NISTIR 7880-3 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2011 

Comparability Studies 

Results for Round Robin LXIX 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 34 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

 

 

 

 

NISTIR 7880-3
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2011 

Comparability Studies 

Results for Round Robin LXIX 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 34 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 

Winter 2011 MMQAP measurement comparability improvement studies: 1) Round Robin LXIX 

Fat-Soluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 34 Total Ascorbic Acid 

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

participants were requested to provide their measurement results by March 7, 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 LXIX: Fat-Soluble Vitamins and Carotenoids in Human Serum ......................... 1
 

Round Robin 34: Vitamin C in Human Serum............................................................................... 2
 

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

Appendix A. Shipping Package Inserts for RR69........................................................................ A1
 

Appendix B. Final Report for RR69 ..............................................................................................B1
 

Appendix C. “All-Lab Report” for RR69 ......................................................................................C1
 

Appendix D. Representative “Individualized Report” for RR69 ............................................... D1
 

Appendix E. Shipping Package Inserts for RR34 ......................................................................... E1
 

Appendix F. Final Report for RR34............................................................................................... F1
 

Appendix G. “All-Lab Report” for RR34..................................................................................... G1
 

Appendix H. Representative “Individualized Report” for RR34............................................... 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 LXIX: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

LXIX comparability study (hereafter referred to as RR69) received five 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 November 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 RR69 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 of “Individualized Report” is reproduced as Appendix D. 

Round Robin 34: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 34 comparability study 

(hereafter referred to as RR34) 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 November 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 RR34 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 RR69 

The following three items were included in each package shipped to an RR69 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
A2
 

 

 

Participant #: ________ Date: _____________ 

Round Robin LXIX: Human Sera 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 372 373 374 375 376 Units* 

total retinol 

trans-retinol 

retinyl palmitate 

retinyl stearate 

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? 

Were the liquid-frozen samples frozen when received? Yes | No 

* we prefer μg/mL 

Comments: 

Mail: M2QAP 

NIST, Stop 6392 

Gaithersburg, MD 20899-6392 

Please return results by 

7-March-2011 Fax: 301-977-0685 

Email: David.Duewer@NIST.gov 

A3
 

 

968d-1

968e-3

968e-2

968e-1

blend

 

Participant #: ________ Date: _____________ 

Round Robin LXIX: 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 

#372 Liquid frozen No 10 mL amber, silver cap 

#373 Liquid frozen No 2 mL amber, green cap 

#374 Liquid frozen No 2 mL amber, blue cap 

#375 Liquid frozen No 2 mL amber, red cap 

#376 Liquid frozen No 2 mL amber, green cap 

Please 1) Open the pack immediately 

2) Check that it contains all of the above samples 

3) Check if the vials are intact 

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

5) Complete the following information 

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

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

1) Date this shipment arrived: ___________________________ 

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

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

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

4) Did the liquid frozen samples arrive frozen? Yes | No 

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

6) When do you anticipate analyzing these samples? ________________________ 

Your prompt return of this information is appreciated. 

The M2QAP Gang 

Mail: M2QAP 

NIST, Stop 6392 Fax: 301-977-0685 

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

A4
 

 

 

Appendix B. Final Report for RR69 

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 LXIX (RR69) report consists of: 

Page 

1-5 

6 

7 

Page 

1 

2 to 

n 

n+1 

Samples. 

Serum

372 

373 

374 

375 

376 

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 RR69. 

Description 

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

Fall, 2007. This was SRM 968d. 

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

This is Level III of SRM 968e. 

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

This is Level II of SRM 968e. 

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

This is Level I of SRM 968e. 

Fresh-frozen, native, multi-donor, prepared in 2008. 

Prior Distributions 

#341 & #344:RR63-3/08, 

#351:RR64-9/08, #361:RR66-9/09 

#359:RR66-9/09 

#358:RR66-9/09 

#357:RR66-9/09 

#356:RR65-3/09, #360:RR66-9/09 

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

measurand in any of the materials, including the very low-level material that used to be SRM 968d. 

2)	 SRM 968e. Sera #373 to #375 are the components of SRM 968e. All three of these materials were 

prepared by blending commercially available materials without spiking. The materials were designed 

to represent relatively low, middling, and relatively high levels of retinol, α-tocopherol and 

β-carotene. SRM 968e is now available for purchase. 

3)	 Environmental Stability. Due to severe weather, RR69 shipping was more than usually chaotic. 

Several sets of RR69 materials arrived thoroughly defrosted. None of the affected labs measured the 

thawed and unthawed materials together under repeatability conditions. However, there were no 

significant (relative to interlaboratory imprecision) differences between results for any of the thawed 

RR69 materials and the measurements each of these labs made for the same materials in RR66. Any 

changes in these materials that may have occurred due to the shipping misadventures were thus well 

within interlaboratory imprecision. 

B3
 

 

Appendix C. “All-Lab Report” for RR69 

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 LXIX Laboratory Results 

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

C2

Lab 372 373 374 375 376 372 373 374 375 376 372 373 374 375 376 372 373 374 375 376 

FSV-BA 0.365 0.715 0.537 0.375 0.775 0.030 0.173 0.070 0.018 0.047 5.67 18.15 9.94 6.61 10.10 

FSV-BB 0.378 0.708 0.554 0.393 0.795 0.008 0.075 0.022 0.009 0.038 5.89 18.23 10.26 6.65 10.45 

FSV-BC 0.354 0.718 0.561 0.352 0.778 

FSV-BD 0.366 0.692 0.606 0.371 0.719 5.80 20.10 11.40 6.40 9.90 

FSV-BE 0.418 0.799 0.598 0.422 0.868 4.20 19.21 10.18 6.54 10.41 

FSV-BF 0.350 0.600 0.490 0.330 0.690 5.90 18.60 10.50 6.80 10.60 

FSV-BG 0.346 0.659 0.506 0.360 0.766 0.018 0.155 0.041 0.010 0.041 5.64 18.72 10.07 6.75 10.84 

FSV-BH 0.242 0.573 0.459 0.304 0.646 5.54 16.93 9.84 6.41 9.87 

FSV-BJ 0.335 0.643 0.507 0.352 0.741 nq 0.083 nq nq nq 6.21 20.27 11.46 7.14 11.20 

FSV-BK 0.438 0.677 0.537 0.385 0.805 6.72 20.08 11.24 7.38 11.49
 

FSV-BL
 0.340 0.690 0.540 0.370 0.770 6.03 18.52 10.77 6.89 10.34 

FSV-BM 0.350 0.719 0.511 0.379 0.739 6.60 20.40 11.40 7.40 10.90 

FSV-BN 0.324 0.616 0.481 0.318 0.614 4.61 17.44 9.20 5.53 8.26 

FSV-BO 0.289 0.539 0.412 0.298 0.607 5.25 16.75 9.04 5.60 9.22 

FSV-BP 0.350 0.650 0.520 0.350 0.730 6.13 15.74 10.00 6.77 9.50 

FSV-BQ 0.360 0.810 1.040 0.410 1.070 8.00 24.00 23.00 8.00 16.00 

FSV-BR 0.335 0.660 0.490 0.350 0.730 5.65 14.70 9.10 6.54 9.28 

FSV-BS ≥0.291 ≥0.661 ≥0.476 ≥0.321 ≥0.745 0.291 0.661 0.476 0.321 0.745 

FSV-BT 0.385 0.517 0.409 0.306 0.607 5.90 19.43 11.07 7.17 11.53 

FSV-BU 0.284 0.694 0.483 0.341 0.669 5.95 20.12 12.23 7.36 11.68 

FSV-BV 0.367 0.708 0.572 0.408 0.802 5.54 18.48 10.89 7.00 10.54 

FSV-BW 0.332 0.623 0.472 0.357 0.707 0.002 0.123 0.027 0.010 0.060 5.49 20.20 10.27 7.04 11.31 

FSV-CC 0.293 0.657 0.477 0.348 0.701 0.281 0.645 0.472 0.347 0.691 2.02 19.68 9.99 6.76 10.49 

FSV-CD 0.359 0.560 0.437 0.319 0.638 0.011 0.125 0.022 nq 0.047 8.52 20.86 11.96 8.05 12.28 

FSV-CE 0.350 0.660 0.520 0.390 0.750 5.73 17.07 10.37 6.84 10.63 

FSV-CG 0.374 0.727 0.556 0.407 0.821 5.66 21.20 11.03 7.12 11.20 

FSV-CI 0.407 0.758 0.585 0.405 0.850 0.015 0.103 0.042 0.015 0.050 5.77 18.63 10.56 6.79 10.70 

FSV-CW 0.343 0.512 0.432 0.346 0.682 0.005 0.088 0.028 0.009 0.049 5.89 18.94 11.00 7.07 11.10 

FSV-CZ 0.324 0.604 0.469 0.339 0.692 5.24 19.13 9.45 6.10 10.69 

FSV-DD 0.380 0.670 0.550 0.500 0.720 

FSV-DQ 5.95 28.06 12.68 6.62 12.87 

FSV-DV 0.357 0.734 0.570 0.401 0.830 4.70 18.90 10.20 6.60 10.10 

FSV-EE 

FSV-EZ 0.336 0.647 0.503 0.361 0.754 nq 0.073 nq nq 0.034 5.81 18.93 10.62 7.02 11.19 

FSV-FK ≥0.321 ≥0.610 ≥0.474 ≥0.336 ≥0.690 0.321 0.610 0.474 0.336 0.690 6.00 17.40 10.00 6.40 10.00 

N 31 31 31 31 31 3 3 3 3 3 7 9 7 6 8 31 31 31 31 31 

Min 0.242 0.512 0.409 0.298 0.607 0.281 0.610 0.472 0.321 0.690 0.002 0.073 0.022 0.009 0.034 2.02 14.70 9.04 5.53 8.26 

Median 0.350 0.660 0.511 0.360 0.739 0.291 0.645 0.474 0.336 0.691 0.011 0.103 0.028 0.010 0.047 5.80 18.93 10.50 6.79 10.63 

Max 0.438 0.810 1.040 0.500 1.070 0.321 0.661 0.476 0.347 0.745 0.030 0.173 0.070 0.018 0.060 8.52 28.06 23.00 8.05 16.00 

SD 0.024 0.071 0.058 0.037 0.073 0.008 0.033 0.009 0.001 0.007 0.341 1.742 0.783 0.371 0.841 

CV 7 11 11 10 10 76 32 33 11 14 6 9 7 5 8 

Npast 31 31 31 31 30 7 5 5 5 5 8 10 7 9 9 32 32 32 32 32 

Medianpast 0.341 0.655 0.504 0.353 0.740 0.318 0.549 0.471 0.330 0.692 0.010 0.090 0.021 0.008 0.045 5.744 18.634 10.300 6.822 10.564 

SDpast 0.030 0.049 0.039 0.033 0.061 0.053 0.102 0.064 0.032 0.097 0.007 0.027 0.007 0.004 0.009 0.853 1.221 0.856 0.540 0.797 

NAV 

NAU 

0.350 0.660 0.509 0.359 0.735 

0.029 0.072 0.057 0.035 0.072 

0.350 0.660 0.509 0.359 0.735 

0.029 0.072 0.057 0.035 0.072 

0.010 0.104 0.028 0.010 0.047 

0.010 0.031 0.012 0.010 0.016 

5.785 18.913 10.530 6.780 10.615 

0.518 1.742 0.818 0.572 0.864 

All Lab Report 
Round Robin LXIX Laboratory Results 

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

C3

Lab 372 373 374 375 376 372 373 374 375 376 372 373 374 375 376 372 373 374 375 376 

FSV-BA 0.086 0.199 0.062 0.083 0.255 0.078 0.388 0.226 0.086 0.260 0.075 0.372 0.216 0.082 0.248 0.003 0.017 0.010 0.003 0.011 

FSV-BB 0.089 0.217 0.067 0.143 0.275 0.078 0.356 0.234 0.093 0.282 0.075 0.342 0.223 0.088 0.266 0.004 0.015 0.010 0.005 0.016 

FSV-BC 

FSV-BD 

FSV-BE 0.078 0.430 0.241 0.089 0.247 

FSV-BF 0.071 0.373 0.220 0.072 0.304 

FSV-BG 0.078 0.463 0.244 0.100 0.279 

FSV-BH 0.060 0.354 0.226 0.074 0.261 0.060 0.331 0.207 0.074 0.237 nq 0.023 0.019 nq 0.024 

FSV-BJ 0.083 0.427 0.243 0.084 0.280 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.056 0.383 0.233 0.074 0.226 

FSV-BO 0.101 0.443 0.254 0.098 0.274 

FSV-BP 0.102 0.400 0.271 0.095 0.273 

FSV-BQ 

FSV-BR 

FSV-BS ≥0.129 ≥0.710 ≥0.451 ≥0.159 ≥0.425 0.129 0.710 0.451 0.159 0.425 

FSV-BT 0.119 0.278 0.129 0.143 0.333 0.076 0.322 0.205 0.079 0.219 0.075 0.331 0.208 0.081 0.228 0.006 0.018 0.013 0.004 0.010 

FSV-BU 0.092 0.420 0.255 0.091 0.280 

FSV-BV 0.069 0.402 0.269 0.104 0.299 

FSV-BW 0.063 0.497 0.268 0.100 0.321 

FSV-CC 

FSV-CD 0.194 0.446 0.326 0.200 0.370 

FSV-CE 0.090 0.410 0.230 0.090 0.320 

FSV-CG 0.069 0.431 0.251 0.093 0.285 0.065 0.411 0.238 0.088 0.269 nq 0.020 0.012 0.005 0.015 

FSV-CI 0.065 0.453 0.259 0.091 0.282 

FSV-CW 0.061 0.225 0.043 0.095 0.275 0.079 0.319 0.208 0.088 0.250 

FSV-CZ 0.102 0.346 0.246 0.102 0.299 

FSV-DD 

FSV-DQ 0.148 0.781 0.435 0.120 0.571 

FSV-DV 

FSV-EE 

FSV-EZ 0.078 0.315 0.196 0.086 0.261 

FSV-FK 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NAV 

NAU 

4 4 4 4 4 

0.061 0.199 0.043 0.083 0.255 

0.088 0.221 0.065 0.119 0.275 

0.119 0.278 0.129 0.143 0.333 

0.021 0.019 0.018 0.036 0.015 

24 9 28 30 5 

5 5 4 4 5 

0.084 0.202 0.072 0.091 0.261 

0.022 0.034 0.022 0.023 0.026 

21 

0.056 

0.078 

0.194 

0.018 

23 

22 

0.076 

0.015 

21 

0.319 

0.410 

0.781 

0.053 

13 

22 

0.388 

0.081 

21 

0.205 

0.244 

0.435 

0.022 

9 

22 

0.241 

0.036 

21 

0.072 

0.091 

0.200 

0.010 

11 

22 

0.090 

0.015 

21 

0.219 

0.280 

0.571 

0.028 

10 

21 

0.274 

0.034 

7 7 7 7 7 

0.060 0.315 0.196 0.074 0.228 

0.075 0.342 0.216 0.086 0.261 

0.129 0.710 0.451 0.159 0.425 

0.004 0.040 0.013 0.006 0.019 

6 12 6 7 7 

9 8 8 8 8 

0.073 0.337 0.210 0.083 0.247 

0.010 0.059 0.024 0.007 0.012 

3 5 5 4 5 

0.003 0.015 0.010 0.003 0.010 

0.004 0.018 0.012 0.005 0.015 

0.006 0.023 0.019 0.005 0.024 

0.003 0.003 0.000 0.006 

16 25 10 40 

5 7 7 4 6 

0.005 0.016 0.012 0.004 0.014 

0.003 0.001 0.001 0.001 0.002 

0.088 0.221 0.065 0.119 0.275 0.078 0.415 0.245 0.092 0.280 

0.019 0.059 0.036 0.016 0.041 

0.075 0.342 0.216 0.086 0.261 

0.011 0.040 0.024 0.012 0.028 

0.075 0.342 0.216 0.086 0.261 

0.011 0.040 0.024 0.012 0.028 

All Lab Report 
 

Round Robin LXIX Laboratory Results 

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

C4

Lab 372 373 374 375 376 372 373 374 375 376 372 373 374 375 376 372 373 374 375 376 372 

FSV-BA 0.258 0.818 0.526 0.200 0.323 0.130 0.405 0.292 0.114 0.183 0.051 0.045 0.069 0.057 0.069 0.022 0.027 0.035 0.022 0.024 

FSV-BB 0.275 0.809 0.576 0.223 0.360 0.115 0.354 0.270 0.104 0.172 0.043 0.037 0.053 0.049 0.059 0.016 0.013 0.020 0.017 0.017 0.059 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 0.272 0.993 0.549 0.211 0.347 0.138 0.500 0.321 0.131 0.199 0.039 0.023 0.045 0.048 0.059 

FSV-BH 0.276 0.927 0.615 0.220 0.367 0.054 0.045 0.074 0.059 0.076 0.043 

FSV-BJ 0.290 0.954 0.627 0.209 0.366 nq nq nq nq 0.052 0.061 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.212 1.041 0.639 0.194 0.307 0.037 0.032 0.051 0.045 0.056 

FSV-BO 0.268 0.614 0.462 0.182 0.276 0.029 0.017 0.036 0.040 0.046 0.069 

FSV-BP 0.246 0.980 0.595 0.201 0.514 0.033 0.028 0.045 0.039 0.043 

FSV-BQ 

FSV-BR 

FSV-BS 0.369 1.546 1.007 0.306 0.394 0.121 0.493 0.369 0.127 0.139 0.058 0.050 0.083 0.100 0.104 0.045 

FSV-BT 0.263 0.779 0.519 0.203 0.311 0.102 0.317 0.261 0.102 0.156 0.035 0.030 0.041 0.038 0.047 0.020 0.031 0.027 0.019 0.022 0.074 

FSV-BU 0.347 1.096 0.695 0.261 0.399 0.045 0.028 0.048 0.054 0.066 

FSV-BV 0.244 0.964 0.693 0.262 0.412 0.045 0.035 0.071 0.071 0.082 

FSV-BW 0.240 1.470 0.710 0.260 0.460 0.074 0.044 0.064 0.062 0.089 

FSV-CC 

FSV-CD 0.345 1.132 0.740 0.287 0.476 0.077 0.082 0.096 0.089 0.102 0.047 0.073 0.064 0.048 0.051 

FSV-CE 

FSV-CG 0.263 1.093 0.673 0.254 0.417 0.121 0.489 0.347 0.131 0.228 0.057 0.071 0.085 0.074 0.092
 

FSV-CI
 0.045 

FSV-CW 0.124 0.353 0.281 0.119 0.187 0.041 0.026 0.045 0.046 0.053 

FSV-CZ 

FSV-DD 

FSV-DQ 0.369 0.996 0.600 0.204 0.465 0.041 0.039 0.062 0.056 0.077 0.074 

FSV-DV 

FSV-EE 

FSV-EZ 

FSV-FK 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NAV 

NAU 

16 16 16 16 16 

0.212 0.614 0.462 0.182 0.276 

0.270 0.987 0.621 0.216 0.381 

0.369 1.546 1.007 0.306 0.514 

0.033 0.160 0.107 0.027 0.070 

12 16 17 13 18 

17 17 17 17 16 

0.268 0.966 0.598 0.241 0.376 

0.059 0.224 0.092 0.013 0.046 

7 7 7 7 7 

0.102 0.317 0.261 0.102 0.139 

0.121 0.405 0.292 0.119 0.183 

0.138 0.500 0.369 0.131 0.228 

0.009 0.125 0.043 0.017 0.024 

7 31 15 15 13 

8 8 8 8 8 

0.116 0.367 0.285 0.117 0.180 

0.018 0.064 0.013 0.017 0.021 

16 16 16 16 17 

0.029 0.017 0.036 0.038 0.043 

0.044 0.036 0.058 0.055 0.066 

0.077 0.082 0.096 0.100 0.104 

0.012 0.013 0.019 0.014 0.021 

27 35 33 25 31 

18 18 18 18 17 

0.038 0.030 0.049 0.047 0.059 

0.006 0.007 0.006 0.008 0.009 

4 4 4 4 4 

0.016 0.013 0.020 0.017 0.017 

0.021 0.029 0.031 0.021 0.023 

0.047 0.073 0.064 0.048 0.051 

0.004 0.013 0.011 0.004 0.005 

21 46 36 18 22 

8 4 4 4 8 

0.015 0.015 0.021 0.016 0.020 

0.002 0.002 0.004 0.004 0.009 

8 

0.043 

0.060 

0.074 

0.020 

34 

11 

0.056 

0.013 

0.268 0.993 0.627 0.220 0.367 

0.062 0.181 0.124 0.053 0.080 

0.121 0.405 0.292 0.119 0.183 

0.021 0.125 0.053 0.021 0.032 

0.044 0.036 0.058 0.055 0.066 

0.012 0.013 0.019 0.014 0.021 

0.021 0.029 0.031 0.021 0.023 0.060 

0.020 

All Lab Report 
Round Robin LXIX Laboratory Results 

Total Zeaxanthin, μg/mL Total Lutein&Zeaxanthin, μg/mL Coenzyme Q10, μg/mL Phylloquinone (K1), ng/mL 2

C5

Lab 372 373 374 375 376 372 373 374 375 376 372 373 374 375 376 372 373 374 375 376 37

FSV-BA 0.083 0.168 0.142 0.108 0.099 

FSV-BB 0.058 0.046 0.037 0.037 0.038 0.097 0.189 0.137 0.107 0.102 

FSV-BC 

FSV-BD 

FSV-BE 1.400 0.930 0.842 0.839 0.749 3.047 0.650 0.568 1.361 0.323 

FSV-BF 

FSV-BG 0.076 0.170 0.124 0.093 0.093 

FSV-BH 0.025 0.030 0.041 0.033 0.024 0.067 0.122 0.105 0.100 0.084
 

FSV-BJ
 1.221 0.920 0.849 0.766 0.717 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.050 0.126 0.099 0.080 0.070 0.0

FSV-BO 0.019 0.016 0.011 0.013 0.006 0.076 0.144 0.125 0.112 0.086 1.796 0.984 0.898 1.001 0.786 

FSV-BP 0.082 0.138 0.140 0.118 0.104 

FSV-BQ 

FSV-BR 

FSV-BS 0.019 0.023 0.032 0.040 0.018 0.063 0.146 0.095 0.105 0.117 

FSV-BT 0.034 0.032 0.032 0.030 0.034 0.108 0.114 0.099 0.100 0.090 1.268 0.817 0.713 0.741 0.613 

FSV-BU 0.074 0.154 0.118 0.104 0.097 !1.61 1.600 1.140 1.050 1.190 

0.0

FSV-BV 0.070 0.137 0.123 0.116 0.093 

FSV-BW 0.141 0.195 0.162 0.166 0.150 0.972 0.575 0.436 0.517 0.298 

FSV-CC 

FSV-CD 0.380 0.567 0.465 0.454 0.385 

FSV-CE 

FSV-CG 0.104 0.231 0.177 0.165 0.145
 

FSV-CI
 0.017 0.018 0.021 0.017 0.014 0.059 0.137 0.093 0.097 0.065 1.410 0.957 0.859 0.813 0.685 3.131 0.599 0.490 1.343 0.304 

FSV-CW 0.070 0.100 0.088 0.087 0.071 

FSV-CZ 1.784 1.086 0.937 0.965 0.747 

FSV-DD 

FSV-DQ 0.032 0.030 0.033 0.033 0.023 0.097 0.260 0.173 0.144 0.143 

FSV-DV 

FSV-EE 1.482 0.993 0.890 0.870 0.773 

FSV-EZ 1.482 0.993 0.890 0.870 0.773 

FSV-FK 

N 7 7 7 7 7 17 17 17 17 17 9 10 10 10 10 2 2 2 2 2 

Min 0.006 0.017 0.016 0.011 0.013 0.050 0.100 0.088 0.080 0.065 0.298 0.972 0.575 0.436 0.517 0.304 3.047 0.599 0.490 1.343 0.0

Median 0.023 0.025 0.030 0.032 0.033 0.076 0.146 0.124 0.107 0.097 0.747 1.446 0.971 0.875 0.854 0.314 3.089 0.625 0.529 1.352 0.0

Max 0.038 0.058 0.046 0.041 0.040 0.380 0.567 0.465 0.454 0.385 0.786 1.796 1.140 1.050 1.190 0.323 3.131 0.650 0.568 1.361 0.0

SD 0.013 0.010 0.010 0.007 0.006 0.019 0.036 0.037 0.015 0.019 0.044 0.246 0.068 0.043 0.148 

CV 58 42 35 21 18 25 24 30 14 20 6 17 7 5 17 

Npast 10 8 8 8 8 19 18 18 18 17 8 5 5 5 6 0 0 0 0 0 

Medianpast 0.024 0.032 0.030 0.036 0.029 0.085 0.142 0.130 0.110 0.097 0.629 1.440 0.990 0.887 0.922 

SDpast 0.009 0.017 0.017 0.013 0.015 0.018 0.026 0.025 0.009 0.020 0.128 0.169 0.067 0.037 0.150 

NAV 

NAU 

0.023 0.025 0.030 0.032 0.033 0.076 0.146 0.124 0.107 0.097 0.747 1.446 0.971 0.875 0.854 

0.013 0.010 0.010 0.009 0.009 0.019 0.036 0.037 0.022 0.020 0.075 0.246 0.097 0.088 0.148 

All Lab Report 
 

 

 

 

 

 

Round Robin LXIX 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: √(S 2

 + 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. 

nq Detected but not quantitatively determined

≥x Concentration greater than or equal to x

! Discrepant value: heterogeneous serum, damaged sample, malfunction, etc.

italics Not explicitly reported but calculated by NIST from reported values

Analyte Code 372 373 374 375 376 

Ubiquinol FSV-BW nd 0.424 0.376 0.282 0.167 

Ubiquinone FSV-BW 0.298 0.548 0.200 0.154 0.350 

Phytofluene FSV-BS 0.221 1.090 0.585 0.138 0.331 

Phytoene FSV-BS nd 0.100 0.030 nd nd 

Legend

All Lab Report 

C6

Page 5 / 6 
 

 

 

 

 

 

Round Robin LXIX 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 

1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 2 1 

1 

1 1 

2 2 1 1 

1 1 1 

1 1 1 1 1 1 1 1 

3 1 2 1 1 1 1 1 1 1 

1 1 1 1 1 1 

2 2 

1 1 

1 2 

2 3 1 1 1 1 2 

2 2 2 1 1 2 2 2 2 1 

1 2 1 4 1 1 1 

4 4 

1 2 

2 4 4 4 3 2 1 1 1 

2 1 1 2 1 1 1 1 2 1 2 

2 2 2 1 1 1 1 1 

2 1 1 1 1 1 1 1 

1 1 1 1 2 2 2 3 

2 4 

2 3 2 4 4 2 3 4 

1 1 1 

2 1 2 1 2 1 1 2 3 

2 1 1 1 2 1 2 1 

2 1 1 1 1 1 2 

1 1 1 1 

3 

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-DQ 4 2 4 2 2 1 4 1 3 CS =

C = Concordance = 

2 

FSV-DV 2 2 

FSV-EZ 1 1 1 1 

FSV-FK 1 1 

n 33 31 18 22 7 16 16 16 8 7 17 Nyou 

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

% 1 52 58 67 77 71 56 75 69 63 57 59 

% 2 39 26 33 9 14 25 19 25 25 43 18 

% 3 6 6 0 0 0 0 6 6 0 0 18 

% 4 3 10 0 14 14 19 0 0 13 0 6 

i 1 

you

∑ 

= 



 





N 

Youi 

NAU 

− 

AP = Apparent Precision = 

i 

1 

Median 

i 

− 



 



 

NAU = NIST Assigned Uncertainty 

you 

For further details, please see 

N 

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. 





 + 2 C + 2 AP 



 

∑ 

= 

N 

i 1 

All Lab Report 

C7

Page 6 / 6 
 

Appendix D. Representative “Individualized Report” for RR69 

Each participant in RR69 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 RR69: 

• Total Retinol 

• Retinyl Palmitate 

• α-Tocopherol 

• γ/β-Tocopherol 

• Total β-Carotene 

• trans-β-Carotene 

• Total cis-β-Carotene 

• Total α-Carotene 

• Total Lycopene 

• trans-Lycopene 

• Total β-Cryptoxanthin 

• Total Lutein 

• Total Zeaxanthin 

• Total Lutein & Zeaxanthin 

• Coenzyme Q10 

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

by participant FSV-BA. 

D1
 

 Set 1 of 38 

Individualized Round Robin LXIX Report: FSV-MA 

Summary 

Serum 372 Serum 373 Serum 374 Serum 375 

D2

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

Total Retinol 0.365 0.350 32 0.715 0.660 32 0.537 0.509 32 0.375 0.359 32 0.7

Retinyl Palmitate 0.03 0.01 8 0.2 0.1 10 0.1 0.0 8 0.02 0.01 7 0.

α-Tocopherol 5.67 5.79 32 18.15 18.91 32 9.94 10.53 32 6.61 6.78 32 10.

γ/β-Tocopherol 1.517 1.394 19 2.469 2.297 19 1.501 1.431 19 1.933 1.844 19 2.5

δ-Tocopherol 0.086 0.088 4 0.199 0.221 4 0.062 0.065 4 0.083 0.119 4 0.2

Total β-Carotene 0.078 0.078 22 0.388 0.415 22 0.226 0.245 22 0.086 0.092 22 0.2

trans-β-Carotene 0.075 0.075 7 0.372 0.342 7 0.216 0.216 7 0.082 0.086 7 0.2

Total cis-β-Carotene 0.003 0.075 3 0.017 0.342 5 0.010 0.216 5 0.003 0.086 4 0.0

Total α-Carotene 0.007 0.010 17 0.015 0.018 15 0.031 0.032 17 0.005 0.009 17 0.0

Total Lycopene 0.258 0.268 17 0.818 0.993 17 0.526 0.627 17 0.200 0.220 17 0.3

trans-Lycopene 0.130 0.121 7 0.405 0.405 7 0.292 0.292 7 0.114 0.119 7 0.1

Total β-Cryptoxanthin 0.051 0.044 16 0.045 0.036 16 0.069 0.058 16 0.057 0.055 16 0.0

Total α-Cryptoxanthin 0.022 0.021 4 0.027 0.029 4 0.035 0.031 4 0.022 0.021 4 0.0

Total Lutein&Zeaxanthin 0.083 0.076 17 0.168 0.146 17 0.142 0.124 17 0.108 0.107 17 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.d

Individualized Report 
D3

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

Total Retinol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 2 / 14 
D4

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

Retinyl Palmitate, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 3 / 14 
D5

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

α-Tocopherol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 4 / 14 
D6

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

γ/β-Tocopherol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 5 / 14 
D7

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

Total β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 6 / 14 
D8

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

trans-β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 7 / 14 
D9

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

Total cis-β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 8 / 14 
D10

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

Total α-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 9 / 14 
D11

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

Total Lycopene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 10 / 14 
D12

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

trans-Lycopene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 11 / 14 
D13

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

Total β-Cryptoxanthin, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 12 / 14 
D14

 Set 1 of 38 

Individualized RR LXIX Report: FSV-BA

Total Lutein&Zeaxanthin, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

341344351361372359373358374357375356360376 

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 

#372 Fresh-frozen, native, multi-donor: SRM968d 63:#341, 63:#344, 64:#351, 66:#361 

#373 Fresh-frozen, native, multi-donor: SRM968e III 66:#359 

#374 Fresh-frozen, native, multi-donor: SRM 968e II 66:#358 

#375 Fresh-frozen, native, multi-donor: SRM 968e I 66:#357 

#376 Fresh-frozen, native, multi-donor: prepared in 2008 64:#356, 66:#360 

Individualized Report Page 13 / 14 
D15

 Set 1 of 37 

Individualized Round Robin LXIX 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 RR34 

The following five items were included in each package shipped to an RR34 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
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 34 

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 7, 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 34 

NIST Micronutrient Measurement Quality Assurance Program
 

Analysis of Control Materials and Test Samples
 

Sample Replicate 1 Replicate 2 Units
 

Dilute Solution 1 μmol/L of Dilute Solution 

Dilute Solution 2 μmol/L of Dilute Solution 

Dilute Solution 3 μmol/L of Dilute Solution 

5% MPA Diluent μmol/L of Diluent 

μmol/L of Sample CS #2 Target: 27.2 ±3.3 μmol/L 

Serum Test Sample #341 μmol/L of Sample 

Serum Test Sample #342 μmol/L of Sample 

Serum Test Sample #343 μmol/L of Sample 

Serum Test Sample #344 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 7, 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 34
 

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

VitC #342 Liquid frozen (1:1 serum:10% MPA) 

VitC #343 Liquid frozen (1:1 serum:10% MPA) 

VitC #344 Liquid frozen (1:1 serum:10% MPA) 

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

Control Solid AA 

Please 1) Open the pack immediately 

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

3) Check if the samples arrived frozen 

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

5) Complete the following information 

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

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

1) Date this shipment arrived: ___________________________ 

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

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

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

4) Did the samples arrive frozen? Yes | No 

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

6) When do you anticipate analyzing these samples? ________________________ 

Your prompt return of this information is appreciated. 

The M2QAP Gang 

Mail: M2QAP 

NIST, Stop 6392 Fax: 301-977-0685 

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

E7
 

 

Appendix F. Final Report for RR34 

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 34 (RR34) 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 RR34 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR34 

samples and control/calibration solutions. 

Serum-based Samples. One serum control and four unknowns were distributed in RR34. 

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

S34:1 SRM 970 level 1, ampouled in mid-1998, previously distributed many times. 

S34:2 Serum 333, ampouled in late 2009, previously distributed as sample S33:3 (RR33, Fall 09 

S34:3 Serum 324, ampouled in late 2009, previously distributed as sample S32:4 (RR32, Spring 09 

S34:4 New material, ampouled in late 2009 

Results. 

1)	 Most 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 S31:1 to S31:4 (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. 

F3
Appendix G. “All-Lab Report” for RR34 

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 Aci

"Round Robin" 34 - March 2011 

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#2 S34:1 S34:2 S3

λmax Amax 

VC-MA 28/02/11 58.8 30.0 14.9 67.1 35.5 17.7 0.0 0.56 1.14 1.000 0.8 1.037 244. 0.5750 555.2 27.9 8.4 16.0 4

VC-MB 14/01/11 57.7 28.6 14.4 57.0 28.4 13.2 0.0 -0.39 0.99 1.000 0.7 1.030 243.5 0.5590 549.8 27.4 7.7 13.9 4

VC-MC 24/03/11 59.7 30.1 14.8 57.3 29.4 14.5 0.0 0.23 0.96 1.000 0.3 1.031 243. 0.5772 549.1 27.6 10.1 17.9 

VC-ME 01/03/11 58.0 29.0 14.1 61.1 30.6 15.2 0.0 0.11 1.05 1.000 0.2 1.033 243. 0.5844 572.4 28.0 9.4 16.6 4

VC-MG 20/01/11 58.4 30.8 16.2 61.1 32.7 18.0 0.0 0.54 1.04 1.000 0.6 1.029 243.9 0.5850 568.4 28.3 9.0 15.6 4

VC-MH 25/01/11 60.6 30.3 15.3 61.3 30.3 15.3 0.0 -0.16 1.01 1.000 0.2 1.029 244.1 0.5907 553.0 27.8 8.9 16.3 4

VC-MI 24/01/11 59.0 30.4 14.3 59.6 30.6 14.6 0.0 0.01 1.01 1.000 0.1 1.030 28.0 9.1 12.8 4

VC-MJ 23/02/11 59.3 29.7 14.8 57.1 29.1 15.0 0.1 0.48 0.96 1.000 0.4 0.999 254a 0.365a 349.2a 34.5 10.5 22.3 

VC-MN 02/02/11 59.5 29.9 14.9 59.2 29.4 14.6 0.0 -0.17 1.00 1.000 0.2 1.026 243.6 0.5881 561.4 26.1 10.2 14.9 4

VC-MP 28/01/11 60.2 30.2 14.7 56.7 28.9 14.0 0.0 0.18 0.94 1.000 0.3 1.032 242. 0.5598 527.7 28.5 9.4 14.8 4

VC-NF 24/02/11 56.8 28.5 14.1 56.8 28.6 14.2 0.0 0.04 1.00 1.000 0.0 1.032 243. 0.5330 533.1 28.5 9.3 15.7 4

VC-NM 03/03/11 54.8 27.6 13.7 54.9 27.2 13.9 0.0 -0.05 1.00 1.000 0.3 1.034 242. 0.5440 563.8 26.9 7.5 13.2 4

G2

N 12 12 12 12 12 12 12 

58.6 29.6 14.7 59.1 30.0 15.0 0.0 

1.6 1.0 0.7 3.3 2.2 1.5 0.0 

N 12 10 10 10 12 12 12 

Average Average 1.028 243.2 0.5696 553.4 28.3 9.1 15.8 4

SD SD 0.010 0.8 0.0198 14.4 2.1 0.9 2.5 

Min 54.8 27.61 13.7 

57.9 28.89 14.3 

58.9 29.95 14.7 

59.5 30.27 14.9 

60.6 30.76 16.2 

1.3 0.6 0.6 

2 2 4 

54.9 27.15 13.2 0.0 

57.0 28.83 14.1 0.0 

58.2 29.40 14.6 0.0 

61.1 30.56 15.2 0.0 

67.1 35.48 18.0 0.1 

2.2 1.4 0.8 0.0 

4 5 6 

Min 0.999 242.0 0.5330 527.7 26.1 7.5 12.8 4

%25 %25 1.029 243.0 0.5592 549.3 27.5 8.7 14.6 4

Median Median 1.031 243.3 0.5761 554.1 28.0 9.2 15.7 4

%75 %75 1.032 243.8 0.5849 563.2 28.3 9.6 16.3 4

Max Max 1.037 244.1 0.5907 572.4 34.5 10.5 22.3 

MADe eSD 0.0 0.7 0.0197 12.5 0.6 0.8 1.4 

CV CV 0.26 0.30 3.4 2.3 2 9 9 

a ) 5% Trichloroacetic acid solution 

All Lab Report 
Appendix H. Representative “Individualized Report” for RR34 

Each participant in RR34 received an “Individualized Report” reflecting their reported 

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

“VC-MA”. 

H1
 

 Set 1 of 13 

Vitamin C "Round Robin" 34 Report: Participant VC-MA
 

MPA Dilute Solution 1 Control/Calibration Solutions 

Density Spectrophotometry Ymeas = Inter + Slope* Xgrav 

g/mL 

1.037 

1.037 

1.036 

1.035 

1.037 

1.039 

λmax Amax E1% 

243.0 0.567 553.2 

242.0 0.569 555.6 

244.0 0.566 546.1 

242.0 0.566 545.1 

244.0 0.560 540.5 

244.0 0.575 555.2 

Inter Slope R2 SEE 

0.3 1.03 1.000 0.64 

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 

Date RR Method 

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 

02/28/11 34 HPLC-EC 

Mean 1.037 243.2 0.57 549.3 Pooled SEE 0.52 

SD 0.001 1.0 0.00 6.2 

CV 0.14 0.40 0.9 1.1 

[TAA] mmol/Lsample 

Rep1 Rep2 Fadj Mean SDdup 

15.5 13.9 0.5 7.4 0.6 

14.5 15.8 0.5 7.6 0.5 

8.4 8.5 1.0 8.5 0.1 

8.0 7.7 1.0 7.8 0.2 

8.9 8.7 1.0 8.8 0.1 

8.8 8.8 1.0 8.8 0.0 

7.8 8.6 1.0 8.2 0.5 

8.3 8.1 1.0 8.2 0.1 

8.6 8.8 1.0 8.7 0.1 

8.7 8.5 1.0 8.6 0.2 

8.3 8.4 1.0 8.3 0.1 

7.3 8.1 1.0 7.7 0.5 

8.5 8.3 1.0 8.4 0.1 

N Mean SDrepeat SDreprod 

13 8.2 0.3 0.5 

Date RR Sample 

09/23/98 11 S11:1:A 

04/02/99 12 S12:1:A 

09/17/01 13 S13:1 

09/27/01 14 S14:3 

09/18/01 15 S15:1 

11/18/02 16 S16:1 

11/13/03 19 S19:4 

02/23/04 20 S20:3 

10/17/05 23 S23:4 

08/28/06 25 S25:1 

08/11/08 29 S29:2 

09/10/09 31 S31:3 

02/28/11 34 S34:1 

09/27/10 33 S33:3 16.6 16.8 1.0 16.7 0.1 

16.3 15.7 1.0 16.0 0.4 

0.6 

02/28/11 34 S34:2 

02/24/10 32 S32:4 2 48.4 0.2 0.6 

02/28/11 34 S34:3 

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 

2 16.4 0.3 

1 58.3 0.2 

49.0 48.6 1.0 48.8 0.3 

47.9 48.1 1.0 48.0 0.1 

02/28/11 34 S34:4 58.1 58.4 1.0 58.3 0.2 

Individualized Report Page 1/2 

H2
 

NIST, RR 22

H3

 Set 1 of 13 

Vitamin C "Round Robin" 34 Report: Participant VC-MA 

Total Ascorbic Acid, μmol/mL 

[Total Ascorbic Acid], μmol/L 

S11:1S12:1S13:1S14:3S15:1S16:1S19:4

Apparent Precision, SD S20:3

S23:4S25:1 S29:2 S31:3 S34:1 S33:3S34:2S32:4S34:3S34:4

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 #341, previously distributed in RRs 11, 12, 13, 14, 15, 16, 19, 20, 23, 25, 29, 31 

S33:2 VitC #342, previously distributed in RR 33 

S33:3 VitC #343, previously distributed in RR 32 

S33:4 VitC #344, new material 

Individualized Report 1 / 2