NISTIR 7880-13 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2006 

Comparability Studies 

Results for Round Robin LIX 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 24 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

 

 

 

 

 

 

 

 

NISTIR 7880-13
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2006 

Comparability Studies 

Results for Round Robin LIX 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 24 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

Chemical Sciences Division 

Materials Measurement Laboratory 

-XQH 2013 

U.S. Department of Commerce 

&DPHURQ).HUU\, Acting Secretary

 National Institute of Standards and Technology 

Patrick D. Gallagher, Under Secretary of Commerce for Standards and Technology and Director 
(This page intentionally blank) 

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Abstract 

The National Institute of Standards and Technology coordinates the Micronutrients Measurement 

Quality Assurance Program (MMQAP) for laboratories that measure fat- and water-soluble vitamins 

and carotenoids in human serum and plasma. This report describes the design of and results for the 

Winter 2006 MMQAP measurement comparability improvement studies: 1) Round Robin LIX FatSoluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 24 Total Ascorbic Acid in 

Human Serum. The materials for both studies were shipped to participants in November 2005; 

participants were requested to provide their measurement results by March 3, 2006. 

Keywords 

Human Serum
	

Retinol, α-Tocopherol, γ-Tocopherol, Total and Trans-β-Carotene
	

Total Ascorbic Acid
	

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Table of Contents 

Abstract............................................................................................................................................... iii
	

Keywords ............................................................................................................................................ iii
	

Table of Contents ............................................................................................................................... iv
	

Introduction......................................................................................................................................... 1
	

Round Robin LIX: Fat-Soluble Vitamins and Carotenoids in Human Serum ............................ 1
	

Round Robin 24: Vitamin C in Human Serum............................................................................... 2
	

References ............................................................................................................................................ 3
	

Appendix A. Shipping Package Inserts for RR59........................................................................ A1
	

Appendix B. Final Report for RR59 .............................................................................................. B1 

Appendix C. “All-Lab Report” for RR59 ...................................................................................... C1
	

Appendix D. Representative “Individualized Report” for RR59 ............................................... D1
	

Appendix E. Shipping Package Inserts for RR24 ......................................................................... E1
	

Appendix F. Final Report for RR24............................................................................................... F1
	

Appendix G. “All-Lab Report” for RR24..................................................................................... G1
	

Appendix H. Representative “Individualized Report” for RR24............................................... H1
	

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Introduction 

Beginning in 1988, the National Institute of Standards and Technology (NIST) has coordinated the 

Micronutrients Measurement Quality Assurance Program (MMQAP) for laboratories that measure 

fat- and water-soluble vitamins and carotenoids in human serum and plasma. The MMQAP 

provides participants with measurement comparability assessment through use of interlaboratory 

studies, Standard Reference Materials (SRMs) and control materials, and methods development and 

validation. Serum-based samples with assigned values for the target analytes (retinol, alphatocopherol, gamma/beta-tocopherol, trans- and total beta-carotene, and total ascorbic acid) and 

performance-evaluation standards are distributed by NIST to laboratories for analysis. 

Participants use the methodology of their choice to determine analyte content in the control and 

study materials. Participants provide their data to NIST, where it is compiled and evaluated for 

trueness relative to the NIST value, within-laboratory precision, and concordance within the 

participant community. NIST provides the participants with a technical summary report concerning 

their performance for each exercise and suggestions for methods development and refinement. 

Participants who have concerns regarding their laboratory’s performance are encouraged to consult 

with the MMQAP coordinators. 

All MMQAP interlaboratory studies consist of individual units of batch-prepared samples that are 

distributed to each participant. For historical reasons these studies are referred to as “Round 

Robins”. The MMQAP program and the nature of its studies are described elsewhere. [1,2] 

Round Robin LIX: Fat-Soluble Vitamins and Carotenoids in Human Serum 

Participants in the MMQAP Fat-Soluble Vitamins and Carotenoids in Human Serum Round Robin 

LIX comparability study (hereafter referred to as RR59) received four lyophilized and one liquidfrozen human serum test samples for analysis. Unless multiple vials were previously requested, 

participants received one vial of each serum. These sera were shipped on dry ice to participants in 

November 2005. The communication materials included in the sample shipment are provided in 

Appendix A. 

Participants are requested to report values for all fat-soluble vitamin-related analytes that are of 

interest to their organizations. Not all participants report values for the target analytes, and many 

participants report values for non-target analytes. 

The final report delivered to every participant in RR59 consists of three documents: 

•	 A cover letter for the current study, a brief description of the other two documents, and a 

discussion of our analysis of the overall results that may be of broad interest. This cover 

letter is reproduced as Appendix B. 

•	 The “All-Lab Report” that lists all of the reported measurement results, a number of 

consensus statistics for analytes reported by more than one participant, and the mean median 

and pooled SD from any prior distributions of the serum. This report also provides a 

numerical “score card” for each participant’s measurement comparability for the more 

commonly reported analytes. This report is reproduced as Appendix C. 

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•	 An “Individualized Report” that graphically analyzes each participant’s results for all 

analytes reported by at least five participants. This report also provides a graphical summary 

of their measurement comparability. The graphical tools used in this report are described in 

detail elsewhere [3]. An example “Individualized Report” is reproduced as Appendix D. 

Round Robin 24: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 24 comparability study 

(hereafter referred to as RR24) received four frozen serum test samples, two frozen control sera, and 

a solid ascorbic acid control material for analysis. Unless multiple vials were previously requested, 

participants received one vial of each material. These sample materials were shipped on dry ice to 

participants in November 2005. The communication materials included in the sample shipment are 

provided in Appendix E. 

The test and control serum materials were prepared by adding equal volumes of 10 % 

metaphosphoric acid (MPA) to human serum that had been spiked with ascorbic acid. While these 

samples contain some dehydroascorbic acid, its content is variable. Therefore, the participants 

report only total ascorbic acid (TAA, ascorbic acid plus dehydroascorbic acid). Participants are also 

encouraged to prepare calibration solutions from the supplied solid control to enable calibrating their 

serum measurements to the same reference standard. 

The final report delivered to every participant in RR24 consists of three documents: 

•	 A cover letter for the current study, a brief description of the other two documents, and a 

discussion of our analysis of overall results that may be of broad interest. This cover letter is 

reproduced as Appendix F. 

•	 The “All-Lab Report” that summarizes all of the reported measurement results and provides 

several consensus statistics. This report is reproduced as Appendix G. 

•	 An “Individualized Report” that graphically analyzes each participant’s results for TAA, 

including a graphical summary of their measurement comparability. The graphical tools 

used in this report are described in detail elsewhere [3]. An example “Individualized Report” 

is reproduced as Appendix H. 

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References 

1 Duewer DL, Brown Thomas J, Kline MC, MacCrehan WA, Schaffer R, Sharpless KE, May WE, 

Crowell JA. NIST/NCI Micronutrients Measurement Quality Assurance Program: Measurement 

Repeatabilities and Reproducibilities for Fat-Soluble Vitamin-Related Compounds in Human 

Sera. Anal Chem 1997;69(7):1406-1413. 

2 Margolis SA, Duewer DL. Measurement Of Ascorbic Acid in Human Plasma and Serum: 

Stability, Intralaboratory Repeatability, and Interlaboratory Reproducibility. Clin Chem 

1996;42(8):1257-1262. 

3 Duewer DL, Kline MC, Sharpless KE, Brown Thomas J, Gary KT, Sowell AL. Micronutrients 

Measurement Quality Assurance Program: Helping Participants Use Interlaboratory Comparison 

Exercise Results to Improve Their Long-Term Measurement Performance. Anal Chem 

1999;71(9):1870-1878. 

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Appendix A. Shipping Package Inserts for RR59 

The following three items were included in each package shipped to an RR59 participant: 

• Cover letter 

• Datasheet 

• Packing List and Shipment Receipt Confirmation Form 

The cover letter and datasheet were enclosed in a sealed waterproof bag along with the 

samples themselves. The packing list was placed at the top of the shipping box, between 

the cardboard covering and the foam insulation. 

A1
November 28, 2005 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National lnatitilte of Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed are the samples (Sera 319 - 3,23) for the first fat-soluble vitamins and carotenoids in serum 

round robin study (Round Robin LIX) for the fiscal year (FY) 06 NIST Micronutrients Measurement 

Quality Assurance Program. You will find one vial of each of one liquid-frozen and four lyophilized 

serum samples for analysis along with a form for reporting your results. When reporting your results, 

please submit one value for each analyte for a given serum sample. If a value is obtained below your 

limit of quantification, please indicate this result on the form by using NQ (Not Quantified). Results are 

due to NIST by March 3, 2006. Results received more than two weeks after the due date will not be 

included in the summary report for this round robin study. The"feedback report concerning the study will 

be provided in April. 

Lyophilized samples should be reconstituted with 1.0 mL of HPLC-grade water or equivalent. We 

recommend that dissolution be facilitated with 3 to 5 min agitation in an ultrasonic bath or at least 30 min 

at room temperature with intermittent swirling. (CAUTION: Vigorous shaking will cause foaming and 

possibly interfere with accurate measurement. The rubber stopper contains phthalate esters that may 

leach into the sample upon intermittent contact of the liquid sample witp the stopper. These esters absorb 

strongly in the UV region and elute near retinal in most LC systems creating analytical problems.) 

Pipette a known volume of serum from the vial for analysis. The final volume of the reconstituted sample 

is greater than 1.0 mL. Water should not be added to the liquid-frozen sample (Serum 323). 

For consistency, we request that laboratories use the following absorptivities (E 1 % cm): retinal, 1843 at 

325 nm (ethanol); retinyl palmitate, 975 at 325 nm (ethanol); a-tocopherol, 75.8 at 292 nm (ethanol); ytocopherol, 91.4 at 298 nm (ethanol); a-carotene, 2800 at 444 nm (hexane); ~-carotene, 2560 at 450 nm 

(et.hanol), 2592 at 452 nm (hexane); lycopene, 3450 at 472 nm (hexane). · 

Please mail or fax your results for Round Robin LIX to: 

Micronutrients Measurement Quality Assurance Program 

NIST 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 

Fax: (301) 977-0685 

If you have questions or comments regarding this study, please can ·me at (301) 975-3120; e-mail me at 

jbthomas@nist.gov; or mail/fax queries to the above address. 

EYTh~~~ Research Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

NISI 

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Participant #: ________ Date: _____________ 

Round Robin LIX: Human Sera 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 319 320 321 322 323 Units* 

total retinol 

trans-retinol 

didehydroretinol 

retinyl palmitate 

α-tocopherol 

γ/β-tocopherol 

δ-tocopherol 

total β-carotene 

trans-β-carotene 

total cis-β-carotene 

total α-carotene 

total lycopene 

trans-lycopene 

total β-cryptoxanthin 

total α-cryptoxanthin 

total lutein 

total zeaxanthin 

total lutein&zeaxanthin

 total coenzyme Q10 

ubiquinol (QH2) 

ubiquinone (Qox) 

phylloquinone (K1) 

25-hydroxyvitamin D 

Other measurands? 

Was the liquid frozen sample #323 frozen when received? Yes | No 

* we prefer μg/mL 

Comments: 

Mail: M2QAP 

NIST, Stop 8392 

Gaithersburg, MD 20899-8392 

Please return results before 

3-Mar-2006 

Fax: 301-977-0685 

Email: David.Duewer@NIST.gov 

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Participant #: ________ Date: _____________ 

Fat-Soluble Vitamins Round Robin LIX
 

NIST Micronutrients Measurement Quality Assurance Program
 

Packing List and Shipment Receipt Confirmation Form 

This box contains: one vial each of the following five FSV M2QAP sera 

Serum Form Reconstitute? 

#319 Lyophilized Yes (1 ml H2O) 

#320 Lyophilized Yes (1 ml H2O) 

#321 Lyophilized Yes (1 ml H2O) 

#322 Lyophilized Yes (1 ml H2O) 

#323 Liquid frozen No 

Please 1) Open the pack immediately 

2) Check that it contains all of the above samples 

3) Check if the ampoules and vials are intact 

4) Store the sera at -20  ̊C or below until analysis 

5) Complete the following information 

6) Fax the completed form to us at 301-977-0685 

(or email requested information to david.duewer@nist.gov) 

1) Date this shipment arrived: ___________________________ 

2) Are all five sera vials intact? Yes | No 

If "No", which one(s) were damaged? 

3) Was there any dry-ice left in cooler? Yes | No 

4) Did the liquid frozen sample #323 arrive frozen? Yes | No 

5) At what temperature are you storing the serum samples? _______  ̊C 

6) When do you anticipate analyzing these samples? ________________________ 

Your prompt return of this information is appreciated. 

The M2QAP Gang 

Mail: M2QAP 

NIST, Stop 8392 Fax: 301-977-0685 

Gaithersburg, MD 20899-8392 Email: David.Duewer@NIST.gov 

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Appendix B. Final Report for RR59 

The following three pages are the final report as provided to all participants: 

•	 Cover letter. 

•	 An information sheet that: 

o	 describes the contents of the “All-Lab” report, 

o	 describes the content of the “Individualized” report, 

o	 describes the nature of the test samples and details their previous distributions, 

if any, and 

o	 summarizes aspects of the study that we believe may be of interest to the 

participants. 

B1
April 10, 2006 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gait.hersburg, Maryland 2089~ 

Enclosed is the summary report of the results for round robin LIX (RR59) of the 2006 NIST 

Micronutrients Measurement Quality Assurance Program (M2

QAP) for the fat-soluble vitamins and 

carotenoids in human serum. Included in this report are: (1) a summary of data and measurement 

comparability scores for all laboratories, (2) a detailed graphical analysis of your results; and (3) a 

graphical summary of your measurement comparability relative to the NIST assigned values. The NISTassigned values are equally weighted means of the medians from this interlaboratory comparison exercise 

and the means from the analyses performed by NIST. 

Data for evaluating laboratory performance in RR59 are provided in text "Score Card" summary, page 6 

of the All Lab Report. Laboratory comparability is summarized as follows: results rated 1 to 3 are within 

1 to 3 standard deviations of the assigned value, respectively; those rated 4 are > 3 standard deviations 

from the assigned value. Similar information is presented in the graphical "target plot" summary, last 

page of your Individualized Report. 

If you have concerns regarding your laboratory's performance, we suggest that you obtain and analyze a 

unit of SRM 968c, Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum. If your 

measured values do not agree with the certified values, we suggest that you contact us for consultation. 

Samples for the second 2006 QA inter laboratory exercise will be shipped starting the week of May 8, 

2006. We will send you a reminder via e-mail or fax a week prior to shipment. It is critical that you 

carefully inspect all samples upon arrival and that you promptly confirm to us that they have arrived. We 

will replace samples (lost or damaged in shipment or miss-packaged by us) only for participants who 

report the problem within one calendar week after the package arrives. 

If you have any questions regarding this report, please contact Dave Duewer at david.duewer@nist.gov 

or me atjbthomas@nist.gov, tel: 301/975-3120, or fax: 301/977-0685. 

Sincerely, 

a ice Brown Thomas 

Research Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Cc: L.C. Sander 

D.L. Duewer 

Enclosures 

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The NIST M2QAP Round Robin LVII (RR59) report consists of: 

Page “All Lab” Report 

1-4 A listing of all results and statistics for analytes reported by at least two laboratories. 

5a A list of results for the analytes reported by only one laboratory. 

5b A legend for the above two lists. 

6 The text Comparability Summary (“Score Card”) of measurement performance. 

Page “Individualized” Report 

1 Your values, the number of labs reporting values, and our assigned values. 

2 to “Four Plot” summaries of your current and past measurement performance, one page for 

n each analyte you report that is also reported by at least 8 other participants. 

n+1 The graphical Comparability Summary (target plot) of measurement performance. 

Samples. The five sera below were distributed in RR59. 

Serum Description Prior Distributions 

319 Lyophilized, native, single-donor, commercially #184:RR28-6/93 

obtained serum. 

320 Lyophilized blend of the #311 augmented serum and #197:RR31-6/94, #211:RR35-9/95; 

stripped serum, in 1+3 ratio (i.e., measurand levels #245:RR43-6/98; #310:RR57-3/05 

should be 1⁄4 those of #321). 

321 Lyophilized blended serum with native carotenoid #198:RR31-6/94, #212:RR35-9/95; 

levels, augmented with retinol, retinyl palmitate, and #246:RR43-6/98; #311:RR57-3/05 

α- and γ-tocopherol. 

322 Lyophilized, native, single-donor, commercially #290:RR53-2/03, #300:RR55-3/04;
	

obtained serum prepared in 2002. The same #312:RR57-3/05 

material was used to prepare #323.
	

323 Fresh-frozen, native, single-donor, commercially #292:RR53-2/03, #301:RR55-3/04;
	

obtained serum prepared in 2002. The same #313:RR57-3/05 

material was used to prepare #322.
	

Results 

1)		 Sera Stability. There was no significant change in the median level for any measurand in any of the 

sera. The measurement variability for some of the very low-level measurands in #320 was 

marginally higher than expected. Note that #319, 320, and 321 were prepared more than 10 years 

ago. 

2)		 Follow-up on Retinyl Palmitate Issue from RR 57: Sera #320 and #321 provide the fifth set of paired 

data for an experiment begun in April, 1994. The material analyzed as serum #320 was prepared 

from a single-source pool spiked with retinol, α-tocopherol, and retinyl palmitate. The material 

analyzed as serum #321 was prepared as a 1:3 blend of the spiked pool and a stripped serum. These 

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materials were also analyzed in last year’s RR57 as sera #310 and #311. At that time, we’d noted 

that the there was considerably less retinyl palmitate in the low-level material than expected and 

speculated on the cause. We are in the process of re-examining all of the available data for these 

materials, and have at least a tentative answer: retinyl palmitate was lost when the blended material 

was filtered. 

The following Figure shows the trends with time for total retinol and retinyl palmitate. The trend for 

the spiked material is represented by the upper solid line), that for the “25%-of-spike” low level 

material is the lower solid line, and the trend of the ratio between the two is the middle solid line. 

The expected value for the ratio is 0.25 (dotted line). All of the bars represent an approximate 95% 

confidence interval on the estimated mean values. The ratios are estimated directly from the “raw” 

low-level / spiked pairs, not just from the summary statistics. 

The pattern for total retinol is about as expected, although the small apparent increase in the values 

for the spiked material is curious. However, the retinyl palmitate ratio for the low-level/spike has 

been considerably less than the expected 0.25 from the beginning. Simplest explanation for the 

difference between the patterns is that some of the hydrophobic retinyl pal imitate spike was lost to 

filtration after blending the spiked-pool and the stripped serum. The variability in the estimates is 

too great to definitively judge whether the ratio actually changed over time. 

We intend to provide a complete analysis of the results for other measurands in these materials 

within the next year. However, your values in serum #320 should be very close to 25% of those in 

#231 for total retinol, α and γ/β-tocopherol, and β-carotene; they should be at least “fairly” close for 

all of the other measurands except retinyl palmitate. 

3)		 Matrix (Lyophilized vs. Fresh-Frozen) Differences. Sera 322 and 323 were prepared from the same 

serum pool. Since we suggest that you reconstitute our lyophilized samples with 1.0 mL water rather 

than to a total volume of 1.0 mL, the measurand levels in #322 should be ≈ 95% of those in #323. 

The observed average ratio ± 95% confidence interval over all measurands with 8 or more 

quantitative measurements is 0.953 ± 0.007. If any of your #322/#323 ratios are much different than 

0.95, you should look at your measurement system for those measurands. If your lyophilized/fresh 

frozen ratios are consistently much different from 0.95, you should review how you reconstitute 

lyophilized materials. 

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Appendix C. “All-Lab Report” for RR59 

The following seven pages are the “All-Lab Report” as provided to all participants, with 

two exceptions: 

• the participant identifiers (Lab) have been altered. 

• the order in which the participant results are listed has been altered. 

The data summary in the “All-Lab Report” has been altered to ensure confidentiality of 

identification codes assigned to laboratories. The only attributed results are those 

reported by NIST. The NIST results are not used in the assessment of the consensus 

summary results of the study. 

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Round Robin LIX Laboratory Results 

All Results in μg/mL 

Total Retinol trans-Retinol Retinyl Palmitate α-Tocopherol 

Lab 319 320 321 322 323 

C2

FSV-BA 0.375 0.230 0.878 0.670 0.705 

FSV-BB 0.383 0.193 0.788 0.630 0.643 

FSV-BC 0.371 0.211 0.834 0.637 0.680 

FSV-BD 0.409 0.202 0.824 0.691 0.688 

FSV-BE 0.354 0.180 0.768 0.602 0.648 

FSV-BF 0.340 0.170 0.760 0.590 0.630 

FSV-BG 0.378 0.210 0.820 0.646 0.676 

FSV-BH 0.354 0.124 0.728 0.622 0.638 

FSV-BI 0.321 0.168 0.680 0.524 0.567 

FSV-BJ 0.349 0.200 0.760 0.585 0.612 

FSV-BK 0.400 0.140 0.843 0.725 0.764 

FSV-BL 0.370 0.170 0.740 0.600 0.630 

FSV-BM 0.327 0.169 0.715 0.542 0.574 

FSV-BN 0.381 0.207 0.814 0.652 0.678 

FSV-BO 0.362 0.248 0.683 0.614 0.701 

FSV-BP 0.311 0.196 0.599 0.506 0.523 

FSV-BQ 0.372 0.195 0.797 0.635 0.670 

FSV-BR ≥0.395 ≥0.194 ≥0.813 ≥0.697 ≥0.689

FSV-BS ≥0.533 ≥0.226 ≥1.272 ≥0.951 ≥1.001

FSV-BT 0.320 0.332 0.655 0.569 0.717 

FSV-BU 0.353 0.145 0.733 0.570 0.611 

FSV-BV 0.380 0.073 0.511 0.735 0.765 

FSV-BW 0.380 0.190 0.810 0.640 0.670 

FSV-CC 0.370 0.190 0.810 0.620 0.650 

FSV-CE 0.370 0.182 0.745 0.809 0.656 

FSV-CF 0.340 0.211 0.775 0.586 0.579 

FSV-CG 0.364 0.185 0.753 0.605 0.631 

FSV-CI 0.372 0.194 0.748 0.613 0.642 

FSV-CP 

FSV-CS 0.371 0.208 0.842 0.596 0.667 

FSV-CT 

FSV-CW 0.388 0.253 0.841 0.552 0.581 

FSV-CZ 0.380 0.210 0.810 0.610 0.650 

FSV-DB 0.335 0.199 0.743 0.572 0.587 

FSV-DF 0.354 0.158 0.797 !0.746 0.623 

FSV-DI 0.390 0.205 0.870 0.672 0.686 

FSV-DQ 

FSV-DV 0.296 0.169 0.624 0.499 0.523 

319 320 321 322 323 

0.395 0.194 0.813 0.697 0.689 

0.533 0.226 1.272 0.951 1.001 

0.370 0.190 0.810 0.620 0.650 

319 320 321 322 323 

0.079 0.013 0.238 0.107 0.114 

0.087 0.013 0.228 0.071 0.078 

0.137 0.027 0.301 0.104 0.109 

0.122 0.055 0.266 0.089 0.094 

0.199 0.051 0.300 0.095 0.095 

0.101 0.044 0.236 0.089 0.091 

0.077 0.034 0.260 0.084 0.089 

0.107 0.042 0.257 0.089 0.099 

0.171 0.074 0.354 0.081 0.082 

0.105 0.035 0.254 0.073 0.075 

319 320 321 322 323 

4.35 1.80 15.14 9.92 10.46 

4.38 1.70 14.81 9.67 10.43 

5.80 3.90 15.80 11.90 11.90 

4.32 3.27 14.03 9.74 10.44 

3.20 3.00 15.60 9.90 10.50 

4.29 3.57 15.32 10.57 10.85 

4.50 3.41 13.04 9.99 10.69 

4.28 3.36 14.42 9.44 10.25 

4.38 4.97 14.35 9.74 10.20 

3.79 2.52 13.45 12.04 9.98 

4.30 3.40 13.40 9.90 9.90 

4.30 3.30 14.50 9.60 11.10 

4.17 3.33 12.81 9.38 9.35 

4.43 3.71 9.84 9.75 10.89 

3.84 2.99 12.93 11.05 10.35 

4.17 4.70 14.50 9.67 9.70 

3.91 3.64 12.60 8.90 9.02 

2.83 2.82 1.55 6.98 6.24 

5.34 4.63 12.89 9.20 9.82 

4.41 2.77 15.21 9.59 11.01 

4.91 5.00 15.64 10.62 11.20 

4.23 3.10 13.30 9.40 9.97 

3.91 2.99 12.92 8.80 9.21 

4.76 3.00 16.60 !6.66 10.20 

4.50 3.90 15.10 9.80 10.10 

3.87 2.12 13.06 8.92 9.38 

4.43 4.72 14.79 9.89 10.71 

5.02 5.16 16.24 11.21 11.67 

5.47 5.25 15.97 11.67 11.65 

2.60 1.43 15.50 9.13 10.00 

5.00 4.30 14.60 10.40 10.90 

4.43 4.75 13.10 9.70 10.20 

4.25 4.30 14.65 10.01 10.40 

4.67 3.14 14.66 10.42 11.04 

4.50 3.30 14.20 9.80 10.40 

N 33 33 33 32 33 3 3 3 3 3 10 10 10 10 10 35 35 35 34 35 

Min 0.296 0.073 0.511 0.499 0.523 0.370 0.190 0.810 0.620 0.650 0.077 0.013 0.228 0.071 0.075 2.60 1.43 1.55 6.98 6.24 

Median 0.370 0.194 0.768 0.612 0.648 0.395 0.194 0.813 0.697 0.689 0.106 0.039 0.259 0.089 0.093 4.35 3.36 14.50 9.78 10.40 

Max 0.409 0.332 0.878 0.809 0.765 0.533 0.226 1.272 0.951 1.001 0.199 0.074 0.354 0.107 0.114 5.80 5.25 16.60 12.04 11.90 

SD 0.023 0.029 0.060 0.044 0.049 0.032 0.015 0.037 0.008 0.010 0.25 0.97 1.55 0.61 0.66 

CV 6 15 8 7 8 30 40 14 10 11 6 29 11 6 6 

Npast 44 41 42 34 34 0 5 5 6 6 8 10 11 12 12 44 42 42 37 37 

Medianpast 0.360 0.193 0.735 0.603 0.639 0.190 0.750 0.603 0.643 0.142 0.051 0.274 0.094 0.101 4.32 3.57 14.22 9.90 10.39 

SDpast 0.034 0.019 0.063 0.043 0.044 0.000 0.000 0.020 0.020 0.025 0.013 0.051 0.022 0.023 0.30 0.53 1.15 0.70 0.66 

NIST 0.383 0.177 0.724 0.632 0.658 4.20 3.24 14.17 10.08 9.98 

Srep 0.002 0.006 0.016 0.014 0.005 0.07 0.14 0.50 0.33 0.17 

Shet 0.003 0.001 0.015 0.004 0.009 0.07 0.13 0.06 0.21 0.11 

SNIST 0.004 0.006 0.022 0.014 0.010 0.10 0.19 0.50 0.39 0.20 

NAV 0.376 0.185 0.744 0.622 0.653 0.395 0.194 0.813 0.697 0.689 0.106 0.039 0.259 0.089 0.093 4.28 3.30 14.34 9.93 10.19 

NAU 0.032 0.031 0.069 0.051 0.052 0.032 0.015 0.059 0.024 0.025 0.46 0.97 1.57 0.80 0.86 

All Lab Report 
 

 

Round Robin LIX Laboratory Results 

All Results in μg/mL 

δ-Tocopherol Total β-Carotene trans-β-Carotene Total cis-β-Carotene 

Lab 319 320 321 322 323 

C3

FSV-BA 0.040 0.029 0.150 0.051 0.058 

FSV-BB 0.052 0.020 0.123 0.039 0.042 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BH 0.046 0.040 0.161 0.059 0.054 

FSV-BI 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.072 0.048 0.198 0.084 0.077 

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG nd nd 0.212 nd nd 

FSV-CI 

FSV-CP 

FSV-CS 

FSV-CT 

FSV-CW 0.029 0.004 0.150 0.014 0.020 

FSV-CZ 

FSV-DB nq nq 0.176 0.272 0.103 

FSV-DF 

FSV-DI 0.055 0.035 0.144 0.048 0.050 

FSV-DQ 

FSV-DV 

319 320 321 322 323 

0.354 0.103 0.750 0.137 0.140 

0.321 0.075 0.669 0.113 0.122 

0.326 0.133 0.752 0.121 0.133 

0.324 0.250 0.778 0.073 0.082 

0.369 0.135 0.803 0.154 0.156 

0.280 0.123 0.599 0.101 0.106 

0.272 0.140 0.590 0.095 0.103 

0.326 0.115 0.719 0.111 0.122 

0.296 0.147 0.611 0.108 0.113 

0.529 0.161 0.597 0.115 0.121 

0.316 0.148 1.508 0.122 0.095 

0.444 0.250 1.200 0.174 0.183 

0.325 0.128 0.625 0.119 0.123 

0.299 0.171 0.582 0.121 0.145 

0.367 0.175 0.775 0.129 0.130 

0.371 0.152 0.790 0.120 0.130 

0.304 0.067 0.768 !0.057 0.112 

0.288 0.132 0.596 0.105 0.111 

≥0.272 ≥0.079 ≥0.624 ≥0.093 ≥0.102

0.358 0.169 0.670 0.145 0.144 

0.424 0.234 0.844 0.148 0.149 

0.353 0.155 0.830 0.135 0.134 

≥0.380 ≥0.182 ≥0.804 ≥0.107 ≥0.115

0.280 0.163 0.534 0.186 0.199 

0.270 0.114 0.534 0.098 0.119 

0.300 0.091 0.663 0.125 0.122 

0.290 0.104 0.651 0.133 0.145 

319 320 321 322 323 

0.332 0.097 0.697 0.130 0.134 

0.299 0.069 0.617 0.108 0.116 

0.280 0.123 0.556 0.101 0.106 

0.269 0.127 0.553 0.102 0.106 

0.294 0.113 0.556 0.107 0.111 

0.268 0.119 0.552 0.100 0.107 

0.272 0.079 0.624 0.093 0.102 

0.380 0.182 0.804 0.107 0.115 

319 320 321 322 323 

0.022 0.006 0.053 0.007 0.005 

0.022 0.006 0.051 0.005 0.006 

nq nq 0.043 nq nq 

0.032 0.025 0.063 0.011 0.013 

0.025 0.014 0.061 0.011 0.010 

0.019 0.013 0.043 0.005 0.005 

N 6 6 8 7 7 25 25 25 24 25 8 8 8 8 8 5 5 6 5 5 

Min 0.029 0.004 0.123 0.014 0.020 0.270 0.067 0.534 0.073 0.082 0.268 0.069 0.552 0.093 0.102 0.019 0.006 0.043 0.005 0.005 

Median 0.049 0.032 0.156 0.051 0.054 0.324 0.140 0.670 0.121 0.123 0.287 0.116 0.587 0.105 0.109 0.022 0.013 0.052 0.007 0.006 

Max 0.072 0.048 0.212 0.272 0.103 0.529 0.250 1.508 0.186 0.199 0.380 0.182 0.804 0.130 0.134 0.032 0.025 0.063 0.011 0.013 

SD 0.009 0.012 0.025 0.021 0.016 0.046 0.036 0.133 0.019 0.023 0.027 0.023 0.065 0.005 0.007 0.002 0.006 0.010 0.004 0.004 

CV 19 38 16 41 30 14 25 20 15 19 9 20 11 5 6 10 46 20 64 62 

Npast 0 10 12 5 6 32 30 30 26 26 5 10 10 12 12 5 7 7 6 6 

Medianpast 0.036 0.140 0.072 0.066 0.353 0.150 0.681 0.111 0.120 0.326 0.148 0.635 0.110 0.118 0.019 0.015 0.052 0.006 0.007 

SDpast 0.013 0.021 0.024 0.026 0.047 0.029 0.086 0.015 0.015 0.029 0.019 0.048 0.010 0.011 0.010 0.008 0.017 0.002 0.002 

NIST 0.329 0.173 0.755 0.125 0.128
 

Srep 0.008 0.002 0.014 0.002 0.001
 

Shet 0.002 0.000 0.012 0.001 0.000
 

SNIST 0.008 0.002 0.018 0.002 0.001
 

NAV 0.049 0.032 0.156 0.051 0.054 0.326 0.156 0.713 0.123 0.125 0.287 0.116 0.587 0.105 0.109 0.022 0.013 0.052 0.007 0.006 

NAU 0.017 0.016 0.031 0.021 0.018 0.047 0.042 0.146 0.020 0.024 0.031 0.023 0.065 0.013 0.014 0.008 0.006 0.021 0.004 0.004 

All Lab Report 
 

 

Round Robin LIX Laboratory Results 

All Results in μg/mL 

Total Lycopene trans-Lycopene Total β-Cryptoxanthin Total α-Cryp

Lab 319 320 321 322 323 

C4

FSV-BA 0.200 0.023 0.165 0.518 0.549 

FSV-BB 0.178 0.027 0.137 0.429 0.453 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 0.139 0.035 0.144 0.499 0.526 

FSV-BG 0.214 0.043 0.202 0.542 0.550 

FSV-BH 0.202 0.035 0.151 0.532 0.555 

FSV-BI 0.157 0.027 0.125 0.375 0.397 

FSV-BJ 0.194 0.024 0.156 0.552 0.580 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.173 0.037 0.143 0.421 0.442 

FSV-BO 0.183 nq 0.163 0.467 0.509 

FSV-BP 0.161 nq 0.398 0.500 0.427 

FSV-BQ 

FSV-BR 

FSV-BS 0.142 0.031 0.170 0.511 0.527 

FSV-BT 0.201 0.030 0.164 0.474 0.487 

FSV-BU 0.198 0.067 0.169 0.434 0.541 

FSV-BV 0.211 0.035 0.162 0.550 0.552 

FSV-BW 0.190 0.015 0.153 0.520 0.580 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 0.190 0.029 0.152 0.469 0.507 

FSV-CI 

FSV-CP 0.175 0.033 0.128 0.477 0.483 

FSV-CS 0.282 0.060 0.249 0.705 0.718 

FSV-CT 0.201 nq 0.146 0.494 0.501 

FSV-CW 

FSV-CZ 

FSV-DB 0.183 nq 0.134 0.441 0.517 

FSV-DF 

FSV-DI 0.163 0.030 0.120 0.466 0.468 

FSV-DQ 0.159 0.022 0.117 0.405 0.465 

FSV-DV 

319 320 321 322 323 

0.115 0.010 0.073 0.297 0.318 

0.082 0.010 0.051 0.210 0.226 

0.106 0.014 0.077 0.281 0.287 

0.093 0.021 0.065 0.230 0.239 

0.087 0.012 0.060 0.201 0.206 

0.110 0.012 0.073 0.286 0.313 

0.094 0.022 0.067 0.208 0.221 

319 320 321 322 323 

0.069 0.002 0.026 0.072 0.074 

0.050 nd 0.019 0.051 0.054 

0.045 0.009 0.015 0.046 0.047 

0.056 0.006 0.024 0.064 0.075 

0.058 nq nq 0.061 0.064 

0.054 0.004 0.018 0.048 0.051 

0.049 nq 0.015 0.049 0.053 

0.054 0.009 0.020 0.056 0.059 

0.021 nq nq 0.018 0.018 

0.135 nq 0.098 0.102 0.092 

0.053 0.007 0.021 0.048 0.051 

0.058 nd 0.027 0.054 0.055 

0.052 0.003 0.015 0.051 0.051 

0.063 nq 0.015 0.060 0.063 

0.071 0.005 0.027 0.075 0.081 

0.077 0.005 0.025 0.079 0.082 

0.054 0.007 0.023 0.055 0.057 

0.049 nq 0.020 0.057 0.057 

0.056 <0.005 0.023 0.057 0.057 

0.049 nq 0.014 0.047 0.055 

0.043 0.006 0.017 0.063 0.062 

319 320 321 

0.032 nd 0.01

0.021 nd 0.00

0.028 nd 0.01

0.019 0.003 0.01

N 22 18 22 22 22 7 7 7 7 7 21 11 19 21 21 4 1 

Min 0.139 0.015 0.117 0.375 0.397 0.082 0.010 0.051 0.201 0.206 0.021 0.002 0.014 0.018 0.018 0.019 0.00

Median 0.187 0.031 0.153 0.485 0.513 0.094 0.012 0.067 0.230 0.239 0.054 0.006 0.020 0.056 0.057 0.025 0.003 0.01

Max 0.282 0.067 0.398 0.705 0.718 0.115 0.022 0.077 0.297 0.318 0.135 0.009 0.098 0.102 0.092 0.032 0.01

SD 0.026 0.006 0.019 0.053 0.058 0.013 0.005 0.008 0.055 0.057 0.007 0.002 0.006 0.010 0.008 0.006 0.00

CV 14 19 13 11 11 14 40 12 24 24 12 30 32 19 14 26 1

Npast 16 21 24 22 22 0 8 8 9 9 11 15 20 23 23 0 7 1

Medianpast 0.183 0.029 0.133 0.477 0.504 0.019 0.074 0.252 0.270 0.065 0.007 0.021 0.051 0.054 0.005 0.01

SDpast 0.042 0.010 0.041 0.060 0.070 0.007 0.017 0.043 0.049 0.012 0.003 0.006 0.008 0.010 0.00

NIST 0.042 nq nq 0.049 0.051
 

Srep 0.003 0.002 0.004
 

Shet 0.000 0.002 0.002
 

SNIST 0.003 0.003 0.005
 

NAV 0.187 0.031 0.153 0.485 0.513 0.094 0.012 0.067 0.230 0.239 0.048 0.006 0.020 0.053 0.054 0.025 0.01

NAU 0.046 0.011 0.039 0.101 0.106 0.016 0.006 0.012 0.055 0.057 0.016 0.002 0.006 0.014 0.014 

All Lab Report 
 

 

Round Robin LIX Laboratory Results 

All Results in μg/mL 

Total Lutein Total Zeaxanthin Total Lutein&Zeaxanthin 

Lab 319 320 321 322 323 

C5

FSV-BA
 

FSV-BB
 0.089 0.012 0.065 0.085 0.089 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 0.086 0.015 0.060 0.114 0.134 

FSV-BH 0.073 0.009 0.040 0.065 0.063 

FSV-BI 0.088 0.016 0.058 0.079 0.085 

FSV-BJ 0.063 0.014 0.046 0.075 0.082 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.084 0.030 0.063 0.079 0.082 

FSV-BO 0.096 nq 0.051 0.080 0.090 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 0.066 0.024 0.050 0.074 0.082 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 0.057 0.007 0.033 0.047 0.051 

FSV-CP 

FSV-CS 0.086 0.017 0.051 0.069 0.071 

FSV-CT 0.116 nq 0.081 0.137 0.139 

FSV-CW 0.087 0.021 0.062 0.082 0.082 

FSV-CZ 

FSV-DB 

FSV-DF 

FSV-DI 0.065 0.011 0.039 0.060 0.064 

FSV-DQ 0.070 nd 0.034 0.071 0.083 

FSV-DV 

319 320 321 322 323 

0.024 0.004 0.022 0.041 0.043 

0.018 0.005 0.020 0.029 0.032 

0.026 nq 0.017 0.034 0.033 

0.023 0.004 0.016 0.028 0.030 

. 

0.024 nd nd 0.022 0.022 

0.012 nq 0.019 0.054 0.055 

0.014 0.006 0.011 0.021 0.033 

0.017 0.003 0.012 0.022 0.024 

0.023 0.008 0.032 0.049 0.052 

0.026 nq nq 0.030 0.026 

0.019 0.008 0.021 0.029 0.030 

0.052 0.004 0.016 0.031 0.024 

319 320 321 322 323 

0.109 0.022 0.081 0.114 0.1

0.113 0.016 0.087 0.126 0.1

0.086 0.017 0.074 0.110 0.1

0.093 0.016 0.066 0.126 0.1

0.099 0.009 0.054 0.099 0.0

0.111 0.020 0.074 0.107 0.1

0.108 0.030 0.063 0.101 0.1

0.109 nq 0.071 0.134 0.1

0.090 nq 0.162 0.110 0.1

0.096 nd 0.089 0.094 0.1

0.071 0.026 0.054 0.087 0.1

0.089 0.017 0.068 0.106 0.1

0.105 0.014 0.072 0.122 0.1

0.095 nq 0.054 0.082 0.0

0.118 0.021 0.083 0.136 0.1

0.074 0.010 0.045 0.069 0.07

0.144 0.025 0.099 0.171 0.1

0.110 0.025 0.083 0.119 0.12

0.142 nq 0.081 0.167 0.1

0.106 0.029 0.083 0.112 0.1

0.084 nq 0.060 0.093 0.1

0.122 ≥0.004 0.050 0.102 0.10

N 14 11 14 14 14 12 8 10 12 12 22 15 22 22 

Min 0.057 0.007 0.033 0.047 0.051 0.012 0.003 0.011 0.021 0.022 0.071 0.009 0.045 0.069 0.0

Median 0.085 0.015 0.051 0.077 0.082 0.023 0.005 0.018 0.030 0.031 0.105 0.020 0.073 0.110 0.1

Max 0.116 0.030 0.081 0.137 0.139 0.052 0.008 0.032 0.054 0.055 0.144 0.030 0.162 0.171 0.1

SD 0.015 0.006 0.015 0.009 0.011 0.005 0.002 0.004 0.007 0.007 0.015 0.007 0.016 0.019 0.0

CV 18 38 29 12 13 22 40 21 23 24 14 34 23 17 

Npast 7 11 13 15 15 0 8 10 13 13 8 18 20 23 

Medianpast 0.066 0.014 0.052 0.078 0.079 0.006 0.018 0.030 0.032 0.115 0.021 0.072 0.108 0.1

SDpast 0.019 0.004 0.011 0.017 0.016 0.003 0.007 0.007 0.007 0.017 0.009 0.013 0.017 0.0

NIST 0.077 nq ≥0.043 0.090 0.090.058 nq 0.043 0.068 0.067 0.020 nq nq 0.022 0.023 

Srep 0.004 0.003 0.000 0.002 0.000 0.002 0.001 0.004 0.002 0.0

Shet 0.006 0.004 0.001 0.002 0.001 0.001 0.002 0.006 0.000 0.0

SNIST 0.007 0.005 0.001 0.003 0.001 0.002 0.002 0.008 0.002 0.0

NAV 0.071 0.015 0.047 0.073 0.074 0.021 0.005 0.018 0.026 0.027 0.091 0.020 0.073 0.100 0.1

NAU 0.026 0.006 0.016 0.017 0.019 0.007 0.003 0.006 0.010 0.010 0.030 0.007 0.016 0.027 0.0

All Lab Report 
 

 

Round Robin LIX Laboratory Results 

All Results in μg/mL 

Coenzyme Q10 Ubiquinol Ubiquinone 25-hydroxyv

Lab 319 320 321 322 323 

C6

FSV-BA
 

FSV-BB
 

FSV-BC
 

FSV-BD
 

FSV-BE
 

FSV-BF
 

FSV-BG
 

FSV-BH
 

FSV-BI
 

FSV-BJ
 0.607 0.140 0.528 0.675 0.730 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 

FSV-BU 

FSV-BV 

FSV-BW 0.155 0.026 0.125 0.137 0.165 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 

FSV-CP 

FSV-CS 

FSV-CT 

FSV-CW 0.780 0.310 0.780 0.740 0.760 

FSV-CZ 0.720 0.230 0.620 0.730 0.770 

FSV-DB 

FSV-DF 

FSV-DI 0.694 0.110 0.595 0.660 0.655 

FSV-DQ 

FSV-DV 

319 320 321 322 323 

0.136 0.014 0.099 0.100 0.129 

0.700 0.076 0.533 0.622 0.749 

319 320 321 322 323 

0.018 0.012 0.026 0.037 0.036 

0.140 0.050 0.188 0.263 0.262 

319 320 321 

0.0048 0.0070 0.01

0.0040 0.0070 0.02

0.0039 0.0274 0.01

0.0044 0.0033 0.00

N 5 5 5 5 5 2 2 2 2 2 2 2 2 2 2 4 4 

Min 0.155 0.026 0.125 0.137 0.165 0.136 0.014 0.099 0.100 0.129 0.018 0.012 0.026 0.037 0.036 0.0039 0.0033 0.00

Median 0.694 0.140 0.595 0.675 0.730 0.418 0.045 0.316 0.361 0.439 0.079 0.031 0.107 0.150 0.149 0.0042 0.0070 0.01

Max 0.780 0.310 0.780 0.740 0.770 0.700 0.076 0.533 0.622 0.749 0.140 0.050 0.188 0.263 0.262 0.0048 0.0274 0.02

SD 0.084 0.089 0.068 0.052 0.078 0.0004 0.0045 0.00

CV 12 64 11 8 11 9 64 

Npast 0 6 7 5 5 0 0 0 0 0 0 0 0 0 0 0 0 

Medianpast 0.090 0.530 0.707 0.770 

SDpast 0.041 0.115 0.122 0.128 

NIST
 

Srep
 

Shet
 

SNIST
 

NAV 0.694 0.140 0.595 0.675 0.730 0.004 0.007 0.0

NAU 0.084 0.089 0.068 0.068 0.078 

All Lab Report 
 

 

 

 

 

Round Robin LIX Laboratory Results
 

All Results in μg/mL
 

Analytes Reported By One Laboratory 

Term 

N 

Min

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NIST 

Srep
 

Shet
 

SNIST
 

NAV 

NAU 

nd 

nq 

<x 

≥x

!

Analyte Code 319 320 321 322 323 

Phylloquinone (K1) x1000 FSV-CI 0.140 0.210 0.740 0.260 0.260 

26-Cyclolycopene-15-diol FSV-DQ 0.066 0.015 0.041 0.058 0.072 

Legend 

Definition

 Number of (non-NIST) quantitative values reported for this analyte

 Minimum (non-NIST) quantitative value reported 

 Median (non-NIST) quantitative value reported

 Maximum (non-NIST) quantitative value reported 

 Standard deviation for (non-NIST) results: 0.741*(3rd Quartile - 1st Quartile)

 Coefficient of Variation for (non-NIST) results: 100*SD/Median

 Mean of N(s) from past RR(s)

 Mean of Median(s) from past RR(s)

 Pooled SD from past RR(s)

 Mean of all analyses (vials x duplicates) reported by a NIST analyst
 

 W ithin-vial pooled standard deviation

 Among-vial pooled standard deviation
 2

)

0.5 Total standard deviation for NIST analyses: (Srep 2

 + Shet 

 NIST Assigned Value

 = (Median + MeanNIST)/2 for analytes reported by NIST analyst(s)

 = Median for analytes reported by ≥ 10 labs but not NIST

2

)

0.5 NIST Assigned Uncertainty: (S2

 + Sbtw 

 S is the maximum of (0.05*NAV, SD, SNIST, eSD) and Sbtw is the standard

 deviation between Medianpart and MeanNIST. The expected long-term SD, eSD,

 is defined in: Duewer, et al. Anal Chem 1997;69(7):1406-1413.

 Not detected (i.e., no detectable peak for analyte)

 Detected but not quantitatively determined

 Concentration at or below the limit of quantification, x

 Concentration greater than or equal to x

 Non-quantitative value: heterogeneous serum, damaged sample, malfunction, etc.

All Lab Report Page 6 / 7 

C7
 

 

 

 

 

 

 

 

Round Robin LIX Laboratory Results
 

Comparability Summary
 

Lab 

FSV-BA 

FSV-BB 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BH 

FSV-BI 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 

FSV-CP 

FSV-CS 

FSV-CT 

FSV-CW 

FSV-CZ 

FSV-DB 

FSV-DF 

FSV-DI 

FSV-DQ 

FSV-DV 

NISTa 

n 

% 1
 

% 2
 

% 3
 

% 4
 

TR aT g/bT bC tbC aC TLy TbX TLu TZ L&Z
 

2 1 1 1 2 1 1 2 1 1 1
 

1 1 2 1 2 1 1 1 2 1 1
 

1
 

2 3 1
 

1 1 1 1
 

1 2 1 2 1 1 1 1
 

1 1 1 2 1 1 1 1 1 1
 

2 1 1 1 1 1 1 1
 

2 1 2 1 1 1 1 1 1 1
 

1 1 1 1 1 1 1
 

2 2 1
 

1 1
 

2 1 2
 

1 1 1 1 1 1 1 1 4
 

2 2 3 2 1 3 2 1 1
 

3 2 3 1 4 4 1
 

1 1 3 1 2
 

1 2 1 3 1
 

4 4 4 3 1 1 1 1
 

3 2 1 1 1 1 1 1
 

1 1 2 1 1 2 1
 

4 2 2 1 1 1 1 1
 

1 1 1 1 2 1 1
 

1 2 1
 

2 1 2 1
 

1 1 1
 

1 2 1 1 1 1 1 2
 

1 1 1 2 1 1 1
 

2 3 1 1 1 2
 

1 2 3 2 1 3 1 1 2 1
 

1 1 1 1 3 2
 

2 3 1 1 3 2 1 2 1 2
 

1 1 3
 

1 1 2 1 1 1
 

1 1
 

1 1 1 1 1 1 1 1
 

1 1 1 1 1 1
 

3 1
 

1 1 1 1 1 1 1 2
 

36 36 23 28 8 20 22 22 15 13 23
 

TR aT g/bT bC tbC aC TLy TbX TLu TZ L&Z
 

61 61 65 68 63 85 86 77 73 77 74
 

25 31 22 18 25 15 5 14 20 8 22
 

8 6 9 14 13 0 5 5 7 15 0
 

6 3 4 0 0 0 5 5 0 0 4
 

Label

Lab 

TR

aT 

g/bT

bC 

tbC 

aC 

TLy

TbX 

TLu 

TZ

L&Z

n 

% 1 

% 2 

% 3 

% 4 

 Definition 

 Participant code 

 Total Retinol 

α-Tocopherol 

 γ/β-Tocopherol 

 Total β-Carotene 

 trans-β-Carotene 

 Total α-Carotene 

 Total Lycopene 

Total β-Cryptoxanthin 

 Total Lutein 

 Total Zeaxanthin 

 Total Lutein & Zeaxanthin 

 number of participants providing quantitative data 

 Percent of CS = 1 (within 1 SD of medians) 

 Percent of CS = 2 (within 2 SD of medians) 

 Percent of CS = 3 (within 3 SD of medians) 

 Percent of CS = 4 (3 or more SD from medians) 

“Comparability Score” 

The Comparability Score (CS) of summarizes your measurement 

performance for a given measurand, relative to the consensus 

medians. CS is the average distance, in standard deviation units, 

that your measurement performance characteristics are from the 

consensus performance. CS is calculated when the number of 

quantitative values you reported for a measurand, Nyou, is at least 

two and the measurand has been reported by 10 or more 

participants. 

CS = MIN(4, INT(1 + C2 + AP 2 )) 

N yo u You − Median C = Concordanc e = i i ∑ Ny ou
 NAU i i
 

N yo u  You i − Median i 

2
 

AP = Apparent Precision = ∑  (Ny ou − 1)  NAU  i  i  

NAU = NIST Assigned Uncertainty, our estimate of the overall 

measurement standard deviation for each sample. The 

estimate includes serum heterogeneity, analytical 

repeatability, and among-participant reproducibility variance 

components. 

For further details, please see: Duewer DL, Kline MC, Sharpless 

KE, Brown Thomas J, Gary KT. Micronutrients Measurement 

Quality Assurance Program: Helping participants use 

interlaboratory comparison exercise results to improve their longterm measurement performance. Anal Chem 1999;71(9):1870-8. 

All Lab Report Page 7 / 7
 

C8
 

 

 

 

Appendix D. Representative “Individualized Report” for RR59 

Each participant in RR59 received an “Individualized Report” reflecting their reported 

results. Each report included a detailed analysis for analytes that were assayed by at least 

five participants. The following analytes met this criterion in RR59: 

• Total Retinol 

• Retinyl Palmitate 

• α-Tocopherol 

• γ/β-Tocopherol 

• δ-Tocopherol 

• Total β-Carotene 

• trans-β-Carotene 

• Total cis-β-Carotene 

• Total α-Carotene 

• Total Lycopene 

• trans-Lycopene 

• Total β-Cryptoxanthin 

• Total Lutein 

• Total Zeaxanthin 

• Total Lutein & Zeaxanthin 

• Coenzyme Q10 

The following 14 pages are the “Individualized Report” for the analytes evaluated by 

participant FSV-BA. 

D1
 

Set 1 of 38 

Individualized Round Robin LIX Report: FSV-BA 

Summary 

Serum 319 Serum 320 Serum 321 Serum 322 

D2

Analyte You NAV n You NAV n You NAV n You NAV n 

Total Retinol 0.375 0.376 33 0.230 0.185 33 0.878 0.744 33 0.670 0.622 32 

Retinyl Palmitate 0.08 0.11 10 0.0 0.0 10 0.2 0.3 10 0.11 0.09 10 

α-Tocopherol 4.35 4.28 35 1.80 3.30 35 15.14 14.34 35 9.92 9.93 34 

γ/β-Tocopherol 1.686 1.653 22 0.486 0.683 22 2.808 2.662 22 1.824 1.766 22 

δ-Tocopherol 0.040 0.049 6 0.029 0.032 6 0.150 0.156 8 0.051 0.051 7 

Total β-Carotene 0.354 0.326 25 0.103 0.156 25 0.750 0.713 25 0.137 0.123 24 

trans-β-Carotene 0.332 0.287 8 0.097 0.116 8 0.697 0.587 8 0.130 0.105 8 

Total cis-β-Carotene 0.022 0.022 5 0.006 0.013 5 0.053 0.052 6 0.007 0.007 5 

Total α-Carotene 0.015 0.016 17 0.003 0.007 14 0.032 0.035 19 0.079 0.078 20 

Total Lycopene 0.200 0.187 22 0.023 0.031 18 0.165 0.153 22 0.518 0.485 22 

trans-Lycopene 0.115 0.094 7 0.010 0.012 7 0.073 0.067 7 0.297 0.230 7 

Total β-Cryptoxanthin 0.069 0.048 21 0.002 0.006 11 0.026 0.020 19 0.072 0.053 21 

Total α-Cryptoxanthin 0.032 0.025 4 nd 1 0.012 0.012 4 0.035 0.026 4 

Total Lutein&Zeaxanthin 0.109 0.091 22 0.02 0.02 15 0.08 0.07 22 0.114 0.100 22 

25-hydroxyvitamin D 0.005 0.004 4 0.007 0.007 4 0.017 0.017 4 0.016 0.017 4 

You : Your reported values for the listed analytes (micrograms/milliliter) 

NAV : NIST Assigned Values, here equal to this RR's median 

n : Number of non-NIST laboratories reporting quantitative values for this analyte in this serum 

nd : Not detected 

Please check our records against your records. Send corrections and/or updates to... 

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 USA Email: 

Individualized Report 
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

Total Retinol 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 2 / 14 

D3
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

Retinyl Palmitate 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 3 / 14 

D4
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

α-Tocopherol 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 4 / 14 

D5
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

γ/β-Tocopherol 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 5 / 14 

D6
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

δ-Tocopherol 

Apparent Precision, SD [Analyte], μg/mL

Your [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 6 / 14 

D7
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

Total β-Carotene 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 7 / 14 

D8
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

trans-β-Carotene 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 8 / 14 

D9
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

Total α-Carotene 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 9 / 14 

D10
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

Total Lycopene 

Apparent Precision, SD [Analyte], μg/mL

Your [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 10 / 14 

D11
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

trans-Lycopene 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 11 / 14 

D12
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

Total β-Cryptoxanthin 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 12 / 14 

D13
For details of the construction and interpretation of these plots, see:

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.

 

Set 1 of 38 

Individualized RR LIX Report: FSV-BA 

Total Lutein&Zeaxanthin 

Apparent Precision, SD [Analyte], μg/mL

184319197211245310320198212246311321290300312322292301313323 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

You, past RRs You, ≥x, past RRs Others, this RR 1st Quartile (25%) 

Serum History Comments 

#319 Lyophilized - 28:184 Native, single-source 

#320 Lyophilized - 31:197, 35:211, 43:245, 57:310 Same as #321, 1:3 diluted with stripped serum 

#321 Lyophilized - 31:198, 35:212, 43:246, 57:311 Augmented, multi-source 

#322 Lyophilized - 53:290, 55:300, 57:312 Native, single-source 

#323 Fresh-frozen: 53:292, 55:301, 57:313 Native, single-source, hemolyzed 

Individualized Report Page 13 / 14 

D14
Set 1 of 38 

Individualized Round Robin LIX Report: FSV-BA
 

Graphical Comparability Summary
 

Total Retinol α-Tocopherol Total β-Carotene 

D15

Retinyl Palmitate γ/β-Tocopherol trans-β-Carotene To

Total Lycopene δ-Tocopherol Total cis-β-Carotene Total L

trans-Lycopene Total β-Cryptoxanthin Total α-Carotene Co

Individualized Report 
 

 

 

Appendix E. Shipping Package Inserts for RR24 

The following five items were included in each package shipped to an RR24 participant: 

•	 Cover letter 

•	 Protocol for Preparation and Analysis of the Ascorbic Acid Solid Control
	

Material
	

•	 Preparation and Validation of Ascorbic Acid Solid Control Material Datasheet 

•	 Analysis of Control Materials and Test Samples Datasheet 

•	 Packing List and Shipment Receipt Confirmation Form 

The cover letter, preparation protocol, and the two datasheets were enclosed in a sealed 

waterproof bag along with the samples themselves. The packing list was placed at the 

top of the shipping box, between the cardboard covering and the foam insulation. 

E1
November 28, 2005 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

The samples within this pac~age constitute Vitamin C Round Robin 24 (RR24) of the fiscal year (FY) 06 

Micronutrients Measurement Quality Assurance Program. 

RR24 consists of four vials of frozen serum test samples (#22, #43, #117, and #119), one vial of ascorbic aeid 

solid control material (Control), and tWQ vials of frozen serum control materials (Control #1 and Control #2). 

Please follow the attached protocols when you prepare and analyze these samples. If you cannot prepare the 

solid control solutions gravimetrically, please prepare equivalent solutions volumetrically and report the exact 

volumes used. (Routine 0.5 g gravimetric measurements are generally 10-fold more accurate than routine 0.5 

mL volumetric measurements.) 

The two serum control materials are a new component of the M2

QAP for Vitamin C. Please use these 

materials to validate the performance of your measurement system before you analyze the test samples. The 

target value and :::::95% confidence interval for Control #1 is 8.41 ±0.61 μmol/L sample; the target-value and 

:::::95% confidence interval for Control ·#2 is 28.05 ±0.49 μmol/L sample. 

Please be aware that sample contact with any oxidant-contaminated surface (vials, glassware, etc.) may degrade 

your measurement system's performance (SA Margolis and E Park, "Stability of Ascorbic Acid in Solutions in 

AutosamplerVials", Clinical Chemistry 2001, 47(8), 1463-1464). You should suspect such degradation if you 

observe unusually large variation in ·replicate analyses. 

The report for RR23 was mailed during the first week of November. If you find your results for RR23 

unsatisfactory, we recommend that you obtain Standard Reference Material (SRM) 970 Ascorbic Acid in 

Serum to validate your methodology and value assign in-house control materials. This SRM may be 

purchased from the Standard Materials Reference Program at NIST (Tel: 301-975-6776, Fax: 301-948-3730, 

or e-mail: srminfo@nist.gov). 

If you have any questions or concerns about the Vitamin C Micronutrients Measurement Quality Assurance 

Program please contact Jeanice Brown Thomas at tel: 301-975-3120, fax: 301-977-0685, or 

e-mail: jbthomas@nist.gov. 

We ask that you return your results for the RR24 samples by March 3, 2006. We would appreciate receiving 

your results as soon as they become available. Please use the attached form. Your results will be kept 

confidential. 

c 

if.aoice Brown Thomas 

Research Chemist 

Analytical Chemistry Division 

Chemical Science and Te.chnology Laboratory 

Enclosures: Protocols, Preparation and Analysis of Control Materials and Analysis of Test Samples 

RR24 Report Form for Ascorbic Acid Solid Control Material Preparation 

RR24 Report Form for Control Material and Test Sample Analyses 

E2
 

 

 

 

 

 

 

 

 

Micronutrient Measurement Quality Assurance Program for
 

Vitamin C
 

Please Read Through Completely BEFORE Analyzing Samples 

Protocol for Preparation and Analysis of the Ascorbic Acid Solid Control Material 

The ascorbic acid solid control material (in the amber vial) should be prepared and used in the 

following manner: 

1)		 Prepare at least 500 mL of 5% mass fraction metaphosphoric acid (MPA) in distilled water. This 

solution will be referred to as the “Diluent” below. 

2)		 Weigh 0.20 to 0.22 g of the ascorbic acid solid control material to 0.0001 g (if possible), dissolve 

it in the Diluent in a 100 mL volumetric flask, and dilute with the Diluent to the 100 mL mark. 

Weigh the amount of Diluent added to 0.1 g. Record the weights. The resulting material will be 

referred to as the “Stock Solution” below. 

3)		 Prepare three dilute solutions of the Stock Solution as follows: 

Dilute Solution 1: Weigh 0.500 mL of the Stock Solution to 0.0001 g into a 100 mL volumetric 

flask; dilute with Diluent to the 100 mL mark. Record the weight. 

Dilute Solution 2: Weigh 0.250 mL of the Stock Solution to 0.0001 g into a 100 mL volumetric 

flask; dilute with Diluent to the 100 mL mark. Record the weight. 

Dilute Solution 3: Weigh 0.125 mL of the Stock Solution to 0.0001 g into a 100 mL volumetric 

flask; dilute with Diluent to the 100 mL mark. Record the weight. 

4)		 Calculate and record the total ascorbic acid concentrations, [TAA], in these Dilute Solutions. 

If you follow the above gravimetric preparation directions, the [TAA] in μmol/L is calculated: 

(g Stock Solution in Dilute Solution 	 ) (⋅ g AA in Stock Solution )⋅(56785 mol/g μ ⋅ L) [TAA] DS = (g AA in Stock Solution ) + (g Diluent in Stock Solution)

For example, if you prepared the Stock Solution with 0.2000 g of solid ascorbic acid and 103.0 g 

of Diluent, then 0.5 mL of the Stock Solution should weigh (0.2+103)/200 = 0.52 g and 

[TAA] DS1 = (0.52 g)(0.2 g)∙(56785 μmol/g·L)/(0.2 + 103 g) = 57.2 μmol/L. Likewise, 0.25 mL 

of the Stock Solution should weigh 0.26 g and [TAA] DS2 = 28.4 μmol/L and 0.125 mL should 

weigh 0.13 g and [TAA] DS3 = 14.2 μmol/L. 

5)		 Measure the ultraviolet absorbance spectrum of Dilute Solution 1 against the Diluent as the blank 

using paired 1 cm path length cuvettes. Record the absorbance at 242, 243, 244, and 245 nm. 

Record the maximum absorbance (Amax ) within this region. Record the wavelength (λmax ) at 

which this maximum occurs. 

The extinction coefficient (E1%) of ascorbic acid at λmax (using a cell with a 1 cm path length) of 

Dilute Solution #1 can be calculated: 

E3
 

 

 

 

 

 

 

 

 

 

 

 

 

 

1% dL (A max )⋅	 ((g AA in Stock Solution ) + (g Diluent in Stock Solution )) E ( ) = g ⋅ cm (g Stock Solution in Dilute Solution 1)⋅(g AA in Stock Solution)

If your spectrophotometer is properly calibrated, λmax should be between 243 and 244 nm and 

E1% should be 550 ± 30 dL/g·cm. If they are not, you should calibrate the wavelength and/or 

absorbance axes of your spectrophotometer and repeat the measurements. 

6)		 Measure and record the concentration of total ascorbic acid in all three dilute solutions and in the 

5% MPA Diluent in duplicate using exactly the same method that you will use for the serum 

control materials and test samples, including any enzymatic treatment. We recommend that you 

analyze these solutions in the following order: Diluent, Dilute Solution 1, Dilute Solution 2, 

Dilute Solution 3, Dilute Solution 3, Dilute Solution 2, Dilute Solution 1, Diluent. 

a)		 Compare the values of the duplicate measurements. Are you satisfied that your measurement 

precision is adequate? 

b)		 Compare the measured with the calculated [TAA] values. This is most conveniently done by 

plotting the measured values on the y-axis of a scatterplot against the calculated values on the 

x-axis. The line through the four {calculated, measured} data pairs should go through the 

origin with a slope of 1.0. Are you satisfied with the agreement between the measured and 

calculated values? 

Do not analyze the serum control materials or test samples until you are satisfied that your 

system is performing properly! 

7)		 Once you have confirmed that your system is properly calibrated, analyze the serum control 

CS #2 (see protocol below). The target values for this materials is 28.1 ±1.0 μmol/L of sample. 

If your measured values are not close to this value, please review your sample preparation 

procedure and whether you followed exactly the same measurement protocol the solutions 

prepared from the solid control material as you used for these serum controls. If the protocols 

differ, please repeat from Step 6 using the proper protocol. If the proper protocol was used, your 

measurement system may not be suitable for MPA-preserved samples. Please contact us: 301-

975-3120 or Jeanice.BrownThomas@NIST.gov. 

Do not analyze the test samples until you are satisfied that your system is performing properly 

and is suitable for the analysis of MPA-preserved serum! 

Protocol for Analysis of the Serum Control Materials and Test Samples 

The serum control material and test samples are in sealed ampoules. They were prepared by adding 

equal volumes of 10% MPA to spiked human serum. We have checked the samples for stability and 

homogeneity. Only the total ascorbic acid is stable. While these samples contain some 

dehydroascorbic acid, its content is variable. Therefore, only total ascorbic acid should be reported. 

The serum control material and test samples should be defrosted by warming at 20 °C for not more 

than 10 min otherwise some irreversible degradation may occur. 

Each serum test sample contains between 0.0 and 80.0 μmol of total ascorbic acid/L of solution. The 

total ascorbic acid in each ampoule should be measured in duplicate. Please report your results in 

μmol/(L of the sample solution) rather than μmol/(L of serum NIST used to prepare the sample). 

E4
 

 

 

 

Participant #: Date: 

Vitamin C Round Robin 24 

NIST Micronutrient Measurement Quality Assurance Program 

Preparation and Validation of Ascorbic Acid Solid Control Material 

STOCK SOLUTION 

Mass of ascorbic acid in the Stock Solution ..................................................__________ g 

Mass of 5% MPA Diluent added to the 100 mL volumetric flask .................__________ g 

DILUTE SOLUTION 1 

Mass of added stock solution (0.5 mL) ..........................................................__________ g 

Mass of 5% MPA Diluent added to the 100 mL volumetric flask .................__________ g 

Absorbance of Dilute Solution 1 at 242 nm...................................................__________ AU
	

Absorbance of Dilute Solution 1 at 243 nm...................................................__________ AU
	

Absorbance of Dilute Solution 1 at 244 nm...................................................__________ AU
	

Absorbance of Dilute Solution 1 at 245 nm...................................................__________ AU
	

Absorbance of Dilute Solution absorbance maximum ..................................__________ AU
	

Wavelength of maximum absorbance............................................................__________ nm
	

Calculated E1% ...............................................................................................__________ dL/g·cm
	

Calculated [TAA] DS1 .....................................................................................__________ μmol/L
	

DILUTE SOLUTION 2 

Mass of added stock solution (0.25 mL) ........................................................__________ g 

Mass of 5% MPA Diluent added to the 100 mL volumetric flask.................__________ g 

Calculated [TAA] DS2 .....................................................................................__________ μmol/L
	

DILUTE SOLUTION 3 

Mass of added stock solution (0.125 mL) ......................................................__________ g 

Mass of 5% MPA Diluent added to the 100 mL volumetric flask .................__________ g 

Calculated [TAA] DS3 .....................................................................................__________ μmol/L
	

Please return by March 3, 2006 

MMQAP Fax: 301-977-0685 

100 Bureau Drive, Stop 8392 Email: david.duewer@nist.gov 

Gaithersburg, MD 20899-8392 

E5
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Participant #: Date: 

Vitamin C Round Robin 24 

NIST Micronutrient Measurement Quality Assurance Program
 

Analysis of Control Materials and Test Samples
 

Sample Replicate 1 Replicate 2 Units
 

Dilute Solution 1 μmol/L of Dilute Solution 

Dilute Solution 2 μmol/L of Dilute Solution 

Dilute Solution 3 μmol/L of Dilute Solution 

5% MPA Diluent μmol/L of Diluent 

μmol/L of Sample Serum Control #1 Target: 8.5 ±0.5 μmol/L 

μmol/L of Sample Serum Control #2 Target: 28.1 ±1.0 μmol/L 

Serum Test Sample #22 μmol/L of Sample 

Serum Test Sample #43 μmol/L of Sample 

Serum Test Sample #117 μmol/L of Sample 

Serum Test Sample #119 μmol/L of Sample 

Were samples frozen upon receipt? Yes | No 

Analysis method: HPLC-EC | HPLC-Fluor DAB | HPLC-OPD | HPLC-UV | AO-OPD | Other
	

If “Other”, please describe:
	

COMMENTS: 

Please return by March 3, 2006 

MMQAP Fax: 301-977-0685 

100 Bureau Drive, Stop 8392 Email: david.duewer@nist.gov 

Gaithersburg, MD 20899-8392 

E6
 

 

 

 

Participant #: ________ Date: _____________ 

Vitamin C Round Robin 24
 

NIST Micronutrients Measurement Quality Assurance Program
 

Packing List and Shipment Receipt Confirmation Form
 

This box contains one vial each of the following seven VitC M2QAP samples: 

Sample Form 

VitC #22 Liquid frozen (1:1 serum:10% MPA) 

VitC #43 Liquid frozen (1:1 serum:10% MPA) 

VitC #117 Liquid frozen (1:1 serum:10% MPA) 

VitC #119 Liquid frozen (1:1 serum:10% MPA) 

CS #1 Liquid frozen (1:1 serum:10% MPA) 

CS #2 Liquid frozen (1:1 serum:10% MPA) 

Control Solid AA 

Please 1) Open the pack immediately 

2) Check that it contains one vial each of the above samples 

3) Check if the samples arrived frozen 

4) Store the samples at -20  ̊C or below until analysis 

5) Complete the following information 

6) Fax the completed form to us at 301-977-0685 

(or email requested information to david.duewer@nist.gov) 

1) Date this shipment arrived: ___________________________ 

2) Are all of the vials intact? Yes | No 

If "No", which one(s) were damaged? 

3) Was there any dry-ice left in cooler? Yes | No 

4) Did the samples arrive frozen? Yes | No 

5) At what temperature are you storing the samples? _______  ̊C 

6) When do you anticipate analyzing these samples? ________________________ 

Your prompt return of this information is appreciated. 

The M2QAP Gang 

Mail: M2QAP 

NIST, Stop 8392 Fax: 301-977-0685 

Gaithersburg, MD 20899-8392 Email: David.Duewer@NIST.gov 

E7
 

 

 

 

 

Appendix F. Final Report for RR24 

The following two pages are the final report as provided to all participants: 

•	 Cover letter. 

•	 An information sheet that: 

o	 describes the contents of the “All-Lab” report, 

o	 describes the content of the “Individualized” report, 

o	 describes the nature of the test samples and details their previous distributions, 

if any, and 

o	 summarizes aspects of the study that we believe may be of interest to the 

participants. 

F1
April18,2006 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed is the summary report of the results for Round Robin 24 (RR 24) for the measurement 

of total ascorbic acid (T AA, ascorbic acid plus dehydroascorbic acid) in human serum. Included 

in this report are a summary of data for all laboratories and an individualized summary of your 

laboratory's measurement performance. The robust median is used to estimate the consensus 

value for all samples, the "median absolute deviation from the median" (MADe) is used to 

estimate the expected standard deviation, and the coefficient of variation (CV) is defined as 

1 OOxMADe/median. 

RR 24 consisted of four test samples (#22, #43, #117, and #119), two serum control materials, 

and one solid control material for preparation ofTAA control solutions. Details regarding the 

samples can be found in the enclosed report. 

If you have concerns regarding your laboratory's perfonnance, we suggest that you obtain and 

analyze a unit of Standard Reference Material (SRM) 970, Vitamin C in Frozen Human Serum. 

SRM 970 can be purchased from the NIST SRM Program at phone: 301-975-6776; fax: 

301-948-3730. If your measured values do not agree with the certified values, we suggest that 

you contact us for consultation. 

Samples for the second vitamin C round robin (RR 25) of the 2006 M2

QAP will be shipped 

during the week of May 8, 2006. 

If you have questions or concerns regarding this report, please contact David Duewer at 

301-975-3935; e-mail: david.duewer@nist.gov or me at 301-975-3120; e-mail: 

jbthomas@nist.gov; or u · 301-977-0685. 

e · ce Brown Thomas 

earch Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

F2

NISI 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

The NIST M2QAP Vitamin C Round Robin 24 (RR24) report consists of 

Page “Individualized” Report 

1 Summarizes your reported values for the nominal 55 mmol/L solution you prepared from the 

ascorbic acid solid control sample, the two serum control samples, and the four serum test 

samples. 

2 Graphical summary of your RR24 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR24 

samples and control/calibration solutions. 

Serum-based Samples. Two serum controls and four unknowns were distributed in RR24. 

CS1 SRM 970 level 1, ampouled in mid-1998. 

CS2 SRM 970 level 2, ampouled in mid-1998. 

S24:1 Serum 22, ampouled in late 2001, previously distributed as sample S17:1 (RR17, Fall 02), 

S19:2 (RR19, Fall 03) and S21:2 (RR21, Fall 04). 

S24:2 Serum 43, ampouled in late 2001, previously distributed as sample S18:2 (RR18, Spring 03), 

S19:3 (RR19, Fall 03), S21:3 (RR21, Fall 04), and S22:3 (RR22, Spring 05). 

S24:3 Serum 117, ampouled in 1995, previously distributed sample 682b=S07:3 (RR7, Spring 95), 

682b=S10:1 (RR10, 1997), and S13:4 (RR13, 2000). 

S24:4 Serum 119, ampouled in 1995, previously distributed sample 688b=S07:2 (RR7, Spring 

1995), 688b=S08:2 (RR8, 1997), and S13:4 (RR13, 2000). 

Results. 

1)		 Nearly all participants who prepared the four 5% metaphosphoric acid (MPA) control/calibration 

solutions (the three “Dilute Solutions” and the “Diluent”) did so correctly. The criteria used to 

evaluate this success are: the density of the 5% MPA (≈1.03 gm/mL), the observed wavelength 

maximum of “Dilute Solution #1”(≈244 nm), the observed absorbance at that maximum (≈0.55 OD), 

the calculated E1% #1”(≈550 dL/g·cm). 

One participant chose to make the solutions in trichloroacetic acid (TCA) rather than MPA. One 

participant appears to have made simple aqueous solutions. Since the test samples are in 5% MPA 

(i.e., 1:1 dilutions of augmented serum in 10% MPA), their measurements of the test samples are not 

necessarily related to their control solution measurements. 

2)		 Judging from the calibration parameters (intercepts close to 0.0, slopes close to 1.0, correlation (R2

) 

close to 1, and the root mean square error or “standard estimate of the error” (SEE) close to 0.0) 

calculated for the control/calibration solutions in the report summary, the measurement systems for 

all participants are linear and reasonably well calibrated. However, several participants have 

measurement systems that perform somewhat differently for the control solutions and the test 

samples. This suggests either that the serum matrix can induce a measurement bias and/or that the 

measurement system used for the control solutions isn’t exactly the same as for the test materials. 

Figuring this out is one of our future projects. 

3)		 Perhaps somewhat surprisingly, there is no evidence for sample degradation in any of the samples – 

including the two that were produced in 1995. 

F3
 

 

 

Appendix G. “All-Lab Report” for RR24 

The following single page is the “All-Lab Report” as provided to all participants, with 

two exceptions: 

• the participant identifiers (Lab) have been altered. 

• the order in which the participant results are listed has been altered. 

The data summary in the “All-Lab Report” has been altered to ensure confidentiality of 

identification codes assigned to laboratories. 

G1
 

 

Micronutrients Measurement Quality Assurance Program for Total Ascorbic Acid 

"Round Robin" 24 - March 2006 

Control / Calibration Samples MPA Dilute Solution 1 Samples 

G2

Density 

Lab Date Dil:1 Dil:2 Dil:3 Dil:1 Dil:2 Dil:3 MPA Inter Slope R2 RMSE g/mL λmax Amax E1% CS#1 CS#2 S24:1 S24:2 S24:3 S24:4 CS#

VC-MA 09/03/06 55.0 27.8 13.9 62.3 31.3 16.3 0.0 0.21 1.13 1.000 0.4 1.031 244. 0.5680 586.7 9.3 29.2 9.7 35.6 59.1 29.2 8

VC-MB 29/12/05 55.9 27.7 14.0 55.0 27.7 13.9 0.0 0.13 0.98 1.000 0.2 1.033 244. 0.5481 556.5 7.5 26.6 8.5 33.3 60.9 27.6 7

VC-MC 26/01/06 55.4 27.6 13.7 59.0 30.4 14.2 0.0 -0.01 1.07 0.999 0.7 1.031 243. 0.5757 589.7 7.5 30.0 11.1 38.3 60.4 27.1 7

VC-ME 03/03/06 56.8 29.2 14.1 58.0 28.9 14.3 0.9 0.33 1.01 0.999 0.8 1.029 243. 0.5712 571.2 8.7 27.5 9.6 32.7 59.7 27.5 8

VC-MG 09/02/06 58.8 30.4 16.0 59.8 27.7 13.7 0.0 -1.65 1.02 0.996 2.1 1.031 243.7 0.5730 553.1 8.1 30.2 10.7 38.2 69.7 31.3 9

VC-MH 09/03/06 62.2 31.1 15.4 63.9 32.2 15.9 0.1 0.15 1.02 1.000 0.1 1.031 244.1 0.6198 565.6 8.9 29.0 9.8 34.6 b 27.6 8

VC-MI 02/03/06 56.6 28.1 13.8 53.9 26.5 12.6 0.0 -0.31 0.95 1.000 0.3 1.031 8.5 28.0 8.3 29.4 62.5 27.4 9

VC-MJ 31/01/06 59.4 29.1 15.1 58.3 30.5 15.3 0.7 0.98 0.97 0.999 1.0 1.022a 250a 0.3650a 349.1a 11.8 31.4 13.6 37.5 59.7 30.2 11

VC-MK 03/02/06 58.9 30.8 14.9 59.8 31.6 14.9 1.2 0.67 1.00 1.000 0.6 1.031 244. 0.5980 576.8 9.6 31.8 12.3 35.6 c 31.7 8

VC-ML 08/03/06 56.5 28.3 14.3 56.2 27.6 13.1 0.0 -0.56 1.00 1.000 0.6 1.026 242. 0.5580 560.9 7.1 27.0 6.8 29.9 55.4 24.8 7

VC-MP 03/03/06 8.5 28.7 32.9 57.9 27.1 

VC-MS 06/03/06 55.4 28.9 11.8 51.2 25.9 10.8 0.2 -0.10 0.92 1.000 0.5 0.992 243. 0.5135 526.6 6.7 32.2 7.9 40.8 78.8 32.8 7

11 11 11 11 11 11 11 10 9 9 9 12 12 11 12 10 12 

57.3 29.0 14.3 57.9 29.1 14.1 0.3 1.026 243.4 0.5695 565.2 8.5 29.3 9.8 34.9 62.4 28.7 8

2.2 1.3 1.1 3.7 2.2 1.6 0.4 0.012 0.7 0.0298 19.2 1.4 1.9 2.0 3.5 6.8 2.4 1

55.0 27.60 11.8 51.2 25.90 10.8 0.0 0.992 242.0 0.5135 526.6 6.7 26.6 6.8 29.4 55.4 24.8 7

55.7 27.97 13.8 55.6 27.64 13.4 0.0 1.029 243.0 0.5580 556.5 7.5 27.9 8.4 32.8 59.3 27.3 7

56.6 28.92 14.1 58.3 28.90 14.2 0.0 1.031 243.7 0.5712 565.6 8.5 29.1 9.7 35.1 60.0 27.6 8

58.8 29.82 15.0 59.8 30.92 15.1 0.4 1.031 244.0 0.5757 576.8 9.0 30.5 10.9 37.7 62.1 30.5 9

62.2 31.07 16.0 63.9 32.15 16.3 1.2 1.033 244.1 0.6198 589.7 11.8 32.2 13.6 40.8 78.8 32.8 11

1.9 1.6 0.6 3.1 2.4 1.6 0.0 0.000 0.6 0.0196 16.6 1.3 2.0 2.1 3.6 2.3 1.6 1

3 6 4 5 8 11 0.04 0.24 3.4 2.9 16 7 21 10 4 6 

Gravimetric, μmol/L Measured, μmol/L Calibration Parameters Spectrophotometry Measured, μmol/L 

N N 

Average Average 

SD SD 

Min Min 

%25 %25 

Median Median 

%75 %75 

Max Max 

MADe eSD 

CV CV 

a) 5% Trichloroacetic acid solution 

b) Miss-labeled sample 

c) Broken ampoule 

All Lab Report 
Appendix H. Representative “Individualized Report” for RR24 

Each participant in RR24 received an “Individualized Report” reflecting their reported 

results. The following two pages are the “Individualized Report” for participant 

“VC-MA”. 

H1
 

Set 1 of 12 

Vitamin C "Round Robin" 24 Report: Participant VC-MA
 

Date RR Method 

11/13/03 19 HPLC-EC 

02/23/04 20 HPLC-EC 

09/13/04 21 HPLC-EC 

03/08/05 22 HPLC-EC 

10/17/05 23 HPLC-EC 

03/09/06 24 HPLC-EC 

Mean 

SD 

CV 

Date RR Sample 

02/23/04 20 CS#1 

09/13/04 21 CS#1 

03/08/05 22 CS#1 

10/17/05 23 CS#1 

03/09/06 24 CS#1 

02/23/04 20 CS#2 

09/13/04 21 CS#2 

03/08/05 22 CS#2 

10/17/05 23 CS#2 

03/09/06 24 CS#2 

11/13/03 19 S19:2 

09/13/04 21 S21:2 

03/08/05 22 S22:1 

03/09/06 24 S24:1 

11/13/03 19 S19:3 

09/13/04 21 S21:3 

03/08/05 22 S22:3 

03/09/06 24 S24:2 

03/09/06 24 S24:3 

MPA Dilute Solution 1
 

Density Spectrophotometry
 

g/mL 

1.026 

1.031 

1.030 

1.034 

1.030 

1.031 

1.03 243.5 0.56 567.0 

0.003 0.5 0.01 9.9 

0.25 0.22 2.0 1.8 

[TAA] mmol/Lsample 

Rep1 Rep2 Fadj Mean SDdup

7.8 8.0 1.0 7.9 0.1 

8.1 7.9 1.0 8.0 0.1 

8.5 8.7 1.0 8.6 0.1 

9.3 9.5 1.0 9.4 0.1 

9.3 9.2 1.0 9.3 0.0 

25.8 26.2 1.0 26.0 0.3 

26.2 27.2 1.0 26.7 0.7 

29.0 29.0 1.0 29.0 0.0 

29.4 30.5 1.0 30.0 0.8 

29.2 29.1 1.0 29.2 0.1 

9.2 9.1 1.0 9.2 0.1 

8.8 8.7 1.0 8.7 0.1 

9.6 9.6 1.0 9.6 0.0 

9.8 9.6 1.0 9.7 0.2 

35.9 35.8 1.0 35.9 0.1 

33.2 32.9 1.0 33.0 0.2 

35.7 35.6 1.0 35.6 0.1 

35.8 35.5 1.0 35.6 0.2 

59.1 59.1 1.0 59.1 0.1 

Control/Calibration Solutions
 

Ymeas = Inter + Slope* Xgrav
 

λmax Amax E1% Inter Slope R2 SEE 

243.0 0.584 561.9 1.1 1.03 0.998 1.24 

243.0 0.552 560.7 -0.4 1.05 1.000 0.65 

244.0 0.555 562.2 -0.1 0.99 1.000 0.10 

243.0 0.559 562.9 0.2 1.06 1.000 0.24 

244.0 0.562 567.9 -0.6 1.09 0.998 1.47 

244.0 0.568 586.7 0.2 1.13 1.000 0.41 

0.68 

0.56 

N Mean SDrepeat SDreprod 

5 8.6 0.1 0.7 

5 28.2 0.5 1.7 

4 9.3 0.1 0.4 

4 35.0 0.2 1.3 

03/09/06 24 S24:4 29.0 29.5 1.0 29.2 0.4 

Please check our records against your records. Send corrections and/or updates to... 

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology 

100 Bureau Drive Stop 8392 Fax: (301) 977-0685 

Gaithersburg, MD 20899-8392 USA Email: david.duewer@nist.gov 

Individualized Report Page 1/2 

H2
 

 

 

 

Set 1 of 12 

Vitamin C "Round Robin" 24 Report: Participant VC-MA 

Total Ascorbic Acid 

[Total Ascorbic Acid], μmol/L 

Your [Total Ascorbic Acid], μmol/L

S17:1S19:2S21:2S22:1S24:1S18:2

Apparent Precision, SD S19:3

S21:3S22:3S24:2S07:3S10:1S24:3S07:2S08:1S24:4 

Median [Total Ascorbic Acid], μmol/L 

Concordance, SD 

3rd Quartile (75%) You, Now NIST Median (50%) You, Past 3 years Others 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8. 

Sample Comments 

S24:1 Serum 22, previously distributed in RRs 17, 19, 21, and 22 

S24:2 Serum 43, previously distributed in RRs 18, 19, 21, and 22 

S24:3 Serum 117, previously distributed in RRs 7 and 10 

S24:4 Serum 119, previously distributed in RRs 7 and 8 

Individualized Report Page 2/2 

H3