NISTIR 7880-2 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2011 

Comparability Studies 

Results for Round Robin LXX 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 35 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

 

 

 

 

 

NISTIR 7880-2
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2011 

Comparability Studies 

Results for Round Robin LXX 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 35 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 2011 MMQAP measurement comparability improvement studies: 1) Round Robin LXX 

Fat-Soluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 35 Total Ascorbic Acid 

in Human Serum. The materials for both studies were shipped to participants in May 2011; 

participants were requested to provide their measurement results by September 19, 2011. 

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 LXX: Fat-Soluble Vitamins and Carotenoids in Human Serum .......................... 1
	

Round Robin 35: Vitamin C in Human Serum............................................................................... 2
	

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

Appendix A. Shipping Package Inserts for RR70........................................................................ A1
	

Appendix B. Final Report for RR70 .............................................................................................. B1 

Appendix C. “All-Lab Report” for RR70 ...................................................................................... C1
	

Appendix D. Representative “Individualized Report” for RR70 ............................................... D1
	

Appendix E. Shipping Package Inserts for RR35 ......................................................................... E1
	

Appendix F. Final Report for RR35............................................................................................... F1
	

Appendix G. “All-Lab Report” for RR35..................................................................................... G1
	

Appendix H. Representative “Individualized Report” for RR35............................................... 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, alpha-tocopherol, gamma/betatocopherol, trans- and total beta-carotene, and total ascorbic acid) and performanceevaluation 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 LXX: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

Round Robin LXX comparability study (hereafter referred to as RR70) received one 

lyophilized and four liquid-frozen 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 2011. 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 RR70 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. 

•	 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 35: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 35 comparability 

study (hereafter referred to as RR35) 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 2011. 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 RR35 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. 
 

 

 

 

 

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. 
 

Appendix A. Shipping Package Inserts for RR70 

The following three items were included in each package shipped to an RR70 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
May 23, 2011 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

Natianal Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed are samples for the second fat-soluble vitamins and carotenoids in serum study (Round Robin 

LXX) for the 2011 NIST Micronutrients Measurement Quality Assurance Program. The set of samples 

(Sera 377- 381) consists of one vial each of four liquid-fro:?en serum samples and one lyophilized sample 

for analysis along with a form for reporting your results. These samples should be stored in the dark at or 

below -20 °C upon receipt. When reporting your results, please submit one value for each analyte for a 

given serum sample. If a value obtained is below your limit of quantification, please ind!cate this result 

on the form by using NQ (Not Quantified). Results are due to NIST by September 19, 2011. Results 

received more than two weeks after the due date may not be included in the summary report for this round 

robin study. The feedback report concerning the study will be distributed in October 2011. 

Samples should be allowed to stand at room temperature under subdued light until thawed. We 

recommend that sample mixing be facilitated with 3 to 5 min agitation in an ultrasonic bath or at least 15 

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 retinol in most LC systems creating analytical problems.) 

Water should not be added to the liquid-frozen samples. 

For consistency, we request that laboratories use the following absorptivities (dL/g ·cm): retinol, 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); 13-carotene, 2560 at 450 nm 

(ethanol), 2592 at 452 nm (hexane); and lycopene, 3450 at 472 nm (hexane). · 

Please report your results for Round Robin LXX by e-mail to david.duewer@nist.gov or fax to 301-977-

0685. If you have questions or comments regarding this study, please call me at (301) 975-3120 or e-mail 

me at jbthomas@nist.g 

Jeanice Brown Thomas 

Program Coordinator/Research Chemist · 

Analytkal Chemistry Division 

Material Measurement Laboratory 

A2
 

 

 

Participant #: ________ Date: _____________ 

Round Robin LXX: Human Sera 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 377 378 379 380 381 Units* 

total retinol 

trans-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 α-cryptoxanthin 

total lutein 

total zeaxanthin 

total lutein&zeaxanthin

 total coenzyme Q10 

ubiquinol (QH2) 

ubiquinone (Qox) 

phylloquinone (K1) 

25-hydroxyvitamin D 

Phytoene 

Phytofluene 

* we prefer μg/mL 

W ere the liquid-frozen samples (378 to 381) frozen when received? Yes | No 

Comments: 

Mail: M2QAP Please return results by 

NIST, Stop 8392 19-Sep-2011 Fax: 301-977-0685 

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

A3
 

 

 

 

Participant #: ________ Date: _____________ 

Fat-Soluble Vitamins Round Robin LXX 

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? Vial/Cap 

#377 Lyophilized Yes Amber/Red 

#378 Liquid frozen No Amber/Blue 

#379 Liquid frozen No Amber/Green 

#380 Liquid frozen No Amber/Green 

#381 Liquid frozen No Amber/Red 

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 (#378 to #381) 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 RR70 

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. 

B1
B2
 

The NIST M2QAP Round Robin LXX (RR70) report consists of: 

Page 

1-4 

5 

6 

Page 

1 

2 to 

n 

n+1 

Samples. 

Serum

377 

378 

379 

380 

381 

Results 

“All Lab” Report 

A listing of all results and statistics for analytes reported by more than one participant. 

A listing of the analytes reported by only one participant and a legend for the list of results 

and statistics.
 

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

“Individualized” Report 

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

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

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

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

Five samples were distributed in RR70. 

Description 

Lyophilized, native serum prepared in 1999. Serum
 

#380 is the liquid-frozen partner of this sample. 

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

2005. This serum was prepared as a blend of the 

#381 pool and a second pool with generally higher 

analyte levels. 

Fresh-frozen, native, multi-donor, prepared in 2009. 

This is Level III of SRM 968e. 

Liquid-frozen, native serum prepared in 1999. 

Serum #377 is the lyophilized partner of this sample.
 

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

2005. This serum was expected to have low levels 

of most analytes. 

Prior Distributions 

#270:RR49-3/01, #276:RR50-9/01, 

#367:RR68-9/10 

#315:RR58-9/05, #335:RR62-9/07 

#359:RR66-9/09, #363:RR67-3/10, 

#373:RR69-3/11 

#267:RR49-9/00, #274:RR50-9/01, 

#368:RR68-9/10 

#316:RR58-9/05, #336:RR62-9/07 

1)	 Sera Stability. There was no significant change in the median level or measurement variability of any 

measurand in any of the materials. 

2)	 SRM 968e. Sera #379 is the “high” retinol, α-tocopherol and β-carotene component of SRM 968e. It 

was prepared without spiking. 

B3
 

 

 

 

Appendix C. “All-Lab Report” for RR70 

The following six 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. 

C1
 Round Robin LXX Laboratory Results 

Total Retinol, μg/mL trans-Retinol, μg/mL Retinyl Palmitate, μg/mL α-Tocopherol, μg/mL γ/β-T

Lab 377 378 379 380 381 

C2

FSV-BA 0.692 0.532 0.713 0.698 0.430 

FSV-BB 0.641 0.486 0.683 0.688 0.397 

FSV-BC 0.652 0.480 0.676 0.669 0.400 

FSV-BD 0.635 0.468 0.649 0.681 0.378 

FSV-BE 0.635 0.530 0.694 0.706 0.393 

FSV-BF 0.600 0.480 0.670 0.640 0.350 

FSV-BG 0.729 0.501 0.674 0.721 0.395 

FSV-BH 0.642 0.466 0.646 0.689 0.373 

FSV-BJ 0.613 0.449 0.608 0.630 0.351 

FSV-BK 0.648 0.499 0.656 0.681 0.403 

FSV-BL 0.660 0.520 0.690 0.660 0.370 

FSV-BM 0.660 0.500 0.640 0.660 0.396 

FSV-BN 0.649 0.417 0.626 0.598 0.333 

FSV-BO 0.520 0.420 0.540 0.580 0.330 

FSV-BP 0.618 0.451 0.631 0.652 0.371 

FSV-BQ 0.620 0.400 0.580 0.530 0.310 

FSV-BR 0.630 0.490 0.650 0.650 0.340 

FSV-BS ≥0.605 ≥0.474 ≥0.719 ≥0.648 ≥0.387 

FSV-BT 0.559 0.461 0.596 0.616 0.356 

FSV-BU 0.607 0.488 0.581 0.606 0.355 

FSV-BV 0.636 0.518 0.657 0.701 0.390 

FSV-BW 0.595 0.444 0.589 0.626 0.354 

FSV-CC 0.647 0.488 0.668 0.664 0.377 

FSV-CD 0.577 0.459 0.584 0.677 0.339 

FSV-CE 0.770 0.480 0.660 0.700 0.430 

FSV-CG 0.672 0.501 0.673 0.673 0.393 

FSV-CI 0.704 0.541 0.741 0.747 0.405 

FSV-CW 0.866 0.499 0.573 0.705 0.363 

FSV-CZ 0.641 0.542 0.637 0.657 0.395 

FSV-DD 0.620 0.460 0.640 0.600 0.360 

FSV-DQ 

FSV-DV 0.677 0.512 0.683 0.686 0.405 

FSV-EE 

FSV-FK 0.597 0.452 0.609 0.609 0.369 

377 378 379 380 381 

0.605 0.474 0.719 0.648 0.387 

0.639 0.483 0.663 0.654 0.371 

377 378 379 380 381 

0.018 0.053 0.181 0.021 0.012 

0.023 0.039 0.064 0.023 0.008 

0.017 0.041 0.115 0.017 0.012 

0.017 0.032 0.062 0.016 0.011 

0.021 0.074 0.107 0.020 0.019 

0.012 0.050 0.108 0.014 0.001 

0.016 0.053 0.094 0.019 0.004 

377 378 379 380 381 

5.93 9.28 18.1 6.17 4.13 

5.45 8.57 16.8 5.84 3.71 

6.30 9.00 18.9 6.60 5.00 

4.62 8.05 16.6 5.18 3.36 

5.40 8.30 16.5 5.60 3.90 

6.95 9.54 19.2 6.87 4.27 

6.24 9.93 19.9 6.63 4.42 

6.16 10.07 19.6 6.47 4.01 

6.00 9.41 18.8 6.50 4.23 

6.46 10.34 19.8 6.46 4.31 

6.20 9.80 18.7 6.90 5.50 

5.67 7.31 16.8 5.28 3.43 

5.10 8.40 15.7 5.50 3.70 

6.36 10.34 18.8 6.63 4.75 

5.00 9.00 17.0 5.00 4.00 

6.50 8.90 19.0 6.20 4.30 

5.67 9.14 18.3 6.28 4.11 

6.05 9.96 19.0 6.20 4.19 

6.65 10.75 19.9 6.99 4.38 

5.42 8.27 16.6 5.71 3.59 

6.26 9.83 20.0 6.39 4.30 

6.93 10.64 19.0 7.50 5.23 

5.10 10.00 20.4 6.65 5.52 

5.33 9.48 17.8 6.19 4.18 

5.71 8.93 18.2 6.18 4.02 

4.42 8.64 17.3 5.54 4.00 

6.35 9.29 18.6 6.08 4.12 

5.70 10.36 22.5 7.02 4.47 

5.80 8.40 16.2 5.80 3.90 

6.00 9.10 17.5 6.40 4.30 

377 3

2.37 1

2.08 1

1.87 1

2.67 1

2.27 1

2.17 1

1.90 1

2.00 1

2.14 1

2.36 1

2.12 1

3.50 1

2.13 1

2.36 1

1.80 1

2.06 1

2.47 2

N 31 31 31 31 31 2 2 2 2 2 7 7 7 7 7 30 30 30 30 30 17 

Min 0.520 0.400 0.540 0.530 0.310 0.605 0.474 0.663 0.648 0.371 0.012 0.032 0.062 0.014 0.001 4.42 7.31 15.7 5.00 3.36 1.80 1

Median 0.641 0.486 0.649 0.664 0.373 0.622 0.479 0.691 0.651 0.379 0.017 0.050 0.107 0.019 0.011 5.97 9.29 18.7 6.24 4.19 2.14 1

Max 0.866 0.542 0.741 0.747 0.430 0.639 0.483 0.719 0.654 0.387 0.023 0.074 0.181 0.023 0.019 6.95 10.75 22.5 7.50 5.52 3.50 2

SD 0.034 0.038 0.040 0.050 0.033 0.002 0.013 0.019 0.004 0.004 0.58 0.98 1.7 0.59 0.28 0.32 0

CV 5 8 6 8 9 11 26 18 19 36 10 11 9 9 7 15 

Npast 36 33 32 39 34 11 6 7 11 6 10 11 10 10 8 40 35 33 42 35 22 

Medianpast 0.635 0.498 0.655 0.666 0.390 0.617 0.490 0.618 0.657 0.385 0.023 0.050 0.089 0.026 0.012 5.97 9.43 18.7 6.39 4.19 2.23 1

SDpast 0.052 0.045 0.060 0.060 0.029 0.040 0.031 0.087 0.048 0.037 0.010 0.009 0.029 0.012 0.004 0.49 0.65 1.4 0.63 0.31 0.17 0

NAV 0.641 0.486 0.649 0.664 0.373 0.017 0.050 0.107 0.019 0.011 5.97 9.29 18.7 6.24 4.19 2.14 1

NAU 0.051 0.039 0.051 0.053 0.033 0.011 0.016 0.028 0.011 0.010 0.58 0.98 1.7 0.59 0.44 0.32 0

All Lab Report 
 Round Robin LXX Laboratory Results 

δ-Tocopherol, μg/mL Total β-Carotene, μg/mL trans-β-Carotene, μg/mL Total cis-β-Carotene, μg/mL Tot

Lab 377 378 379 380 381 

C3

FSV-BA 0.101 0.107 0.208 0.079 0.105 

FSV-BB 0.079 0.108 0.191 0.079 0.098 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BH 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 0.025 0.021 0.029 0.021 0.019 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-CC 

FSV-CD 

FSV-CE 

FSV-CG 0.129 0.179 0.280 0.129 0.134 

FSV-CI 

FSV-CW 0.063 0.090 0.196 0.086 0.078 

FSV-CZ 

FSV-DD 

FSV-DQ 

FSV-DV 

FSV-EE 

FSV-FK 

377 378 379 380 381 

0.501 0.291 0.419 0.518 0.038 

0.454 0.329 0.340 0.482 0.040 

0.462 0.272 0.405 0.484 0.036 

0.440 0.240 0.380 0.480 0.030 

0.507 0.262 0.460 0.587 0.041 

0.453 0.258 0.389 0.483 0.031 

0.481 0.248 0.392 0.526 0.030 

0.429 0.199 0.343 0.395 0.021 

0.397 0.296 0.368 0.473 0.051 

0.503 0.242 0.377 0.528 0.074 

≥0.408 ≥0.212 ≥0.376 ≥0.398 ≥0.025 

0.502 0.282 0.390 0.510 0.050 

0.569 0.286 0.345 0.556 nq 

0.492 0.279 0.400 0.564 0.039 

0.290 0.232 0.325 0.473 0.034 

0.748 0.474 0.443 0.808 0.083 

0.350 0.280 0.450 0.390 0.090 

0.389 0.297 0.384 0.484 0.042 

0.464 0.238 0.435 0.502 0.029 

0.392 0.257 0.333 0.460 0.036 

0.421 0.266 0.347 0.433 0.069 

0.551 0.182 0.249 0.468 0.045 

377 378 379 380 381 

0.473 0.271 0.398 0.496 0.036 

0.409 0.256 0.317 0.444 0.035 

0.444 0.250 0.380 0.473 0.031 

0.408 0.212 0.376 0.398 0.025 

0.445 0.246 0.337 0.455 0.042 

0.373 0.280 0.368 0.467 0.039 

377 378 379 380 381 

0.028 0.020 0.021 0.021 0.003 

0.029 0.018 0.015 0.021 0.001 

0.009 0.008 0.008 0.010 nq 

0.021 0.014 0.023 0.019 0.003 

0.017 0.017 0.016 0.017 nq 

377 

0.020 0

0.016 0

0.016 0

0.012 0

nq 0

0.030 0

0.016 0

0.024 0

0.006 0

0.015 0

0.026 0

0.016 0

0.005 0

0.036 0

0.021 0

0.027 0

0.016 0

0.020 0

N 5 5 5 5 5 21 21 21 21 20 6 6 6 6 6 5 5 5 5 3 17 

Min 0.025 0.021 0.029 0.021 0.019 0.290 0.182 0.249 0.390 0.021 0.373 0.212 0.317 0.398 0.025 0.009 0.008 0.008 0.010 0.001 0.005 0

Median 0.079 0.107 0.196 0.079 0.098 0.462 0.266 0.384 0.484 0.040 0.427 0.253 0.372 0.461 0.035 0.021 0.017 0.016 0.019 0.003 0.016 0

Max 0.129 0.179 0.280 0.129 0.134 0.748 0.474 0.460 0.808 0.090 0.473 0.280 0.398 0.496 0.042 0.029 0.020 0.023 0.021 0.003 0.036 0

SD 0.032 0.026 0.018 0.012 0.029 0.061 0.036 0.055 0.039 0.014 0.027 0.018 0.025 0.022 0.006 0.010 0.004 0.007 0.003 0.006 0

CV 41 24 9 15 30 13 13 14 8 35 6 7 7 5 18 47 26 45 16 39 

Npast 6 6 5 6 6 28 22 22 28 21 11 12 8 12 12 8 7 6 9 6 23 

Medianpast 0.108 0.114 0.215 0.119 0.100 0.492 0.286 0.399 0.521 0.040 0.439 0.272 0.340 0.475 0.038 0.026 0.019 0.018 0.026 0.003 0.020 0

SDpast 0.042 0.013 0.034 0.117 0.012 0.064 0.029 0.072 0.074 0.008 0.040 0.023 0.069 0.042 0.006 0.006 0.004 0.004 0.008 0.002 0.005 0

NAV 0.079 0.107 0.196 0.079 0.098 0.462 0.266 0.384 0.484 0.040 0.427 0.253 0.372 0.461 0.035 0.021 0.017 0.016 0.019 0.003 0.016 0

NAU 0.032 0.026 0.036 0.021 0.029 0.065 0.039 0.055 0.067 0.014 0.045 0.028 0.040 0.049 0.008 0.010 0.006 0.007 0.007 0.006 0

All Lab Report 
 Round Robin LXX Laboratory Results 

Total Lycopene, μg/mL trans-Lycopene, μg/mL Total β-Cryptoxanthin, μg/mL Total α-Cryptoxanthin, μg/mL Tota

Lab 377 378 379 380 381 

C4

FSV-BA 0.221 0.225 0.95 0.231 0.136 

FSV-BB 0.199 0.209 0.73 0.202 0.113 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 0.205 0.211 0.96 0.229 0.144 

FSV-BH 0.229 0.248 1.03 0.241 0.144 

FSV-BJ 0.143 0.168 0.81 0.156 0.076 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.224 0.199 0.91 0.206 0.113 

FSV-BO 0.180 0.188 0.61 0.185 0.104 

FSV-BP 0.254 0.233 1.00 0.278 0.253 

FSV-BQ 

FSV-BR 

FSV-BS 0.219 0.216 0.90 0.214 0.158 

FSV-BT 0.209 0.216 0.83 0.212 0.151 

FSV-BU 0.221 0.231 0.75 0.256 nq
 

FSV-BV
 0.218 0.245 0.98 0.258 0.150 

FSV-BW 0.100 0.200 0.86 0.220 0.100 

FSV-CC 

FSV-CD 0.332 0.369 1.05 0.349 0.214 

FSV-CE 

FSV-CG 0.195 0.272 0.97 0.244 0.161 

FSV-CI 

FSV-CW 

FSV-CZ 

FSV-DD 

FSV-DQ 0.350 0.188 0.68 0.302 0.217 

FSV-DV 

FSV-EE 

FSV-FK 

377 378 379 380 381 

0.136 0.128 0.446 0.147 0.072 

0.100 0.097 0.314 0.111 0.052 

0.128 0.116 0.500 0.160 0.083 

0.150 0.143 0.604 0.149 0.099 

0.142 0.135 0.388 0.148 0.082 

0.124 0.154 0.478 0.151 0.088 

0.108 0.117 0.354 0.126 0.067 

377 378 379 380 381 

0.065 0.056 0.054 0.065 0.043 

0.041 0.039 0.032 0.045 0.029 

0.055 0.044 0.024 0.053 0.036 

0.050 0.053 0.037 0.054 0.039 

0.029 0.033 0.017 0.028 0.017 

0.054 0.042 0.057 0.051 0.028 

0.035 0.036 0.015 0.038 0.026 

0.046 0.048 0.050 0.054 0.049 

0.033 0.021 0.060 0.029 0.022 

0.037 0.034 0.031 0.042 0.026 

0.044 0.042 0.027 0.045 nq 

0.034 0.034 0.020 0.036 0.025 

0.062 0.064 0.054 0.067 0.045 

0.065 0.070 0.063 0.067 0.049 

0.040 0.040 0.026 0.049 0.029 

0.067 0.060 0.044 0.070 0.049 

377 378 379 380 381 

0.039 0.022 0.033 0.037 0.016 

0.019 0.010 0.013 0.021 0.007 

0.018 0.014 0.028 0.020 0.020 

0.029 0.013 0.040 0.031 nq 

377 378 

0.099 0.068 

0.083 0.063 

0.072 0.057 

0.095 0.076 

0.062 0.035 

0.080 0.054 

0.086 0.079 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NAV 

NAU 

16 16 16 16 15 

0.100 0.168 0.61 0.156 0.076 

0.219 0.216 0.91 0.230 0.144 

0.350 0.369 1.05 0.349 0.253 

0.025 0.025 0.12 0.037 0.045 

11 12 14 16 32 

23 20 17 24 20 

0.226 0.243 0.96 0.234 0.151 

0.034 0.037 0.19 0.036 0.029 

0.219 0.216 0.91 0.230 0.144 

0.053 0.052 0.17 0.055 0.045 

7 7 7 7 7 

0.100 0.097 0.314 0.111 0.052 

0.128 0.128 0.446 0.148 0.082 

0.150 0.154 0.604 0.160 0.099 

0.021 0.018 0.086 0.004 0.015 

17 14 19 3 19 

10 9 8 10 9 

0.123 0.119 0.399 0.134 0.069 

0.024 0.019 0.092 0.021 0.012 

0.128 0.128 0.446 0.148 0.082 

0.022 0.022 0.086 0.026 0.015 

16 16 16 16 15 

0.029 0.021 0.015 0.028 0.017 

0.045 0.042 0.035 0.050 0.029 

0.067 0.070 0.063 0.070 0.049 

0.015 0.012 0.022 0.015 0.010 

33 28 64 29 35 

22 21 17 24 21 

0.048 0.045 0.032 0.051 0.035 

0.009 0.007 0.011 0.008 0.004 

0.045 0.042 0.035 0.050 0.029 

0.015 0.012 0.022 0.015 0.010 

4 4 4 4 3 

0.018 0.010 0.013 0.020 0.007 

0.024 0.014 0.031 0.026 0.016 

0.039 0.022 0.040 0.037 0.020 

0.008 0.003 0.009 0.008 

34 23 29 31 

5 5 4 6 9 

0.023 0.020 0.021 0.027 0.009 

0.005 0.010 0.008 0.003 0.002 

0.024 0.014 0.031 0.026 0.016 

7 7 

0.062 0.035 

0.083 0.063 

0.099 0.079 

0.017 0.014 

20 22 

13 14 

0.086 0.063 

0.021 0.011 

0.083 0.063 

0.017 0.014 

All Lab Report 
 Round Robin LXX Laboratory Results 

Total Zeaxanthin, μg/mL Total Lutein&Zeaxanthin, μg/mL Coenzyme Q10, μg/mL Phylloquinone (K1), ng/mL 25-hyd

Lab 377 378 379 380 381 

C5

FSV-BA
 

FSV-BB
 0.042 0.0265 0.064 0.044 0.0186 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BH 0.054 0.0198 0.032 0.051 0.0142 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 

FSV-BO 0.026 0.0110 0.020 0.028 0.0050 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 0.006 0.0010 0.006 0.006 0.0020 

FSV-BT 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-CC 

FSV-CD 

FSV-CE 

FSV-CG 

FSV-CI 0.018 0.0090 0.013 0.020 0.0060 

FSV-CW 

FSV-CZ 

FSV-DD 

FSV-DQ 0.026 0.0110 0.020 0.028 0.0085 

FSV-DV 

FSV-EE 

FSV-FK 

377 378 379 380 381 

0.149 0.112 0.182 0.146 0.0540 

0.141 0.094 0.209 0.146 0.0407 

0.133 0.088 0.157 0.125 0.0375 

0.138 0.083 0.154 0.136 0.0309 

0.099 0.052 0.116 0.091 0.0140 

0.121 0.087 0.152 0.140 0.0320 

0.113 0.076 0.161 0.126 0.0370 

0.068 0.036 0.084 0.072 0.0130 

0.100 0.077 0.126 0.113 0.0370 

0.111 0.075 0.164 0.099 nq 

0.112 0.074 0.119 0.116 

0.222 0.176 0.273 0.246 

0.153 0.114 0.196 0.169 

0.098 0.063 0.115 0.102 0.0280 

0.206 0.110 0.195 0.175 

0.112 0.090 0.182 0.123 0.0325 

0.0320 

0.1060 

0.0530 

0.0463 

377 378 379 380 381 

0.840 0.66 1.39 0.87 0.650 

0.780 0.77 1.50 0.90 0.540 

0.930 1.08 1.54 1.00 0.950 

0.754 0.63 1.11 0.87 0.680 

0.910 0.64 1.27 0.92 0.700 

0.609 0.59 1.31 0.81 0.496 

0.761 0.57 1.14 0.67 0.618 

0.775 0.68 1.41 0.68 0.626 

0.967 0.93 1.86 1.15 0.881 

0.882 0.74 1.52 0.95 0.704 

377 378 379 380 381 

2.841 1.241 3.610 6.081 0.242 

0.978 0.438 1.212 1.042 0.102 

377 3

0.010 0.

0.015 0.

0.011 0.

N 6 6 6 6 6 16 16 16 16 15 10 10 10 10 10 2 2 2 2 2 3 

Min 0.006 0.0010 0.006 0.006 0.0020 0.068 0.036 0.084 0.072 0.0130 0.609 0.57 1.11 0.67 0.496 0.978 0.438 1.212 1.042 0.102 0.010 0.

Median 0.026 0.0110 0.020 0.028 0.0073 0.117 0.085 0.159 0.125 0.0370 0.810 0.67 1.40 0.89 0.665 1.910 0.840 2.411 3.562 0.172 0.011 0.

Max 0.054 0.0265 0.064 0.051 0.0186 0.222 0.176 0.273 0.246 0.1060 0.967 1.08 1.86 1.15 0.950 2.841 1.241 3.610 6.081 0.242 0.015 0.

SD 0.018 0.0080 0.014 0.018 0.0056 0.027 0.016 0.051 0.031 0.0090 0.095 0.11 0.19 0.11 0.064 

CV 69 73 69 64 77 23 18 32 24 24 12 16 13 12 10 

Npast 11 11 8 12 12 21 21 18 23 20 7 6 8 10 6 7 

Medianpast 0.036 0.0220 0.029 0.038 0.0160 0.124 0.086 0.143 0.128 0.0383 0.815 0.62 1.38 0.76 0.561 0.010 

SDpast 0.009 0.0046 0.013 0.011 0.0038 0.020 0.010 0.031 0.022 0.0106 0.171 0.10 0.20 0.18 0.102 0.004 

NAV 0.026 0.0110 0.020 0.028 0.0073 0.117 0.085 0.159 0.125 0.0370 0.810 0.67 1.40 0.89 0.665 0.011 0.

NAU 0.018 0.0080 0.014 0.018 0.0056 0.027 0.018 0.051 0.031 0.0090 0.095 0.11 0.19 0.11 0.067 

All Lab Report 
 

 

 

 

 

Round Robin LXX Laboratory Results 

Analytes Reported By One Laboratory 

Term 

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

Min Minimum (non-NIST) quantitative value reported

Median Median (non-NIST) quantitative value reported

Max Maximum (non-NIST) quantitative value reported

SD Adjusted median absolute deviation from the median of the non-NIST results 

CV Coefficient of Variation for (non-NIST) 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)

NIST Mean of NIST results

NAV NIST Assigned Value 

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

 = Median for analytes reported by ≥ 5 labs but not NIST

NAU NIST Assigned Uncertainty: √(S2

 + Sbtw 2)

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

 deviation between Median and NIST. 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

? Non-quantitative value: extrapolated beyond upper limit of calibration curve

italics Not explicitly reported but calculated by NIST from reported values

Analyte Code 377 378 379 380 381 

Phytofluene, μg/mL FSV-BS 0.049 0.082 0.351 0.052 0.040 

Phytoene, μg/mL FSV-BS nd nd 0.124 nd nd 

Legend

All Lab Report 

C6

Page 5 / 6 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Round Robin LXX Laboratory Results 

Comparability Summary 

Lab 

FSV-BA 

FSV-BB 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BH 

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-CD 

FSV-CE 

FSV-CG 

FSV-CI 

FSV-CW 

FSV-CZ 

FSV-DD 

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

2 1 1 1 1 1 1 2 2 

1 1 1 1 1 1 1 1 1 3 1 

1 

1 1 

1 2 1 1 

1 2 1 

2 1 2 2 1 1 1 1 

1 1 1 1 1 1 1 1 1 2 1 

1 1 1 1 2 2 1 

1 1 

1 1 

1 2 

2 2 2 2 1 1 2 

2 2 1 1 1 2 1 1 1 1 

1 1 2 4 2 2 1 

2 2 

1 1 

1 2 2 2 1 2 2 2 3 

2 1 1 1 1 1 1 1 1 

1 1 1 2 2 1 1 1 

1 2 1 1 1 1 1 1 

1 2 1 2 2 2 

1 1 

2 2 3 4 4 3 2 4 

2 2 3 

1 1 1 1 1 2 1 2 2 

2 1 1 1 2 1 1 1 

3 2 1 1 1 1 2 

1 1 1 2 

1 

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) summarizes your measurement 

performance for a given analyte relative to the consensus 

medians in this study. CS is the average distance (in units of 

standard deviation) of your measurement performance 

characteristics from the consensus performance. CS is 

calculated when the number of quantitative values you reported, 

Nyou, is at least two and at least six participants reported 

quantitative values for the analyte. 

We define CS as follows: 

MINIMUM 4,INTEGER 1 



 

2 FSV-DQ 2 3 2 1 2 2 1 1 1 CS = + 



 C2 + AP

FSV-DV 1 1 

∑ 

= 

Nyou You 

i 1 

FSV-FK 1 1 i −Median i 

NAU n 32 30 17 22 6 17 16 16 7 6 16 i C = Concordance = 

Nyou 

TR aT g/bT bC tbC aC TLy TbX TLu TZ L&Z 2 you

∑ 

= 

N 

i 1 

















i 

% 4 0 0 0 5 0 12 0 0 0 0 6 NAU = NIST Assigned Uncertainty 

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 long-term measurement 

performance. Anal Chem 1999;71(9):1870-8. 

Youi 

N 

−Median 

NAU i 

1 

% 1 69 60 82 55 83 53 63 56 86 50 63 

% 2 28 40 6 36 17 35 31 44 14 33 25 AP = Apparent Precision = 

% 3 3 0 12 5 0 0 6 0 0 17 6 you −

All Lab Report 

C7

Page 6 / 6 
 

 

 

 

 

 

Appendix D. Representative “Individualized Report” for RR70 

Each participant in RR70 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 RR70: 

• 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 sixteen pages are the “Individualized Report” for the analytes evaluated by 

participant FSV-BA. 

D1
 

 Set 1 of 36 

Individualized Round Robin LXX Report: FSV-BA 

Summary 

Serum 377 Serum 378 Serum 379 Serum 380 S

D2

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

Total Retinol 0.641 0.641 31 0.486 0.486 31 0.683 0.649 31 0.688 0.669 31 0.3

Retinyl Palmitate 0.02 0.02 7 0.0 0.1 7 0.1 0.1 7 0.02 0.02 7 0.0

α-Tocopherol 5.45 5.97 30 8.57 9.29 30 16.79 18.65 30 5.84 6.24 30 3.7

γ/β-Tocopherol 2.081 2.144 17 1.644 1.709 17 2.156 2.170 17 2.186 2.285 17 1.6

δ-Tocopherol 0.079 0.079 5 0.108 0.107 5 0.191 0.196 5 0.079 0.079 5 0.0

Total β-Carotene 0.454 0.462 21 0.329 0.266 21 0.340 0.384 21 0.482 0.484 21 0.0

trans-β-Carotene 0.409 0.427 6 0.256 0.253 6 0.317 0.372 6 0.444 0.461 6 0.0

Total cis-β-Carotene 0.029 0.021 5 0.018 0.017 5 0.015 0.016 5 0.021 0.019 5 0.0

Total α-Carotene 0.016 0.016 17 0.055 0.052 18 0.009 0.015 15 0.017 0.019 17 0.0

Total Lycopene 0.199 0.219 16 0.209 0.216 16 0.733 0.907 16 0.202 0.230 16 0.1

trans-Lycopene 0.100 0.128 7 0.097 0.128 7 0.314 0.446 7 0.111 0.148 7 0.0

Total β-Cryptoxanthin 0.041 0.045 16 0.039 0.042 16 0.032 0.035 16 0.045 0.050 16 0.0

Total α-Cryptoxanthin 0.019 0.024 4 0.010 0.014 4 0.013 0.031 4 0.021 0.026 4 0.0

Total Lutein 0.099 0.083 7 0.068 0.063 7 0.145 0.123 7 0.102 0.085 7 0.0

Total Zeaxanthin 0.042 0.026 6 0.026 0.011 6 0.064 0.020 6 0.044 0.028 6 0.0

Total Lutein&Zeaxanthin 0.141 0.117 16 0.094 0.085 16 0.209 0.159 16 0.146 0.125 16 0.0

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 Tel: (

100 Bureau Drive Stop 8392 Fax: (

Gaithersburg, MD 20899-8392 USA Email: david.du

Individualized Report 
 

D3

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total Retinol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

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

Median [Analyte], μg/mL 

Long-term Precision, SD 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 2 / 16 
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Retinyl Palmitate, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Median [Analyte], μg/mL 

Concordance, SD 

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

Long-term Precision, SD 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 3 / 16 

D4
 

D5

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

α-Tocopherol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

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

Median [Analyte], μg/mL 

Long-term Precision, SD 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 4 / 16 
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

γ/β-Tocopherol, μg/mL Your [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379

Median [Analyte], μg/mL 

Concordance, SD 

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

Long-term Precision, SD 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 5 / 16 

D6
 

D7

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

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

Median [Analyte], μg/mL 

Long-term Precision, SD 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 6 / 16 
 

D8

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

trans-β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

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

Median [Analyte], μg/mL 

Long-term Precision, SD 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 7 / 16 
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total cis-β-Carotene, μg/mL Your [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379

Median [Analyte], μg/mL 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 8 / 16 

D9
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total α-Carotene, μg/mL Your [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379

Median [Analyte], μg/mL 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 9 / 16 

D10
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total Lycopene, μg/mL Your [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379

Median [Analyte], μg/mL 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 10 / 16 

D11
 

D12

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

trans-Lycopene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

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

Median [Analyte], μg/mL 

Long-term Precision, SD 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 11 / 16 
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total β-Cryptoxanthin, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Median [Analyte], μg/mL 

Concordance, SD 

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

Long-term Precision, SD 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 12 / 16 

D13
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total Lutein, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

Your [Analyte], μg/mL 

Median [Analyte], μg/mL 

270276367377267274368380315335378316336381359363373379 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 13 / 16 

D14
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total Zeaxanthin, μg/mL 

270276367377267274368380315335378316336381359363373379 

[Analyte], μg/mL

Median [Analyte], μg/mL 

Your [Analyte], μg/mL 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 14 / 16 

D15
 

 Set 1 of 36 

Individualized RR LXX Report: FSV-BA

Total Lutein&Zeaxanthin, μg/mL Your [Analyte], μg/mL Apparent Precision, SD 

Apparent Precision, SD [Analyte], μg/mL

270276367377267274368380315335378316336381359363373379

Median [Analyte], μg/mL 

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 Comments History 

#377 Lyophilized, same native pool as #380 49#270, 50#276, 68#367 

#378 Fresh-frozen, native, multi-donor 58#315, 62#335 

#379 Fresh-frozen, native, multi-donor: SRM 968e III 66#359, 67#363, 69#373 

#380 Fresh-frozen, same native pool as #377 48#267, 50#274, 68#368 

#381 Fresh-frozen, native, multi-donor 58#316, 62#336 

Individualized Report Page 15 / 16 

D16
D17

 Set 1 of 35 

Individualized Round Robin LXX Report: FSV-BA 

Graphical Comparability Summary 

Total Retinol α-Tocopherol Total β-Carotene T

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

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 RR35 

The following five items were included in each package shipped to an RR35 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
May23, 2011 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryl~nd 20899- _ 

The samples within this package constitute Vitamin C Round Robin 35 (RR35) of the 201 lMicronutrients 

Measurement Quality Assurance Program. RR35 consists of four vials of frozen serum test samples (#351, #352 

#353, and #354), one vial of frozen control serum (CS #1), 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 'I-re generally 10-fold m?re 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 for CS #1 is S.41 μmol/L of sample; the ::::95% confidence interval for the target value is 

7.75 to 9.07 μmol/L of 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 

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

observe unusually large variation in replicate analyses. 

Please report your results (using the attached form) for RR35 by e-mail to david.duewer@nist.gov or fax to 

301-977-0685 by September 19, 2011. If you have questions or comments regarding this study, please call 

me at (301) 975-3120 or e-mail me atjbthomas@nist.gov. 

Pro a Coordinator/Research Chemist 

An 1 cal Chemistry Division 

Che ·cal Science and Technology Laboratory 

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

RR35 Report Form for Ascorbic Acid Solid Control Material Preparation 

RR35 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 = 29.4 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 ) + (gDiluent 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 recalibrate 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 at 301-

975-3120 or jbthomas@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 35 

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 September 19, 2011 

MMQAP Fax: 301-977-0685 

100 Bureau Drive, Stop 6392 Email: david.duewer@nist.gov 

Gaithersburg, MD 20899-6392 

E5
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Participant #: Date: 

Vitamin C Round Robin 35 

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 

Target: 8.41 μmol/L CS #1 (7.75 μmol/L to 9.07 μmol/L; 

95 % confidence interval) 

Serum Test Sample #351 μmol/L of Sample 

Serum Test Sample #352 μmol/L of Sample 

Serum Test Sample #353 μmol/L of Sample 

Serum Test Sample #354 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 September 19, 2011 

MMQAP Fax: 301-977-0685 

100 Bureau Drive, Stop 6392 Email: david.duewer@nist.gov 

Gaithersburg, MD 20899-6392 

E6
 

 

SRM970 Lv1

New1 (5)

New4 (31)

New5 (46)

SRM970 Lv2

 

 

Participant #: ________ Date: _____________ 

Vitamin C Round Robin 35
 

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

VitC #352 Liquid frozen (1:1 serum:10% MPA) 

VitC #353 Liquid frozen (1:1 serum:10% MPA) 

VitC #354 Liquid frozen (1:1 serum:10% MPA) 

CS #1 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 6392 Fax: 301-977-0685 

Gaithersburg, MD 20899-6392 Email: David.Duewer@NIST.gov 

E7
 

 

 

 

Appendix F. Final Report for RR35 

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
November 21, 2011 

bear CoHeague: 

UNITED STATES DEPARTMENT OF COMMERCE Na~l!•I Ina~ Qf S~ndarda and Te~h"afqn 

Geit.herst;Jurg, Maryland 20899-

En~losed is the summary report of the resul~ fo~ Round Robin ~5 (!UUS) for the measurement of total 

ascorbic acid (TAA, asco.rbic acid plus qehydroi;s·corbic acid).in human serum. Inclllded in this report 

are a summary of data for all laboratories and an i~divic;luaJized summary of your laboratory's 

measurement performance. The robust median is used to estimate the consensili; value for all samples, 

the "median absolu~e deviation from the median" (MADe) ·is U$ed to estimate the e!(pected standard 

deviation, and the coefficient ofvariatio.n (CV) is defined as lOOxMADe/median. 

RR35 consisted of four test samples (8351, S352, 8353, and 8354), one serum control material (C8#1), 

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 concern~ regarding your laboratory's performance, we suggest that you obtain and analyze a 

unit of8tand(lra.Reference Material.(8R,M) 970, Vitamin C in Frozen Human SeruJll. SRM 970 can be 

purehased from the NIST SRM Progrtl!ll at phone: 301-975-6776; fax: 301-948-3730. If your measured - _,,- " ' r • ..,• ~.... • • • ,• ~ .. t '• • • ' 

'values do not agree with the certified values~ we suggest that you contact us for c_orisultatioQ. 

Samples for the first vi!J!,m.in C ·round robin (R;R36) of the 2012 M2QAP will be shipped starting 

January·9., 2012., Please contact us immediately if this schedule is problematic for:.yourlaboratory. 

If you ha~e questions_ or concerns regarding this report, please contact David Duewer at 301-975-3935; email: david.duewer@nist.gov or me at 301-975-3320; e-mail: jbthomas@nist.gov; or fax: 301-977-0685. 

Je ice Bro~ Thomas, M.B.A. 

esearch Chemist 

Analytical Chemistry Division 

Material Measurement Laboratory 

Enclosures 

Cc: L. C. 8~nder 

~~~ David L. Duewer, Ph.D. 

Resear_ch Chemometrician 

Analytical Chemistry Divisio~ 

Material Measurement Laboratory 

NISI 

F2
The NIST M2

QAP Vitamin C Round Robin 35 (RR35) 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 RR35 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR35 

samples and control/calibration solutions. 

Serum-based Samples. One serum control and four unknowns were distributed in RR35. 

CS#1 SRM 970 level 1, ampouled in mid-1998. 

S35:1 Ampouled in late 2009, previously distributed as sample S33:3 (RR33, Fall 09) and S34:2 

(RR34, Spring 10) 

S35:2 Ampouled in late 2009, previously distributed as sample S32:2 (RR32, Spring 09) and S34:2 

(RR34, Spring 10) 

S35:3 Ampouled in late 2009, previously distributed as sample S32:3 (RR32, Spring 09) 

S35:4 Ampouled in late 2009, previously distributed as sample S32:4 (RR32, Spring 09) and S34:3 

(RR34, Spring 10) 

Results. 

1)	 All participants who prepared the four 5% 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 (≈0.58 OD), the calculated E1% #1”(≈560 

dL/g·cm). 

2)	 The Measured = a+b*Gravimetric calibration parameters for the control/calibration solutions 

(columns 10 to 13 of the All Lab Report) indicate that the measurement systems for all participants 

are linear (R2

 close to 1 and RMS close to 0.0) and well calibrated (intercepts range from -0.4 to 0.6 

and slopes range from 0.94 to 1.14). 

3)	 The Measured = p+q*Median regression parameters for samples S35:1 to S35:4 (columns 23 to 26 of 

the All Lab Report) confirm the linearity of all measurement systems (R2

 close to 1 and RMS close to 

0.0). 

4)	 There is no evidence of sample degradation. 

F3
 

 

 

Appendix G. “All-Lab Report” for RR35 

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" 35 - October 2011 

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 RMS g/mL λmax Amax E1% CS#1 S35:1 S35:2 S35:3 S35:4 Inter Slope R2 

VC-MA 24/08/11 58.9 28.9 14.4 60.8 29.5 15.1 0.0 0.00 1.03 1.000 0.2 1.036 242. 0.5680 547.7 9.0 16.6 24.6 33.4 50.0 -0.02 1.07 0.99

VC-MB 13/06/11 57.9 29.2 14.6 60.1 30.2 15.2 0.0 0.02 1.04 1.000 0.1 1.029 244. 0.5650 553.9 8.5 15.2 23.7 31.7 47.5 -0.33 1.03 1.00

VC-MC 18/08/11 60.1 30.3 15.0 61.9 31.3 15.4 0.0 -0.01 1.03 1.000 0.0 1.030 243. 0.5894 556.9 8.6 16.9 26.2 33.6 51.4 0.24 1.10 0.99

VC-ME 05/07/11 57.7 28.7 14.3 58.4 28.4 15.2 0.0 0.16 1.01 1.000 0.7 1.030 243.3 0.5681 558.8 8.4 15.0 22.2 28.2 41.9 1.96 0.86 1.00

VC-MG 29/08/11 60.4 30.8 15.7 63.5 31.9 15.9 0.0 -0.32 1.05 1.000 0.4 1.028 243.8 0.5900 555.0 8.1 14.4 23.2 31.1 48.3 -2.11 1.08 1.00

VC-MH 26/07/11 60.6 30.7 15.1 59.4 30.1 14.9 0.0 0.03 0.98 1.000 0.1 1.031 243.7 0.5970 559.2 8.4 15.8 23.9 30.9 45.5 1.64 0.94 1.00

VC-MI 29/07/11 54.8 27.3 13.6 55.2 27.1 13.6 0.0 -0.11 1.01 1.000 0.2 1.034 b 14.1 21.8 28.9 43.5 -0.15 0.94 1.00

VC-MJ 13/09/11 57.5 27.6 15.0 56.4 27.3 14.0 0.3 -0.01 0.98 1.000 0.5 1.024 255a 0.35a 345.4a 11.6 20.8 28.2 35.6 50.2 6.49 0.94 1.00

VC-MN 02/08/11 56.4 28.4 14.5 58.5 29.4 14.7 0.0 -0.13 1.04 1.000 0.2 1.034 243.9 0.5347 538.5 8.7 14.1 21.6 27.7 40.3 1.82 0.83 1.00

VC-NM 08/08/11 55.0 28.5 15.2 57.4 29.0 16.2 0.0 -0.01 1.04 1.000 0.5 1.031 243. 0.5430 560.1 7.7 13.1 20.5 30.1 41.5 -0.33 0.92 0.98

10 10 10 10 10 10 10 10 8 8 8 9 10 10 10 10 

57.9 29.0 14.7 59.2 29.4 15.0 0.0 1.031 243.3 0.5694 553.8 8.8 15.6 23.6 31.1 46.0 

2.1 1.2 0.6 2.5 1.6 0.8 0.1 0.003 0.7 0.0224 7.3 1.1 2.2 2.3 2.5 4.0 

54.8 27.29 13.6 55.2 27.07 13.6 0.0 1.024 242.0 0.5347 538.5 7.7 13.1 20.5 27.7 40.3 

56.7 28.41 14.4 57.6 28.57 14.8 0.0 1.029 243.0 0.5595 552.3 8.4 14.2 21.9 29.2 42.3 

57.8 28.80 14.8 58.9 29.43 15.1 0.0 1.031 243.5 0.5681 556.0 8.5 15.1 23.5 31.0 46.5 

59.8 30.03 15.1 60.6 30.17 15.3 0.0 1.033 243.8 0.5896 558.9 8.7 16.4 24.4 33.0 49.6 

60.6 30.80 15.7 63.5 31.90 16.2 0.3 1.036 244.0 0.5970 560.1 11.6 20.8 28.2 35.6 51.4 

2.8 1.2 0.5 2.5 1.3 0.5 0.0 0.002 0.7 0.0321 4.5 0.3 1.4 2.2 3.4 5.3 

5 4 3 4 4 3 0.23 0.27 5.7 0.8 3 10 9 11 11 

Grav, μmol/L Measured, μmol/L Measured = a + b*Grav Spectrophotometry Measured, μmol/L Measured = p+q*

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 ) By our err, provided with CS#2 rather than CS#1 

All Lab Report 
 

Appendix H. Representative “Individualized Report” for RR35 

Each participant in RR35 received an “Individualized Report” reflecting their reported 

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

“VC-MA”. 

H1
 

 

 Set 1 of 11 

Vitamin C "Round Robin" 35 Report: Participant VC-MA
 

MPA Dilute Solution 1 Control/Calibration Solutions 

Density Spectrophotometry Ymeas = Inter + Slope* Xgrav 

Date RR Method 

03/03/09 30 HPLC-EC 

09/10/09 31 HPLC-EC 

02/24/10 32 HPLC-EC 

09/27/10 33 HPLC-EC 

02/28/11 34 HPLC-EC 

08/24/11 35 HPLC-EC 

g/mL 

1.037 

1.036 

1.035 

1.037 

1.039 

1.039 

λmax 

242.0 

244.0 

242.0 

244.0 

244.0 

242.0 

Amax E1% 

0.569 555.6 

0.566 546.1 

0.566 545.1 

0.560 540.5 

0.575 555.2 

0.568 547.7 

Inter Slope R2 SEE 

0.2 1.03 1.000 0.40 

-0.1 1.02 1.000 0.20 

0.3 1.03 1.000 0.46 

0.4 1.08 1.000 0.43 

0.6 1.14 1.000 0.78 

0.0 1.03 1.000 0.24 

Mean 1.037 243.0 0.57 548.4 Pooled SEE 0.46 

SD 0.002 1.1 0.00 5.9 

CV 0.18 0.45 0.9 1.1 

[TAA] mmol/Lsample 

3 25.8 0.2 1.1 

2 33.2 0.3 0.3 

3 48.9 0.2 1.0 

Date RR Sample 

09/27/10 33 S33:3 

02/28/11 34 S34:2 

08/24/11 35 S35:1 

02/24/10 32 S32:2 

09/27/10 33 S33:4 

08/24/11 35 S35:2 

02/24/10 32 S32:3 

08/24/11 35 S35:3 

02/24/10 32 S32:4 

02/28/11 34 S34:3 

08/24/11 35 S35:4 

Rep1 

16.6 

16.3 

16.1 

Rep2 

16.8 

15.7 

17.1 

Fadj 

1.0 

1.0 

1.0 

Mean 

16.7 

16.0 

16.6 

SDdup 

0.1 

0.4 

0.7 

N Mean SDrepeat SDreprod 

3 16.4 0.5 0.5 

26.2 

26.9 

24.7 

33.4 

33.4 

49.0 

47.9 

50.2 

26.0 

26.4 

24.5 

32.8 

33.4 

48.6 

48.1 

49.8 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

26.1 

26.7 

24.6 

33.1 

33.4 

48.8 

48.0 

50.0 

0.1 

0.4 

0.2 

0.5 

0.1 

0.3 

0.1 

0.3 

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 6392 Fax: (301) 977-0685 

Gaithersburg, MD 20899-6392 USA Email: david.duewer@nist.gov 

Individualized Report Page 1 / 2 

H2
 

 

NIST, RR 22

H3

 Set 1 of 11 

Vitamin C "Round Robin" 35 Report: Participant VC-MA 

Total Ascorbic Acid, μmol/mL 

[Total Ascorbic Acid], μmol/L 

S33:3S34:2S35:1S32:2 Apparent Precision, SD S33:4S35:2S32:3S35:3S32:4 S34:3 S35:4 

Your [Total Ascorbic Acid], μmol/L 

Median [Total Ascorbic Acid], μmol/L 

Concordance, SD 

3rd Quartile (75%) You, this RR Median (50%) You, past RRs Others, this RR 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 

S35:1 VitC #351, previously distributed in RRs 33 and 34 

S35:2 VitC #352, previously distributed in RR 32 and 33 

S35:3 VitC #353, previously distributed in RR 32 

S35:4 VitC #354, previously distributed in RR32 and 34 

Individualized Report Page 2 / 2