NISTIR 7880-10 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2007 

Comparability Studies 

Results for Round Robin LXII 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 27 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

 

 

 

 

NISTIR 7880-10
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2007 

Comparability Studies 

Results for Round Robin LXII 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 27 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

Chemical Sciences Division 

Materials Measurement Laboratory 

April, 2013 

U.S. Department of Commerce 

Rebecca Blank, 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) 

ii
 
 

 

 

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 

Summer 2007 MMQAP measurement comparability improvement studies: 1) Round Robin LXII 

Fat-Soluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 27 Total Ascorbic Acid 

in Human Serum. The materials for both studies were shipped to participants in May 2007; 

participants were requested to provide their measurement results by September 28, 2007. 

Keywords 

Human Serum
 

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

Total Ascorbic Acid
 

iii 
 

 

 

 

 

 

 

 

Table of Contents 

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

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

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

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

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

Round Robin 27: Vitamin C in Human Serum............................................................................... 2
 

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

Appendix A. Shipping Package Inserts for RR62........................................................................ A1
 

Appendix B. Final Report for RR62 ..............................................................................................B1
 

Appendix C. “All-Lab Report” for RR62 ......................................................................................C1
 

Appendix D. Representative “Individualized Report” for RR62 ............................................... D1
 

Appendix E. Shipping Package Inserts for RR27 ......................................................................... E1
 

Appendix F. Final Report for RR27............................................................................................... F1
 

Appendix G. “All-Lab Report” for RR27..................................................................................... G1
 

Appendix H. Representative “Individualized Report” for RR27............................................... H1
 

iv 
 

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 LXII: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

LXII comparability study (hereafter referred to as RR62) received one lyophilized and four 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 

May 2007. 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 RR62 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. 

1
 
 

 

 

•	 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 27: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 27 comparability study 

(hereafter referred to as RR27) received four frozen serum test samples, one frozen control serum, 

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 May 2007. 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 RR27 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. 

2
 
 

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. 

3
 
Appendix A. Shipping Package Inserts for RR62 

The following three items were included in each package shipped to an RR62 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
May29, 2007 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute at Standards and Tachnalagy 

Gaithersburg, Maryland 20899-· 

Enclosed are the samples (Sera 334-338) for the second fat-soluble vitamins and carotenoids in serum 

round robin study (Round Robin Dill) for the fiscal year (FY) 07 NIST Micronutrients Measurement 

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

lyophilized sample for analysis along with a form for reporting your results. When reporting your results, 

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

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

due to NIST by September 28, 2007. Results received more than two weeks after the due date will not 

be included in the summary report for this round robin study. 

Lyophilized samples should be reconstituted with 1.0 mL ofHPLC-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 with 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 samples (Sera 335-338). 

For consistency, we request that laboratories use the following absorptivities (dL/g•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); P-carotene, 2560 at 450 nm 

(ethanol), 2592 at 452 nm (hexane); lycopene, 3450 at 472 nm (hexane). At the request of the 

participants who attended the QA workshop on May 2, also attached is a suggest~d protocol for preparing 

calibration solutions. 

Please mail or fax your results 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 call me at (301) 975-3120; e-mail me at 

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

alytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

NISI 

A2
 

 

 

Participant #: ________ Date: _____________ 

Round Robin LXII: Human Sera 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 334 335 336 337 338 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? 

* we prefer μg/mL 

Were the liquid-frozen samples (335 to 338) frozen when received? Yes | No 

Comments: 

Mail: M2QAP Please return results before 

NIST, Stop 8392 28-Sep-2007 Fax: 301-977-0685 

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

A3
 

 

 

 

Participant #: ________ Date: _____________ 

Fat-Soluble Vitamins Round Robin LXII
 

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? 

#334 Lyophilized Yes (1 ml H2O) 

#335 Liquid frozen No 

#336 Liquid frozen No 

#337 Liquid frozen No 

#338 Liquid frozen No 

Please 1) Open the pack immediately 

2) Check that it contains all of the above samples 

3) Check if the 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 samples 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 

A4
 

 

Appendix B. Final Report for RR62 

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
December 7, 2007 

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 LXIl (RR62) of the 2007 NIST 

Micronutrients Measurement Quality Assurance Program (M2QAP) 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. 

Data for evaluating laboratory performance in RR62 are provided in text "S~ore Card" summary, page 6 

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

I 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 Individualize.d Report. 

We are sorry that SRM 968c, Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum is no 

longer available. If you have concerns regarding your laboratory's performance, we suggest that you 

analyze an in-house control material. If you do not currently have such a material, please contact us. 

Samples for the first 2008 'QA interlaboratory exercise were shipped during the week of November 5, 

2007. Please contact us immediately if you have not received your scheduled shipment. If you have any 

questions regarding this report, please contact Dave Duewer at david.duewer@nist.gov or me at 

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

' 

es 

... 

arch 

~~( Chemist ~ lytical Chemistry Division 

Chemical Science and Technology Laboratory 

Cc: Lane C. Sander 

David L. Duewer 

NISI 

B2
 

The NIST M2QAP Round Robin LXI (RR62) report consists of: 

Page “All Lab” Report 

1-4 A listing of all results and statistics for all analytes. 

5 A legend for the list of results and statistics. 

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 RR62. 

Serum 

334 

335 

336 

337 

338 

Description 

Lyophilized; augmented with retinyl palmitate, γand δ-tocopherol, trans-α- and β-carotene, translycopene, and zeaxanthin; prepared in Fall 1997. 

Fresh-frozen, native, multi-donor, prepared in 

Spring 2005. 

Fresh-frozen, native, multi-donor, prepared in 

Spring 2005. 

Fresh-frozen, native, single-donor serum prepared in 

Spring 2006. 

Fresh-frozen, native, single-donor serum prepared in 

Spring 2006. 

Prior Distributions 

#241:RR42-3/98 

#315:RR58-9/05 

#316:RR58-9/05 

#329:RR61-3/07 

#326:RR60-9/06, #331:RR61-3/07 

Results 

There was no significant change in the median level or variability of any measurand in any of the sera, 

with the possible exception of zeaxanthin in Serum #334. A number of carotenoids in this material were 

augmented, using phospholipid slurries. 

The following figure displays the “Concordance” (the agreement among participants) and the “Apparent 

Precision” (the average within-participant agreement among samples) for a number of analytes over the 

past 23 years. (These performance characteristics are more fully described in Duewer, Kline, Sharpless, 

and Thomas, NIST Micronutrients Measurement Quality Assurance Program: Characterizing the 

Measurement Community’s Performance over Time, Analytical Chemistry 2000;72:4163-4170.) While 

concordance for most analytes has improved or remained stable over the past several years (total retinol 

may, unfortunately, be an exception), it appears that apparent (im)precision for α-carotene is increasing. 

We hope to present you with a number of new samples having higher levels of α-carotene and other 

“minor” carotenoids in the coming year. 

B3
Total Retinol 

Apparent Precision, %RSD Concordance, %RSD 

20
 

15
 

10
 5
 

Total α-Carotene 

α-Tocopherol 

γ/β-Tocopherol 

Total β-Carotene 

Ctrl A-D 

0 

SRM 968

20
 

15
 

10
 5
 

SRM 968aSRM 968b

SRM 968c 

0 

1986 1989 1992 1995 1998 2001 2004 2007
 

Intercomparison Date 

B4
 

 

Appendix C. “All-Lab Report” for RR62 

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. 

C1
Round Robin LXII Laboratory Results 

(μg/mL) 

Total Retinol trans-Retinol Retinyl Palmitate α-Tocopherol 

Lab 334 335 336 337 338 

C2

FSV-BA 0.465 0.505 0.423 0.540 0.321 

FSV-BB 0.519 0.583 0.438 0.615 0.348 

FSV-BC 0.428 0.512 0.412 0.538 0.316 

FSV-BD 0.444 0.466 0.376 0.510 0.319 

FSV-BE 0.431 0.487 0.406 0.521 0.305 

FSV-BF 0.430 0.490 0.400 0.510 0.310 

FSV-BG 0.469 0.543 0.411 0.548 0.305 

FSV-BH 0.382 0.411 0.336 0.443 0.255 

FSV-BI 0.376 0.485 0.380 0.489 0.291 

FSV-BJ 0.403 0.467 0.368 0.498 0.288 

FSV-BK 0.510 0.530 0.390 0.550 0.290 

FSV-BL 0.430 0.430 0.370 0.460 0.260 

FSV-BM 0.401 0.459 0.336 0.493 0.310 

FSV-BN 0.442 0.454 0.370 0.483 0.262 

FSV-BO 0.372 0.424 0.347 0.435 0.275 

FSV-BP 0.467 0.540 0.440 0.542 0.320 

FSV-BQ 0.541 0.565 0.408 0.566 0.338 

≥0.450 ≥0.470 ≥0.300 ≥0.510 ≥0.280 FSV-BR 

≥0.391 ≥0.443 ≥0.329 ≥0.461 ≥0.289 FSV-BS 

FSV-BT 0.396 0.512 0.378 0.587 0.289 

FSV-BU 0.441 0.463 0.367 0.481 0.280 

FSV-BV 0.344 0.408 0.336 0.419 0.179 

FSV-BW 0.400 0.500 0.380 0.510 0.310 

≥0.413 ≥0.482 ≥0.367 ≥0.493 ≥0.286 FSV-BX 

FSV-CC 0.460 0.520 0.370 0.520 0.310 

FSV-CE 0.500 0.620 0.470 0.650 0.370 

FSV-CF 0.531 0.570 0.436 0.595 0.349 

FSV-CG 0.596 0.544 0.411 0.571 0.333 

FSV-CI 0.453 0.506 0.400 0.513 0.307 

FSV-CS 0.583 0.581 0.469 0.549 0.348 

FSV-CW 0.463 0.622 0.484 0.618 0.303 

≥0.420 ≥0.520 ≥0.410 ≥0.550 ≥0.340 FSV-DD 

FSV-DF 0.459 0.544 0.419 0.462 0.331 

FSV-DI 0.414 0.494 0.384 0.532 0.305 

≥0.790 ≥0.640 ≥0.491 ≥0.636 ≥0.370 FSV-DV 

FSV-EE 0.369 0.456 0.316 0.415 0.282 

334 335 336 337 338 

0.450 0.470 0.300 0.510 0.280 

0.391 0.443 0.329 0.461 0.289 

0.413 0.482 0.367 0.493 0.286 

0.440 0.500 0.370 0.500 0.310 

0.42 0.52 0.41 0.55 0.34 

0.790 0.640 0.491 0.636 0.370 

334 335 336 337 338 

0.029 0.041 0.011 0.068 0.067 

0.018 0.047 0.007 0.058 0.013 

0.038 0.076 0.016 0.055 0.021 

nq 0.045 nq 0.045 nq 

0.018 0.043 0.011 0.043 0.010 

0.012 0.072 0.012 0.050 0.012 

0.019 0.044 0.008 0.045 0.017 

0.023 0.059 0.011 0.067 0.017 

0.014 0.050 0.008 0.039 0.009 

334 335 336 337 338 

6.27 9.26 4.19 24.22 8.44 

6.61 9.54 4.19 23.81 8.90 

6.10 8.80 4.50 22.00 9.00 

6.29 9.38 4.10 23.52 8.36 

6.42 9.41 4.42 24.70 8.70 

6.88 10.38 4.27 25.15 8.64 

5.79 8.33 3.76 21.43 7.24 

5.90 9.79 4.35 24.86 8.90 

6.50 9.98 4.54 27.69 8.73 

5.97 9.27 4.12 21.95 8.71 

6.90 8.60 4.30 22.00 8.20 

5.40 8.80 4.60 21.70 8.40 

6.06 8.64 4.05 22.09 7.06 

6.20 9.40 4.30 24.00 8.30 

7.21 9.82 4.04 21.96 8.53 

6.92 10.60 4.31 28.10 8.79 

6.30 9.80 3.60 24.50 9.20 

7.22 10.56 4.36 26.51 8.72 

5.73 10.02 4.66 24.00 9.74 

6.25 9.40 4.28 26.24 8.96 

5.35 7.64 3.49 19.90 8.06 

6.35 9.45 3.97 23.80 8.56 

6.06 9.35 3.90 23.71 8.22 

6.95 10.37 4.72 24.69 9.31 

5.72 9.55 3.61 25.11 8.71 

6.70 9.50 4.80 24.80 9.40 

6.41 9.44 4.09 25.00 8.46 

6.31 9.24 3.95 23.66 8.26 

6.40 9.12 3.98 22.70 7.87 

8.57 13.66 5.32 37.18 11.36 

6.25 9.10 4.08 23.60 8.40 

7.30 10.30 4.50 25.60 8.80 

5.50 8.50 3.90 20.40 7.60 

3

3

4

4

3

4

3

3

3

3

3

4

3

3

3

5

3

4

3

4

5

3

N 31 31 31 31 31 6 6 6 6 6 8 9 8 9 8 33 33 33 33 33 

Min 0.344 0.408 0.316 0.415 0.179 0.391 0.443 0.300 0.461 0.280 0.012 0.041 0.007 0.039 0.009 5.35 7.64 3.49 19.90 7.06 3

Median 0.442 0.505 0.390 0.520 0.307 0.430 0.491 0.368 0.505 0.300 0.019 0.047 0.011 0.050 0.015 6.30 9.41 4.19 24.00 8.64 3

Max 0.596 0.622 0.484 0.650 0.370 0.790 0.640 0.491 0.636 0.370 0.038 0.076 0.016 0.068 0.067 8.57 13.66 5.32 37.18 11.36 5

SD 0.049 0.059 0.034 0.047 0.024 0.006 0.011 0.002 0.010 0.005 0.48 0.52 0.32 2.16 0.44 0

CV 11 12 9 9 8 30 24 22 19 32 8 6 8 9 5 

NIST 0.437 0.491 0.399 0.517 0.307 6.49 9.46 4.16 23.72 8.51 3

Npast 47 35 36 32 32 0 6 6 5 5 7 12 8 10 9 46 36 36 33 35 

Medianpast 0.437 0.490 0.389 0.520 0.306 0.488 0.402 0.510 0.308 0.054 0.053 0.012 0.057 0.025 6.42 9.45 4.18 23.69 8.41 3

SDpast 0.042 0.025 0.023 0.042 0.026 0.015 0.006 0.005 0.026 0.023 0.53 0.76 0.30 1.56 0.55 0

NAV 0.441 0.500 0.384 0.513 0.307 0.430 0.491 0.368 0.505 0.300 0.018 0.045 0.010 0.045 0.013 6.29 9.40 4.19 23.81 8.56 3

NAU 0.050 0.060 0.032 0.049 0.026 0.035 0.040 0.030 0.041 0.025 0.011 0.015 0.010 0.015 0.011 0.54 0.74 0.44 2.12 0.68 0

All Lab R eport 
Round Robin LXII Laboratory Results 

(μg/mL) 

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

Lab 334 335 336 337 338 

C3

FSV-BA 0.119 0.114 0.103 0.161 0.093 

FSV-BB 0.166 0.098 0.096 0.120 0.071 

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-BX 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 0.113 0.129 nd nd nd 

FSV-CI 

FSV-CS 

FSV-CW 0.177 0.128 0.122 0.037 0.095 

FSV-DD 

FSV-DF 

FSV-DI 0.140 0.105 0.096 0.042 0.072 

FSV-DV 

FSV-EE 

334 335 336 337 338 

0.160 0.287 0.042 0.580 0.152 

0.152 0.262 0.036 0.528 0.118 

0.135 0.271 0.032 0.506 0.155 

0.158 0.233 0.043 0.593 0.148 

0.150 0.259 0.033 0.583 0.129 

0.129 0.241 0.029 0.474 0.126 

0.104 0.257 0.026 0.566 0.144 

0.158 0.237 0.034 0.496 0.116 

0.202 0.292 0.045 0.537 0.173 

0.188 0.293 nd 0.562 0.150 

≥0.169 ≥0.286 ≥0.030 ≥0.542 ≥0.147

0.189 0.295 0.045 0.519 0.137 

0.148 0.285 0.038 0.555 0.130 

0.139 0.265 0.039 0.555 0.170 

0.145 0.320 0.038 0.590 0.160 

≥0.165 ≥0.254 ≥0.039 ≥0.529 ≥0.135

0.140 0.290 0.040 0.620 0.160 

0.164 0.287 0.039 0.574 

≥0.185 ≥0.303 ≥0.050 ≥0.558

0.222 0.347 0.050 0.604 

≥0.176 ≥0.356 ≥0.005 ≥0.721

0.142 0.294 0.041 0.505 

0.145 

≥0.108

0.139 

≥0.103

0.133 

334 335 336 337 338 

0.152 0.271 0.038 0.545 0.144 

0.145 0.245 0.033 0.495 0.113 

0.150 0.259 0.033 0.550 0.129 

0.147 0.223 0.030 0.456 0.111 

0.166 0.238 0.045 0.450 0.128 

0.169 0.286 0.030 0.542 0.147 

0.176 0.274 0.041 0.480 0.127 

0.165 0.254 0.039 0.529 0.135 

0.155 0.267 0.036 0.534 0.136 

0.185 0.303 0.050 0.558 0.108 

0.176 0.356 0.005 0.721 0.103 

334 335 336 

0.008 0.016 0.004 

0.008 0.017 0.003 

nq nq nq 

0.010 0.013 0.003 

0.037 0.054 nd 

0.012 0.021 0.004 

0.009 0.020 nd 

N 5 5 4 3 4 18 18 17 18 18 11 11 11 11 11 6 6 4 

Min 0.113 0.098 0.096 0.037 0.071 0.104 0.233 0.026 0.474 0.116 0.145 0.223 0.005 0.450 0.103 0.008 0.013 0.003 

Median 0.140 0.114 0.100 0.081 0.083 0.151 0.286 0.039 0.559 0.145 0.165 0.267 0.036 0.534 0.128 0.010 0.019 0.004 

Max 0.177 0.129 0.122 0.161 0.095 0.222 0.347 0.050 0.620 0.173 0.185 0.356 0.050 0.721 0.147 0.037 0.054 0.004 

SD 0.035 0.017 0.009 0.066 0.016 0.017 0.024 0.006 0.045 0.017 0.016 0.022 0.006 0.045 0.018 0.002 0.003 0.001 

CV 25 15 9 82 20 11 9 15 8 12 10 8 18 8 14 25 18 21 

NIST 0.166 0.280 0.045 0.553 0.148 

Npast 0 7 7 6 6 30 25 24 19 23 9 12 12 11 10 4 8 7 

Medianpast 0.115 0.100 0.058 0.088 0.171 0.285 0.042 0.548 0.146 0.174 0.277 0.039 0.507 0.133 0.008 0.020 0.003 

SDpast 0.006 0.014 0.094 0.092 0.033 0.033 0.010 0.046 0.019 0.013 0.024 0.005 0.034 0.014 0.004 0.003 

NAV 0.119 0.105 0.096 0.120 0.072 0.150 0.285 0.039 0.555 0.144 0.160 0.263 0.037 0.532 0.129 0.010 0.019 0.004 

NAU 0.026 0.024 0.024 0.042 0.010 0.077 0.023 0.018 0.029 0.008 0.056 0.015 0.004 0.006 

All Lab R eport 
Round Robin LXII Laboratory Results 

(μg/mL) 

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

Lab 334 335 336 337 338 

C4

334 335 336 337 338 

0.484 0.229 0.143 0.255 0.576 

0.479 0.216 0.136 0.249 0.485 

0.494 0.199 0.118 0.268 0.520 

0.564 0.247 0.143 0.299 0.587 

0.365 0.198 0.113 0.215 0.478 

0.572 0.290 0.186 0.341 0.693 

0.477 0.213 0.129 0.262 0.501 

0.592 0.255 0.184 0.263 0.615 

0.405 0.598 0.521 0.336 0.586 

0.401 0.191 0.111 0.211 0.462 

0.451 0.255 0.161 0.260 0.535 

0.554 0.237 0.152 0.250 0.554 

0.533 0.233 0.150 0.292 0.699 

0.640 0.270 0.161 0.265 0.700 

0.563 0.262 0.153 0.306 0.604 

0.675 0.343 0.199 0.346 0.680 

0.505 0.265 0.180 0.300 0.510 

334 335 336 337 338 

0.329 0.141 0.077 0.147 0.349 

0.261 0.114 0.070 0.109 0.248 

0.286 0.096 0.053 0.117 0.257 

0.315 0.117 0.068 0.121 0.266 

0.311 0.141 0.081 0.095 0.289 

0.258 0.101 0.057 0.088 0.243 

0.358 0.138 0.076 0.125 0.322 

0.319 0.108 0.048 0.086 0.267 

334 335 336 337 338 

0.078 0.063 0.046 0.127 0.129 

0.060 0.045 0.045 0.106 0.096 

0.072 0.045 0.033 0.098 0.103 

0.061 0.044 0.035 0.100 0.109 

0.052 0.046 0.033 0.099 0.111 

0.047 0.037 0.031 0.086 0.084 

0.050 0.037 0.026 0.089 0.094 

0.055 0.043 0.035 0.090 0.105 

0.070 0.040 nd 0.079 0.048 

0.044 0.036 0.026 0.084 0.095 

0.059 0.048 0.036 0.094 0.103 

0.064 0.045 0.039 0.104 0.116 

0.040 0.032 0.025 0.083 0.097 

0.050 0.045 0.036 0.094 0.109 

0.070 0.044 0.035 0.099 0.113 

0.094 0.068 0.049 0.140 0.153 

0.068 0.051 0.037 0.086 0.093 

0.068 0.050 0.035 0.123 0.119 

FSV-BA 0.231 0.057 0.007 0.308 0.015 

FSV-BB 0.236 0.050 0.004 0.297 0.011 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 0.211 0.042 0.012 0.296 0.016 

FSV-BH 0.401 0.054 nq 0.326 nq 

FSV-BI 0.306 0.055 0.005 0.289 0.013 

FSV-BJ 0.275 0.060 nq 0.359 0.012 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.350 0.048 0.006 0.294 0.012 

FSV-BO 0.384 0.053 0.006 0.292 0.014 

FSV-BP 0.280 0.053 nd 0.282 nd 

FSV-BQ 

FSV-BR 

FSV-BS 0.431 0.071 0.007 0.355 0.036 

FSV-BT 0.300 0.055 0.008 0.245 0.021 

FSV-BU 0.367 0.069 0.020 0.296 0.026 

FSV-BV 0.396 0.054 0.005 0.344 0.018 

FSV-BW 0.200 0.037 0.006 0.170 0.024 

FSV-BX 0.327 0.048 0.000 0.275 0.010 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 0.447 0.071 nd 0.386 0.019 

FSV-CI 0.237 0.075 0.022 0.289 0.036 

FSV-CS 0.375 0.070 0.007 0.343 0.010 

FSV-CW 0.472 0.070 0.004 0.391 0.006 

FSV-DD 

FSV-DF 

FSV-DI 0.270 0.060 0.015 0.245 0.045 

FSV-DV 

FSV-EE 

334 

0.036 

0.020 

0.012 

0.023 

N 

Min 

Median 

Max 

SD 

CV 

NIST 

Npast 

Medianpast 

SDpast 

NAV 

NAU 

20 20 16 

0.200 0.037 0.000 

0.316 0.055 0.007 

0.472 0.075 0.022 

0.093	 0.013 0.003 

29 23 44 

0.281	 0.054 nq 

25 23 18 

0.308 0.057 0.008 

0.094 0.008 0.004 

0.311 0.055 0.007 

0.086 0.017 0.004 

20 

0.170 

0.296 

0.391 

0.042 

14 

0.282 

19 

0.316 

0.044 

0.295 

0.075 

18 

0.006 

0.016 

0.045 

0.008 

54 

0.019 

19 

0.016 

0.005 

0.016 

0.008 

17 

0.365 

0.505 

0.675 

0.065 

13 

17 

0.191 

0.247 

0.598 

0.036 

15 

17 

0.111 

0.152 

0.521 

0.033 

21 

17 

0.211 

0.265 

0.346 

0.033 

13 

17 

0.462 

0.576 

0.700 

0.078 

13 

8 

0.258 

0.313 

0.358 

0.031 

10 

8 

0.096 

0.116 

0.141 

0.024 

21 

8 

0.048 

0.069 

0.081 

0.015 

21 

8 

0.086 

0.113 

0.147 

0.021 

19 

8 

0.243 

0.267 

0.349 

0.032 

12 

18 

0.040 

0.061 

0.094 

0.014 

23 

0.063 

25 

0.060 

0.014 

0.060 

0.014 

18 

0.032 

0.045 

0.068 

0.005 

11 

0.049 

24 

0.045 

0.009 

0.045 

0.011 

4 

0.012 

0.022 

0.036 

0.006 

28 

26 23 23 17 20 

0.474 0.238 0.150 0.269 0.585 

0.085 0.038 0.025 0.024 0.063 

0.505 0.247 0.152 0.265 0.576 

0.104 0.058 0.039 0.062 0.116 

17 

0.025 

0.035 

0.049 

0.003 

8 

0.036 

24 

0.035 

0.005 

0.035 

0.009 

18 

0.079 

0.096 

0.140 

0.012 

13 

0.092 

17 

0.097 

0.017 

0.094 

0.021 

18 

0.048 

0.104 

0.153 

0.013 

12 

0.117 

20 

0.108 

0.027 

0.103 

0.023 

9 9 9 7 7 

0.417 0.122 0.069 0.100 0.298 

0.080 0.012 0.007 0.016 0.049 

0.299 0.116 0.069 0.113 0.262 

0.054 0.029 0.015 0.021 0.047 

4 

0.033 

0.022 

All Lab R eport	 
Round Robin LXII Laboratory Results 

(μg/mL) 

Total Lutein Total Zeaxanthin Total Lutein&Zeaxanthin Coenzyme Q

Lab 334 335 336 337 338 

C5

FSV-BA
 

FSV-BB
 0.050 0.069 0.018 0.172 0.161 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 0.072 0.055 0.030 0.153 0.155 

FSV-BH 0.037 0.046 0.013 0.115 0.095 

FSV-BI 0.043 0.054 0.021 0.122 0.122 

FSV-BJ 0.063 0.057 0.025 0.135 0.130 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.161 0.048 0.004 0.138 0.128 

FSV-BO 0.044 0.060 0.022 0.147 0.145 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-BX 0.061 0.080 0.024 0.180 0.187 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 0.076 0.089 0.038 0.182 0.189 

FSV-CS 0.053 0.065 0.024 0.025 0.058 

FSV-CW 0.063 0.096 0.023 0.222 0.206 

FSV-DD 

FSV-DF 

FSV-DI 0.170 0.074 0.028 0.141 0.165 

FSV-DV 

FSV-EE 

334 335 336 337 338 

0.094 0.034 0.019 0.042 0.109 

0.035 0.017 0.016 0.029 0.056 

0.101 0.016 0.012 0.023 0.072 

0.123 0.025 0.016 0.036 0.072 

0.017 0.021 0.011 0.031 0.059 

0.119 0.018 0.011 0.019 0.062 

0.110 0.010 0.007 0.022 0.066 

0.093 0.022 0.022 0.028 0.054 

0.116 0.020 0.015 0.128 0.132 

0.094 0.022 0.016 0.027 0.057 

334 335 336 337 338 

0.117 0.085 0.039 0.174 0.214 

0.144 0.103 0.037 0.214 0.270 

0.088 0.061 0.034 0.165 0.178 

0.138 0.062 0.025 0.138 0.167 

0.166 0.079 0.037 0.158 0.194 

0.183 0.075 0.020 0.177 0.200 

0.163 0.078 0.033 0.166 0.207 

0.170 0.068 0.066 0.102 0.089 

0.117 0.078 0.007 0.200 0.278 

0.116 0.096 0.049 0.179 0.199 

0.138 0.085 0.039 0.189 0.231 

0.133 0.080 0.034 0.177 0.252 

0.160 0.086 0.025 0.170 0.220 

0.171 0.090 0.031 0.202 0.252 

0.199 0.125 0.058 0.256 0.301 

0.169 0.111 0.060 0.210 0.243 

0.169 0.085 0.039 0.153 0.190 

0.157 0.118 0.049 0.249 0.263 

334 335 336 

0.56 0.62 0.52 

0.31 0.44 0.46 

0.60 0.64 0.62 

0.14 0.47 0.40 

0.64 0.67 0.63 

0.51 0.61 0.65 

N 12 12 12 12 12 10 10 10 10 10 18 18 18 18 18 6 6 6 

Min 0.037 0.046 0.004 0.025 0.058 0.017 0.010 0.007 0.019 0.054 0.088 0.061 0.007 0.102 0.089 0.14 0.44 0.40 

Median 0.062 0.062 0.023 0.144 0.150 0.098 0.021 0.016 0.029 0.064 0.159 0.085 0.037 0.177 0.217 0.54 0.61 0.57 

Max 0.170 0.096 0.038 0.222 0.206 0.123 0.034 0.022 0.128 0.132 0.199 0.125 0.066 0.256 0.301 0.64 0.67 0.65 

SD 0.018 0.015 0.004 0.031 0.033 0.016 0.003 0.003 0.008 0.011 0.026 0.012 0.011 0.027 0.042 0.17 0.10 0.11 

CV 29 25 17 22 22 16 17 21 28 17 16 14 30 15 19 32 16 20 

NIST 0.155 0.078 0.039 0.173 0.205 0.061 0.061 0.027 0.151 0.144 0.094 0.017 0.012 0.022 0.061 

Npast 13 16 14 13 14 11 12 13 11 11 24 23 22 17 20 0 6 6 

Medianpast 0.047 0.064 0.025 0.157 0.146 0.112 0.023 0.017 0.026 0.062 0.158 0.087 0.039 0.187 0.211 0.62 0.55 

SDpast 0.014 0.008 0.007 0.016 0.036 0.031 0.006 0.004 0.004 0.018 0.039 0.006 0.010 0.020 0.055 0.10 0.09 

NAV 0.057 0.062 0.023 0.144 0.141 0.098 0.019 0.014 0.029 0.064 0.152 0.082 0.036 0.176 0.210 0.54 0.61 0.57 

NAU 0.022 0.013 0.005 0.026 0.026 0.033 0.006 0.005 0.009 0.017 0.036 0.017 0.008 0.037 0.044 0.17 0.10 0.11 

All Lab R eport 
Round Robin LXII Laboratory Results 

(μg/mL) 

Ubiquinol Ubiquinone Phylloquinone (K1) x1000 25-hydroxyvitamin D x1

C6

Lab 334 335 336 337 338 334 335 336 337 338 334 335 336 337 338 334 335 336 337 

FSV-BA 

FSV-BB 0.020 0.011 nq 0.01

FSV-BC 

FSV-BD 

FSV-BE 0.259 0.853 0.181 1.698 0.645 

FSV-BF 

FSV-BG 

FSV-BH 

FSV-BI 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.005 0.016 0.006 0.02

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 

FSV-BU 

FSV-BV 

FSV-BW 0.06 0.25 0.27 0.19 1.12 0.25 0.20 0.19 0.29 0.17 

FSV-BX 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 0.164 0.667 0.130 1.272 0.523 

FSV-CS 

FSV-CW 

FSV-DD 

FSV-DF 

FSV-DI 0.13 0.64 0.93 0.05 1.62 0.48 0.24 0.05 0.65 0.16 0.270 0.600 0.230 0.940 0.520 

FSV-DV 

FSV-EE 

N 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 2 2 1 

Min 0.059 0.247 0.271 0.045 1.120 0.249 0.197 0.050 0.290 0.160 0.16 0.60 0.13 0.94 0.52 0.005 0.011 0.01

Median 0.096 0.444 0.601 0.118 1.370 0.362 0.218 0.119 0.470 0.164 0.26 0.67 0.18 1.27 0.52 0.013 0.014 0.006 0.02

Max 0.133 0.640 0.930 0.191 1.620 0.475 0.239 0.187 0.650 0.168 0.27 0.85 0.23 1.70 0.65 0.020 0.016 0.02

SD 

CV 

NIST 

Npast 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Medianpast 0.01

SDpast 0.00

NAV 0.259 0.667 0.181 1.272 0.523
 

NAU
 

All Lab R eport 
 

 

Round Robin LXII Laboratory Results
 

Term Legend 

N Number of quantitative values reported for this analyte 

Min Minimum quantitative value reported 

Median Median quantitative value reported 

Max Maximum quantitative value reported 

SD Standard deviation for results: (Median Absolute Difference from the median)/0.674 

CV Coefficient of Variation for results: 100*SD/Median 

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

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

SDpast Pooled SD from past RR(s) 

NAV NIST Assigned Value: Median, when sufficient data are available 

NAU NIST Assigned Uncertainty: Max(0.05*NAV, SD, eSD). The expected long-term SD, eSD,

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

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

nq Detected but not quantitatively determined 

≤x Concentration at or below the limit of quantification, x 

italics Not explictly reported but calculated by NIST from reported values 

All Lab Report Page 6 / 7 

C7
 

 

 

 

 

 

 

Round Robin LXII Laboratory Results
 

Comparability Summary
 

Lab 

0??? 

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-BX 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 

FSV-CS 

FSV-CW
 

FSV-DD
 

FSV-DF
 

FSV-DI
 

FSV-DV
 

FSV-EE
 

NIST 

n 

% 1
 

% 2
 

% 3
 

% 4
 

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

1 1 1 1 1 1 1 2 1
 

2 1 1 1 1 1 1 1 1 2 1
 

1
 

1 1
 

1 1 1 1
 

1 1 1
 

1 1 1 1 2 1 1 1 1 2
 

2 2 1 1 1 1 1 1 2 1 2
 

1 1 2 1 1 1 1 1 1 1
 

1 1 1 2 1 1 1 1
 

1 1
 

2 1
 

1 2
 

1 2 2 1 2 1 1 1 3 2 2
 

2 1 2 2 2 1 1 1 1 1 1
 

1 2 1 1 4 2 3
 

2 2
 

2 1
 

2 2 2 1 1 2 1 1 3
 

1 2 1 1 1 1 1 1 2
 

1 1 1 1 2 1 1 1
 

3 2 2 1 1 1 2 1
 

1 1 4 1 2 1 1 1
 

1 1 2 1 1 1 1 2 2 1
 

1 2
 

3 1 1
 

2 1
 

2 1 1 1 1 2 1 3 3
 

1 1 1 2 2 3 2 1 2
 

2 1 1 2 1 2 1 3 4 1
 

2 4 3 3 4 2 1 3 1 2
 

1
 

1
 

1 1 1 1 3 1 3
 

4 2
 

2 2
 

1 1 1 1 1 1 1 1 1
 

37 34 22 23 11 21 17 19 13 11 19
 

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

59 65 64 78 64 62 88 79 46 64 53
 

32 32 27 17 27 29 6 16 23 27 32
 

5 0 5 4 0 10 0 5 31 0 16
 

3 3 5 0 9 0 6 0 0 9 0
 

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
 

i NAU 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 RR62 

Each participant in RR62 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 RR62: 

• Total Retinol 

• trans-Retinol 

• Retinyl Palmitate 

• α-Tocopherol 

• γ/β-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 13 pages are the “Individualized Report” for the analytes evaluated by 

participant FSV-BA. 

D1
 

 Set 1 of 41 

Individualized Round Robin LXII Report: FSV-BA 

Summary 

Serum 334 Serum 335 Serum 336 Serum 337 

D2

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

Total Retinol 0.465 0.441 31 0.505 0.500 31 0.423 0.384 31 0.540 0.513 31 

Retinyl Palmitate 0.03 0.02 8 0.0 0.0 9 0.0 0.0 8 0.07 0.05 9 

α-Tocopherol 6.27 6.29 33 9.26 9.40 33 4.19 4.19 33 24.22 23.81 33 

γ/β-Tocopherol 3.501 3.750 21 1.829 1.795 21 1.774 1.730 21 1.119 0.940 21 

δ-Tocopherol 0.119 0.119 5 0.114 0.105 5 0.103 0.096 4 0.161 0.120 4 

Total β-Carotene 0.160 0.150 18 0.287 0.285 18 0.042 0.039 17 0.580 0.555 18 

trans-β-Carotene 0.152 0.160 11 0.271 0.263 11 0.038 0.037 11 0.545 0.532 11 

Total cis-β-Carotene 0.008 0.010 6 0.016 0.019 6 0.004 0.004 4 0.035 0.038 7 

Total α-Carotene 0.231 0.311 20 0.057 0.055 20 0.007 0.007 16 0.308 0.295 20 

Total Lycopene 0.484 0.505 17 0.229 0.247 17 0.143 0.152 17 0.255 0.265 17 

trans-Lycopene 0.329 0.299 8 0.141 0.116 8 0.077 0.069 8 0.147 0.113 8 

Total β-Cryptoxanthin 0.078 0.060 18 0.063 0.045 18 0.046 0.035 17 0.127 0.094 18 

Total α-Cryptoxanthin 0.036 0.022 4 0.033 0.025 4 0.018 0.018 3 0.050 0.037 4 

Total Lutein&Zeaxanthin 0.117 0.152 18 0.085 0.082 18 0.039 0.036 18 0.174 0.176 18 

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 

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 
 

NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

Total Retinol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

241334315335316336329337326331338 

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 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 2 / 13 

D3
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

Retinyl Palmitate, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 3 / 13 

D4
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

α-Tocopherol, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 4 / 13 

D5
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

γ/β-Tocopherol, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 5 / 13 

D6
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

Total β-Carotene, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 6 / 13 

D7
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

trans-β-Carotene, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 7 / 13 

D8
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

Total α-Carotene, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 8 / 13 

D9
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

Total Lycopene, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

241334315335316336329337326331338 

Apparent Precision, SD 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 9 / 13 

D10
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

trans-Lycopene, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 10 / 13 

D11
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

Total β-Cryptoxanthin, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 11 / 13 

D12
NIST, this RR

 

 Set 1 of 41 

Individualized RR LXII Report: FSV-BA

Total Lutein&Zeaxanthin, μg/mL 

[Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

Apparent Precision, SD 

241334315335316336329337326331338 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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.
 

Serum History Comments 

#334 Lyophilized, 42:#241 Augmented (RP,gT,dT,bC,aC,Z,Ly) 

#335 Fresh frozen, 58:#315 Native, multi-source 

#336 Fresh frozen, 58:#316 Native, multi-source 

#337 Fresh frozen, 61:#329 Native, single-source 

#338 Fresh frozen: 60:#326, 61:#331 Native, single-source 

Individualized Report Page 12 / 13 

D13
 Set 1 of 41 

Individualized Round Robin LXII Report: FSV-BA 

Graphical Comparability Summary
 

Total Retinol α-Tocopherol Total β-Carotene 

D14

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 RR27 

The following five items were included in each package shipped to an RR27 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
May 29, 2007 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

The samples within this package constitute Vitamin C Round Robin 27 (RR27) of the 2007 Micronutrients 

Measurement Quality Assurance Program. 

RR27 consists of four vials of frozen serum test samples (#36, #56, #115, and #118), one vial of frozen control 

serum (CS #2) and one vial of ascorbic' acid solid control material (Control) 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.) 

Please use the control serum to validate the performance of your measurement system before you analyze the 

test samples. The target value and ;::::95% confidence interval for target value and ~95% confidence interval for 

CS #2 is 28.1 ±1.0 μmol/L of sample. 

The report for RR26 was mailed the week of May 4, 2007. If you find your results for RR26 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). 

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 

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

observe unusually large variation in replicate analyses. 

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 these RR27 samples by September 28, 2007. We would appreciate 

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

kept confidential. 

e ce Brown Thomas 

Re earch Chemist 

alytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures: Pr<?tocols, Preparation and Analysis of Control Materials and Analysis of Test Samples 

RR27 Report Form for Ascorbic Acid Solid Control Material Preparation 

RR27 Report Form for Control Material and Test Sample Analyses 

NISI 

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 27 

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 before September 28, 2007 

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 27 

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 CS #2 

Target: 28.1 ±1.0 μmol/L 

Serum Test Sample #36 μmol/L of Sample 

Serum Test Sample #46 μmol/L of Sample 

Serum Test Sample #56 μmol/L of Sample 

Serum Test Sample #114 μmol/L of Sample 

Serum Test Sample #118 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 before September 28, 2007 

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 27
 

NIST Micronutrients Measurement Quality Assurance Program
 

Packing List and Shipment Receipt Confirmation Form
 

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

Label Form
 

VitC #36 Liquid frozen (1:1 serum:10% MPA) 

VitC #56 Liquid frozen (1:1 serum:10% MPA) 

VitC #114 Liquid frozen (1:1 serum:10% MPA) 

VitC #118 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 RR27 

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
February 15, 2013 

Dear Colleague: 

UNn'ED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed is the summary report of the results for Round Robin 27 (RR27) for the measurement 

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

in this report are a summary of data for all laboratories and an individualized sU.mmary 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 27 consisted of four test samples (#36, #56, #114, and #118), one serum control material, 

and one solid control material for preparation of T AA control solutions. Details regarding the 

samples can be found in the enclosed report. 

If you have concerns regarding your laboratory's performance, 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. 

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 fax: 3 -977-0685. 

I ) ex 

e ice Brown Thomas 

search Chemist 

alytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

Cc: L. C. Sander 

D.L. Duewer 

F2
 

 

The NIST M2QAP Vitamin C Round Robin 27 (RR27) 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 serum control sample, and the four serum test 

samples. 

2 Graphical summary of your RR27 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR27 

samples and control/calibration solutions. 

Serum-based Samples. One serum control and four unknowns were distributed in RR27. 

CS#2 SRM 970 level 2, ampouled in mid-1998. 

S27:1 Serum 36, ampouled in late 2001, previously distributed as sample S17:2 (RR17, Fall 02), 

S18:1 (RR18, Spring 03), S20:1 (RR20, Spring 04), S22:2 (RR22, Spring 05), and S23:2 

(RR23, Fall 05). 

S27:2	 Serum 56, ampouled in late 2001, previously distributed as sample S16:3 (RR16, Spring 02), 

S17:3 (RR17, Fall 02),S20:2 (RR20, Spring 04), S21:4 (RR21, Fall 04), and S23:3 (RR23, 

Fall 05). 

S27:3 Serum 114, ampouled in 1995, previously distributed as sample 188a in (RR9, Summer 96). 

S27:4 Serum 118, ampouled in 1995, previously distributed as sample 688a in (RR8, Fall 95) and 

(RR9, Summer 96). 

Results. 

1)	 All participants who prepared the four 5% MPA control/calibration solutions 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 

(≈0.58 OD), the calculated E1% #1”(≈560 dL/g·cm). 

2)	 Judging from the calibration parameters calculated for the control/calibration solutions (intercepts 

close to 0.0, slopes close to 1.0, R2

 close to 1, and RMS close to 0.0), the measurement systems for 

most participants are linear and fairly well calibrated. However, several measurement systems 

perform somewhat differently for the control solutions than with the serum samples. 

3)	 Sample S27:2 (Serum 56): One participant with concordant results for the other serum materials 

reported low results for this high-level material. While other participants reported systematically low 

results for all materials, there were no other anomalous results for this material. Evaluation of the 

participant’s prior results for S27:2 material suggests that variable results with high-level materials 

may be characteristic of the particular measurement system. While a seal-defect in the ampoule 

analyzed is possible, we do not believe that this six-year old material per se has degraded. 

4)	 Sample S27:4 (Serum 118): The median result for this material is unchanged from 1995 values. 

However, four participants reported discordantly high values for this low-level material. Since 

“degradation” should not increase [TAA], we do not believe that the apparent increased variability 

results from storage – particularly since several of these participants reported systematically higher 

than expected results. However, it is plausible that some ampoules have become miss-identified over 

the years. If we distribute this material again, it will be accompanied by the low-level CS#1. 

F3
Appendix G. “All-Lab Report” for RR27 

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" 27 - September 2007 

Control / Calibration Samples MPA Dilute Solution 1 Sample

G2

Density 

Lab Date Dil:1 Dil:2 Dil:3 Dil:1 Dil:2 Dil:3 MPA Inter Slope R2 RMS g/mL λmax Amax E1% CS#2 S27:1 S27:2 S27:3 S27:4 C

VC-MA 05/10/07 57.2 28.5 14.0 56.8 28.1 13.9 0.0 -0.05 0.99 1.000 0.1 1.032 242. 0.5610 557.2 27.7 22.6 48.1 28.5 13.8 

VC-MB 09/07/07 57.6 28.6 14.2 58.6 29.7 14.7 0.0 0.23 1.02 1.000 0.3 1.029 244. 0.5650 557.3 27.1 18.1 45.9 27.4 13.2 

VC-MC 16/07/07 56.0 28.1 13.9 59.0 30.3 15.2 0.0 0.39 1.05 1.000 0.5 1.030 243. 0.5486 556.0 28.4 22.6 47.9 28.4 13.4 

VC-ME 18/07/07 56.9 29.2 14.3 59.2 29.1 14.4 0.0 -0.45 1.04 0.999 0.8 1.037 243. 0.5610 559.7 27.6 22.1 33.4 27.5 14.5 

VC-MG 13/08/07 61.1 31.0 16.5 62.3 30.5 15.8 0.0 -0.62 1.02 0.999 0.7 1.029 243.5 0.6170 573.8 29.0 26.1 51.4 35.1 18.3 

VC-MH 28/08/07 62.4 31.1 15.5 62.5 31.1 15.4 0.0 -0.08 1.00 1.000 0.1 1.031 244.1 0.6220 566.4 27.4 21.1 44.7 28.4 13.9 

VC-MI 06/08/07 56.5 28.3 14.0 59.5 29.2 14.6 0.0 -0.21 1.05 1.000 0.4 1.027 27.5 20.3 45.3 26.7 13.2 

VC-MJ 25/09/07 48.2 24.6 12.3 51.3 27.8 14.1 10.1 6.84 0.89 0.974 3.7 1.029 254 a 0.303 a 356.8 a 29.7 26.0 51.2 36.4 18.2 

VC-MK 13/08/07 57.5 28.7 14.5 60.8 27.8 15.9 4.8 2.61 0.98 0.990 3.0 1.030 244. 0.5682 560.7 35.9 26.5 51.1 42.4 20.1 

VC-MN 28/09/07 61.1 30.6 15.0 63.4 30.9 14.3 0.0 -0.70 1.04 0.999 0.8 1.031 244. 0.6051 562.3 29.3 25.8 48.9 31.9 21.3 

VC-MU 19/09/07 57.2 28.8 13.8 54.5 25.9 12.8 0.0 -0.46 0.95 0.999 0.9 1.030 245. 0.5426 538.4 23.0 14.8 39.8 19.3 9.1 

11 11 11 11 11 11 11 11 9 9 9 11 11 11 11 11 

57.4 28.9 14.4 58.9 29.1 14.6 1.4 1.030 243.6 0.5767 559.1 28.4 22.3 46.1 30.2 15.4 

3.7 1.8 1.1 3.6 1.6 0.9 3.2 0.003 0.9 0.0299 9.5 3.1 3.7 5.5 6.1 3.6 

48.2 24.58 12.3 51.3 25.85 12.8 0.0 1.027 242.0 0.5426 538.4 23.0 14.8 33.4 19.3 9.1 

56.7 28.41 13.9 57.7 27.95 14.2 0.0 1.029 243.0 0.5610 557.2 27.4 20.7 45.0 27.5 13.3 

57.2 28.74 14.2 59.2 29.15 14.6 0.0 1.030 244.0 0.5650 559.7 27.7 22.6 47.9 28.4 13.9 

59.3 29.93 14.8 61.5 30.43 15.3 0.0 1.031 244.0 0.6051 562.3 29.2 25.9 50.0 33.5 18.3 

62.4 31.08 16.5 63.4 31.05 15.9 10.1 1.037 245.0 0.6220 573.8 35.9 26.5 51.4 42.4 21.3 

1.1 0.8 0.5 3.6 2.0 0.9 0.0 0.0 0.7 0.0243 3.9 0.9 4.7 4.7 2.5 1.1 

2 3 3 6 7 6 0.13 0.30 4.3 0.7 3 21 10 9 8 

MADe eSD 

CV CV 

Median Median 

%75 %75 

Max Max 

Min Min 

%25 %25 

N N 

Average Average 

SD SD 

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

a) 5% Trichloroacetic acid solution 

3/18/2013 
Appendix H. Representative “Individualized Report” for RR27 

Each participant in RR27 received an “Individualized Report” reflecting their reported 

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

“VC-MA”. 

H1
 

Set 1 / 11 

Vitamin C "Round Robin" 27 Report: Participant VC-MA
 

MPA Dilute Solution 1 Control/Calibration Solutions 

Density Spectrophotometry Ymeas = Inter + Slope* Xgrav 

Date RR Method 

03/08/05 22 HPLC-EC 

10/17/05 23 HPLC-EC 

03/09/06 24 HPLC-EC 

08/28/06 25 HPLC-EC 

03/20/07 26 HPLC-EC 

10/05/07 27 HPLC-EC 

g/mL 

1.034 

1.030 

1.031 

1.039 

1.033 

1.032 

λmax Amax E1% 

243.0 0.559 562.9 

244.0 0.562 567.9 

244.0 0.568 586.7 

242.0 0.555 557.4 

244.0 0.573 554.3 

242.0 0.561 557.2 

Inter Slope R2 SEE 

0.2 1.06 1.000 0.24 

-0.6 1.09 0.998 1.47 

0.2 1.13 1.000 0.41 

0.8 0.95 0.999 0.92 

0.3 1.00 1.000 0.31 

-0.1 0.99 1.000 0.14 

Mean 1.033 243.2 0.56 564.4 0.58 

SD 0.003 1.0 0.01 12.0 0.51 

CV 0.31 0.40 1.2 2.1 

[TAA] mmol/Lsample 

6 23.6 0.5 1.0 

6 48.6 1.5 1.4 

2 27.1 0.2 2.0 

Date RR Sample 

03/08/05 22 CS#2 

10/17/05 23 CS#2 

03/09/06 24 CS#2 

08/28/06 25 CS#2 

10/05/07 27 CS#2 

12/12/02 17 S17:2 

03/20/03 18 S18:1 

02/23/04 20 S20:1 

03/08/05 22 S22:2 

10/17/05 23 S23:2 

10/05/07 27 S27:1 

11/18/02 16 S16:3 

12/12/02 17 S17:3 

02/23/04 20 S20:2 

09/13/04 21 S21:4 

10/17/05 23 S23:3 

10/05/07 27 S27:2 

06/19/96 09 S09:2 

10/05/07 27 S27:3 

Rep1 Rep2 Fadj Mean SDdup 

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 

27.2 28.1 1.0 27.6 0.6 

28.1 27.4 1.0 27.7 0.5 

N Mean SDrepeat SDreprod 

5 28.7 0.5 1.0 

23.3 23.4 1.0 23.4 0.1 

22.7 23.7 1.0 23.2 0.7 

25.1 24.1 1.0 24.6 0.7 

22.7 22.7 1.0 22.7 0.0 

25.5 24.4 1.0 24.9 0.8 

22.9 22.4 1.0 22.6 0.4 

49.9 44.9 1.0 47.4 3.5 

49.7 49.1 1.0 49.4 0.4 

50.6 50.0 1.0 50.3 0.4 

47.1 47.0 1.0 47.0 0.0 

49.8 48.8 1.0 49.3 0.7 

48.6 47.6 1.0 48.1 0.8 

51.7 51.1 0.5 25.7 0.2 

28.5 28.6 1.0 28.5 0.1 

29.1 23.8 0.5 13.2 1.9 

13.9 13.7 1.0 13.8 0.2 

ND 08 2 13.5 1.3 1.0 

06/19/96 09 S09:1 

10/05/07 27 S27:4 

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 / 11 

Vitamin C "Round Robin" 27 Report: Participant VC-MA 

Total Ascorbic Acid 

[Total Ascorbic Acid], μmol/L 

Your [Total Ascorbic Acid], μmol/L 

S17:2S18:1S20:1S22:2S23:2S27:1S16:3S17:3S20:2S21:4S23:3S27:2S09:2S27:3S08:2S09:1S27:4

S22:CS#2S23:CS#2S24:CS#2S25:CS#2S27:CS#2 

Median [Total Ascorbic Acid], μmol/L 

Apparent Precision, SD 

Concordance, SD 

You, this RR control 

Median (50%) 

3rd Quartile (75%) You, this RR samples 

You, past samples You, past controls 

1st Quartile (25%) Others, this RR 

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 

S27:1 VitC #36, previously distributed in RRs 17, 18, 20, 22, and 27 

S27:2 VitC #56, previously distributed in RRs 16, 17, 20, 21, and 23 

S27:3 VitC #114, previous distributed in RR 9 

S27:4 VitC #118, previous distributed in RR 8 and 9 

Individualized Report Page 2 / 2 

H3