proficiency test report - coresta · 𝜎𝑝: the “standard deviation for proficiency...

Smokeless Tobacco Sub-Group

Proficiency Test Report

The Determination of Arsenic, Beryllium, Cadmium, Chromium, Cobalt, Nickel, Lead,

and Selenium in Reference Materials

September 2015

Author and Sub-Group Secretary:

Karl Wagner, Ph.D.

Altria Client Services

Co-Author and Statistical Analysis:

Michael Morton, Ph.D.


Table of Contents

1. Summary ............................................................................................................................. 3

2. Introduction ......................................................................................................................... 3

3. Organisation ........................................................................................................................ 3

3.1 Participants .................................................................................................................. 3

3.2 Protocol ........................................................................................................................ 4

4. Data – Descriptive Statistics ............................................................................................... 4

5. Data – Statistical Analysis .................................................................................................. 4

6. Results – Z-Scores .............................................................................................................. 6

7. Conclusion ........................................................................................................................ 11

APPENDIX A: Study Protocol ............................................................................................... 13

APPENDIX B: Data Tables .................................................................................................... 18

STS-CTR-Metals Proficiency Study – September 2015 3/21

1. Summary

In December 2014 through March 2015, the CORESTA Smokeless Tobacco Sub-Group

(STS) and Routine Analytical Chemistry Sub-Group (RAC) conducted a proficiency study to

determine arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), cobalt (Co), nickel

(Ni), lead (Pb), and selenium (Se) in three certified reference materials and in a CORESTA

Reference Product (CRP3). Nineteen laboratories participated in this study.

2. Introduction

The objective of this proficiency study was to provide an initial assessment of laboratory

capabilities for the analysis of specific trace elements in several tobacco and non-tobacco

plant matrices. Laboratories were requested to determine As, Be, Cd, Cr, Co, Ni, Pb, and Se

using inductively coupled plasma mass spectrometry (ICP-MS).

3. Organisation

3.1 Participants

A list of the participating laboratories is provided in Table 1. The laboratories are listed in

alphabetical order. The laboratory codes used in this report do not correspond to the same

order as provided in Table 1.

Table 1: List of Participating Laboratories

Participating Laboratories

Arista Laboratories, United States

British American Tobacco, Souza Cruz S.A, Brazil

Canadian Border Service Agency, Canada

China National Tobacco Quality Supervision and Test Center, China

Centers for Disease Control and Prevention, Tobacco Products Laboratory, United States

Enthalpy Analytical, United States

Essentra Scientific Services, United Kingdom

Eurofins Food & Agro Testing, Sweden

Global Laboratory Services, United States

Imperial Tobacco Group, Reemtsma, Germany

Imperial Tobacco Group, SEITA, France

Japan Tobacco, Leaf Tobacco Research Center, Japan

KT&G R&D Center, Republic of Korea

Labstat International, Canada

Lorillard Tobacco Company, United States

Philip Morris International TPTL, Switzerland

R.J. Reynolds Tobacco Company, United States

Swedish Match, Sweden

Technical Center of Shanghai Tobacco Group Co., LTD Shanghai, China


3.2 Protocol

The study included three certified reference materials and CRP3. Sample descriptions are

provided in Table 2. The two tobacco reference materials do not contain significant levels of

Se; therefore, BCR402 (White Clover) was included as this plant matrix has significant

levels of Se. Participating laboratories were responsible for procuring the samples for the

study. Each participant was requested to determine three replicates under repeatability

conditions, using their validated method. Data were reported on an as-is basis and not

corrected for moisture. A microwave digestion method was provided for reference, but use of

the digestion method was not required. Additional details are provided in the study protocol

which is given in Appendix A. The only deviation noted by the participants was that Lab 3

used ICP-OES instead of ICP-MS.

Table 2: Sample Identification

Sample Product Type

INCT-OBTL-5 Oriental Basma Tobacco Leaves

INCT-PVTL-6 Polish Virginia Tobacco Leaves

BCR-402 White Clover

CRP3 CORESTA Reference Product 3, American-style loose dry snuff powder

4. Data – Descriptive Statistics

The data tables, with descriptive statistics, are provided in Appendix B. The data are

provided on an as-is basis without any correction for moisture.

5. Data – Statistical Analysis

The assigned values for each element, for each sample, were developed from the certified or

informational values provided in the certificates of analysis, if available. If certified or

informational values were not available, the assigned values were the median values from this

study.

The certified and informational values provided in the certificates of analysis were given on a

dry weight basis; however, the results in this study were expressed on an as-is basis. For this

reason, the dry weight values from the certificates of analysis were converted to an as-is basis.

The conversion to an as-is basis was based on moisture measurements (oven volatiles) made

by three participating laboratories. The average percent moisture values of the reference

materials, determined by the three laboratories, are given in Table 3.

Table 3: Percent Oven Volatiles

Sample Average Percent Moisture

INCT-OBTL-5 4.6%

INCT-PVTL-6 3.8%

BCR-402 7.8%

CRP3 Not determined


It was necessary to determine the standard deviations for the proficiency assessment in order

to calculate z-statistics. The standard deviations were calculated from the Horwitz equation

and are presented in Table 4. The Horwitz equation was originally developed by William

Horwitz based on the observation that over a wide concentration range, the interlaboratory

variation can be approximated by an exponential function of the concentration of the analyte.

The equation has been refined, since its original introduction and we use the version of the

equation given in Thompson1. The updated version of the Horwitz equation used here is

given as:

𝜎𝑝 = 0.01√𝑐, 13.8% ≤ 𝑐

𝜎𝑝 = 0.02𝑐0.8495, 120𝑛𝑔

𝑔≤ 𝑐 < 13.8%

𝜎𝑝 = 0.22𝑐, 𝑐 < 120𝑛𝑔

𝑔

Where:

𝜎𝑝: The “standard deviation for proficiency assessment.”

c: The concentration of the element on a gram of analyte per gram sample basis.

The concentration used in the calculation was the assigned value.

The standard deviations are given in Table 4.

Z-statistics were calculated for each laboratory to assess the lab performance. The z-statistic

is defined as:

𝑧 =𝑥 − 𝑥𝑎

𝜎𝑝

Where:

𝑥: The value obtained by the laboratory

𝑥𝑎: The “assigned value” based on the certified or informational value if available,

or on the study median.

𝜎𝑝: The “standard deviation for proficiency assessment.”

The z-statistics (z-scores) are presented in the Results section.

1 Thompson, Michael, “Recent trends in inter-laboratory precision at ppb and sub-ppb concentrations in relation

to fitness for purpose criteria in proficiency testing,” The Analyst, 2000, 125, 385-386.


Table 4: Assigned Values

INCT-OBTL-5 (ng/g)

As

C Be

I Cd

C Cr

I Co

C Pb

C Ni

C Se

M

Certified or Informational Value

(dry weight) 668 81.2 2640 6300 981 2010 8500 --

Assigned Value (as-is)

637 77 2519 6011 936 1918 8110 88

St dev (as-is)ǂ 109 17 351 734 151 278 947 19

INCT-PVTL-6 (ng/g)

As

C Be

M Cd

C Cr

I Co

C Pb

C Ni

C Se

M


(dry weight) 138 -- 2230 911 154 972 1490 --


133 20.0 2144 876 148 935 1433 49

St dev (as-is)ǂ 29 4.39 306 143 32 151 217 10

BCR-402 (ng/g)

As

C Be

M Cd

M Cr

I Co

C Pb

M Ni

I Se

C


(dry weight) 93 -- -- 5190 178 -- 8250 6700


86 6.43 163 4785 164 485 7607 6178

St dev (as-is)ǂ 19 1.42 34 605 34 87 897 751

CRP3 (ng/g)

As

M Be

M Cd

M Cr

M Co

M Pb

M Ni

M Se

M


(dry weight) -- -- -- -- -- -- -- --


287 30.2 1470 8531 1125 790 6730 116

St dev (as-is)ǂ 55 6.64 222 988 177 131 808 25

C: The assigned value was based upon the ‘certified’ value provided in the certificate of analysis.

I: The assigned value was based upon the ‘informational’ value provided in the certificate of analysis.

M: The assigned value was based upon the group median.

ǂ:

The standard deviations were calculated from the Horwitz equation.

--: ‘Certified’ or ‘informational’ values are not available.

6. Results – Z-Scores

The values obtained by each laboratory, for each element, are given in Appendix B. The

corresponding z-statistics are given in Tables 5 – 8. As a general rule, the z-scores are

regarded as reasonable if -2 < z < 2 and generally thought to be unacceptable if |z|>3.

Laboratories should consider |z| between 2 and 3 as a warning signal.


Table 5: Z-Score Results for INCT-OBTL-5

Lab # AsC Be

I Cd

C Cr

I Co

C Pb

C Ni

C Se

M

1 1.3 -0.3 1.2 -1.1 0.3 -0.5 0.6 11.5

2 2.0 -1.1 1.2 -3.0 ND -0.5 -1.2 0.0

3 -1.0 -0.5 0.9 -2.0 -0.4 -0.9 0.8 <LOD

4 1.5 ND 2.7 0.1 ND -0.1 -0.2 -1.0

5 1.2 2.1 1.4 1.0 0.3 0.4 0.8 -2.2

6 1.0 -1.9 0.6 -0.9 -1.0 -0.4 0.2 5.9

7 0.2 -2.0 -0.9 -4.8 -2.1 -1.7 -2.6 23.3

8 0.2 0.7 0.0 -2.6 0.3 0.3 0.5 <LOD

9 0.3 -1.0 1.3 -2.6 -0.4 -0.1 -0.3 -1.8

10 1.8 -1.8 0.8 -2.6 -0.4 -0.9 0.3 <LOD

11 1.1 -0.2 1.0 -1.1 -0.5 -0.4 -0.5 -1.7

12 -0.1 <LOD -0.4 -3.3 -1.6 -1.2 -2.0 <LOD

13 2.4 -0.1 0.6 -2.8 -0.6 0.4 -0.7 8.3

14 ND ND ND ND ND ND ND ND

15 0.2 0.1 0.2 -1.7 0.7 -0.6 2.0 -2.7

16 0.2 0.3 0.5 -2.0 -1.3 -0.9 -1.1 1.0

17 2.7 ND 1.7 -2.7 ND 0.4 0.1 0.0

18 -0.2 ND 1.6 -2.0 -0.6 ND -0.6 ND

19 -0.1 -0.7 0.7 -1.4 0.0 0.0 -0.2 36.7




ND: the element was not determined by the laboratory

<LOD: Signifies the analyte was below the LOD specified by the laboratory


Table 6: Z-Score Results for INCT-PVTL-6

Lab # AsC Be

M Cd

C Cr

I Co

C Pb

C Ni

C Se

M

1 -0.1 0.1 1.2 -1.3 0.7 -1.8 0.1 3.2

2 0.4 -0.7 1.1 -2.5 ND -1.8 -1.6 -0.6

3 <LOD -0.1 1.7 -1.8 0.0 0.5 1.5 <LOD

4 0.2 ND 2.9 -0.8 ND -1.4 -0.7 -1.0

5 0.0 1.2 1.2 -0.9 0.2 -1.1 -0.2 -2.0

6 0.2 <LOD 0.4 -1.8 0.1 -1.6 0.4 1.8

7 -0.7 -2.0 -0.8 -3.6 -1.1 -2.0 -1.7 9.6

8 0.4 4.2 -0.2 0.6 0.5 -1.3 0.1 <LOD

9 -0.4 -2.7 0.6 -3.9 -0.7 -1.8 -2.7 -2.8

10 0.0 <LOD 0.8 -2.7 -0.4 -1.7 -0.8 <LOD

11 0.5 0.1 1.1 -1.7 0.0 -1.5 -0.8 -1.5

12 -0.9 <LOD 0.6 -2.5 -0.3 -1.8 -1.1 <LOD

13 0.8 -0.1 0.7 -2.7 -0.4 -1.5 -0.9 <LOD


15 -0.3 1.3 0.3 -2.0 1.2 -0.9 1.1 -1.9

16 0.2 <LOD 0.7 -3.4 -0.2 -1.8 -1.1 6.1

17 0.8 ND 1.5 -1.8 ND -1.6 -1.2 0.6

18 -0.6 ND 1.5 0.9 0.3 ND 1.2 ND

19 0.8 <LOD 0.9 1.4 1.0 -1.0 2.0 11.4







Table 7: Z-Score Results for BCR-402

Lab # AsC Be

M Cd

M Cr

I Co

C Pb

M Ni

I Se

C

1 1.3 <LOD 0.7 2.0 0.2 0.7 1.9 1.0

2 1.4 -0.8 0.6 -1.2 ND 0.1 -0.1 2.3

3 <LOD 0.2 0.6 0.5 -0.7 2.4 1.8 2.0

4 0.7 ND 1.4 0.5 ND -0.1 1.2 1.7

5 0.1 0.1 0.0 0.5 -0.4 0.0 1.9 0.6

6 10.8 <LOD -0.6 0.2 -0.6 0.2 0.7 0.9

7 0.0 -2.2 -0.5 -4.2 -1.7 -1.1 -2.0 0.7

8 0.9 6.2 -1.4 0.4 0.3 0.4 0.4 0.6

9 -0.3 -3.2 0.7 -0.7 -0.5 -0.5 0.6 0.8

10 0.6 <LOD -0.2 0.6 -0.4 -0.4 1.7 1.2

11 0.9 0.0 0.0 0.3 -0.4 0.2 1.1 1.0

12 <LOD <LOD -0.8 -0.9 -1.1 -0.4 -0.1 -0.8

13 1.4 -0.8 -0.1 -0.5 -0.6 0.0 1.0 1.0


15 0.7 2.5 -0.2 -0.4 0.6 0.1 3.7 0.0

16 0.6 <LOD 0.1 -0.7 -2.8 0.0 0.7 -0.1

17 1.5 ND 1.6 -3.4 ND -0.3 -0.8 2.4

18 0.3 ND 3.1 -1.1 -0.8 ND -1.2 ND

19 7.7 <LOD -1.0 1.0 0.8 1.2 -0.2 0.0







Table 8: Z-Score Results for CRP3

Lab # AsM

BeM Cd

M Cr

M Co

M Pb

M Ni

M Se

M

1 0.0 0.2 0.3 1.4 0.6 -0.3 0.9 7.9

2 0.1 -0.2 0.2 -1.8 ND 0.0 -1.4 0.0

3 5.3 0.3 0.0 0.4 -0.1 0.7 0.9 <LOD

4 0.1 ND 1.6 0.0 ND -0.2 0.3 -0.5

5 -0.1 1.7 0.4 1.3 0.6 0.6 1.3 -1.6

6 -0.2 -2.1 0.2 1.3 -0.7 -0.9 0.9 3.2

7 -0.8 -1.7 -1.6 -4.6 -1.9 -1.9 -3.6 10.9

8 -0.1 -1.1 -1.4 0.3 0.2 0.4 -0.5 3.2

9 -1.2 -0.2 0.1 -0.3 -0.2 -0.1 -0.3 -3.0

10 0.2 <LOD 0.0 0.9 0.0 -0.5 0.7 -1.3

11 0.3 0.6 0.1 0.9 0.0 0.5 0.2 -1.1

12 -0.8 <LOD -0.6 -0.9 -0.9 -0.5 -0.9 -1.7

13 0.9 1.2 -0.4 -0.2 0.0 0.5 0.0 7.6

14 0.5 ND -0.5 0.4 ND 0.0 -0.5 3.5

15 -0.1 1.9 0.3 0.0 2.8 1.2 4.6 -1.4

16 -0.5 <LOD 0.0 -0.4 -0.6 -0.3 -0.5 -1.5

17 0.7 ND 0.6 -4.2 ND 0.1 -1.8 3.4

18 -1.1 ND -0.5 -1.0 -1.2 ND -1.5 ND

19 4.2 -0.2 -0.3 0.5 0.5 0.0 1.7 54.6





7. Conclusion

The overall results of the proficiency study, showing the percentage of acceptable results

where |z|≤2, are given in Table 9. Notable observations include the following:

The results demonstrate that participating laboratories showed the least agreement

with the determination of selenium in all samples. It is worth noting that the

zscore results for selenium also show the greatest deviation from |z|=2 as

compared to the other elements (e.g. z=54.6 for CRP3).

Laboratories also showed poor agreement with the certified values for chromium in

INCT-OBTL-5 and INCT-PVTL-6. The median value of chromium among the

participating laboratories was close to two standard deviations below the assigned

values for both samples.

Although most laboratories showed acceptable results for lead with values within

two standard deviations of the assigned value, the median of the lab values for lead

for INCT-PVTL-6 was just over 1.6 standard deviations below the assigned value.

A recommendation for future metals studies is that all laboratories report data for the certified

reference materials on a dry weight basis so that these data do not need to be converted to an

as-is basis. Moisture (oven volatiles) should be determined following the instruction provided

in the certificate of analyses.

Table 9: Proficiency Study Results

Element Assigned Value

(ng/g)

Number of Scores |z|≤2

Total Number of Scoresǂ

Percent |z|≤2

INCT-OBTL-5

AsC 637 16 18 89

BeI 77 13 14 93

CdC 2519 17 18 94

CrI 6011 10 18 56

CoC 936 14 15 93

PbC 1918 17 17 100

NiC 8110 17 18 94

SeM 88 6 13 46

INCT-PVTL-6

AsC 133 17 17 100

BeM 20 8 10 80

CdC 2144 17 18 94

CrI 876 11 18 61

CoC 148 15 15 100

PbC 935 17 17 100

NiC 1433 17 18 94

SeM 49 7 12 58


Element Assigned Value

(ng/g)

Number of Scores |z|≤2

Total Number of Scoresǂ

Percent |z|≤2

BCR-402

AsC 86 14 16 88

BeM 6.43 6 10 60

CdM 163 17 18 94

CrI 4785 16 18 89

CoC 164 14 15 93

PbM 485 16 17 94

NiI 7607 17 18 94

SeC 6178 15 17 88

CRP3

AsM 287 17 19 89

BeM 30.2 11 12 92

CdM 1470 19 19 100

CrM 8531 17 19 89

CoM 1125 14 15 93

PbM 790 18 18 100

NiM 6730 17 19 89

SeM 116 8 17 47




ǂ: Laboratories that reported <LOD or did not determine the element in the matrix were not included in the sum.


APPENDIX A: Study Protocol

SMOKELESS TOBACCO SUB-GROUP

Metals Proficiency Study

Protocol

December 3, 2014

Author and Study Coordinator:

Karl Wagner (Altria Client Services Inc.), U.S.A.

Co-Author Statistical Analysis:

Michael Morton, Ph D.

(Altria Client Services Inc.), U.S.A.

Confidentiality Notice: All data in this Collaborative Study should be handled in the strictest

of confidence by all participating laboratories.


1. Introduction

The purpose of interlaboratory proficiency testing is to provide participating laboratories with

an objective means of assessing laboratory capability. Additionally, proficiency testing is an

important component of a quality system and is a requirement of ISO 17025.

2. Objective

The objective of this proficiency study is to provide an initial assessment of laboratory

capabilities for the analysis of specific trace elements in several certified reference materials

and in CORESTA Reference Product 3 (CRP3). Arsenic, Beryllium, Cadmium, Chromium,

Cobalt, Lead, Nickel, and Selenium will be determined in the matrices using inductively

coupled plasma mass spectrometry (ICP-MS).

3. Time schedule

Date Activity

November 25, 2014 Laboratories state their intention to participate and order standard reference materials

December 3, 2014 Finalize protocol and distribute

March 1, 2015 Laboratories submit results by this date

April 29, 2015 Discuss results at STS meeting in Hangzhou, China

4. Participating Laboratories

The following laboratories have kindly agreed to take part in the study:

2015 Metals Proficiency Study Participants


Arista Laboratories

British American Tobacco, Souza Cruz S.A

China National Tobacco Quality Supervision and Test Center

Enthalpy Analytical

Essentra Scientific Services

Eurofins Food & Agro Testing, Sweden

Global Laboratory Services

Japan Tobacco, Inc.

Imperial Tobacco Group, Reemtsma

Imperial Tobacco Group, SEITA

KT&G R&D Center

Labstat International

Lorillard Tobacco Company


2015 Metals Proficiency Study Participants

Microbac Laboratories, Wilson

Philip Morris International, Brazil

Philip Morris International, Neuchâtel (PPQ, OC Lab)

PT HM Sampoerna, Tbk

R.J. Reynolds Tobacco Company

Shanghai Tobacco Group Co., Ltd

Swedish Match Northern Europe

5. Samples

5.1 Selection

1) Oriental Basma Tobacco Leaves (INCT-OBTL-5)

2) Polish Virginia Tobacco Leaves (INCT-PVTL-6)

3) White Clover (BCR-402)

4) CRP3

The three reference materials are available from LGC Standards (www.lgcstandards.com).

CRP3 is available from North Carolina State University.

Note that different versions of the certified tobacco materials were available in the past.

Please ensure that you use the correct version for this study (INCT-OBTL-5 and INCT-

PVTL-6). Earlier versions of these materials will have different suffixes and are not suitable.

5.2 Storage

The three standard reference materials should be stored as specified by the distributer. CRP3

should be stored at −20°C).

6. Analysis

6.1 Analytes

The following analyses should be determined by each participating laboratory using ICP-MS:

Arsenic, Beryllium, Cadmium, Chromium, Cobalt, Lead, Nickel, and Selenium.

6.2 Methods

Laboratories should use their in house instrumental method. A closed vessel microwave

digestion procedure is provided in Appendix A for reference; however, use of the procedure is

not a requirement for this study.

6.3 Replicates

Conduct three (3) independent replicate preparations per sample.

http://www.lgcstandards.com/


7. Data Reporting

1) The analytes should be reported in units of ng/g, on an as-is basis.

2) Data above the LOD, but below the LOQ should be reported and footnoted to indicate

the value was below the LOQ, but above the LOD.

3) If the instrumental result is less than the LOD, the numerical LOD should be reported

with a “<” symbol (e.g. <0.201).

The completed data sheet, provided below, should be sent to [email protected].

Microsoft Excel 97-2003 Worksheet

8. Statistical Analysis

Data for the certified reference materials will be compared to the certified values or reference

values, if available. Z-Scores will also be calculated for all samples.

9. Presentation of the Results

The final output will be a presentation for discussion at the spring STS meeting which is

scheduled to be held in Hangzhou, China on April 29, 2015.

Protocol Appendix A: Proposed Closed Vessel Microwave Digestion

Procedure

1. Sample Preparation

1.1. At the time of analysis, samples should be allowed to equilibrate to room

temperature before weighing.

1.2. Samples should be ground to a particle size of less than 1mm before digestion.

2. Sample digestion

2.1. Closed vessel microwave assisted acid digestion is used for the digestion of organic

material. This method should be regarded as a basic guideline for developing a

digestion procedure and not standard operating procedure. The manufacturer’s

instructions for the microwave digestion unit should be consulted before

developing a digestion method. This method will not dissolve refractory samples

such as silicates and may exhibit poor recovery for analytes bound in such matrices.

The goal of this digestion procedure is to digest the organic matrix in the sample

using nitric acid by maintaining a temperature of 200°C.Using an analytical

balance, weigh approximately 0.5g of sample into a microwave digestion vessel

and record the weight to the nearest 0.1 mg. If a pouched product is analysed, unit

pouches should be weighed for digestion.

mailto:[email protected]


Note: The LOQ will be affected by the amount of tobacco digested. Some samples may

react more vigorously to the digestion procedure. In these cases, the sample weights and

/or digestion procedure will need to be adjusted accordingly.

2.2. Add 5.0±0.1 mL of nitric acid and gently swirl the sample being careful not to

deposit the sample on the vessel wall.

2.3. Screw the cap onto the digestion vessel and either leave the lid loose or leave the

vent cap loose to let digestion gases escape. Let the samples predigest in an

exhaust hood for a minimum of 1 hour and up to overnight before proceeding to the

microwave. The sample should no longer be effervescent when the vessel is sealed.

2.4. Tighten the digestion vessel cap and the vent cap. Place the microwave vessels into

the microwave and enter a digestion program based on manufacturer’s

specifications in order to reach a temperature of 150 °C over a period of 15

minutes. Allow the samples to cool and then remove the vessels from the

microwave unit and open the vessels to vent them.

2.5. Reseal the vessels and place the microwave vessels into the microwave and enter a

digestion program based on manufacturer’s specifications in order to reach a

temperature of 200 °C over a period of 15 minutes. Maintain 200 °C for an

additional 15 minutes. Allow the samples to cool and then remove them from the

microwave.

2.6. Quantitatively transfer the contents of each vessel to a 100mL graduated,

polypropylene vial or flask. Carefully rinse the digestion vessel with Type 1 water

and add to the polypropylene vial. Dilute the samples to 100mL final volume with

Type 1 water. Cap the samples and mix well.

2.7. The samples will have a final nitric acid concentration of approximately 5%. The

calibration standard used for analysis should also have a final nitric acid

concentration of 5%.


APPENDIX B: Data Tables

INCT-OBTL-5 (ng/g, as-is basis)

Lab # As C

Be I

Cd C

Cr I

Co C

Pb C

Ni C

Se M

Assigned Value 637 77 2519 6011 936 1918 8110 88

1 782 ± 21 72.4 ± 0.6 2942 ± 23 5192 ± 110 974 ± 10 1767 ± 70 8673 ± 84 310 ± 43

2 857 ± 46 59.3 ± 0.6 2925 ± 95 3815 ± 155 ND 1770 ± 40 6948 ± 235 88 ± 2

3 524 ± 20 68.3 ± 0.8 2818 ± 42 4524 ± 93 882 ± 22 1658 ± 143 8867 ± 414 <2000

4 799 ± 79 ND 3454 ± 345 6062 ± 481 ND 1882 ± 80 7892 ± 648 68 ± 10

5 763 ± 24 112.5 ± 5.4 2992 ± 26 6736 ± 309 986 ± 23 2022 ± 91 8853 ± 162 45 ± 1

6 742 ± 19 44.8 ± 1.8 2727 ± 42 5383 ± 339 790 ± 4 1797 ± 49 8318 ± 274 202 ± 9

7 659 ± 9 43 ± 8.5 2207 ± 27 2494 ± 99 621 ± 3 1435 ± 67 5656 ± 92 539 ± 13

8 663 ± 27 88.9 ± 7 2507 ± 78 4074 ± 79 980 ± 24 2003 ± 42 8589 ± 257 <125

9 673 ± 32 61.3 ± 1.9 2962 ± 90 4119 ± 405 869 ± 33 1892 ± 106 7856 ± 217 54 ± 23

10 835 ± 22 47.6 ± 6.3 2785 ± 47 4127 ± 157 882 ± 16 1678 ± 57 8389 ± 19 <60

11 761 ± 13 74.9 ± 0.8 2872 ± 10 5187 ± 164 863 ± 14 1819 ± 44 7658 ± 87 54 ± 2

12 632 ± 49 <61 2363 ± 185 3618 ± 225 690 ± 33 1598 ± 76 6261 ± 416 <60

13 897 ± 19 75.1 ± 1.5 2737 ± 10 3926 ± 96 846 ± 15 2024 ± 64 7463 ± 92 249 ± 25


15 657 ± 6 79.1 ± 4.7 2588 ± 48 4727 ± 113 1046 ± 30 1762 ± 25 9980 ± 254 36 ± 7

16 662 ± 41 83.0ǂ 2711 ± 296 4558 ± 184 740 ± 30 1670 ± 186 7108 ± 569 108 ± 15

17 932 ± 27 ND 3100 ± 52 4042 ± 430 ND 2018 ± 148 8170 ± 483 88 ± 31

18 614 ± 40 ND 3075 ± 199 4510 ± 331 842 ± 56 ND 7577 ± 456 ND

19 629 ± 67 65.9 ± 17.8 2770 ± 75 4953 ± 268 938 ± 39 1921 ± 52 7966 ± 109 799 ± 216

C: The assigned value was based upon the ‘certified’ value provided in the certificate of analysis. This value was converted to an as-is basis.

I: The assigned value was based upon the ‘informational’ value provided in the certificate of analysis. This value was converted to an as-is basis.


ǂ: Only one replicate was above the LOD; therefore, a standard deviation was not calculated


“<” Symbol: Signifies the analyte was below the LOD specified by the laboratory


INCT-PVTL-6 (ng/g, as-is basis)

Lab # AsC Be

M Cd

C Cr

I Co

C Pb

C Ni

C Se

M

Assigned Value 133 20.0 2144 876 148 935 1433 49

1 131 ± 4 20.2 ± 0.3 2497 ± 31 688 ± 16 169 ± 2 662 ± 15 1459 ± 3 74 ± 5

2 143 ± 4 16.8 ± 0.3 2468 ± 37 522 ± 40 ND 661 ± 24 1094 ± 4 38 ± 3

3 <400 19.7 ± 1.2 2662 ± 61 613 ± 34 147 ± 3 1010 ± 124 1768 ± 30 <2000

4 138 ± 17 ND 3027 ± 183 761 ± 61 ND 726 ± 45 1282 ± 84 34 ± 7

5 133 ± 4 25.4 ± 0.5 2506 ± 42 742 ± 58 155 ± 3 767 ± 107 1380 ± 39 24 ± 1

6 138 ± 8 <13 2252 ± 54 622 ± 24 153 ± 6 689 ± 12 1512 ± 58 61 ± 3

7 112 ± 2 11 ± 1 1911 ± 16 361 ± 41 114 ± 2 632 ± 131 1063 ± 65 135 ± 8

8 144 ± 5 38.3 ± 5.1 2071 ± 28 961 ± 29 163 ± 5 744 ± 6 1449 ± 14 <125

9 121 ± 7 8.1 ± 5.9 2326 ± 135 320 ± 42 127 ± 3 664 ± 91 850 ± 70 17 ± 11

10 132 ± 4 <40 2376 ± 52 492 ± 15 135 ± 4 677 ± 117 1254 ± 63 <60

11 146 ± 3 20.5 ± 0.2 2470 ± 22 640 ± 56 149 ± 2 704 ± 10 1268 ± 12 29 ± 2

12 107 ± 5 <61 2314 ± 9 514 ± 25 138 ± 6 669 ± 15 1186 ± 65 <60

13 155 ± 6 19.5 ± 0.8 2351 ± 41 485 ± 31 136 ± 1 705 ± 35 1237 ± 17 <180


15 125 ± 3 25.6 ± 3.7 2243 ± 9 595 ± 34 186 ± 4 794 ± 102 1677 ± 37 25 ± 1

16 138 ± 34 <62 2364 ± 22 384 ± 41 142 ± 4 669 ± 21 1188 ± 38 102 ± 4

17 156 ± 3 ND 2599 ± 36 622 ± 125 ND 686 ± 42 1176 ± 37 49 ± 7

18 114 ± 14 ND 2595 ± 371 1006 ± 100 158 ± 21 ND 1693 ± 505 ND

19 157 ± 60 <20 2423 ± 210 1079 ± 63 179 ± 10 784 ± 93 1872 ± 83 152 ± 106







BCR-402 (ng/g, as-is basis)

Lab # AsC Be

M Cd

M Cr

I Co

C Pb

M Ni

I Se

C

Assigned Value 86 6.43 163 4785 164 485 7607 6178

1 109 ± 10 <12 189 ± 7 6006 ± 172 172 ± 4 542 ± 41 9286 ± 113 6955 ± 139

2 111 ± 12 5.3 ± 0.2 185 ± 14 4036 ± 150 ND 490 ± 27 7533 ± 85 7927 ± 390

3 <400 6.7 ± 0.1 184 ± 25 5113 ± 66 138 ± 8 696 ± 32 9212 ± 158 7707 ± 167

4 100 ± 6 ND 210 ± 15 5113 ± 399 ND 479 ± 19 8675 ± 403 7460 ± 122

5 87 ± 7 6.5 ± 0.9 163 ± 2 5113 ± 95 151 ± 6 485 ± 27 9275 ± 228 6640 ± 254

6 290 ± 13 <13 143 ± 6 4919 ± 106 145 ± 6 500 ± 28 8210 ± 105 6863 ± 143

7 85 ± 4 3.3 ± 2.1 148 ± 11 2229 ± 83 107 ± 2 393 ± 24 5840 ± 160 6716 ± 61

8 102 ± 8 15.2 ± 0.3 115 ± 11 5035 ± 367 175 ± 12 521 ± 22 7982 ± 343 6626 ± 149

9 81 ± 2 1.9 ± 0.6 187 ± 26 4375 ± 69 145 ± 14 446 ± 20 8157 ± 201 6810 ± 332

10 98 ± 9 <40 156 ± 6 5133 ± 204 149 ± 2 450 ± 22 9140 ± 271 7087 ± 250

11 102 ± 7 6.4 ± 0.3 164 ± 6 4937 ± 140 150 ± 7 500 ± 20 8601 ± 78 6907 ± 152

12 <61 <61 138 ± 11 4239 ± 331 125 ± 13 448 ± 50 7490 ± 687 5577 ± 465

13 113 ± 7 5.3 ± 0.6 161 ± 10 4466 ± 106 143 ± 1 483 ± 14 8461 ± 89 6896 ± 206


15 98 ± 7 9.9 ± 1.4 157 ± 12 4528 ± 250 185 ± 12 498 ± 29 10933 ± 335 6204 ± 100

16 97 ± 11 <57 166 ± 12 4350 ± 721 67 ± 3 485 ± 60 8204 ± 894 6109 ± 272

17 115 ± 17 ND 219 ± 42 2719 ± 856 ND 461 ± 24 6898 ± 801 7965 ± 314

18 92 ± 9 ND 271 ± 55 4102 ± 161 135 ± 12 ND 6566 ± 245 ND

19 230 ± 104 <20 130 ± 11 5411 ± 2617 191 ± 100 585 ± 178 7402 ± 2543 6145 ± 382







CRP3 (ng/g, as-is basis)

Lab AsM Be

M Cd

M Cr

M Co

M Pb

M Ni

M Se

M

Assigned Value 287 30.2 1470 8531 1125 790 6730 116

1 287 ± 6 31.3 ± 0.3 1543 ± 2 9904 ± 27 1239 ± 9 756 ± 4 7478 ± 82 317 ± 19

2 295 ± 15 29.1 ± 1.1 1525 ± 25 6790 ± 406 ND 794 ± 38 5571 ± 204 116 ± 10

3 581 ± 58 32.1 ± 1.4 1465 ± 17 8906 ± 81 1102 ± 19 885 ± 33 7452 ± 137 <2000

4 290 ± 11 ND 1815 ± 34 8531 ± 1058 ND 770 ± 22 6949 ± 165 104 ± 3

5 280 ± 8 41.6 ± 0.7 1558 ± 45 9792 ± 24 1239 ± 20 867 ± 8 7768 ± 149 76 ± 9

6 276 ± 12 16.3 ± 2.1 1508 ± 6 9825 ± 218 993 ± 19 673 ± 15 7467 ± 55 198 ± 8

7 241 ± 5 19 ± 2.6 1107 ± 9 3937 ± 314 795 ± 2 548 ± 15 3841 ± 148 392 ± 23

8 279 ± 8 23 ± 2.6 1166 ± 5 8803 ± 238 1153 ± 51 839 ± 13 6346 ± 161 196 ± 26

9 220 ± 17 29 ± 5.5 1485 ± 50 8201 ± 194 1084 ± 25 773 ± 16 6454 ± 228 40 ± 8

10 300 ± 5 <40 1465 ± 75 9456 ± 253 1132 ± 55 723 ± 27 7325 ± 113 83 ± 4

11 305 ± 6 34.5 ± 2.3 1495 ± 6 9469 ± 46 1125 ± 14 857 ± 12 6867 ± 103 87 ± 3

12 242 ± 28 <61 1329 ± 123 7685 ± 774 967 ± 88 725 ± 68 6021 ± 505 73 ± 11

13 338 ± 3 38.1 ± 1.5 1387 ± 11 8340 ± 97 1131 ± 10 854 ± 32 6730 ± 182 310 ± 19

14 313 ± 9 ND 1363 ± 17 8956 ± 66 ND 787 ± 7 6307 ± 22 204 ± 9

15 281 ± 3 42.7 ± 4.9 1530 ± 39 8494 ± 137 1613 ± 16 945 ± 69 10440 ± 144 80 ± 2

16 259 ± 16 <61 1470 ± 18 8130 ± 988 1014 ± 9 757 ± 23 6289 ± 536 79 ± 13

17 325 ± 10 ND 1597 ± 22 4411 ± 745 ND 805 ± 42 5305 ± 476 201 ± 16

18 224 ± 33 ND 1357 ± 163 7509 ± 960 912 ± 118 ND 5482 ± 754 ND

19 521 ± 67 28.7 ± 9.7 1400 ± 89 9055 ± 209 1210 ± 8 794 ± 83 8114 ± 169 1504 ± 431






proficiency test report - coresta · 𝜎𝑝: the “standard deviation for proficiency...

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