NISTIR 7880-4 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2010 

Comparability Studies 

Results for Round Robin LXVIII 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 33 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

 

 

 

 

NISTIR 7880-4
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2010 

Comparability Studies 

Results for Round Robin LXVIII 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 33 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 2010 MMQAP measurement comparability improvement studies: 1) Round Robin LXVIII 

Fat-Soluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 33 Total Ascorbic Acid 

in Human Serum. The materials for both studies were shipped to participants in June 2010; 

participants were requested to provide their measurement results by September 27, 2010. 

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

Round Robin 33: Vitamin C in Human Serum............................................................................... 2
 

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

Appendix A. Shipping Package Inserts for RR68........................................................................ A1
 

Appendix B. Final Report for RR68 ..............................................................................................B1
 

Appendix C. “All-Lab Report” for RR68 ......................................................................................C1
 

Appendix D. Representative “Individualized Report” for RR68 ............................................... D1
 

Appendix E. Shipping Package Inserts for RR33 ......................................................................... E1
 

Appendix F. Final Report for RR33............................................................................................... F1
 

Appendix G. “All-Lab Report” for RR33..................................................................................... G1
 

Appendix H. Representative “Individualized Report” for RR33............................................... 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 LXVIII: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

LXVIII comparability study (hereafter referred to as RR68) 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 

June 2010. 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 RR68 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 33: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 33 comparability study 

(hereafter referred to as RR33) 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 June 2010. 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 RR33 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 RR68 

The following three items were included in each package shipped to an RR68 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
June 3, 2010 

Dear Colleague: 

I 

... 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 2089S:. 

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

LXVIII) for the 2010 NIST Micronutrients Measurement Quality Assurance Program. The set of samples 

(Sera 367 - 371) consists of one lyophilized sample and one vial each of four liquid-frozen serum samples 

for apalysis 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 snbmit one value for each analyte for a 

given serum sample. If a value obtained is below your limit of quaμtification, please mdicate this result 

on the form by using NQ (No{ Quantified). Results are due to NIST by September 27, 2010. , 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 2010. 

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 retinal in most LC systems creating analytical problems.) 

Water should not be added to the liquid-frozen samples. Add water (1 mL) only to the lyophilized 

serum #367. 

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 run (ethanol); a.-carotene, 2800 at 444 nm (hexane); ~-carotene, 2560 at 450 nm 

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

Please report your results for Round Robin LXVIII 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 oremail me at jbthomas@nist. 

eanic Brown Thoma i • 

se ch Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

A2
 

 

 

Participant #: ________ Date: _____________ 

Round Robin LXVIII: Human Sera 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 367 368 369 370 371 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 (368 to 371) frozen when received? Yes | No 

Comments: 

Mail: M2QAP Please return results by 

NIST, Stop 8392 27-Sep-2010 Fax: 301-977-0685 

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

A3
 

 

 

 

Participant #: ________ Date: _____________ 

Round Robin LXVIII: Human Sera 

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 

#367 Lyophilized Yes Amber/Red 

#368 Liquid frozen No Amber/Green 

#369 Liquid frozen No Amber/Red 

#370 Liquid frozen No Clear/Green 

#371 Liquid frozen No Amber/Blue 

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 (#368 to #371) 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 RR68 

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

The NIST M2

QAP Round Robin LXVIII (RR68) report consists of: 

Page 

1-4 

5 

6 

Page 

1 

2 to 

n 

n+1 

Samples. 

Serum 

367 

368 

369 

370 

371 

Results 

“All Lab” Report 

A listing of all results and statistics for all analytes. 

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 RR68. 

Description 

Lyophilized, native serum. Serum #368 is the liquidfrozen partner of this sample. 

Liquid-frozen, native serum. Serum #367 is the 

lyophilized partner of this sample. 

Liquid-frozen 1+0.19 blend of a normal serum and a 

low-normal serum spiked with trans-β-carotene in a 

lipoprotein carrier. The same materials were used to 

prepare #370 and #371. 

Liquid-frozen 1+0.08 blend of the materials used to 

prepare #369. 

Liquid-frozen 1+0.03 blend of the materials used to 

prepare #369. 

Prior Distributions 

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

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

#355:RR66 – 3/09 

#354:RR66 - 3/09 

#353:RR65 – 3/09 

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

measurand in any of the materials. 

2) Sera #367 and #368. This lyophilized / liquid-frozen commutability pairs were prepared from the 

same serum pool. The measurand concentrations in the lyophilized sera are expected and generally 

observed to be about 95 % of the level in their liquid-frozen analogues. This is a simple dilution 

effect, since the lyophilized sera are reconstituted with 1 mL of water rather than to the original 1 mL 

total volume. 

3) Sera #353, #354, and #355. These materials are all mixtures of the same β-carotene-deficient but 

otherwise fairly normal serum and a trans-β-carotene spiking solution. This solution was prepared in 

the late 1990’s by mixing trans-β-carotene and high- and low-density lipoproteins into a low-normal 

B3
serum followed by extensive mixing and filtering. After further mixing and filtering in 2008: Serum 

#353 was spiked with just enough of the solution to raise the level of trans-β-carotene to a lownormal level, #354 was spiked to a reasonably high level and #355 was spike to very high level. All 

three materials were previously distributed in M2

QAP Round Robin LXV (RR65). 

Figure 1 displays the results for all of the trans-β-carotene results for these materials in both RR65 

and RR68, with RR65 to the left and RR68 to the right. Each line represents the results for a single 

participant. The X-axis spacing of the dilution series materials reflects the relative proportion of the 

spike so that ideal results will produce a straight line. Results for #352 and #356 in RR65 and for 

#367 and #368 in RR68 are displayed in an effort to separate method calibration from intrinsic 

material effects. 

0.2 

0.4 

0.6 

0.8 

1.0 

1.2 

1.4 

Total 

β-Carotene, mg/mL 

Too low Just right 

Too high Median±15% 

RR65, Mar-2009 RR68, Sep-2010 

0.0
 

356352355356357367368371370369

Serum 

The thick black lines bound the region ± 15 % about the median result; the green lines denote participant 

results that (mostly) fall within this region. The red lines denote dilutions-series results that (mostly) are 

too low and the green lines denote results that are (mostly) too high. 

While the results for the dilution series in RR68 are somewhat more consistent than those in RR65, in 

both RR there is greater “scatter” among the dilution series than for the other two materials distributed in 

the same RR. This suggests that the augmented β-carotene may indeed behave somewhat differently than 

does the native material. While the “too low” results plausibly arise from extraction processes that do not 

completely extract β-carotene, the “too high” results are less easily explained - unless they are in fact the 

“true” values for a really complete extraction. 

B4
 

 

Appendix C. “All-Lab” Report for RR68 

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 LXVIII Laboratory Results 

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

C2

Lab 367 368 369 370 371 367 368 369 370 371 367 368 369 370 371 367 368 369 370 371 

FSV-BA 0.625 0.695 0.284 0.318 0.309 0.021 0.026 0.069 0.070 0.067 6.18 6.61 7.58 8.20 8.26 

FSV-BB 0.611 0.698 0.291 0.321 0.307 0.034 0.027 0.036 0.020 0.016 6.03 6.57 7.17 8.00 7.99 

FSV-BC 0.626 0.648 0.313 0.314 0.317 

FSV-BD 0.630 0.667 0.308 0.345 0.312 6.70 6.90 7.90 8.60 8.70 

FSV-BE 0.720 0.778 0.338 0.370 0.374 6.08 6.47 7.20 8.33 8.33 

FSV-BF 0.640 0.660 0.290 0.300 0.310 6.30 6.60 7.40 8.20 8.10 

FSV-BG 0.627 0.663 0.275 0.308 0.307 0.016 0.016 0.027 0.026 0.023 5.86 6.13 6.84 7.83 7.92 

FSV-BH 0.514 0.560 0.231 0.260 0.252 5.56 5.88 6.61 7.32 7.80 

FSV-BJ 0.616 0.662 0.286 0.311 0.307 6.09 6.56 7.21 8.28 8.16 

FSV-BK 0.619 0.617 0.260 0.287 0.288 6.44 6.57 7.46 8.33 8.26 

FSV-BL 0.660 0.690 0.290 0.320 0.320 6.03 6.46 7.32 8.18 8.18 

FSV-BM 0.846 0.849 0.444 0.439 0.445 6.60 6.55 7.56 8.72 7.92 

FSV-BN 0.678 0.755 0.300 0.300 0.304 0.018 0.027 0.012 0.014 0.015 5.95 6.69 6.94 7.21 7.03 

FSV-BNa 0.644 0.716 0.299 0.299 0.303 6.11 6.76 7.00 7.15 7.19 

FSV-BO 0.632 0.663 0.286 0.315 0.314 5.70 6.20 6.90 7.90 7.90 

FSV-BP 0.653 0.650 0.268 0.284 0.292 5.70 5.92 7.46 7.95 7.96 

FSV-BQ 0.600 0.640 0.260 0.280 0.300 6.00 6.00 7.00 8.00 8.00 

FSV-BR 0.610 0.610 0.250 0.280 0.280 6.05 6.54 7.50 8.20 8.00 

FSV-BS ≥0.621 ≥0.654 ≥0.251 ≥0.282 ≥0.279 0.621 0.654 0.251 0.282 0.279 

FSV-BT 0.598 0.657 0.357 0.376 0.359 6.10 6.91 7.40 8.51 8.86 

FSV-BU 0.607 0.600 0.231 0.329 0.279 5.68 5.71 6.29 6.98 6.90 

FSV-BV 0.665 0.685 0.286 0.323 0.309 5.94 5.97 6.76 7.75 7.72 

FSV-BW 0.630 0.690 0.290 0.320 0.320 0.027 0.035 0.005 0.011 0.011 6.76 6.72 7.40 8.86 8.64 

FSV-CC 0.581 0.629 0.245 0.167 0.167 0.574 0.615 0.240 0.163 0.162 5.89 6.38 7.04 5.22 5.17 

FSV-CD 0.660 0.630 0.320 0.350 0.350 0.030 0.030 0.030 0.020 nq 7.62 7.67 7.61 8.88 8.86 

FSV-CE 0.652 0.620 0.342 0.334 0.301 6.40 6.66 7.25 8.18 8.13 

FSV-CF 0.617 0.654 0.278 0.286 0.271 6.50 6.80 7.50 7.90 7.90 

FSV-CI 0.698 0.750 0.298 0.345 0.332 0.024 0.022 0.022 nq nq 5.86 6.12 6.84 8.04 7.62 

FSV-CW 0.950 0.803 0.430 0.403 0.428 0.010 0.010 0.009 0.009 0.010 5.01 5.75 6.19 7.16 6.94 

FSV-CZ 0.622 0.703 0.311 0.328 0.322 5.54 6.19 6.69 7.30 7.38 

FSV-DA 0.640 0.655 0.291 0.312 0.313 0.640 0.655 0.291 0.312 0.313 0.016 0.018 0.011 0.012 0.013 5.78 5.91 6.71 7.62 7.68 

FSV-DD 0.560 0.590 0.260 0.290 0.270 

FSV-DV 0.861 0.882 0.374 0.391 0.403 4.20 4.80 4.30 4.90 6.10 

FSV-EE 0.562 0.589 0.290 0.290 0.288 6.10 8.60 9.60 12.10 10.00 

N 33 33 33 33 33 3 3 3 3 3 9 9 9 8 7 31 31 31 31 31 

Min 0.514 0.560 0.231 0.167 0.167 0.574 0.615 0.240 0.163 0.162 0.010 0.010 0.005 0.009 0.010 4.20 4.80 4.30 4.90 5.17 

Median 0.630 0.662 0.290 0.315 0.309 0.621 0.654 0.251 0.282 0.279 0.021 0.026 0.022 0.017 0.015 6.03 6.54 7.20 8.00 7.96 

Max 0.950 0.882 0.444 0.439 0.445 0.640 0.655 0.291 0.312 0.313 0.034 0.035 0.069 0.070 0.067 7.62 8.60 9.60 12.10 10.00 

SD 0.034 0.049 0.031 0.037 0.019 0.007 0.006 0.016 0.009 0.006 0.365 0.504 0.445 0.489 0.445 0

CV 5 7 11 12 6 35 23 74 52 39 6 8 6 6 6 

Npast 38 42 28 28 28 9 9 5 5 5 11 11 8 8 8 45 48 31 31 31 

Medianpast 0.638 0.668 0.293 0.320 0.318 0.617 0.657 0.260 0.290 0.290 0.024 0.026 0.022 0.021 0.014 5.940 6.319 6.900 7.909 7.800 2

SDpast 0.059 0.065 0.019 0.027 0.027 0.040 0.048 0.044 0.047 0.046 0.011 0.014 0.020 0.021 0.015 0.541 0.691 0.593 0.755 0.697 0

NAV 

NAU 

0.630 0.662 0.290 0.315 0.309 

0.050 0.052 0.031 0.037 0.026 

0.621 0.654 0.251 0.282 0.279 0.021 0.026 0.022 0.017 0.015 

0.011 0.012 0.016 0.011 0.011 

6.030 6.540 7.200 8.000 7.960 

0.531 0.559 0.597 0.646 0.644 

2

0

All Lab Report 
Round Robin LXVIII Laboratory Results 

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

C3

Lab 367 368 369 370 371 367 368 369 370 371 367 368 369 370 371 367 368 369 370 371 

FSV-BA 0.095 0.100 0.093 0.096 0.083 0.483 0.513 0.807 0.431 0.294 0.440 0.467 0.744 0.407 0.272 0.043 0.047 0.063 0.025 0.023 

FSV-BB 0.098 0.106 0.088 0.093 0.089 0.446 0.459 0.803 0.404 0.272 0.411 0.436 0.757 0.383 0.259 0.035 0.023 0.046 0.020 0.013 

FSV-BC 

FSV-BD 

FSV-BE 0.418 0.409 0.575 0.252 0.201
 

FSV-BF
 0.603 0.665 1.494 0.672 0.334
 

FSV-BG
 0.573 0.589 1.140 0.599 0.391 

FSV-BH 0.520 0.553 1.167 0.576 0.378 0.504 0.537 1.129 0.558 0.365 0.016 0.016 0.038 0.018 0.013 

FSV-BJ 0.470 0.525 0.918 0.434 0.299 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.536 0.605 1.054 0.453 0.288 0.505 0.566 0.960 0.425 0.269 0.031 0.039 0.094 0.028 0.019 

FSV-BNa 0.542 0.608 1.064 0.470 0.285 

FSV-BO 0.537 0.586 0.913 0.511 0.345 

FSV-BP 0.443 0.395 0.898 0.331 0.145 

FSV-BQ 

FSV-BR 

FSV-BS ≥0.553 ≥0.501 ≥0.901 ≥0.400 ≥0.378 0.553 0.501 0.901 0.400 0.378 

FSV-BT 0.128 0.108 0.117 0.128 0.079 0.467 0.493 0.887 0.482 0.303 0.437 0.463 0.828 0.450 0.281 0.025 0.025 0.050 0.028 0.018 

FSV-BU 0.484 0.528 1.095 0.588 0.375 

FSV-BV 0.510 0.524 0.799 0.441 0.317 

FSV-BW 1.170 1.160 0.930 0.614 0.444 

FSV-CC 

FSV-CD 0.550 0.560 0.870 0.600 0.480 

FSV-CE 0.394 0.489 0.750 0.387 0.270
 

FSV-CF
 

FSV-CI
 0.533 0.559 1.105 0.544 0.347 

FSV-CW 0.084 0.090 0.077 0.086 0.077 0.413 0.455 0.980 0.486 0.319 

FSV-CZ 0.332 0.374 0.723 0.332 0.233
 

FSV-DA
 0.143 0.160 0.120 0.146 nd 0.453 0.468 0.737 0.379 0.255 0.428 0.442 0.676 0.352 0.237 0.025 0.025 0.061 0.027 0.017 

FSV-DD 

FSV-DV 

FSV-EE 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NAV 

NAU 

5 5 5 5 4 

0.084 0.090 0.077 0.086 0.077 

0.098 0.106 0.093 0.096 0.081 

0.143 0.160 0.120 0.146 0.089 

0.021 0.009 0.024 0.015 0.004 

21 8 26 15 5 

7 6 4 4 4 

0.113 0.126 0.061 0.084 0.092 

0.050 0.143 0.009 0.029 0.022 

21 

0.332 

0.484 

1.170 

0.077 

16 

32 

0.496 

0.055 

21 

0.374 

0.525 

1.160 

0.090 

17 

32 

0.519 

0.065 

21 

0.575 

0.913 

1.494 

0.208 

23 

20 

0.912 

0.190 

21 

0.252 

0.470 

0.672 

0.124 

26 

20 

0.472 

0.079 

21 

0.145 

0.303 

0.480 

0.063 

21 

20 

0.307 

0.042 

7 7 7 7 7 

0.411 0.436 0.676 0.352 0.237 

0.440 0.467 0.828 0.407 0.272 

0.553 0.566 1.129 0.558 0.378 

0.043 0.046 0.125 0.036 0.019 

10 10 15 9 7 

14 15 7 7 7 

0.439 0.479 0.870 0.455 0.303 

0.039 0.039 0.055 0.040 0.033 

6 

0.016 

0.028 

0.043 

0.008 

27 

10 

0.026 

0.004 

6 

0.016 

0.025 

0.047 

0.008 

33 

10 

0.027 

0.008 

6 

0.038 

0.055 

0.094 

0.013 

23 

5 

0.043 

0.010 

6 

0.018 

0.026 

0.028 

0.003 

12 

5 

0.021 

0.001 

6 

0.013 

0.018 

0.023 

0.004 

25 

5 

0.014 

0.000 

0.098 0.106 0.093 0.096 0.081 

0.023 0.024 0.024 0.023 

0.484 0.525 0.913 0.470 0.303 

0.077 0.090 0.208 0.124 0.063 

0.440 0.467 0.828 0.407 0.272 

0.046 0.049 0.125 0.043 0.029 

0.028 0.025 0.055 0.026 0.018 

0.010 0.009 0.023 0.009 0.006 

All Lab Report 
 

Round Robin LXVIII Laboratory Results 

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

C4

Lab 367 368 369 370 371 367 368 369 370 371 367 368 369 370 371 367 368 369 370 371 36

FSV-BA 0.202 0.251 0.482 0.526 0.491 0.118 0.129 0.247 0.274 0.261 0.052 0.055 0.090 0.101 0.099 0.025 0.025 0.021 0.026 0.026
 

FSV-BB
 0.225 0.251 0.490 0.513 0.502 0.110 0.122 0.200 0.225 0.230 0.046 0.049 0.083 0.088 0.087 0.023 0.024 0.024 0.027 0.027 0.10

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 0.248 0.254 0.482 0.524 0.529 0.157 0.161 0.292 0.315 0.307 0.050 0.055 0.082 0.096 0.095
 

FSV-BH
 0.307 0.329 0.667 0.723 0.726 0.059 0.063 0.144 0.133 0.127 0.06

FSV-BJ 0.237 0.230 0.424 0.521 0.495 0.031 0.033 0.044 0.061 0.068 0.06

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.235 0.254 0.457 0.423 0.408 0.148 0.158 0.281 0.245 0.234 0.054 0.059 0.078 0.087 0.084 0.07

FSV-BNa 0.235 0.256 0.520 0.470 0.448 0.046 0.055 0.075 0.078 0.078
 

FSV-BO
 0.209 0.219 0.391 0.465 0.467 0.046 0.048 0.080 0.086 0.087 0.1

FSV-BP 0.255 0.196 0.485 0.521 0.389 0.040 0.041 0.073 0.087 0.060
 

FSV-BQ
 

FSV-BR
 

FSV-BS
 0.264 0.261 0.343 0.331 0.507 0.141 0.146 0.146 0.137 0.212 0.038 0.038 0.055 0.064 0.065 0.06

FSV-BT 0.205 0.215 0.348 0.414 0.411 0.127 0.141 0.182 0.217 0.214 0.047 0.051 0.085 0.088 0.086 0.022 0.024 0.033 0.034 0.033
 

FSV-BU
 0.211 0.223 0.440 0.492 0.516 0.051 0.054 0.083 0.105 0.105
 

FSV-BV
 0.245 0.250 0.493 0.560 0.556 0.060 0.061 0.131 0.133 0.128 

FSV-BW 0.330 0.340 0.560 0.750 0.650 0.040 0.040 0.080 0.090 0.090
 

FSV-CC
 

FSV-CD
 0.340 0.340 0.400 0.410 0.390 0.060 0.070 0.100 0.110 0.100 0.020 0.020 0.020 0.040 0.020
 

FSV-CE
 

FSV-CF
 

FSV-CI
 0.08

FSV-CW 0.117 0.135 0.232 0.250 0.262 0.043 0.047 0.083 0.087 0.084
 

FSV-CZ
 

FSV-DA
 0.203 0.213 0.446 0.473 0.464 0.122 0.127 0.221 0.244 0.248 0.042 0.048 0.086 0.093 0.092 0.021 0.024 0.026 0.028 0.029 0.08

FSV-DD 

FSV-DV 

FSV-EE 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NAV 

NAU 

16 16 16 16 16 

0.202 0.196 0.343 0.331 0.389 

0.236 0.251 0.470 0.503 0.493 

0.340 0.340 0.667 0.750 0.726 

0.039 0.036 0.056 0.052 0.060 

16 14 12 10 12 

27 28 15 15 15 

0.222 0.226 0.467 0.515 0.519 

0.032 0.036 0.066 0.085 0.092 

8 8 8 8 8 

0.110 0.122 0.146 0.137 0.212 

0.125 0.138 0.227 0.245 0.241 

0.157 0.161 0.292 0.315 0.307 

0.017 0.015 0.053 0.035 0.031 

14 11 23 14 13 

12 12 7 7 7 

0.122 0.132 0.235 0.233 0.228 

0.026 0.023 0.072 0.027 0.025 

17 17 17 17 17 

0.031 0.033 0.044 0.061 0.060 

0.046 0.051 0.083 0.088 0.087 

0.060 0.070 0.144 0.133 0.128 

0.009 0.006 0.007 0.012 0.013 

19 12 9 13 15 

25 27 16 16 16 

0.049 0.051 0.082 0.093 0.091 

0.010 0.009 0.011 0.011 0.014 

5 5 5 5 5 

0.020 0.020 0.020 0.026 0.020 

0.022 0.024 0.024 0.028 0.027 

0.025 0.025 0.033 0.040 0.033 

0.001 0.001 0.004 0.003 0.003 

7 3 19 11 10 

5 6 5 5 5 

0.024 0.028 0.028 0.035 0.034 

0.006 0.003 0.004 0.006 0.010 

0.06

0.07

0.1

0.0

2

0.09

0.02

0.236 0.251 0.470 0.503 0.493 

0.056 0.059 0.098 0.104 0.102 

0.125 0.138 0.227 0.245 0.241 

0.022 0.024 0.053 0.044 0.043 

0.046 0.051 0.083 0.088 0.087 

0.011 0.012 0.019 0.020 0.020 

0.022 0.024 0.024 0.028 0.027 

0.001 0.001 0.004 0.003 0.003 

0.07

0.0

All Lab Report 
Round Robin LXVIII Laboratory Results 

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

C5

Lab 367 368 369 370 371 367 368 369 370 371 367 368 369 370 371 367 368 369 370 371 3

FSV-BA 0.107 0.118 0.144 0.159 0.160
 

FSV-BB
 0.060 0.062 0.065 0.069 0.053 0.155 0.171 0.195 0.208 0.208
 

FSV-BC
 

FSV-BD
 

FSV-BE
 0.903 0.983 0.991 1.110 0.882 2.584 0.778 0.793 0.794
 2.384 

FSV-BF
 

FSV-BG
 0.117 0.122 0.156 0.179 0.179
 

FSV-BH
 0.050 0.064 0.069 0.064 0.043 0.113 0.129 0.157 0.180 0.162 0

FSV-BJ 0.703 0.711 0.805 0.863
 0.552 

FSV-BK
 

FSV-BL
 

FSV-BM
 

FSV-BN
 0.031 0.040 0.045 0.032 0.033 0.108 0.112 0.140 0.156 0.137 

FSV-BNa 0.115 0.128 0.140 0.155 0.150 0

FSV-BO 0.016 0.021 0.023 0.026 0.015 0.134 0.142 0.180 0.200 0.211 1.022 0.886 1.015 1.004 0.953 0

FSV-BP 0.116 0.100 0.164 0.187 0.170
 

FSV-BQ
 

FSV-BR
 

FSV-BS
 0.042 0.063 0.070 0.075 0.040 0.103 0.113 0.144 0.160 0.179
 

FSV-BT
 0.108 0.119 0.176 0.197 0.190 0.862 0.995 1.140 1.137
 0.820 

FSV-BU
 0.113 0.121 0.153 0.190 0.192 0.650 1.570 1.460 1.500 0.770 0

FSV-BV 0.112 0.113 0.151 0.173 0.176 

FSV-BW 0.110 0.120 0.170 0.180 0.190 0.946 0.778 0.896 1.009
 0.714 

FSV-CC
 

FSV-CD
 0.170 0.160 0.220 0.250 0.240
 

FSV-CE
 

FSV-CF
 

FSV-CI 0.025 0.030 0.032 0.033 0.024 0.110 0.118 0.149 0.165 0.166 0.822 0.903 1.040 1.010 0.785 2.357 0.643 0.721 0.731 2.174 

FSV-CW 0.180 0.150 0.233 0.228 0.248
 

FSV-CZ
 0.798 0.788 0.821 0.835
 0.682 

FSV-DA
 0.041 0.059 0.062 0.062 0.042 0.123 0.122 0.171 0.189 0.187 0

FSV-DD 

FSV-DV 

FSV-EE 0.843 0.945 1.071 1.089 0.802 

N 7 7 7 7 7 17 17 17 17 17 9 9 9 9 9 2 2 2 2 2 

Min 0.015 0.016 0.021 0.023 0.026 0.103 0.100 0.140 0.155 0.137 0.552 0.650 0.711 0.805 0.835 2.174 2.357 0.643 0.721 0.731 0

Median 0.040 0.041 0.059 0.062 0.062 0.113 0.121 0.157 0.180 0.179 0.785 0.843 0.903 1.015 1.010 2.279 2.471 0.711 0.757 0.763 0

Max 0.053 0.060 0.064 0.070 0.075 0.180 0.171 0.233 0.250 0.248 0.953 1.022 1.570 1.460 1.500 2.384 2.584 0.778 0.793 0.794 0

SD 0.011 0.015 0.008 0.011 0.019 0.007 0.012 0.019 0.025 0.019 0.105 0.089 0.136 0.176 0.148 0

CV 27 36 14 18 30 6 10 12 14 11 13 11 15 17 15 

Npast 14 15 7 7 7 23 26 16 16 16 6 10 7 7 7 0 0 0 0 0 

Medianpast 0.035 0.037 0.050 0.057 0.060 0.130 0.132 0.159 0.180 0.185 0.830 0.683 0.933 0.980 1.077 

SDpast 0.008 0.008 0.028 0.019 0.022 0.024 0.025 0.033 0.044 0.036 0.196 0.242 0.188 0.090 0.123 

0

0

NAV 

NAU 

0.040 0.041 0.059 0.062 0.062 0.113 0.121 0.157 0.180 0.179 0.785 0.843 0.903 1.015 1.010 

0.011 0.015 0.016 0.017 0.019 0.023 0.025 0.033 0.038 0.037 0.105 0.089 0.136 0.176 0.148 

All Lab Report 
 

 

 

 

 

 

 

Round Robin LXVIII Laboratory Results 

Analytes Reported By a Single 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 Standard deviation for (non-NIST) results: 0.741*(3rd Quartile - 1st Quartile)

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)

NNIST Number of units evaluated at NIST

MeanNIST Mean of NIST results

Srep NIST's within-vial pooled standard deviation

Shet NIST's among-vial pooled standard deviation 

SNIST Combined standard deviation for NIST analyses: √(Srep 2

 + Shet 2)

NAV NIST Assigned Value

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

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

NAU NIST Assigned Uncertainty: √(S 2

 + Sbtw 2)

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

 deviation between Median and MeanNIST. 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 greater than or equal to x

italics Not explicitly reported but calculated by NIST from reported values 

Analyte Code 367 368 369 370 371 

Ubiquinol FSV-BW 0.714 0.670 0.223 0.371 0.399 

Ubiquinone FSV-BW nd 0.276 0.554 0.524 0.610 

Phytofluene FSV-DA nd nd 0.118 0.106 0.113 

Phytoene FSV-DA 0.013 0.012 0.055 0.081 0.071 

Legend

All Lab Report 

C6

Page 5 / 6 
 

 

 

 

 

 

 

Round Robin LXVIII 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-BNa 

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-CF 

FSV-CI
 

FSV-CW
 

FSV-CZ
 

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

1 1 3 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 2 1 2 

1 

1 2 

2 1 1 2 

1 1 2 

1 1 1 2 1 1 1 1 

3 1 1 1 3 1 2 3 1 1 1 

1 1 1 1 1 1 2 1 

1 1 

1 1 

4 1 

2 1 2 1 2 2 1 1 1 2 1 

1 1 1 3 1 1 1 

1 1 1 1 1 1 1 3 3 1 

1 1 2 1 1 1 1 

1 1 

2 1 

1 1 3 4 2 2 2 1 1 

2 1 1 1 1 1 1 1 1 

2 2 1 1 1 1 1 1 

1 1 1 1 1 1 2 1 

1 2 1 4 2 2 1 1 

4 3 

2 2 2 2 4 2 2 2 

1 1 1 

1 1 

2 1 1 1 2 1 2 1 

4 2 1 1 1 1 3 

1 1 1 2 

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 

you Youi Median i 

NAU i 

FSV-DA 1 1 1 1 2 1 1 1 1 1 1 

∑ 

= 





 N 

i 1 

FSV-DV 4 4 

CS = 



 





 

2 2 + C + AP FSV-DD 2 

FSV-EE 2 4 

n 34 31 17 22 7 18 16 17 8 7 17 C = Concordance = 

Nyou 

1i 

you

∑ 

= 

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















i 

% 4 12 6 0 5 0 11 0 0 0 0 0 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 59 74 82 68 43 67 75 71 63 57 82 

% 2 26 16 12 27 29 17 25 24 25 29 12 AP = Apparent Precision = − % 3 3 3 6 0 29 6 0 6 13 14 6 you 

All Lab Report 

C7

Page 6 / 6 
 

Appendix D. Representative “Individualized Report” for RR68 

Each participant in RR68 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 RR68: 

• 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 α-Cryptoxanthin 

• Total Lutein 

• Total Zeaxanthin 

• Total Lutein & Zeaxanthin 

• Coenzyme Q10 

• 25-Hydroxyvitamin D 

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

by participant FSV-BA. 

D1
 

 Set 1 of 37 

Individualized Round Robin LXVIII Report: FSV-BA 

Summary 

Serum 367 Serum 368 Serum 369 Serum 370 S

D2

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

Total Retinol 0.625 0.630 33 0.695 0.662 33 0.284 0.290 33 0.318 0.315 33 0.30

Retinyl Palmitate 0.02 0.02 9 0.0 0.0 9 0.1 0.0 9 0.07 0.02 8 0.07 

α-Tocopherol 6.18 6.03 31 6.61 6.54 31 7.58 7.20 31 8.20 8.00 31 8.26 

γ/β-Tocopherol 2.696 2.191 17 2.829 2.311 17 3.469 2.765 17 3.644 3.138 17 3.75

δ-Tocopherol 0.095 0.098 5 0.100 0.106 5 0.093 0.093 5 0.096 0.096 5 0.08

Total β-Carotene 0.483 0.484 21 0.513 0.525 21 0.807 0.913 21 0.431 0.470 21 0.29

trans-β-Carotene 0.440 0.440 7 0.467 0.467 7 0.744 0.828 7 0.407 0.407 7 0.27

Total cis-β-Carotene 0.043 0.028 6 0.047 0.025 6 0.063 0.055 6 0.025 0.026 6 0.02

Total α-Carotene 0.016 0.021 18 0.020 0.021 18 0.031 0.032 18 0.034 0.034 18 0.03

Total Lycopene 0.202 0.236 16 0.251 0.251 16 0.482 0.470 16 0.526 0.503 16 0.49

trans-Lycopene 0.118 0.125 8 0.129 0.138 8 0.247 0.227 8 0.274 0.245 8 0.26

Total β-Cryptoxanthin 0.052 0.046 17 0.055 0.051 17 0.090 0.083 17 0.101 0.088 17 0.09

Total α-Cryptoxanthin 0.025 0.022 5 0.025 0.024 5 0.021 0.024 5 0.026 0.028 5 0.02

Total Lutein&Zeaxanthin 0.107 0.113 17 0.118 0.121 17 0.144 0.157 17 0.159 0.180 17 0.16

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: (3

100 Bureau Drive Stop 8392 Fax: (3

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

Individualized Report 
D3

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

Total Retinol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 2 / 14 
D4

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

Retinyl Palmitate, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 3 / 14 
D5

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

α-Tocopherol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 4 / 14 
D6

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

γ/β-Tocopherol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 5 / 14 
D7

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

Total β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 6 / 14 
D8

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

trans-β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 7 / 14 
D9

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

Total cis-β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 8 / 14 
D10

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

Total α-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 9 / 14 
D11

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

Total Lycopene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 10 / 14 
D12

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

trans-Lycopene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 11 / 14 
D13

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

Total β-Cryptoxanthin, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 12 / 14 
D14

 Set 1 of 37 

Individualized RR LXVIII Report: FSV-BA

Total Lutein&Zeaxanthin, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

270276367267274368355369354370353371 

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 

#367 Lyophilized, same native pool as #368 49#270, 50#276 

#368 Fresh-frozen, same native pool as #367 48#267, 50#274 

#369 126+4 mixture of single-donor #371 with spike pool 65#355 

#370 120+10 mixture of single-donor #371 with spike pool 65#354 

#371 105+25 mixture of single-donor #371 with spike pool 65#353 

Individualized Report Page 13 / 14 
D15

 Set 1 of 35 

Individualized Round Robin LXVIII Report: FSV-BA 

Graphical Comparability Summary
 

Total Retinol α-Tocopherol Total α-Carotene T

trans-Retinol γ/β-Tocopherol Total Lycopene Tot

Retinyl Palmitate Total β-Carotene trans-Lycopene Total L

trans-β-Carotene Total β-Cryptoxanthin Co

Individualized Report 
Appendix E. Shipping Package Inserts for RR33 

The following five items were included in each package shipped to an RR33 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
June 3, 2010 

Dear Colleague: 

UNrrED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

The samples within this package constitute Vitamin C Round Robin 33 (RR33) of the 2010 Micronutrients · 

Measurement Quality Assurance Program. RR33 consists of four vials of frozen serum test samples (#331, #332, 

#333, and #334), 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 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 #1 

is 8.4 ±1.8 μmol/L of sample. 

The report for RR32 was e-mailed in April. If you find your results for RR32 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 phone: 301-975-3120, fax: 301-977-0685, or 

e-mail: jbthomas@nist.gov. 

We ask that you return your results for these RR33 samples by September 27, 2010. We would appreciate 

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

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

RR33 Report Form for Ascorbic Acid Solid Control Material Preparation 

RR33'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 33 

NIST Micronutrient Measurement Quality Assurance Program 

Preparation and Validation of Ascorbic Acid Solid Control Material 

STOCK SOLUTION 

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

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

DILUTE SOLUTION 1 

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

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

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

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

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

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

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

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

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

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

DILUTE SOLUTION 2 

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

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

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

DILUTE SOLUTION 3 

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

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

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

Please return by March 15, 2010 

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 33 

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 #1 Target: 8.4 ±1.8 μmol/L 

Serum Test Sample #331 μmol/L of Sample 

Serum Test Sample #332 μmol/L of Sample 

Serum Test Sample #333 μmol/L of Sample 

Serum Test Sample #334 μmol/L of Sample 

Were samples frozen upon receipt? Yes | No 

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

If “Other”, please describe: 

COMMENTS: 

Please return by March 15, 2010 

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 33
 

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

VitC #332 Liquid frozen (1:1 serum:10% MPA) 

VitC #333 Liquid frozen (1:1 serum:10% MPA) 

VitC #334 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 8392 Fax: 301-977-0685 

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

E7
 

 

Appendix F. Final Report for RR33 

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
F2
The NIST M2

QAP Vitamin C Round Robin 33 (RR33) 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 RR33 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR33 

samples and control/calibration solutions. 

Serum-based Samples. One serum control and four unknowns were distributed in RR33. 

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

S33:1 Serum 331, ampouled in late 2001, previously distributed as sample S18:2 (RR18, Spring 

03), S19:3 (RR19, Fall 03), S21:3 (RR21, Fall 04), S22:3 (RR22, Spring 05), S24:2 (RR24, 

Spring 06)., S26:2 (RR26, Spring 07), S31:2 (RR31, Fall 09). 

S33:2 Serum 332, ampouled in 1995, previously distributed as sample 688a in (RR8, Fall 95) and 

(RR9, Summer 96) and S27:4 (RR27, Fall 07). 

S33:3 Serum 333, ampouled in Fall 09, initial distribution 

S33:4 Serum 334, ampouled in Fall 09, previously distributed as sample S32:2 (RR32, 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 reasonably well calibrated (intercepts range from ­

0.6 to 0.8 and slopes range from 0.98 to 1.08). 

3)	 The Measured = p+q*Median regression parameters for samples S33:1 to S33:4 (columns 23 to 26 of 

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

 close to 1 and RMS close 

to 0.0). 

4)	 There is no evidence of sample degradation in any of the materials. Note that S33:1 and S33:2 were 

prepared 12 and 15 years ago, respectively. 

F3
Appendix G. “All-Lab Report” for RR33 

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
 

 

12 12 

-0.59 0.98 

0.84 1.08 

 

Micronutrients Measurement Quality Assurance Program for Total Ascorbic Aci

"Round Robin" 33 - September 2010 

Control / Calibration Samples MPA Dilute Solution 1 

Measured = a + b*Grav Density Spectrophotometry Measured, μmo

Grav, μmol/L Measured, μmol/L 

E1% Lab Date Dil:1 Dil:2 Dil:3 Dil:1 Dil:2 Dil:3 MPA Inter Slope R2 RMS g/mL CS#1 S33:1 S33:2 S3

λmax Amax 

VC-MA 27/09/10 58.8 30.0 15.0 63.9 33.0 17.0 0.0 0.38 1.08 1.000 0.4 1.037 244. 0.5600 540.5 9.7 36.4 15.1 

VC-MB 23/07/10 57.8 29.0 14.2 58.6 28.9 14.5 0.0 -0.10 1.01 1.000 0.3 1.030 243.5 0.5730 563.3 8.0 33.6 13.4 

VC-MC 29/06/10 58.7 29.7 14.7 57.5 28.7 13.8 0.0 -0.30 0.98 1.000 0.3 1.031 243. 0.5611 543.1 9.0 35.7 15.8 

VC-ME 15/09/10 57.4 28.8 14.3 59.8 28.2 15.0 0.0 -0.34 1.04 0.999 1.1 1.031 243. 0.5836 577.2 9.0 31.2 14.2 

VC-MG 01/09/10 63.3 32.9 17.2 64.5 33.1 16.8 0.0 -0.35 1.02 1.000 0.4 1.028 243.7 0.6360 570.1 8.6 32.8 13.4 

VC-MH 15/09/10 61.7 30.8 15.2 60.5 30.0 15.0 0.0 -0.02 0.98 1.000 0.1 1.029 243.6 0.6412 590.4 8.5 33.3 14.0 

VC-MI 26/07/10 55.7 28.1 13.8 56.4 28.2 14.0 0.0 -0.07 1.01 1.000 0.2 1.035 9.9 33.3 14.8 

VC-MJ 23/07/10 58.3 28.0 14.6 59.9 30.3 14.4 0.0 0.12 1.03 0.999 1.1 1.020 11.2 36.9 15.8 2

255a 0.367a 357.2a 

VC-MN 27/09/10 60.5 30.6 15.4 62.9 33.3 17.4 0.0 0.84 1.04 0.999 1.0 1.027 243.8 0.6445 605.1 8.9 35.1 15.5 

VC-MP 02/09/10 58.0 28.8 14.5 59.1 27.7 14.2 0.0 -0.59 1.02 0.999 0.9 1.034 242. 0.5417 530.2 7.6 33.2 12.9 

VC-MU 23/09/10 59.9 30.2 14.7 59.9 30.1 13.9 0.0 -0.34 1.00 1.000 0.5 1.030 241. 0.5770 546.9 8.5 31.8 10.5 

VC-NE 15/09/10 57.9 29.0 14.6 56.5 27.2 13.4 0.0 -0.59 0.98 0.999 0.7 1.031 243. 0.5660 555.5 8.3 32.9 14.1 

G2

N 12 12 12 12 12 12 12 

59.0 29.6 14.9 59.9 29.9 14.9 0.0 

2.1 1.4 0.8 2.7 2.2 1.4 0.0 

N 12 10 10 10 12 12 12 

Average Average 1.030 243.1 0.5884 562.2 8.9 33.8 14.1 

SD SD 0.004 0.9 0.0378 23.7 1.0 1.8 1.5 

Min 55.7 28.04 13.8 

57.8 28.79 14.5 

58.5 29.32 14.6 

60.0 30.29 15.0 

63.3 32.91 17.2 

1.4 1.1 0.5 

2 4 3 

56.4 27.20 13.4 0.0 

58.3 28.18 13.9 0.0 

59.8 29.46 14.4 0.0 

61.1 31.00 15.4 0.0 

64.5 33.31 17.4 0.0 

2.7 1.9 0.8 0.0 

4 6 6 

Min 1.020 241.0 0.5417 530.2 7.6 31.2 10.5 

%25 %25 1.029 243.0 0.5623 544.0 8.4 32.9 13.4 

Median Median 1.031 243.3 0.5750 559.4 8.8 33.3 14.1 

%75 %75 1.032 243.7 0.6229 575.4 9.2 35.2 15.2 

Max Max 1.037 244.0 0.6445 605.1 11.2 36.9 15.8 2

MADe eSD 0.003 0.6 0.0214 25.3 0.5 1.4 1.2 

CV CV 0.31 0.2 3.7 4.5 6.3 4.3 8.8 

a ) 5% Trichloroacetic acid solution 

b ) Mislabeled sample 

All Lab Report 
Appendix H. Representative “Individualized Report” for RR33 

Each participant in RR33 received an “Individualized Report” reflecting their reported 

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

“VC-MA”. 

H1
 Set 1 of 14 

Vitamin C "Round Robin" 33 Report: Participant VC-MA
 

Date RR Method 

03/04/08 28 HPLC-EC 

08/11/08 29 HPLC-EC 

03/03/09 30 HPLC-EC 

09/10/09 31 HPLC-EC 

02/24/10 32 HPLC-EC 

09/27/10 33 HPLC-EC 

Mean 

SD 

CV 

Date RR Sample 

03/04/08 28 CS#1 

03/03/09 30 CS#1 

09/27/10 33 CS#1 

03/20/03 18 S18:2 

11/13/03 19 S19:3 

09/13/04 21 S21:3 

03/08/05 22 S22:3 

03/09/06 24 S24:2 

03/20/07 26 S26:2 

09/10/09 31 S31:2 

09/27/10 33 S33:1 

ND 08 

06/19/96 09 S09:1 

10/05/07 27 S27:4 

09/27/10 33 S33:2 

09/27/10 33 S33:3 

02/24/10 32 S32:2 

09/27/10 33 S33:4 

MPA Dilute Solution 1
 

Density Spectrophotometry
 

g/mL 

1.035 

1.037 

1.037 

1.036 

1.035 

1.037 

1.036 243.0 0.57 550.5 

0.001 0.9 0.00 8.0 

0.07 0.37 0.7 1.4 

[TAA] mmol/Lsample 

Rep1 Rep2 Fadj Mean SDdup 

9.1 9.0 1.0 9.0 0.1 

8.3 8.0 1.0 8.1 0.2 

9.8 9.6 1.0 9.7 0.2 

35.1 36.0 1.0 35.6 0.6 

35.9 35.8 1.0 35.9 0.1 

33.2 32.9 1.0 33.0 0.2 

35.7 35.6 1.0 35.6 0.1 

35.8 35.5 1.0 35.6 0.2 

35.0 35.4 1.0 35.2 0.3 

33.9 33.7 1.0 33.8 0.2 

36.7 36.2 1.0 36.4 0.3 

29.1 23.8 0.5 13.2 1.9 

13.9 13.7 1.0 13.8 0.2 

15.3 14.9 1.0 15.1 0.3 

16.6 16.8 1.0 16.7 0.1 

26.2 26.0 1.0 26.1 0.1 

26.9 26.4 1.0 26.7 0.4 

Control/Calibration Solutions
 

Ymeas = Inter + Slope* Xgrav
 

λmax Amax E1% Inter Slope R2 SEE 

243.0 0.572 562.2 0.7 1.03 0.999 0.99 

243.0 0.567 553.2 0.3 1.03 1.000 0.64 

242.0 0.569 555.6 0.2 1.03 1.000 0.40 

244.0 0.566 546.1 -0.1 1.02 1.000 0.20 

242.0 0.566 545.1 0.3 1.03 1.000 0.46 

244.0 0.560 540.5 0.4 1.08 1.000 0.43 

Pooled SEE 0.57 

N Mean SDrepeat SDreprod 

3 9.0 0.1 0.8 

8 35.1 0.3 1.1 

3 14.0 1.1 1.1 

2 26.4 0.3 0.4 

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

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology 

100 Bureau Drive Stop 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 14 

Vitamin C "Round Robin" 33 Report: Participant VC-MA 

Total Ascorbic Acid, μmol/mL 

[Total Ascorbic Acid], μmol/L 

S18:2S19:3S21:3S22:3S24:2S26:2

Apparent Precision, SD S31:2

S33:1S08:2S09:1 S27:4 S33:2 S33:3 S32:2 S33:4 

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 

S33:1 VitC #331, previously distributed in RRs 18, 19, 21, 22, 24, 26, 31 

S33:2 VitC #332, previously distributed in RRs 8, 9, 27 

S33:3 VitC #333, new material 

S33:4 VitC #334, previously distributed in RR 32 

Individualized Report	 Page 2 / 2