6 not available linear 1/x2 13C- Linoleic 

C14:1n5 Myristoleic acid 1.42 142 0.29 not available quadratic 1/x2 Myristic-d27 

C14:0 Myristic acid 10.1 1012 4.90 not available quadratic 1/x2 Myristic-d27 

C17:0 Margaric acid 1.50 150 3.36 not available quadratic 1/x Margaric-d3 

C24:1n9 Nervonic acid 1.95 195 0.69 not available quadratic 1/x2 Tetracosanoic-d4 

C18:1n9 Oleic acid 85.0 8496 17.7 not available linear 1/x2 13C-Oleic 

C15:0 Pentadecanoic acid 0.95 95.0 0.75 not available linear 1/x2 Pentadecanoic-d3 

C16:1n7 Palmitoleic acid 25.1 2514 6.56 not available quadratic 1/x2 Palmitoleic-d14 

C16:0 Palmitic acid 87.4 8742 78.1 not available quadratic 1/x2 Palmitic-d31 

C18:4n3 Stearidonic acid 0.47 46.9 0.24 not available quadratic 1/x Arachidic-d39 

C18:0 Stearic acid 25.0 2505 39.1 not available quadratic 1/x2 Stearic-d35 

C23:0 Tricosanoic acid 0.98 97.6 0.90 not available linear 1/x2 Docosanoic-d4 

C18:1n7 cis -Vaccenic acid 7.42 742 2.31 not available quadratic 1/x2 13C-Oleic 

7 C20:4n6 Arachidonic acid 317 2952 Linear 1/x Docosahexaenoic-d5 

C20:5n3 Eicosapentaenoic acid 12.50 116 Linear 1/x Docosahexaenoic-d5 

C22:6n3 Docosahexaenoic acid 38.1 354 Linear 1/x Docosahexaenoic-d5 

8 C14:0 Myristic 54.70 1094.7 Linear Equal Margaric 

C16:0 Palmitic 195 3899.7 Linear Equal Margaric 

C16:1n7 Palmitoleic 49.1 982.6 Linear Equal Margaric 

C18:0 Stearic 87.90 1757.6 Linear Equal Margaric 

C18:1n9 Oleic 177 3540.1 Linear Equal Margaric 

C18:2n6 Linoleic 178.3 3565.3 Linear Equal Margaric 

C18:3n3 alpha-Linolenic 22.40 448.9 Linear Equal Margaric 

C20:1n9 11-Eicosenoic 20.10 402.5 Linear Equal Margaric 

C20:3n6 homo-gamma-Linolenic 20.4 407.8 Linear Equal Margaric 

C20:4n6 Arachidonic 82.1 1641.9 Linear Equal Arachidonic-d8 

C20:5n3 Eicosapentaenoic 82.6 1652.8 Linear Equal Arachidonic-d8 

C22:4n6 Docosatetraenoic 18.80 375.9 Linear Equal Arachidonic-d8 

C22:5n3 Docosapentaenoic 18.9 378.1 Linear Equal Arachidonic-d8 

C22:6n3 Docosahexaenoic 38.0 760.9 Linear Equal Arachidonic-d8 

43
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table A-3 (cont) Calibration information 

Lab Fatty Acid 

Code Fatty Acid Name Lowest std 

(μmol/L) 

Highest std 

(μmol/L) 

LOD 

(μmol/L) 

LOQ 

(μmol/L) Curve Type Weighting IS used for quantitation 

9 C14:0 Myristic acid 24.3 608 0.33 Linear none Myristic-d27 

C14:1n5 Myristoleic acid 4.11 103 0.29 Linear none Myristic-d27 

C16:0 Palmitic acid 315 7896 17 Linear none Palmitic-13C16 

C16:1n7 Palmitoleic acid 47.9 1198 0.76 Linear none Palmitoleic-13C16 

C18:0 Stearic acid 80 2000 4.02 Linear none Stearic-d35 

C18:1n7 cis-Vaccenic acid 31.6 790 1.06 Linear none cis-Vaccenic-13C5 

C18:1n9 Oleic acid 240 5994 14.3 Linear none Oleic-13C18 

C18:2n6 Linoleic acid 320 8007 4.9 Linear none Linoleic-13C18 

C18:3n3 alpha-Linolenic acid 15.9 398 0.82 Linear none alpha-Linolenic-d14 

C18:3n6 gamma-Linolenic acid 8.18 204 0.43 Linear none alpha-Linolenic-d14 

C20:0 Arachidic acid 8.05 201 0.47 Linear none Arachicic-d39 

C20:1n9 11-Eicosenoic acid NA NA NA NA NA NA NA 

C20:2n6 11,14-Eicosadienoic acid 2.07 51.7 0.16 Linear none Arachicic-d39 

C20:3n6 homo-gamma-Linolenic acid 9.96 249 1 Linear none Arachidonic-d8 

C20:4n6 Arachidonic acid 79.3 1983 0.36 Linear none Arachidonic-d8 

C20:5n3 Eicosapentaenoic acid 31.4 786 1.29 Linear none Eicosapentaenoic-d5 

C22:0 Docosanoic acid 8.02 200 1.77 Linear none Docosanoic-d43 

C22:1n9 Docosenoic acid NA NA NA NA NA NA NA 

C22:4n6 Docosatetraenoic acid 4.15 104 0.34 Linear none Docosahexaenoic-d5 

C22:5n3 Docosapentaenoic acid 8.15 204 0.51 Linear none Docosahexaenoic-d5 

C22:5n6 Docosapentaenoic acid 4.23 106 0.33 Linear none Docosahexaenoic-d5 

C22:6n3 Docosahexaenoic acid 40 999 1.96 Linear none Docosahexaenoic-d5 

C24:0 Lignoceric acid 8.05 201 1.59 Linear none Lignoceric-d47 

C24:1n9 Nervonic acid 8.03 201 1.38 Linear none Lignoceric-d47 

10 C 10:0 Capric acid 0.0839 4028.7492 2.6858 26.8583 Linear Equal weight% Methyl-nonadecanoate 

C 12:0 Lauric acid 0.0729 3501.5101 2.3343 23.3434 Linear Equal weight% Methyl-nonadecanoate 

C 14:0 Myristic acid 0.0645 3096.2999 2.0642 20.6420 Linear Equal weight% Methyl-nonadecanoate 

C 16:0 Palmitic acid 0.0578 2775.1476 1.8501 18.5010 Linear Equal weight% Methyl-nonadecanoate 

C 18:0 Stearic Acid 0.0524 2514.3553 1.6762 16.7624 Linear Equal weight% Methyl-nonadecanoate 

C 20:0 Arachidic acid 0.0479 2298.3680 1.5322 15.3225 Linear Equal weight% Methyl-nonadecanoate 

C 22:0 Docosanoic acid 0.0441 2116.5526 1.4110 14.1104 Linear Equal weight% Methyl-nonadecanoate 

C 24:0 Lignoceric acid 0.0409 1961.3940 1.3076 13.0760 Linear Equal weight% Methyl-nonadecanoate 

C 12:1 Dodecenoic acid 0.0736 3534.7746 2.3565 23.5652 Linear Equal weight% Methyl-nonadecanoate 

C 14:1 Myristoleic acid 0.0650 3122.2823 2.0815 20.8152 Linear Equal weight% Methyl-nonadecanoate 

C 16:1 Palmitoleic acid 0.0583 2796.0015 1.8640 18.6400 Linear Equal weight% Methyl-nonadecanoate 

C 18:1n-7 cis-Vaccenic acid 0.0527 2531.4619 1.6876 16.8764 Linear Equal weight% Methyl-nonadecanoate 

C 18:1n-9 Oleic acid 0.0527 2531.4619 1.6876 16.8764 Linear Equal weight% Methyl-nonadecanoate 

C 20:1n-9 11-Eicosenoic acid 0.0482 2312.6535 1.5418 15.4177 Linear Equal weight% Methyl-nonadecanoate 

C 22:1n-9 Docosenoic acid 0.0443 2128.6614 1.4191 14.1911 Linear Equal weight% Methyl-nonadecanoate 

C 24:1n-9 Nervonic acid 0.0411 1971.7882 1.3145 13.1453 Linear Equal weight% Methyl-nonadecanoate 

C 18:2n-6 Linoleic acid 0.0531 2548.8019 1.6992 16.9920 Linear Equal weight% Methyl-nonadecanoate 

C 18:3n-6 gamma-Linolenic acid 0.0535 2566.3820 1.7109 17.1092 Linear Equal weight% Methyl-nonadecanoate 

C 20:2n-6 11,14-Eicosadienoic acid 0.0485 2327.1169 1.5514 15.5141 Linear Equal weight% Methyl-nonadecanoate 

C 20:3n-6 hommo-gamma-Linolenic acid 0.0488 2341.7632 1.5612 15.6118 Linear Equal weight% Methyl-nonadecanoate 

C 20:4n-6 Arachidonic acid 0.0491 2356.5942 1.5711 15.7106 Linear Equal weight% Methyl-nonadecanoate 

C 22:2n-6 Docosadienoic acid 0.0446 2140.9089 1.4273 14.2727 Linear Equal weight% Methyl-nonadecanoate 

C 22:4n-6 Docosatetraenoic acid 0.0451 2165.8323 1.4439 14.4389 Linear Equal weight% Methyl-nonadecanoate 

C 18:3n-3 alpha-Linolenic acid 0.0535 2566.3820 1.7109 17.1092 Linear Equal weight% Methyl-nonadecanoate 

C 20:3n-3 Eicosatrienoic acid 0.0488 2341.7632 1.5612 15.6118 Linear Equal weight% Methyl-nonadecanoate 

C 20:5n-3 Eicosapentaenoic acid 0.0494 2371.6150 1.5811 15.8108 Linear Equal weight% Methyl-nonadecanoate 

C 22:5n-3 Docosapentaenoic acid, n3 0.0454 2178.5132 1.4523 14.5234 Linear Equal weight% Methyl-nonadecanoate 

C 22:6n-3 Docosahexaenoic acid 0.0457 2191.3428 1.4609 14.6090 Linear Equal weight% Methyl-nonadecanoate 

44
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
Table A-3 (cont) Calibration information 

Lab Fatty Acid 

Code Fatty Acid Name Lowest std (μmol/L) 

Highest std 

(μmol/L) 

LOD 

(μmol/L) 

LOQ 

(μmol/L) Curve Type Weighting IS used for quantitation 

11 No information 

12 C14:0 Myristic Acid 0.0495 165 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C14:1n5 Myristoleic Acid 0.0083 27.7 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C16:0 Palmitic Acid 0.0592 197 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C16:1n7 Palmitoleic Acid 0.0075 24.8 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C18:0 Stearic Acid 0.0402 134 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C18:1n7 Vaccenic Acid 0.0030 9.8 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C18:1n9 Oleic Acid 0.0270 89.9 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C18:2n6 Linoleic Acid 0.0204 67.9 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C18:3n3 Alpha Linolenic Acid 0.0109 36.2 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C18:3n6 Gamma Linolenic Acid 0.0040 13.4 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C20:0 Arachidic Acid 0.0061 20.4 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C20:1n9 11-Eicosenoic Acid 0.0123 41.1 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C20:2n6 11-14-Eicosadienoic Acid 0.0070 23.4 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C20:3n6 Homogamma Linolenic Acid 0.0036 12.0 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C20:4n6 Arachidonic Acid 0.0344 114.8 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C20:5n3 Eicosapentaenoic Acid 0.0051 17.0 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C22:0 Behenic Acid 0.0056 18.8 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C22:1n9 Erucic Acid 0.0075 25.1 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C22:4n6 Docosic Acidtraenoic Acid 0.0081 27.0 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C22:5n3 Docosapentaenoic Acid 0.0068 22.7 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C22:5n6 Docosapentaenoic Acid N6 0.0078 26.0 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C22:6n3 Docosahexaenoic Acid (DHA) 0.0188 62.7 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C24:0 Ignoceric Acid 0.0052 17.4 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C24:1n9 Nervonic Acid 0.0084 27.9 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C12:0 Lauric Acid 0.0373 124.4 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C15:0 Pentadecanoic Acid 0.0078 26.0 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C16:1n7t 9t-Palmitelaidic Acid (Omega 7) 0.0084 27.9 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C17:0 Heptadecanoic Acid 0.0070 23.4 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C17:1n9 10-Heptadecenoic Acid 0.0071 23.6 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

9c,11t-CLA 9c,11t-Conjugated Linoleic Acid 0.0073 24.5 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C18:4n3 Stearidonic Acid 0.0012 4.1 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C19:0 Nonadecanoic Acid 0.0064 21.3 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C20:3n3 11-14-17 Eicosatrienoic Acid 0.0055 18.3 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C20:4n3 Arachidonic Acid (Omega 3) 0.0030 10.0 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C21:0 Heneicosanoic Acid 0.0031 10.3 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

C22:2n6 13-16-Docosadienoic Acid 0.0070 23.3 quadratic 1/x Glyceryl Tri(hexadecanoate-d31) 

13 No information 

45
 

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Table A-4 Additional notes provided by laboratories 

Lab # Note: 

1 a

trans-vaccenic acid coelutes with cis-vaccenic acid 

ND = not determined 

2 C20:1n9 and C20:2n6 were not quantitated 

11 Method was not quantitative so data were withdrawn. 

12 (total fatty acid data) C22:1n9 (Docosenoic acid) was used as a surrogate. 

12 (free fatty acid data) C22:1n9 (Docosenoic acid) was used as a surrogate. 

46
 

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Appendix B. 

Charts of interlaboratory data received for the individual fatty acids in each 

material (in terms of μM) with the median identified for the three unknown 

samples and the certified or reference value with associated confidence interval 

identified for SRM 1950. 

The charts are presented in the order of an individual fatty acid in each of the four 

materials (unknown 004, unknown 005, unknown 006, and SRM 1950) with the 

fatty acids in the order presented in Table 1. If fewer than four laboratories 

reported numerical data for a fatty acid, no chart is presented. 

The error bars for each data point represent the laboratory’s standard deviation 

from their analysis of three subsamples. 

47
 

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80 

130 

180 

230 

280 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C14:0 in Unk 004 

median value 161 μM 

50 

70 

90 

110 

130 

150 

170 

190 

210 

230 

250 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C14:0 in Unk005 

median value 107 μM 

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120 

140 

160 

180 

200 

220 

240 

260 

280 

300 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C14:0 in Unk006 

median value 134 μM 

0 

50 

100 

150 

200 

250 

300 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C14:0 in SRM 1950 

Reference value (80.1 ± 17.0) μM 

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0 

5 

10 

15 

20 

25 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C14:1n5 in Unk 004 

median value 13.9 μM 

0 

5 

10 

15 

20 

25 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C14:1n5 in Unk005 

median value 7.80 μM 

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0 

5 

10 

15 

20 

25 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C14:1n5 in Unk006 

median value 9.63 μM 

0 

5 

10 

15 

20 

25 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C14:1n5 in SRM 1950 

Reference value (7.1 ± 0.1 ) μM 

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2500 

3000 

3500 

4000 

4500 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C16:0 in Unk 004 

median value 3048 μM 

2200 

2300 

2400 

2500 

2600 

2700 

2800 

2900 

3000 

3100 

3200 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C16:0 in Unk005 

median value 2423 μM 

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2000 

2200 

2400 

2600 

2800 

3000 

3200 

3400 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C16:0 in Unk006 

median value 2608 μM 

2000 

2200 

2400 

2600 

2800 

3000 

3200 

3400 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C16:0 in SRM 1950 

Certified value (2364 ± 77) μM 

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200 

250 

300 

350 

400 

450 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C16:1n7 in Unk 004 

median value 297 μM 

100 

150 

200 

250 

300 

350 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C16:1n7 in Unk005 

median value 187 μM 

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150 

170 

190 

210 

230 

250 

270 

290 

310 

330 

350 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C16:1n7 in Unk006 

median value 202 μM 

150 

200 

250 

300 

350 

400 

450 

500 

550 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C16:1n7 in SRM 1950 

Certified value (215 ± 26) μM 

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500 

600 

700 

800 

900 

1000 

1100 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:0 in Unk 004 

median value 716 μM 

500 

550 

600 

650 

700 

750 

800 

850 

900 

950 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:0 in Unk005 

median value 701 μM 

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550 

600 

650 

700 

750 

800 

850 

900 

950 

1000 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:0 in Unk006 

median value 713 μM 

500 

550 

600 

650 

700 

750 

800 

850 

900 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:0 in SRM 1950 

Certified value (644 ± 41) μM 

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100 

150 

200 

250 

300 

350 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:1n7 in Unk 004 

median value 177 μM 

50 

70 

90 

110 

130 

150 

170 

190 

210 

230 

250 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:1n7 in Unk005 

median value 131 μM 

58
 

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100 

120 

140 

160 

180 

200 

220 

240 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:1n7 in Unk006 

median value 137 μM 

100 

150 

200 

250 

300 

350 

400 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:1n7 in SRM 1950 

Reference value (136 ± 3) μM 

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1200 

1700 

2200 

2700 

3200 

3700 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:1n9 in Unk 004 

median value 2306 μM 

1200 

1400 

1600 

1800 

2000 

2200 

2400 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:1n9 in Unk005 

median value 1896 μM 

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1000 

1200 

1400 

1600 

1800 

2000 

2200 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:1n9 in Unk006 

median value 1901 μM 

100 

600 

1100 

1600 

2100 

2600 

3100 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:1n9 in SRM 1950 

Certified value (1614 ± 154) μM 

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2700 

2900 

3100 

3300 

3500 

3700 

3900 

4100 

4300 

4500 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:2n6 in Unk 004 

median value 3531 μM 

2500 

2700 

2900 

3100 

3300 

3500 

3700 

3900 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:2n6 in Unk005 

median value 3300 μM 

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2500 

2700 

2900 

3100 

3300 

3500 

3700 

3900 

4100 

4300 

4500 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:2n6 in Unk006 

median value 3539 μM 

2100 

2600 

3100 

3600 

4100 

4600 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:2n6 in SRM 1950 

Certified value (2838 ± 143 ) μM 

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40 

60 

80 

100 

120 

140 

160 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:3n3 in Unk 004 

median value 85.6 μM 

40 

50 

60 

70 

80 

90 

100 

110 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:3n3 in Unk005 

median value 73.3 μM 

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40 

50 

60 

70 

80 

90 

100 

110 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:3n3 in Unk006 

median value 72.3 μM 

40 

45 

50 

55 

60 

65 

70 

75 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:3n3 in SRM 1950 

Certified value (54.6 ± 3.6) μM 

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40 

45 

50 

55 

60 

65 

70 

75 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:3n6 in Unk 004 

median value 55.7 μM 

40 

45 

50 

55 

60 

65 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:3n6 in Unk005 

median value 50.9 μM 

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40 

45 

50 

55 

60 

65 

70 

75 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:3n6 in Unk006 

median value 48.8 μM 

25 

30 

35 

40 

45 

50 

55 

60 

65 

70 

75 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C18:3n6 in SRM 1950 

Reference value (39.9 ± 8.5) μM 

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10 

15 

20 

25 

30 

35 

40 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:0 in Unk 004 

median value 20.3 μM 

10 

15 

20 

25 

30 

35 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:0 in Unk005 

median value 20.2 μM 

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10 

15 

20 

25 

30 

35 

40 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:0 in Unk006 

median value 22.2 μM 

10 

12 

14 

16 

18 

20 

22 

24 

26 

28 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:0 in SRM 1950 

Reference value (18.0 ± 0.5) μM 

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0 

5 

10 

15 

20 

25 

30 

35 

40 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:1n9 in Unk 004 

median value 17.3 μM 

0 

5 

10 

15 

20 

25 

30 

35 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:1n9 in Unk005 

median value 15.3 μM 

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0 

5 

10 

15 

20 

25 

30 

35 

40 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:1n9 in Unk006 

median value 13.5 μM 

0 

5 

10 

15 

20 

25 

30 

35 

40 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:1n9 in SRM 1950 

Reference value (11.5 ± 0.5) μM 

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10 

12 

14 

16 

18 

20 

22 

24 

26 

28 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:2n6 in Unk 004 

median value 24.3 μM 

15 

17 

19 

21 

23 

25 

27 

29 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:2n6 in Unk005 

median value 22.5 μM 

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15 

17 

19 

21 

23 

25 

27 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:2n6 in Unk006 

median value 20.1 μM 

10 

12 

14 

16 

18 

20 

22 

24 

26 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:2n6 in SRM 1950 

Reference value (18.8 ± 0.6) μM 

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90 

110 

130 

150 

170 

190 

210 

230 

250 

270 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:3n6 in Unk 004 

median value 164 μM 

65 

85 

105 

125 

145 

165 

185 

205 

225 

245 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:3n6 in Unk005 

median value 161 μM 

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70 

90 

110 

130 

150 

170 

190 

210 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:3n6 in Unk006 

median value 135 μM 

90 

100 

110 

120 

130 

140 

150 

160 

170 

180 

190 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:3n6 in SRM 1950 

Reference value (139 ± 4) μM 

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400 

900 

1400 

1900 

2400 

2900 

3400 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:4n6 in Unk 004 

median value 722 μM 

450 

950 

1450 

1950 

2450 

2950 

3450 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:4n6 in Unk005 

median value 775 μM 

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350 

550 

750 

950 

1150 

1350 

1550 

1750 

1950 

2150 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:4n6 in Unk006 

median value 646 μM 

450 

550 

650 

750 

850 

950 

1050 

1150 

1250 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:4n6 in SRM 1950 

Reference value (984 ± 180) μM 

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20 

40 

60 

80 

100 

120 

140 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:5n3 in Unk 004 

median value 59.8 μM 

40 

60 

80 

100 

120 

140 

160 

180 

200 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:5n3 in Unk005 

median value 80.4 μM 

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50 

70 

90 

110 

130 

150 

170 

190 

210 

230 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:5n3 in Unk006 

median value 125 μM 

20 

30 

40 

50 

60 

70 

80 

90 

100 

110 

120 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C20:5n3 in SRM 1950 

Reference value (38.6 ± 0.5) μM 

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0 

10 

20 

30 

40 

50 

60 

70 

80 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:0 in Unk 004 

median value 53.7 μM 

0 

10 

20 

30 

40 

50 

60 

70 

80 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:0 in Unk005 

median value 56.9 μM 

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0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:0 in Unk006 

median value 56.5 μM 

0 

10 

20 

30 

40 

50 

60 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:0 in SRM 1950 

Certified value (47.8 ± 4.6) μM 

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0 

5 

10 

15 

20 

25 

30 

35 

40 

45 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:1n9 in Unk 004 

median value 10.3 μM 

0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:1n9 in Unk005 

median value 6.48 μM 

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0 

10 

20 

30 

40 

50 

60 

70 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:1n9 in Unk006 

median value 6.95 μM 

0 

10 

20 

30 

40 

50 

60 

70 

80 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:1n9 in SRM 1950 

Reference value (3.4 ± 1.3) μM 

83
 

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15 

20 

25 

30 

35 

40 

45 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:4n6 in Unk 004 

median value 25.8 μM 

10 

15 

20 

25 

30 

35 

40 

45 

50 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:4n6 in Unk005 

median value 21.1 μM 

84
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
 

10 

15 

20 

25 

30 

35 

40 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:4n6 in Unk006 

median value 18.5 μM 

20 

30 

40 

50 

60 

70 

80 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:4n6 in SRM 1950 

Reference value (25.5 ± 0.6) μM 

85
 

______________________________________________________________________________________________________ 

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10 

20 

30 

40 

50 

60 

70 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:5n3 in Unk 004 

median value 48.7 μM 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:5n3 in Unk005 

median value 50.3 μM 

86
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
 

10 

20 

30 

40 

50 

60 

70 

80 

90 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:5n3 in Unk006 

median value 46.0 μM 

10 

20 

30 

40 

50 

60 

70 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:5n3 in SRM 1950 

Reference value (38.5 ± 0.7) μM 

87
 

______________________________________________________________________________________________________ 

This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
10 

15 

20 

25 

30 

35 

40 

45 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:5n6 in Unk 004 

median value 21.3 μM 

10 

15 

20 

25 

30 

35 

40 

45 

50 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:5n6 in Unk005 

median value 15.8 μM 

88
 

______________________________________________________________________________________________________ 

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5 

10 

15 

20 

25 

30 

35 

40 

45 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:5n6 in Unk006 

median value 12.4 μM 

10 

15 

20 

25 

30 

35 

40 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:5n6 in SRM 1950 

Reference value (19.5 ± 0.4) μM 

89
 

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50 

70 

90 

110 

130 

150 

170 

190 

210 

230 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:6n3 in Unk 004 

median value 139 μM 

60 

80 

100 

120 

140 

160 

180 

200 

220 

240 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:6n3 in Unk005 

median value 166 μM 

90
 

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75 

95 

115 

135 

155 

175 

195 

215 

235 

255 

275 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:6n3 in Unk006 

median value 176 μM 

80 

90 

100 

110 

120 

130 

140 

150 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C22:6n3 in SRM 1950 

Reference value (118 ± 21) μM 

91
 

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0 

10 

20 

30 

40 

50 

60 

70 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C24:0 in Unk 004 

median value 46.0 μM 

0 

10 

20 

30 

40 

50 

60 

70 

80 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C24:0 in Unk005 

median value 52.7 μM 

92
 

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0 

10 

20 

30 

40 

50 

60 

70 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C24:0 in Unk006 

median value 50.2 μM 

0 

10 

20 

30 

40 

50 

60 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C24:0 in SRM 1950 

Reference value (46.6 ± 2.6) μM 

93
 

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10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C24:1n9 in Unk 004 

median value 64.3 μM 

10 

20 

30 

40 

50 

60 

70 

80 

90 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C24:1n9 in Unk005 

median value 61.3 μM 

94
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C24:1n9 in Unk006 

median value 77.5 μM 

10 

20 

30 

40 

50 

60 

70 

80 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C24:1n9 in SRM 1950 

Reference value (71.3 ± 3.2) μM 

95
 

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20 

22 

24 

26 

28 

30 

32 

34 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C15:0 in Unk 004 

median value 26.5 μM 

20 

25 

30 

35 

40 

45 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C15:0 in Unk005 

median value 26.6 μM 

96
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
10 

15 

20 

25 

30 

35 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C15:0 in Unk006 

median value 22.3 μM 

0 

5 

10 

15 

20 

25 

30 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C15:0 in SRM 1950 

Reference value (4.56 ± 0.04) μM 

97
 

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20 

30 

40 

50 

60 

70 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C17:0 in Unk 004 

median value 28.6 μM 

20 

30 

40 

50 

60 

70 

80 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C17:0 in Unk005 

median value 28.7 μM 

98
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
20 

25 

30 

35 

40 

45 

50 

55 

60 

65 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C17:0 in Unk006 

median value 26.3 μM 

10 

15 

20 

25 

30 

35 

40 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

μM 

Lab 

C17:0 in SRM 1950 

Reference value (17.6 ± 0.7) μM 

99
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
 

Appendix C. 

Participants in the third interlaboratory analytical comparison study of total fatty 

acid concentrations in human serum (alphabetical order unrelated to the laboratory 

numbering in this report) 

Bumrungrad Hospital Public Company Limited 

Bangkok 10110 

THAILAND 

Sukon Chalachiva 

Centers for Disease Control and Prevention 

Clinical Chemistry Branch 

Atlanta, GA 30341 

Heather Kuiper 

Centers for Disease Control and Prevention 

Nutritional Biomarkers Branch 

Atlanta, GA 30341 

Carissa Powers and Rosemary Schleicher 

Harvard Chan School of Public Health 

Boston, MA 

Jeremy Furtado and Matthew Lopes 

Matar Pathology 

Clinical Chemistry 

South Brisbane, Queensland 4101 

AUSTRALIA 

Matthew Reimer 

Mayo Clinic 

Biochemical Genetics Laboratory 

Rochester, MN 55905 

Angela Tauscher 

Minnesota Deptartment of Health 

Public Health Laboratory 

Saint Paul, MN 55155 

Shane Olund 

100
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146
National Institute of Standards and Technology 

Chemical Sciences Division 

Gaithersburg, MD 20899 

Michele Schantz 

UCLA 

Center for Human Nutrition 

Los Angeles, CA 90095 

Susanne Henning 

University of Michigan 

Cancer Center 

Ann Arbor, MI 48109 

Jianwei Ren and Zora Djuric 

University of Utah 

Moran Eye Center 

Salt Lake City, UT 84106 

Aruna Gorusupudi and Paul S. Bernstein 

University of Waterloo 

Department of Kinesiology 

Waterloo, Ontario N2L 5W7 

CANADA 

Ken Stark 

USDA-ARS 

Western Human Nutrition Center 

Davis, CA 95616 

William Keyes and John Newman 

101
 

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This publication is available free of charge from: http://dx.doi.org/10.6028/NIST.IR.8146