report of an interlaboratory comparison from the...

Report EUR 26468 EN

20 13

Juliana Silva Félix, Giorgia Beldì

and Catherine Simoneau

ILC001-2013 – Proficiency Testing on Food Simulant E containing a cocktail of potential migrant substances

Report of an Interlaboratory Comparison

from the European Reference Laboratory

for Food Contact Materials

European Commission

Joint Research Centre

Institute for Health and Consumer Protection

Contact information

Catherine Simoneau

Address: Joint Research Centre, Via Enrico Fermi 2749, TP 260, 21027 Ispra (VA), Italy

E-mail: [email protected]

Tel.: +39 0332 78 5889

Fax: +39 0332 78 5707

http://ihcp.jrc.ec.europa.eu/

http://www.jrc.ec.europa.eu/

This publication is a Reference Report by the Joint Research Centre of the European Commission.

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JRC87459

EUR 26468 EN

ISBN 978-92-79-35268-3 (pdf)

ISSN 1831-9424 (online)

doi:10.2788/6263

Luxembourg: Publications Office of the European Union, 2013

© European Union, 2013

Reproduction is authorised provided the source is acknowledged.

Printed in Italy

EURL – FCM ILC001-2013 on food simulant E containing unknown substances

EC-JRC-IHCP, CAT Unit

Action Programme 15014

2013

EURL Food Contact Materials

No SANCO/2013/FOOD SAFETY076-Food Contact Materials

Juliana Silva Félix, Giorgia Beldì and Catherine Simoneau


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Table of content

1. Executive Summary .................................................................................................................. 5

2. Introduction ............................................................................................................................... 6

3. Scope ....................................................................................................................................... 7

4. Time frame................................................................................................................................ 7

5. Test material ............................................................................................................................. 7

5.1. Sample preparation ............................................................................................................ 8

5.2. Homogeneity assessment .................................................................................................. 8

5.3. Stability test........................................................................................................................ 8

5.4. Distribution of the sample kits ............................................................................................ 9

6. Instructions to the participants .................................................................................................. 9

7. Evaluation of the results ............................................................................................................ 9

7.1. General observations ......................................................................................................... 9

7.2. Statistical evaluation of results ......................................................................................... 10

7.2.1. Assigned value .............................................................................................................. 10

7.2.2. Target standard deviation .............................................................................................. 10

7.2.3. Kernel density ............................................................................................................... 10

7.2.4. z-score .......................................................................................................................... 10

8. Results .................................................................................................................................... 11

8.1. Preliminary considerations ............................................................................................... 11

8.2. Laboratories performance and z-scores ........................................................................... 11

9. Final conclusion ...................................................................................................................... 29

Acknowledgements ..................................................................................................................... 30

10. References ........................................................................................................................... 31

11. Annexes ................................................................................................................................ 32


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1. Executive Summary

Food simulant E, also commercially named Tenax®, was established in Regulation (EU) No 10/2011 for testing specific migration into dry foodstuffs [1]. The first Interlaboratory Comparison (ILC) on Food Simulant E was carried out in 2011-2012. The general aim was to establish precision criteria of an optimised method for the analysis a number of migrants representing different physicochemical characteristics (n=5) in Tenax® and from a migration test from a fortified plastic film into Tenax® and subsequent quantification. Volunteer laboratories with some experience in simulant E participated using a Standard Operating Procedure (SOP) prepared by the European Reference Laboratory for Food Contact Material (EURL-FCM) [2]. The 2013 Interlaboratory Comparison (ILC001-2013) was taken as a further step since it was planned to 1) expand the range of polarity and volatility of the substances under investigation; 2) test the ability of laboratories i.e. take it to the next level being a proficiency testing (PT) with choice of any analytical method and 3) include unknown substances to test the screening ability (identification and quantification) of the laboratories. The test material used in this exercise was the spiked food simulant E prepared by the EURL-FCM. Before sending the sample to the participants, a list containing the name of 10 chemical substances was distributed, from which five would be present in the simulant. Other two unknown substances not included in the list were also added to the simulant. The choice of the substances was based on the relevant scientific literature related to migration from food contact materials (plastic and paperboard) into simulant E [2-6]. The concentration of each substance in the simulant was the closest as possible to its own specific migration limit (SML), when available in Regulation (EU) 10/2011 or tailored for the exercise. The substances chosen for the exercise 2013 were acetophenone (ACPH), benzophenone (BP), caprolactam (CAP), diethylhexyladipate (DEHA), 2,4-di-tert-butylphenol (DTBP), 2-ethyl-1-hexanol (ETHX) and 1-octene (OCT). The homogeneity and stability studies were performed by the EURL-FCM laboratory. There were 35 participants from 26 countries to whom samples were dispatched. 30 laboratories submitted results, of which 24 were NRLs, 5 were OCLs and one was the EURL-FCM itself. The participants were invited to report four replicate measurements under repeatability conditions. This was done by most of the participants. The participants were free to use their own analytical methods or use the SOP [2] that the EURL provided as a guide. The assigned values were obtained as consensus values after applying robust statistics to the results obtained from the participants. Laboratory results were rated with z-scores in accordance with ISO 13528 [7]. Reproducibility standard deviations (%) calculated by DIN 38402 A45 for the different substances in food simulant E are summarised below.

Substance SML mg/kg Assigned value mg/kg Reprod. SD % at the assigned value

ACPH - 11.03 18.12

BP 0.6 0.7 30.02

CAP 15 11.89 37.63

DEHA 18 8.37 32.52

DTBP - 6.98 12.29

ETHX 30 9.24 23.54

OCT 15 12.13 32.20

The participation of the laboratories on this PT on the identification and quantification of ACPH, BP, CAP, DEHA, DTBP, ETHX and OCT in the simulant E was satisfactory regarding the number of received results as well as overall performance.


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2. Introduction ILC studies are an essential and very important element of laboratory quality assurance, which allows individual laboratories to compare their analytical results with those from other laboratories while providing them objective standards to perform against. It is one of the core duties of the European Reference Laboratories to organise interlaboratory comparisons, as stipulated in Regulation (EC) No 882/2004 of the European Parliament and of the Council [8]. In accordance with the above requirements the EURL-FCM organised in 2013 interlaboratory comparison tests for the network of appointed NRLs. The scopes of the ILC tests for 2013 were discussed and established on the plenaries with all NRLs. It was agreed that the aim of one of the ILCs would be the evaluation of the laboratory performance on the identification and the quantification of 7 substances in food simulant E (e.g. Tenax®), of which 5 would be out of a list containing several substance names and 2 would remain undisclosed. Tenax® is a trademark of poly(2,6-diphenyl-p-phenylene oxide), which in Regulation (EU) No 10/2011 [1] is established as food simulant E for testing specific migration into dry foodstuffs. It is a porous polymer, which has extremely high adsorption capacity. Table 1 shows the list that the EURL established as potential choices or range for the 5 substances potentially fortified in simulant E. Table 1. List of the potential substances potentially added to the food simulant E

List of Substances CAS number

Benzophenone 119-61-9

1-Octene 111-66-0

Laurolactam 947-04-6

Chimassorb 81 1843-05-6

Diethylhexyl adipate 103-23-1

Diphenylbutadiene 538-81-8

Caprolactam 105-60-2

2-Ethyl-1-hexanol 104-76-7

Irganox 1076 2082-79-3

Benzyl butyl phthatale 85-68-7

They were chosen as model substances because they were reported in the literature as migrants from plastic packaging materials and/or from paperboard into food simulant E, and also due to their adequate stability in that particular simulant. Of those, 5 were chosen for spiking as follows: benzophenone (BP) which is a light stabilizer (UV absorber), diethylhexyladipate (DEHA) which is used as plasticizer in plastic food packaging, 2-ethyl-1-hexanol (ETHX) and 1-octene (OCT) which are monomers or starting substances. In addition, simulant E was fortified with two "unknown" substances, i.e. substances which remained undisclosed until the completion of the exercise. These substances were Acetophenone (ACPH) which can be used for production of coatings, inks and adhesives, and 2,4-di-tert-butylphenol (DTBP) which is a degradation product of antioxidants as Irgafos 168. The laboratories participating in the ILC001-2013 exercise were asked to identify and to quantify the model substances in the simulant at one concentration level. The participants


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were free to use their own analytical methods, since this exercise was a PT. They were invited to report four replicate measurements in repeatability conditions. 3. Scope The scope of this ILC was a PT with two objectives:

to test the laboratory performance of the appointed NRLs and OCLs to identify the substances BP, CAP, DEHA, ETHX and OCT added to food simulant E for dry foods;

to test the laboratory performance of the NRLs and OCLs to identify undisclosed substances (e.g. ACPH , DTBP)

to quantify all the substances described above that were added to food simulant E. The assessment of the measurement results was undertaken on the basis of requirements laid down in international standards and guidelines [7, 9-11]. 4. Time frame During the plenary meeting (EURL – Food Contact Materials and its Network of NRLs) held on the 26th of June 2013, the EURL disclosed the list containing the names of 10 chemical substances (Table 1). Only five substances from that list had been added to the food simulant E. Other two unknown substances not included in the list were added to the same batch of the simulant E. The NRLs had the task identify and quantify all substances. The ILC001-2013 was officially launched on the 9th of July 2013. Invitation letters and instructions were sent to the participants (Annexes 1 and 5). The laboratories were invited to fill in a letter of confirmation of their participation (Annex 2). The final batch of food simulant E, spiked with the seven substances at one concentration level was prepared by the EURL-FCM from 09 to 11 September 2013. The sample was dispatched to the participants on the 12th of September 2013, together with the shipping kit (Annex 3). The participants were asked to fill in a letter of confirmation of the receipt of the samples (Annex 4). The deadline for reporting was set to the 30th of October 2013. 5. Test material The sample kit sent to the participants is shown in Table 2. The non-spiked food simulant E, from the same batch as the spiked one, was sent to the participants for control purposes. Additionally, virgin Tenax® was provided to NRLs for calibration purposes. Table 2. Sample kit for the ILC001-2013 Name Sample

TNX1 One bottle with 20 g of the spiked food simulant E

Blank TNX1 One vial with 5 g of the not spiked food simulant E

Virgin TNX One box with 10 g of virgin Tenax® TA 60/80 (Supelco) – NRLs only


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5.1. Sample preparation Preparation and homogenization of the test materials were done by the EURL-FCM laboratory according to the procedure described in Annex 6. After spiking and homogenization, 20 g portions of the spiked simulant E were filled into glass amber bottles. 5.2. Homogeneity assessment The samples were tested for homogeneity by the EURL Laboratory. Ten randomly selected test specimens for the sample TNX1 were analysed in duplicate to quantify ACPH, BP, CAP, DEHA, DTBP, ETHX and OCT. Homogeneity was evaluated according to ISO 13528 [7], F-test and IUPAC International Harmonized Protocol [11] using the ProLab Software [12]. The homogeneity results and their statistical evaluation were obtained using Horwitz as target standard deviation (Annex 8). All test materials showed sufficient homogeneity. 5.3. Stability test Randomly selected specimens for sample TNX1 were stored at 3 different temperature conditions (4ºC, 20°C and 40ºC). The test samples were monitored for stability by the EURL laboratory for all substances from the date of preparation (homogeneity assessment) to the closing of the ILC001-2013. The stability was evaluated as described in ISO GUIDE 35:2006 [13]. The evaluation of data was carried out by performing a linear regression on the experimentally determined concentrations of ACPH, BP, CAP, DEHA, DTBP, ETHX and OCT (mean values) versus time (days). For a stable material, it is expected that the intercept is (within uncertainty) equal to the assigned value, whereas the slope does not differ significantly from zero. Using the linear regression equation: Y(ACPH, BP, CAP, DEHA, DTBP, ETHX and OCT mg/kg) = b0 +b1 X (time, days) the slope is not significantly different from zero if the following requirement is respected;

where b1 is the slope obtained from the linear regression, t0.95,n-2 is the Student’s t-factor for n-2 degrees of freedom and p = 0.95 (95% level of

confidence) and s(b1) is the uncertainty associated with the slope. This can be calculated as follows:


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The value of s (standard deviation of the time-points) can be obtained from:

where n is the number of points of the linear regression. The stability results and their statistical evaluation are given in Annex 9. It should be pointed out that no significant trend was observed for the test sample at all temperature conditions (4ºC, 20°C and 40ºC) for the time span of the ILC001-2013. It was concluded that the substances were stable for at least two months following their preparation. 5.4. Distribution of the sample kits

The sample kits were dispatched to the participants by the EURL-FCM on the 12th of September 2013. Each participant received a box containing the test materials as follows:

One amber glass bottle with 20 g of the spiked food simulant E (TNX1)

One glass vial with 5 g of the food simulant E not spiked, from the same batch of the spiked one (Blank TNX1)

One plastic box containing virgin Tenax® TA 60/80 (10 g) – (NRLs only). and accompanying letters:

Instructions on sample handling and on compilation of the results (Annex 5);

Confirmation of receipt (Annex 4);

Electronic excel file for reporting the results (Annex 7). 6. Instructions to the participants Instructions were given to all participants in the letters that accompanied the sample (Annex 5). Laboratories were asked to report 4 results for each substance using the unit of measure indicated in the electronic excel file for reporting the results (Annex 7). Participants were free to use their own analytical methods. However, the SOP [2] validated in the previous exercise on Food Simulant E was also distributed as a guide if needed. 7. Evaluation of the results

7.1. General observations There were 35 participants to whom samples were dispatched (EURL, 29 NRLs + 5 national control laboratories from Germany and Spain) and 30 of which submitted results. The ILC was closed permanently at the beginning of November for statistical interpretation.


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7.2. Statistical evaluation of results The statistical evaluation of the results was performed using the ProLab software [12]. 7.2.1. Assigned value As the “true” values for the concentration of each evaluated substance could not be known due to the complexity of sample preparation and possible loss of substances during the evaporation step, the assigned value was evaluated according to Q-method/Hampel estimator (DIN 38402 A45) [14]. A robust mean of the results reported by the participants was chosen as a consensus for the assigned value in the ILC001-2013. The results reported as "smaller than" (<values) were not used in any calculation. No evaluation of these measurement results was done and no scores were given. 7.2.2. Target standard deviation

The value of target standard deviation (p) determines the limits of satisfactory performance in an ILC test. It should be set as a value that reflects best practices for the analysis in question. In most cases Horwitz SD [7], a general model commonly used for chemical application, is a good compromise but does not reflect different levels of complexity of a given analytical method. If the target standard deviation is not chosen realistically the interpretation “satisfactory”, “questionable” and “unsatisfactory” would not be valid. On the other hand, the standard deviation of the reproducibility in collaborative trials can be considered as an appropriate indicator of the best agreement between laboratories.

The p of each substance evaluated in this ILC001-2013 was its reproducibility SD. However

the p was also calculated using Horwitz. 7.2.3. Kernel density Kernel density plots were additionally used to identify multi-modality in the reported values' distributions. Frequently analytical results from a collaborative study are not normally distributed or contain values from different populations giving rise to multiple distribution modes. These modes can be visualised by using Kernel density plots [15, 16]. Kernel density plots were computed by the ProLab software from the analytical results by representing the individual numeric values each as a normalized Gaussian distribution centered on the respective analytical value. The sum of these normal distributions formed then the Kernel density distribution. 7.2.4. z-score Individual laboratory performance was expressed in terms of z-score in accordance with ISO 13528 [7] and the International Harmonised Protocol [11]. The z-scores compared the participant's deviation from the assigned value with the target standard deviation accepted for the PT:

p

assignedlab Xxz

)(

Where: xlab is the measurement result (mean value) reported by a participant;


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Xassigned is the assigned value; σp is the target standard deviation for proficiency assessment. The z-score can be interpreted as follow: |z|≤2 satisfactory result; 2<|z|≤3 questionable result; |z|>3 unsatisfactory result.

In this exercise the z-scores calculated with the reproducibility SD as p were used to assess

the performance of the laboratories. Nevertheless, the z-scores with Horwitz SD as p were also calculated. 8. Results 8.1. Preliminary considerations Thirty laboratories submitted results, of which 24 were from NRL network, 5 were OCLs (4 from Germany and 1 from Spain) and one was the EURL-FCM itself. As requested, most of the laboratories reported four replicate results under repeatability conditions. The participation of the laboratories was regarded as satisfactory concerning the number of received results (86% of participation). 8.2. Laboratories performance and z-scores The EURL-FCM collected information about the different procedures used by the participants in the exercise (Annex 10). The reported methodologies refer to the different stages of the analysis, such as: cleaning of the simulant, extraction of substances from the simulant, calibration and quantification, analytical technique and chromatographic column. The procedure for cleaning described in the SOP [2] of 6 hours of Soxhlet with acetone was used by 80% of the laboratories. Hexane, acetone and acetonitrile were the solvents most commonly used for the extraction. Most of the laboratories performed the calibration spiking the matrix and the quantification using internal standard. Gas chromatography coupled to mass spectrometer was chosen by 80% of the participants with the capillary columns HP-5MS and DB-17HT. The overall performance for individual substance was evaluated taking into account the results submitted (Figure 1). The blue bars represent the number of laboratories able to identify the substance. The yellow bars denote to the number of laboratories that quantified the substance and the green bars mean the number of laboratories that quantified the substance within the tolerance limits. The overall performance of the laboratories regarding all the 7 evaluated substances is shown in Table 3. Concerning the identification, 83% of the participants were able to identify at least 5 substances (25 results out of 30). It is important to note that 15 laboratories could identify all the 7 substances. In relation to the quantification, 61% of the participants were able to quantify all the 7 substances within the tolerance limit (17 results out of 28 quantitative results).


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Table 3. Overall performance of the laboratories in the identification and quantification of the substances Lab. code

Identified substances

Total n. substances

Percentage (%)

Successful Quantified substances

Total n. substances

Percentage (%)

Successful Quant. subst.

within tolerance limit

Total n. substances

Percentage (%)

Overall Successful

LC0002 7 7 100 Yes 7 7 100 Yes 6 7 86 Yes

LC0003 2 7 29 No 2 7 29 No 2 7 29 No

LC0004 7 7 100 Yes 7 7 100 Yes 6 7 86 Yes

LC0004B 7 7 100 Yes 7 7 100 Yes 6 7 86 Yes

LC0005 4 7 57 No 4 7 57 No 3 7 43 No

LC0006 3 7 43 No 3 7 43 No 1 7 14 No

LC0007 6 7 86 Yes 3 7 43 No 0 7 0 No

LC0008 1 7 14 No 1 7 14 No 1 7 14 No

LC0010 7 7 100 Yes 7 7 100 Yes 7 7 100 Yes

LC0011 0 7 0 No 0 7 0 No 0 7 0 No

LC0013 6 7 86 Yes 6 7 86 Yes 6 7 86 Yes

LC0016 6 7 86 Yes 4 7 57 No 4 7 57 No

LC0017 7 7 100 Yes 7 7 100 Yes 7 7 100 Yes

LC0018 6 7 86 Yes 6 7 86 Yes 6 7 86 Yes

LC0020 7 7 100 Yes 5 7 71 Yes 3 7 43 No

LC0024 5 7 71 Yes 3 7 43 No 3 7 43 No

LC0025 7 7 100 Yes 7 7 100 Yes 7 7 100 Yes

LC0028 6 7 86 Yes 6 7 86 Yes 6 7 86 Yes

LC0029 0 7 0 No 0 7 0 No 0 7 0 No

LC0031 7 7 100 Yes 7 7 100 Yes 7 7 100 Yes

LC0034 0 7 0 No 0 7 0 No 0 7 0 No

LC0037 6 7 86 Yes 6 7 86 Yes 5 7 71 Yes

LC0038 7 7 100 Yes 7 7 100 Yes 7 7 100 Yes

LC0040 7 7 100 Yes 7 7 100 Yes 7 7 100 Yes

LC0041 7 7 100 Yes 7 7 100 Yes 7 7 100 Yes

LC0043 0 7 0 No 0 7 0 No 0 7 0 No

LC0044 0 7 0 No 0 7 0 No 0 7 0 No

LC0047 7 7 100 Yes 7 7 100 Yes 7 7 100 Yes

LC0048 7 7 100 Yes 7 7 100 Yes 6 7 86 Yes

LC0049 6 7 86 Yes 0 7 0 No 0 7 0 No

LC0050 6 7 86 Yes 6 7 86 Yes 4 7 57 No

LC0055 4 7 57 No 4 7 57 No 3 7 43 No

LC0056 7 7 100 Yes 6 7 86 Yes 0 7 0 No

LC0059 6 7 86 Yes 0 7 0 No 0 7 0 No

LC0064 7 7 100 Yes 6 7 86 Yes 5 7 71 Yes


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0

5

10

15

20

25

30

35

ACPH BP CAP DEHA DTBP ETHX OCT

Nu

mb

er

of

La

bo

rato

rie

sIdentification and quantification of the substances

Identified Quantified Quantified within tolerance limit

Figure 1. General overview of the results obtained for each substance BP and DEHA had been already the subject of a quantification exercise in simulant E in the previous ILC exercise. The repeatability SD and reproducibility SD from both exercises are shown in Table 4. In the ILC002-2012 the participants had to follow strictly a single method (SOP) to quantify these substances in simulant E. In the ILC001-2013, BP and DEHA were quantified using different analytical methods chosen by the participants. This approach could explain higher values obtained for the reproducibility SD in the ILC001-2013. The repeatability SDs achieved in both ILC exercises are similar, although in the present ILC the participants applied different analytical methods. These findings indicate that the approaches do not differ regarding their repeatability. Table 4. Repeatability SD and reproducibility SD for BP and DEHA in Simulant E

Substance

ILC02-2011 ILC001-2013

Assigned value (mg/kg)

Reprod. SD

Repeat.SD

Assigned value (mg/kg)

Reprod. SD

Repeat.SD

BP 0.49 20 8 0.70 30 7

DEHA 17.49 21 7 8.37 33 6

Summaries of the results obtained for ACPH, BP, CAP, DEHA, DTBP, ETHX and OCT with their robust repeatability SD and robust reproducibility SD calculated by ProLab software according to Q-method/Hampel estimator (DIN 38402 A45) [14] as well as assigned values, target standard deviations and z-scores, are given in Tables 5-12 and Figures 2-8. In Tables 6-12 z-scores calculated against two different target SDs are presented.

30 participants


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Table 5. Summary of results for ACPH, BP, CAP, DEHA, DTBP, ETHX and OCT calculated according to DIN 38402 A45

ProLab Results SUBSTANCES

ACPH BP CAP DEHA DTBP ETHX OCT

Assigned value = Robust Mean, mg/kg 11.03 0.70 11.89 8.37 6.98 9.24 12.13

Robust Repeatability SD, mg/kg 0.81 0.05 1.05 0.49 0.42 0.62 1.13

Robust Reproducibility SD, mg/kg 2.00 0.21 4.47 2.72 0.86 2.17 3.90

Target SD (Reproducibility SD), mg/kg 2.00 0.21 4.47 2.72 0.86 2.17 3.90

Target SD (Horwitz), mg/kg 1.23 0.12 1.31 0.97 0.83 1.06 1.33

Rel. target SD (Reproducibility SD), % 18.12 30.02 37.63 32.52 12.29 23.54 32.20

Rel. target SD (Horwitz), % 11.15 16.88 11.02 11.62 11.94 11.45 10.99

Rel. Repeatability SD, % 7.37 6.99 8.82 5.83 5.95 6.66 9.29

Lower limit of tolerance, mg/kg 7.03 0.28 2.94 2.93 5.27 4.89 4.32

Upper limit of tolerance, mg/kg 15.02 1.12 20.83 13.82 8.70 13.59 19.93

Laboratories 18 25 21 28 17 23 23

Test results 71 99 81 111 67 91 91


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Table 6. Summary of the z-scores against different target SD for ACPH

z-scores for ACPH

Laboratory classical Horwitz Reproducibility SD

LC0002 -1.567 -0.964

LC0004 2.607 1.604

LC0004B 2.107 1.296

LC0010 0.077 0.047

LC0017 -0.255 -0.157

LC0018 1.841 1.132

LC0025 -0.781 -0.481

LC0028 0.596 0.366

LC0031 1.281 0.788

LC0037 -1.099 -0.676

LC0038 -0.324 -0.199

LC0040 -0.102 -0.063

LC0041 0.435 0.268

LC0047 -1.587 -0.976

LC0048 -0.061 -0.038

LC0050 -2.238 -1.376

LC0056 41.903 25.773

LC0064 -0.761 -0.468


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Table 7. Summary of the z-scores against different target SD for BP

z-scores for BP


LC0002 -0.962 -0.541

LC0004 8.436 4.743

LC0004B 6.278 3.530

LC0005 -1.505 -0.846

LC0006 4.417 2.484

LC0010 0.060 0.034

LC0013 -1.695 -0.953

LC0016 -0.320 -0.180

LC0017 0.949 0.533

LC0018 2.746 1.544

LC0020 0.289 0.162

LC0024 -1.822 -1.024

LC0025 -1.145 -0.644

LC0028 0.378 0.212

LC0031 -0.489 -0.275

LC0037 -1.039 -0.584

LC0038 -0.722 -0.406

LC0040 -0.595 -0.335

LC0041 -1.420 -0.798

LC0047 -0.320 -0.180

LC0048 5.284 2.971

LC0050 -0.849 -0.477

LC0055 3.339 1.877

LC0056 30.664 17.241

LC0064 -1.187 -0.668


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Table 8. Summary of the z-scores against different target SD for CAP

z-scores for CAP


LC0002 3.673 1.076

LC0003 -1.155 -0.338

LC0004 -0.824 -0.242

LC0004B 1.263 0.370

LC0010 -0.170 -0.050

LC0013 1.620 0.474

LC0016 1.927 0.564

LC0017 2.351 0.689

LC0018 1.994 0.584

LC0020 -8.296 -2.430

LC0024 -5.366 -1.572

LC0025 0.038 0.011

LC0028 -3.898 -1.142

LC0031 2.013 0.590

LC0038 0.277 0.081

LC0040 2.314 0.678

LC0041 -2.374 -0.695

LC0047 1.536 0.450

LC0048 -0.342 -0.100

LC0050 -7.585 -2.222

LC0056 8.729 2.557


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Table 9. Summary of the z-scores against different target SD for DEHA

z-scores for DEHA


LC0002 1.880 0.672

LC0003 -4.880 -1.744

LC0004 2.368 0.846

LC0004B 2.803 1.001

LC0005 0.510 0.182

LC0006 12.282 4.388

LC0007 -7.009 -2.504

LC0008 -0.017 -0.006

LC0010 0.186 0.066

LC0013 -0.320 -0.114

LC0016 -1.089 -0.389

LC0017 0.854 0.305

LC0018 0.543 0.194

LC0020 -3.270 -1.168

LC0024 -3.119 -1.114

LC0025 1.811 0.647

LC0028 2.044 0.730

LC0031 1.494 0.534

LC0037 21.183 7.568

LC0038 1.063 0.380

LC0040 -1.554 -0.555

LC0041 1.510 0.539

LC0047 1.057 0.378

LC0048 1.371 0.490

LC0050 -3.158 -1.128

LC0055 11.716 4.186

LC0056 75.184 26.863

LC0064 0.238 0.085


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Table 10. Summary of the z-scores against different target SD for DTBP

z-scores for DTBP


LC0002 2.378 2.311

LC0004 0.490 0.476

LC0004B -1.288 -1.251

LC0010 0.230 0.223

LC0013 -0.409 -0.398

LC0017 -0.430 -0.418

LC0025 0.610 0.593

LC0028 1.069 1.039

LC0031 0.259 0.252

LC0037 0.379 0.369

LC0038 -0.604 -0.587

LC0040 0.068 0.066

LC0041 0.829 0.806

LC0047 -0.370 -0.360

LC0048 -0.460 -0.447

LC0055 -0.412 -0.400

LC0064 -3.125 -3.037


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Table 11. Summary of the z-scores against different target SD for ETHX

z-scores for ETHX


LC0002 1.225 0.596

LC0004 1.861 0.905

LC0004B 1.485 0.722

LC0005 -7.303 -3.551

LC0007 -6.972 -3.391

LC0010 -3.234 -1.573

LC0013 0.409 0.199

LC0016 0.390 0.190

LC0017 1.343 0.653

LC0018 1.336 0.650

LC0020 -1.904 -0.926

LC0025 -0.809 -0.393

LC0028 1.305 0.635

LC0031 2.187 1.063

LC0037 0.981 0.477

LC0038 0.132 0.064

LC0040 -0.073 -0.036

LC0041 -0.227 -0.110

LC0047 -0.366 -0.178

LC0048 0.478 0.232

LC0050 -6.537 -3.179

LC0056 75.970 36.946

LC0064 0.281 0.137


- 21 -

Table 12. Summary of the z-scores against different target SD for OCT Seven sets of figures for TNX1 sample are presented below. Each set included: individual laboratories values and their mean and standard deviation (first graphic), Kernel density plot (second graphic) and z- scores (third graphic).

z-scores for OCT


LC0002 -0.794 -0.271

LC0004 0.974 0.332

LC0004B 0.974 0.332

LC0005 -0.640 -0.218

LC0006 -1.347 -0.460

LC0007 -9.045 -3.087

LC0010 -0.038 -0.013

LC0013 4.216 1.439

LC0017 1.077 0.368

LC0018 3.396 1.159

LC0020 -7.179 -2.450

LC0025 1.525 0.521

LC0031 2.327 0.794

LC0037 1.126 0.384

LC0038 0.672 0.229

LC0040 -2.556 -0.872

LC0041 -0.893 -0.305

LC0047 2.158 0.736

LC0048 1.826 0.623

LC0050 -4.653 -1.588

LC0055 -2.132 -0.728

LC0056 74.959 25.583

LC0064 1.062 0.362


- 22 -

PROLab Plus

Laboratory

LC

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50

LC

00

47

LC

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02

LC

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37

LC

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25

LC

00

64

LC

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38

LC

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17

LC

00

40

LC

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48

LC

00

10

LC

00

41

LC

00

28

LC

00

31

LC

00

18

LC

00

04

B

LC

00

04

LC

00

56

mg

/kg

70

60

50

40

30

20

10

00

Sample: Spiked TenaxMeasurand: AcetophenoneMethod: DIN 38402 A45No. of laboratories: 18

Assigned value: 11.025 mg/kg (Empirical value)Rel. target s.d.: 18.12% (Empirical value)Rel. repeatability s.d.: 7.37%Range of tolerance: 7.029 - 15.022 mg/kg (|Z Score| <= 2.00)

Ass

igne

d valu

e

Mea

nLimit of tolerance

Limit of tolerance

mg/kg70605040302010

Pro

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bili

ty d

en

sity

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Up

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nce

Assigned value (Mean): 11.025 ± 0.882 mg/kg

Mo

de

1: 1

0.6

40

mg

/kg

(9

4 %

)

Mo

de

2: 5

9.2

20

mg

/kg

(3

%)

Mo

de

3: 6

4.6

10

mg

/kg

(1

%)

Mo

de

4: 6

7.0

60

mg

/kg

(1

%)

PROLab Plus

Laboratory

LC

00

50

LC

00

47

LC

00

02

LC

00

37

LC

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25

LC

00

64

LC

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38

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17

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40

LC

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48

LC

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10

LC

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41

LC

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28

LC

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31

LC

00

18

LC

00

04

B

LC

00

04

LC

00

56

z-s

co

re

27.5

25.0

22.5

20.0

17.5

15.0

12.5

10.0

7.5

5.0

2.5

0.0

-2.5

-5.0

Measurand: Acetophenone

Limit of tolerance

Limit of tolerance

Assessment = DIN38402 A45; Assigned value = M; Target s.d. = S; |Z Score| <= 2

Figure 2. Summary of the laboratories test results for ACPH with theirs repeatability SD (1st graph), Kernel density plot (2nd graph) and z-scores (3rd graph)


- 23 -

PROLab Plus

Laboratory

LC

00

24

LC

00

13

LC

00

05

LC

00

41

LC

00

64

LC

00

25

LC

00

37

LC

00

02

LC

00

50

LC

00

38

LC

00

40

LC

00

31

LC

00

16

LC

00

47

LC

00

10

LC

00

20

LC

00

28

LC

00

17

LC

00

18

LC

00

55

LC

00

06

LC

00

48

LC

00

04

B

LC

00

04

LC

00

56

mg

/kg

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

-0.5

-1.0

Sample: Spiked TenaxMeasurand: benzophenoneMethod: DIN 38402 A45No. of laboratories: 25


Ass

igne

d valu

e

Mea

nLimit of tolerance

Limit of tolerance

mg/kg54.543.532.521.510.5

Pro

ba

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ty d

en

sity

Lo

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nce

Up

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r lim

it o

f to

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nce


Mo

de

1: 0

.59

0 m

g/k

g (

73

%)

Mo

de

2: 1

.22

0 m

g/k

g (

20

%)

Mo

de

3: 1

.68

5 m

g/k

g (

4 %

)

Mo

de

4: 3

.61

5 m

g/k

g (

1 %

)

Mo

de

5: 3

.78

5 m

g/k

g (

1 %

)

Mo

de

6: 4

.95

0 m

g/k

g (

1 %

)

PROLab Plus

Laboratory

LC

00

24

LC

00

13

LC

00

05

LC

00

41

LC

00

64

LC

00

25

LC

00

37

LC

00

02

LC

00

50

LC

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38

LC

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40

LC

00

31

LC

00

16

LC

00

47

LC

00

10

LC

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20

LC

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28

LC

00

17

LC

00

18

LC

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55

LC

00

06

LC

00

48

LC

00

04

B

LC

00

04

LC

00

56

z-s

co

re

18

16

14

12

10

8

6

4

2

0

-2

-4

Measurand: benzophenone

Limit of tolerance

Limit of tolerance


Figure 3. Summary of the laboratories test results for BP with theirs repeatability SD (1st graph), Kernel density plot (2nd graph) and z-scores (3rd graph)


- 24 -

PROLab Plus

Laboratory

LC

00

20

LC

00

50

LC

00

24

LC

00

28

LC

00

41

LC

00

03

LC

00

04

LC

00

48

LC

00

10

LC

00

25

LC

00

38

LC

00

04

B

LC

00

47

LC

00

13

LC

00

16

LC

00

18

LC

00

31

LC

00

40

LC

00

17

LC

00

02

LC

00

56

mg

/kg

30

28

25

23

20

18

15

13

10

08

05

03

00

-03

-05

Sample: Spiked TenaxMeasurand: CaprolactamMethod: DIN 38402 A45No. of laboratories: 21


Ass

igne

d valu

e

Mea

n

Limit of tolerance

Limit of tolerance

mg/kg302520151050-5

Pro

ba

bili

ty d

en

sity

Lo

we

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it o

f to

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nce

Up

pe

r lim

it o

f to

lera

nce


Mo

de

1: 2

.52

5 m

g/k

g (

10

%)

Mo

de

2: 1

3.5

15

mg

/kg

(9

0 %

)

PROLab Plus

Laboratory

LC

00

20

LC

00

50

LC

00

24

LC

00

28

LC

00

41

LC

00

03

LC

00

04

LC

00

48

LC

00

10

LC

00

25

LC

00

38

LC

00

04

B

LC

00

47

LC

00

13

LC

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16

LC

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18

LC

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31

LC

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40

LC

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17

LC

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02

LC

00

56

z-s

co

re

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

-2.0

-2.5

-3.0

-3.5

Measurand: Caprolactam

Limit of tolerance

Limit of tolerance


Figure 4. Summary of the laboratories test results for CAP with theirs repeatability SD (1st graph), Kernel density plot (2nd graph) and z-scores (3rd graph)


- 25 -

PROLab Plus

Laboratory

LC

00

07

LC

00

03

LC

00

20

LC

00

50

LC

00

24

LC

00

40

LC

00

16

LC

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13

LC

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08

LC

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10

LC

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64

LC

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05

LC

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18

LC

00

17

LC

00

47

LC

00

38

LC

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48

LC

00

31

LC

00

41

LC

00

25

LC

00

02

LC

00

28

LC

00

04

LC

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04

B

LC

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55

LC

00

06

LC

00

37

LC

00

56

mg

/kg

100

90

80

70

60

50

40

30

20

10

00

-10

Sample: Spiked TenaxMeasurand: diethylhexyladipateMethod: DIN 38402 A45No. of laboratories: 28


Ass

igne

d valu

e

Mea

nLimit of tolerance

Limit of tolerance

mg/kg1009080706050403020100

Pro

ba

bili

ty d

en

sity

Lo

we

r lim

it o

f to

lera

nce

Up

pe

r lim

it o

f to

lera

nce


Mo

de

1: 9

.50

0 m

g/k

g (

85

%)

Mo

de

2: 2

0.1

00

mg

/kg

(7

%)

Mo

de

3: 2

4.3

00

mg

/kg

(2

%)

Mo

de

4: 3

0.3

00

mg

/kg

(1

%)

Mo

de

5: 3

6.9

00

mg

/kg

(1

%)

Mo

de

6: 6

4.3

00

mg

/kg

(1

%)

Mo

de

7: 8

3.9

00

mg

/kg

(2

%)

Mo

de

8: 9

3.9

00

mg

/kg

(1

%)

PROLab Plus

Laboratory

LC

00

07

LC

00

03

LC

00

20

LC

00

50

LC

00

24

LC

00

40

LC

00

16

LC

00

13

LC

00

08

LC

00

10

LC

00

64

LC

00

05

LC

00

18

LC

00

17

LC

00

47

LC

00

38

LC

00

48

LC

00

31

LC

00

41

LC

00

25

LC

00

02

LC

00

28

LC

00

04

LC

00

04

B

LC

00

55

LC

00

06

LC

00

37

LC

00

56

z-s

co

re

27.5

25.0

22.5

20.0

17.5

15.0

12.5

10.0

7.5

5.0

2.5

0.0

-2.5

-5.0

Measurand: diethylhexyladipate

Limit of tolerance

Limit of tolerance


Figure 5. Summary of the laboratories test results for DEHA with theirs repeatability SD (1st graph), Kernel density plot (2nd graph) and z-scores (3rd graph)


- 26 -

PROLab Plus

Laboratory

LC

00

64

LC

00

04

B

LC

00

38

LC

00

48

LC

00

17

LC

00

55

LC

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13

LC

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47

LC

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40

LC

00

10

LC

00

31

LC

00

37

LC

00

04

LC

00

25

LC

00

41

LC

00

28

LC

00

02

mg

/kg

11

10

09

08

07

06

05

04

03

02

Sample: Spiked TenaxMeasurand: 2,4-di-tert-butylphenolMethod: DIN 38402 A45No. of laboratories: 17


Ass

igne

d valu

e

Mea

n

Limit of tolerance

Limit of tolerance

mg/kg1110987654

Pro

ba

bili

ty d

en

sity

Lo

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it o

f to

lera

nce

Up

pe

r lim

it o

f to

lera

nce


Mo

de

1: 3

.32

8 m

g/k

g (

2 %

)

Mo

de

2: 6

.79

2 m

g/k

g (

96

%)

Mo

de

3: 1

0.6

96

mg

/kg

(1

%)

PROLab Plus

Laboratory

LC

00

64

LC

00

04

B

LC

00

38

LC

00

48

LC

00

17

LC

00

55

LC

00

13

LC

00

47

LC

00

40

LC

00

10

LC

00

31

LC

00

37

LC

00

04

LC

00

25

LC

00

41

LC

00

28

LC

00

02

z-s

co

re

5

4

3

2

1

0

-1

-2

-3

-4

-5

Measurand: 2,4-di-tert-butylphenol

Limit of tolerance

Limit of tolerance


Figure 6. Summary of the laboratories test results for DTBP with theirs repeatability SD (1st graph), Kernel density plot (2nd graph) and z-scores (3rd graph)


- 27 -

PROLab Plus

Laboratory

LC

00

05

LC

00

07

LC

00

50

LC

00

10

LC

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20

LC

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LC

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47

LC

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41

LC

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40

LC

00

38

LC

00

64

LC

00

16

LC

00

13

LC

00

48

LC

00

37

LC

00

02

LC

00

28

LC

00

18

LC

00

17

LC

00

04

B

LC

00

04

LC

00

31

LC

00

56

mg

/kg

110

100

90

80

70

60

50

40

30

20

10

00

-10

Sample: Spiked TenaxMeasurand: 2-Ethyl 1-HexanolMethod: DIN 38402 A45No. of laboratories: 23


Ass

igne

d valu

e

Mea

nLimit of tolerance

Limit of tolerance

mg/kg1101009080706050403020100

Pro

ba

bili

ty d

en

sity

Lo

we

r lim

it o

f to

lera

nce

Up

pe

r lim

it o

f to

lera

nce


Mo

de

1: 1

.87

0 m

g/k

g (

13

%)

Mo

de

2: 9

.79

0 m

g/k

g (

82

%)

Mo

de

3: 7

0.4

00

mg

/kg

(1

%)

Mo

de

4: 8

5.9

10

mg

/kg

(1

%)

Mo

de

5: 1

00

.65

0 m

g/k

g (

1 %

)

Mo

de

6: 1

01

.31

0 m

g/k

g (

1 %

)

PROLab Plus

Laboratory

LC

00

05

LC

00

07

LC

00

50

LC

00

10

LC

00

20

LC

00

25

LC

00

47

LC

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41

LC

00

40

LC

00

38

LC

00

64

LC

00

16

LC

00

13

LC

00

48

LC

00

37

LC

00

02

LC

00

28

LC

00

18

LC

00

17

LC

00

04

B

LC

00

04

LC

00

31

LC

00

56

z-s

co

re

40

35

30

25

20

15

10

5

0

-5

-10

Measurand: 2-Ethyl 1-Hexanol

Limit of tolerance

Limit of tolerance


Figure 7. Summary of the laboratories test results for ETHX with theirs repeatability SD (1st graph), Kernel density plot (2nd graph) and z-scores (3rd graph)


- 28 -

PROLab Plus

Laboratory

LC

00

07

LC

00

20

LC

00

50

LC

00

40

LC

00

55

LC

00

06

LC

00

41

LC

00

02

LC

00

05

LC

00

10

LC

00

38

LC

00

04

LC

00

04

B

LC

00

64

LC

00

17

LC

00

37

LC

00

25

LC

00

48

LC

00

47

LC

00

31

LC

00

18

LC

00

13

LC

00

56

mg

/kg

140

120

100

80

60

40

20

00

Sample: Spiked TenaxMeasurand: 1-OcteneMethod: DIN 38402 A45No. of laboratories: 23


Ass

igne

d valu

e

Mea

nLimit of tolerance

Limit of tolerance

mg/kg140120100806040200

Pro

ba

bili

ty d

en

sity

Lo

we

r lim

it o

f to

lera

nce

Up

pe

r lim

it o

f to

lera

nce


Mo

de

1: 1

.26

0 m

g/k

g (

7 %

)

Mo

de

2: 1

3.4

40

mg

/kg

(8

8 %

)

Mo

de

3: 9

4.5

00

mg

/kg

(1

%)

Mo

de

4: 1

04

.16

0 m

g/k

g (

1 %

)

Mo

de

5: 1

17

.04

0 m

g/k

g (

1 %

)

Mo

de

6: 1

32

.30

0 m

g/k

g (

1 %

)

PROLab Plus

Laboratory

LC

00

07

LC

00

20

LC

00

50

LC

00

40

LC

00

55

LC

00

06

LC

00

41

LC

00

02

LC

00

05

LC

00

10

LC

00

38

LC

00

04

LC

00

04

B

LC

00

64

LC

00

17

LC

00

37

LC

00

25

LC

00

48

LC

00

47

LC

00

31

LC

00

18

LC

00

13

LC

00

56

z-s

co

re

28

25

23

20

18

15

13

10

8

5

3

0

-3

-5

Measurand: 1-Octene

Limit of tolerance

Limit of tolerance


Figure 8. Summary of the laboratories test results for OCT with theirs repeatability SD (1st graph), Kernel density plot (2nd graph) and z-scores (3rd graph)


- 29 -

9. Final conclusion The participation of NRLs and OCLs in the ILC001-2013 was satisfactory particiation with thirty laboratories out of 35 which reported results (86% of participation). The laboratories' performance concerning the identification of the unknown substances was satisfactory, with 25 correct results out of 30 (83%), even taking into account the complexity of the exercise. Regarding the quantification within tolerance limits, 17 results out of 28 were satisfactory, which represented a success rate of 61%. This was however for all substances, therefore for a very challenging exercise that included undisclosed substances (unknowns). Considering the individual substances, more than 80% of satisfactory quantification within tolerance limits was achieved (ACPH 94%, BP 80%, CAP 86%, DEHA 82%, DTBP 88%, ETHX 83% and OCT 87%). This exercise was the first Proficiency Testing carried out at EU level on food simulant E with the aim to evaluate the performance of the National Reference Laboratories across the Member States. It was therefore a very positive first-time result. In addition, this ILC001-2013 provided the first successful attempt to derive data at EU level for identification and quantification of potential unknown migrants, at the SML levels in food simulant E. These migrants are commonly found in food contact materials such as plastic packaging and paperboard.


- 30 -

Acknowledgements The NRLs and OCLs participating in this exercise - listed below - are kindly acknowledged.

NRLs

AUSTRIA Austrian Agency for Health and Food Safety (AGES), Wien

BELGIUM Institute of Public Health, ISSP-LP, Bruxelles

BULGARIA National Centre for Public Health Protection, Sofia

CYPRUS Laboratory for Control of Food Contact Materials and Control of Toys

Ministry of Health, State General Laboratory (SGL), Nicosia

CZECH NIPH - NRL for Food Contact Materials and for Articles for children under 3 years old, National

Institute of Public Health (SZU’), Praha

DENMARK Department of Food Chemistry, Danish Veterinary and Food Administration, Lystrup

DENMARK Danish Veterinary and Food Administration Laboratory Århus, Lystrup

ESTONIA Health Protection Inspectorate - Central Laboratory of Chemistry, Tallinn

FINLAND Finnish Customs Laboratory, Espoo

FRANCE Centre for Energy Material and Packaging - Laboratoire National d'Essais, Trappes Cedex

FRANCE SCL Laboratoire de Bordeaux-Pessac, Pessac

GERMANY Bundesinstitut für Risikobewertung (BFR) (Federal Institute for Risk Assessment),

Berlin

GREECE General Chemical State Laboratory, D’ Chemical Service of Athens, Section Laboratory of

Articles and Materials in Contact with Foodstuffs, Athens

HUNGARY Central Agricultural Office, Food and Feed Safety Directorate, Food Toxicology National

Reference Laboratory, Budapest

IRELAND Public Analyst Laboratory - Sir Patrick Duns Hospital, Dublin

ITALY Istituto Superiore di Sanità, Laboratorio Esposizione e rischio da materiali, c/o Dipartimento

ambiente e connessa prevenzione primaria, Roma

LUXEMBOURG Laboratoire National de Santé, Division du Controle des Denrées Alimentaires, Luxembourg

POLAND Laboratory of Department of Food and Consumer Articles Research, National Institute of

Hygene, Warsaw

SLOVAKIA National Reference Centre and Laboratory for material and articles intended to come into

contact with food, Regional Public Health Authority In Poprad (RUVZ)

SLOVENIA National Institute of Public Health of Republic of Slovenia, Department of Sanitary Chemistry,

Ljubijana

SPAIN Centro Nacional de Alimentación, Agencia Española de Seguridad Alimentaria y Nutrición

(AESAN), Madrid

THE NETHERLANDS Food and Consumer Product Safety Authority (VWA), Ministry of Economic Affairs, Agriculture

and Innovation, Groningen

OCLs

GERMANY Landesamt für Verbraucherschutz Sachsen-Anhalt, Halle

GERMANY Landesuntersuchungsanstalt für das Gesundheits- und Veterinärwesen Sachsen, Dresden

GERMANY Chemisches und Veterinäruntersuchungsamt, Fellbach

GERMANY Niedersächsisches Amt für Verbraucherschutz und Lebensmittelsicherheit (LAVES), Lüneburg

SPAIN Laboratorio de Salud Pública, Alicante


- 31 -

10. References

[1] Regulation EC10/2011 of the European Parliament and the Council of 14 January 2011 on plastic materials and articles intended to come into contact with food

[2] Beldì et al. 2012. Development of a harmonised method for specific migration into the new simulant for dry foods established in Regulation 10/2011; Establishment of precision criteria from an EU interlaboratory comparison organised by the EURL Food Contact Materials for the quantification from and migration into poly(2,6-diphenyl phenylene oxide). European Commission - Joint Research Centre - Institute for Health and Consumer Protection - EUR 25680. doi:10.2788/76804

[3] Félix et al. 2012. Analytical Bioanalytical Chemistry 403:2869-2882. doi: 10.1007/s00216-012-5965-z

[4] Canellas et al. 2012. Journal of Chromatography A 1235: 141-148. doi: 10.1016/j.chroma.2012.02.039

[5] Poças et al. 2011. Food Control 22: 303-312. doi:10.2788/76804

[6] Nerín et al. 2002. Journal of Agricultural and Food Chemistry 50: 7488-7492. doi: 10.1021/jf0257143

[7] ISO 13528:2005; Statistical Methods for Use in Proficiency Testing by Interlaboratory Comparisons

[8] Regulation (EC) No 882/2004 of the European Parliament and of the Council of 29 April 2004 on official controls performed to ensure the verification of compliance with feed and food law, animal health and animal welfare rules

[9] M. Thompson, Analyst, (2000), 125, 385-386

[10] T. Linsinger et al., Accreditation and Quality Assurance in Analytical Chemistry (2001), 6, 20-25

[11] The International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories by M. Thompson et al., Pure and Applied Chemistry (2006), 78, 145–196

[12] ProLab Software – QuoData, Drezden – www.quodata.de

[13] ISO GUIDE 35:2006; Reference materials–General and statistical principles for

certification.

[14] DIN 38402 A45 Ringversuche zur externen Qualitätskontrolle von Laboratorien.

[15] AMC, Representing data distributions with kernel density estimates. AMC Technical Brief, 2006, http://www.rsc.org/images/brief4_tcm18-25925.pdf

[16] P.J. Lowthian and M. Thompson, Bump-Hunting for the proficiency tester - searching for multimodality. The Analyst, 2002. 127: p. 1359, https://www.swetswise.com/eAccess/viewAbstract.do?articleID=14625081

http://www.quodata.de/


- 32 -

11. Annexes

Annex 1. Invitation letter to the laboratories to ILC001-2013

Annex 2. Letter for confirmation of participation to ILC001-2013

Annex 3. Shipping kit letter accompanying the sample TNX1 to ILC001-2013

Annex 4. Letter of confirmation of receipt of the sample to ILC001-2013

Annex 5. Letter Instructions for the compilation of the results from ILC001-2013

Annex 6. Procedure for the preparation of the spiked food simulant E

Annex 7. Form for the compilation of the results in non-electronic format

Annex 8. Results of the homogeneity study

Annex 9. Results of the stability study and the statistical evaluation

Annex 10. Methodologies used by the participants


- 33 -

Annex 1. Invitation letter to the laboratories to ILC001-2013

EUROPEAN COMMISSION GENERAL DIRECTORATE JRC JOINT RESEARCH CENTRE Institute for Health and Consumer Protection – IHCP Unit Chemical Assessment and Testing

Ispra July 9th

, 2013

Dear Madam, Sir Interlaboratory Comparison (ILC) exercise on food simulant E

On behalf of the EURL for food contact materials, I would like to invite you to participate in an Interlaboratory comparison (ILC) exercise for the determination of known and unknown substances in food simulant E which is due to start by the beginning of September. As agreed in the last EURL-NRL FCM plenary, the scope of this ILC exercise is a Proficiency testing, laboratories are free to use their own methods. This ILC aims at the extraction and identification/quantification of substances from food simulant E. There is no migration experiment in this exercise. You will receive a list of ten substances. Only five substances from that list have been spiked into the food simulant E. You need to identify and quantify them. Additionally you should be able to identify and quantify other two unknown substances, also spiked in the same simulant E but not included in the list described above. I would like to remind you that it is a duty for you as an NRL-FCM to participate in the ILCs organised by the EURL-FCM since the work programme is decided with your agreement. For this reason we require all of you to actively participate in this exercise. There is no charge for participation. We have pre-registered everyone, which means we will send test kits to all of you. We however need to receive the proformat of your participation for our own administrative purposes. Kindly send back the proformat by 19

th

July to: Juliana Silva Félix ([email protected]).

The samples will be sent to you in the beginning of September. You will find additional information on the form “Shipping kit ILC001 2013” that you will receive by e-mail. You will also receive more detailed instructions for the compilation of the results on the form "Instructions Excel ILC001 2013". The deadline for submission of results is 30

th October 2013.

If you have any question, please contact Juliana Silva Félix ([email protected]). Sincerely yours,

Catherine Simoneau

Dr. Catherine Simoneau Operating Manager, European Reference Laboratory for Food Contact Materials European Commission, DG-Joint Research Centre Institute for Health and Consumer Protection Unit Chemical Assessment and Testing, T.P. 260 Ispra Va 21020 Italy

Cc: P. Aguar (JRC), D. Rembges (JRC)

A. Schaefer, B. Schupp (SANCO)

mailto:[email protected]



- 34 -

Annex 2. Letter for confirmation of participation to ILC001-2013


Ispra July 9th 2013

Participation to EURL-FCM ILC001 2013 Interlaboratory comparison (ILC) exercise

on food simulant E

CONFIRMATION OF PARTICIPATION

Your Name:

Organization:

Address:

E-mail:

Phone:

item YES NO

I have already the package with the files for filling the results and especially RingDat3.exe file from last year and I need only lab files for this year’s ILC

I don’t have the package with the files for filling the results from last year

Kindly send back this proformat to: Juliana Silva Félix ([email protected]) by the 19th of July 2013. The samples will be sent to you in the beginning of September. You will find additional information in the kit sent. The deadline for submission of results is 30th October 2013. Sincerely yours,

Catherine Simoneau



- 35 -

Annex 3. Shipping kit letter accompanying the sample TNX1 to ILC001 2013


Ispra 9th July 2013

Shipping kit for Interlaboratory comparison (ILC) exercise on food simulant E - EURL-FCM ILC001 2013

Shipping kit - samples

- TNX1 – One glass bottle containing food simulant E spiked with the unknown substances1

- Blank TNX1 – For control purposes: one glass vial containing the food simulant E not spiked, from the same batch of the spiked one

- One plastic box containing virgin Tenax® TA 60/80 (10 g)* – (NRLs only) Shipping kit – documentation (send by email)

Letter of confirmation of receipt (Sample Receipt ILC001 2013) ; Letter with instructions for the compilation of the results for interlaboratory

comparative testing (Instructions Excel ILC001 2013); Electronic excel file” ILC001 2013 test result TNX.xls”.

Storage

- Sample TNX1 – should be kept in the fridge at + 4°C. Instructions Use the excel form “ILC001 2013 test result TNX.xls” to provide your results. 1 Phthalates eventually present in the food simulant E could come from contamination source and were not intentionally spiked.

* Remember that the Tenax® must be cleaned before the first use.


- 36 -

Annex 4. Letter of confirmation of receipt of the sample to ILC001 2013


Ispra July 9th 2013

Participation to Interlaboratory comparison (ILC) exercise on food simulant E - EURL-FCM ILC001 2013

CONFIRMATION OF RECEIPT OF THE SAMPLES

Please return this form to confirm that the sample package has arrived. In case the package

is damaged, please state this on the form and contact us immediately.

Your Name:

Organization:

E-mail:

Phone:

Any remarks …………………….

Date arrival package …………………….

Signature …………………….

Kindly send back this form to: Juliana Silva Félix ([email protected]) Sincerely yours,

Dr. Catherine Simoneau Operating Manager, ЕU Laboratory for Food Contact Materials European Commission, DG-Joint Research Centre Institute for Health and Consumer Protection Unit CAT, T.P. 260 Ispra Va 21020 Italy



- 37 -

Annex 5. Letter Instructions for the compilation of the results from ILC001 2013


Ispra July 9

th 2013

Instructions for the compilation of the results for Interlaboratory comparison

(ILC) exercise on food simulant E - EURL-FCM ILC001 2013

DEADLINE: Monday, October 30th

2013

You can find in the table below a list of ten substances. Only five substances from that list are spiked

in the food simulant E. You need to identify and quantify them. Additionally you should be able to

identify and quantify other two unknown substances, also spiked in the same simulant E but not

included in the list.

LIST OF 10 SUBSTANCES

1-Octene

DEHA

Diphenylbutadiene

Benzophenone

Laurolactam

Irganox 1076

2-Ethyl-1-hexanol

Benzyl butyl phthalate

Chimasorb 81

Caprolactam

UNKNOWN SUBSTANCES

XXX

XXX

Perform four replicates for the sample TNX1 and report the name of the substances and their

concentration using the unit of measure specified in the Excel form “ILC001 2013 test result TNX.xls”.

Please fill your results and send it back by e-mail to Juliana Silva Félix (juliana.silva-

[email protected]) by October 30th

2013. If you have any question, please contact Juliana Silva

Félix ([email protected]), ph. +39.0332.789782

Sincerely yours,

Dr. Catherine Simoneau Operating Manager, ЕU Laboratory for Food Contact Materials European Commission, DG-Joint Research Centre Institute for Health and Consumer Protection Unit CAT, T.P. 260 Ispra Va 21020 Italy





- 38 -

Annex 6. Procedure for the preparation of the spiked food simulant E 1. Washing of the 10 L round bottom flask:

10 L mixing round bottom flask was washed in a dish washer, then filled with the deionised water (resistivity 18 MΩ.cm @ 25 °C) and mixed;

The water was removed;

The mixing bottle was filled with 0.5 L of pentane (Aldrich, HPLC grade + 99%) and shaked;

Pentane was removed. 2. Preparation of the spiking solutions: a) Stock solution of ACPH, BP, DEHA, DTBP, ETHX and OCT in hexane (approx. 1000 mg/L)

50 mg of each compound was weighted separately into a 50 mL class A volumetric flask and dissolved in hexane;

the flask was filled up to the mark with hexane. b) Stock solution of CAP in ethanol (approx. 1000 mg/L)

50 mg of caprolactam was weighted into a 50 mL class A volumetric flask and dissolved in ethanol;

the flask was filled up to the mark with ethanol. c) Spiking solution of ACPH, BP, CAP, DEHA, DTBP, ETHX and OCT in pentane

10 mL of ACPH, 0.6 mL of BP, 15 mL of CAP, 9 mL of DEHA, 7.5 mL of DTBP, 10 mL of ETHX and 15 mL of OCT (from the stock solutions) were pipetting into the 2 L volumetric flask;

the flask was filled up to the mark with pentane; 3. Preparation of the spiking food simulant E:

1 kg of the cleaned simulant was weighted and transferred into the 10 L round bottom flask;

2 L of the spiking solution in pentane was add to the simulant;

The volumetric flask was rinsed by other 2 liters of pentane and all the solvent was collected into the round bottom flask;

The flask was closed and the simulant was mixed continuously for 2.5 hours;

The flask was opened and the simulant was mixed till the complete evaporation of the pentane (approximately 2 days).


- 39 -

Annex 7. Form for the compilation of the results in non-electronic format

I. Determination of the subtances from the list reported in the form "Instructions Excel ILC001 2013.doc"

No. Substance name Replicate 1 (mg/kg) Replicate 2 (mg/kg) Replicate 3 (mg/kg) Replicate 4 (mg/kg) remark

1

2

3

4

5

II. Determination of the unknown substances

1

2

Place and date

.................. ........................

Laboratory Manager Signature

FCM EURL-NRL ILC 2013_001 Food Simulant E

TEST RESULTS

Lab Code - LC00......

TNX 1


- 40 -

Annex 8. Results of the homogeneity study

Measurand Mean

(mg/kg) Mode

s(target) s(target)

[%]

F-test Check for significant

heterogeneity

ISO 13528 Check for sufficient

homogeneity

Harmonized Protocol Test on significant

heterogeneity

1-OCT 14.502 HORWITZ 10.697 OK OK OK

ETHX 9.470 HORWITZ 11.405 OK OK OK

ACPH 10.549 HORWITZ 11.221 OK OK OK

CAP 11.944 HORWITZ 11.014 OK OK OK

DTBP 6.364 HORWITZ 12.108 OK OK OK

BP 0.645 HORWITZ 17.090 OK OK OK

DEHA 9.348 HORWITZ 11.427 OK OK OK


- 41 -

Annex 9. Results of the stability study and the statistical evaluation

Compound Test

condition Intercept

(b0) Slope (b1)

s(b1) t(α=0.95,n-

2)·s(b1) |b1|< t(α=0.95,n-

2)·s(b1)

ACPH

40ºC 10.6176 -0.0016 0.0029 0.0092 OK

20ºC 10.5903 -0.0004 0.0034 0.0107 OK

4ºC 10.5829 -0.0001 0.0013 0.0043 OK

BP

40ºC 0.6227 -0.0003 0.0004 0.0013 OK

20ºC 0.6235 -0.0003 0.0004 0.0011 OK

4ºC 0.6236 -0.0002 0.0004 0.0012 OK

CAP

40ºC 11.7981 0.0148 0.0080 0.0254 OK

20ºC 12.1394 0.0075 0.0095 0.0301 OK

4ºC 12.2614 0.0054 0.0093 0.0297 OK

DEHA

40ºC 9.1618 -0.0033 0.0127 0.0404 OK

20ºC 9.2355 0.0110 0.0105 0.0334 OK

4ºC 9.2017 0.0127 0.0138 0.0439 OK

DTBP

40ºC 6.0009 -0.0147 0.0066 0.0209 OK

20ºC 6.3496 0.0031 0.0031 0.0100 OK

4ºC 6.2302 -0.0042 0.0036 0.0116 OK

ETHX

40ºC 9.4671 -0.0041 0.0042 0.0132 OK

20ºC 9.4132 -0.0004 0.0041 0.0130 OK

4ºC 9.4102 0.0007 0.0027 0.0085 OK

1-OCT

40ºC 13.4768 -0.0080 0.0459 0.1460 OK

20ºC 13.6078 -0.0107 0.0299 0.0951 OK

4ºC 13.9415 -0.0142 0.0434 0.1382 OK

A) 1-Octene

y = -0.0142x + 13.9415

y = -0.0107x + 13.6078

y = -0.0080x + 13.4768

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

0 10 20 30 40 50 60

1-OCTENE

4°C

20°C

40°C

mg

/kg

Time [days]


- 42 -

B) 2-Ethyl-1-hexanol

y = 0.0007x + 9.4102

y = -0.0004x + 9.4132

y = -0.0041x + 9.4671

6.00

7.00

8.00

9.00

10.00

11.00

12.00

0 10 20 30 40 50 60

2-ETHYL-1-HEXANOL

4°C

20°C

40°C

mg

/kg

Time [days]

C) Acetophenone

y = -0.0001x + 10.5829

y = -0.0004x + 10.5903

y = -0.0016x + 10.6176

9.00

9.50

10.00

10.50

11.00

11.50

12.00

0 10 20 30 40 50 60

ACETOPHENONE

4°C

20°C

40°C

mg

/kg

Time [days]

D) Caprolactam

y = 0.0054x + 12.2614

y = 0.0075x + 12.1394

y = 0.0148x + 11.7981

10.00

10.50

11.00

11.50

12.00

12.50

13.00

13.50

14.00

0 10 20 30 40 50 60

CAPROLACTAM

4°C

20

40°C

mg

/kg

Time [days]


- 43 -

E) 2,4-Di-tert-butylphenol

y = -0.0042x + 6.2302

y = 0.0031x + 6.3496

y = -0.0147x + 6.0009

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

0 10 20 30 40 50 60

2,4-DI-TERT-BUTYLPHENOL

4°C

20°C

40°C

mg

/kg

Time [days]

F) Benzophenone

y = -0.0002x + 0.6236

y = -0.0003x + 0.6235

y = -0.0003x + 0.6227

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0 10 20 30 40 50 60

BENZOPHENONE

4°C

20°C

40°C

mg

/kg

Time [days]

G) DEHA

y = 0.0127x + 9.2017

y = 0.0110x + 9.2355

y = -0.0033x + 9.1618

5.00

6.00

7.00

8.00

9.00

10.00

11.00

12.00

13.00

0 10 20 30 40 50 60

BIS(2-ETHYLHEXYL) ADIPATE

4°C

20°C

40°C

mg

/kg

Time [days]


- 44 -

Annex 10. Methodologies used by the participants

6h Soxhlet ACTN80%

ACTN4%

Reflux diethylether

4%

Soxhlet ≠ solvents

4%

MEOH (5X)4%

ASE ACTN4%

Cleaning Tenax

HX60%

ACTN10%

ACN12%

Headspace5%

MEOH5%

Diethylether2%

HX-DCM2%

ETOH2%

THF2%

Extraction

Spiking Tenax75%

Solvents18%

Solvents/ Tenax

7%

Calibration

Internal Standard

69%

External Standard

31%

Quantification

GC-MS80%

GC-FID8%

HPLC-DAD6%

LC-MS3%

NMR3%

Analytical Technique

HP-5MS58%

DB-17HT16%

SBP-6245%BP-20/ODS2

2%

DB-12%

C182%

RTX-5 amine3%

TG-17Sil MS3%

RTX-35MS3%

HT-8PCB3%

CPWAX3%

Chromatographic Column


- 45 -

European Commission

EUR 26468 EN – Joint Research Centre – Institute for Health and Consumer Protection

Title: Report of an Interlaboratory Comparison from the European Reference Laboratory for Food Contact Materials:

ILC001-2013 – Proficiency Testing on Food Simulant E containing a cocktail of potential migrant substances

Author(s): Juliana Silva Félix, Giorgia Beldì and Catherine Simoneau

Luxembourg: Publications Office of the European Union

2013 – 45 pp. – 21.0 x 29.7 cm

EUR – Scientific and Technical Research series –ISSN 1831-9424 (online)

ISBN 978-92-79-35268-3 (pdf)

doi:10.2788/6263

Abstract This report presents the results of the EU Interlaboratory comparison (ILC) of the EURL-FCM, which were obtained in the identification and the quantification of unknown substances in the food simulant E. Regulation (EU) No 10/2011 establishes poly(2,6-diphenyl-p-phenylene oxide) (e.g. Tenax®) as food simulant E for testing migration compliance of plastics in contact with dry foodstuffs. The choice of the substances was based on the recent scientific literature related to migration from food contact materials (plastic and paperboard) into simulant E. The simulant E was spiked with 7 substances at given concentrations the closest as possible to its own specific migration limit (SML), when available in Regulation (EU) 10/2011 or tailored for the exercise. A list containing 10 substances in which 5 were effectively present in the simulant was distributed to the participants. The other 2 unknown substances were not reported in the list. Homogeneity and stability studies were conducted. As this ILC was a proficiency testing, the National Reference Laboratories (NRLs) and the Official Control Laboratories (OCLs) had to identify and quantify the unknown substances using analytical methods of their choice. The laboratories performance was successful with more than 61% satisfactory results over the entire exercise which was quite complex and extensive. Considering the individual substances, more than 80% of satisfactory quantification within tolerance limits was achieved (ACPH 94%, BP 80%, CAP 86%, DEHA 82%, DTBP 88%, ETHX 83% and OCT 87%). The laboratories performance concerning the identification of the unknown substances was successful, with 25 correct results out of 30 (83%), even taking into account the complexity of the exercise. This exercise was the first Proficiency Testing carried out at EU level on Food Simulant E with the aim to evaluate the performance of the National Reference Laboratories among the Member States. The ILC001-2013 provided the first successful attempt to derive data at EU level for identification and quantification of potential migrants including unknowns coming from food contact material, as plastic packaging and paperboard, in food simulant E.


- 46 -46

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As the Commission’s in-house science service, the Joint Research Centre’s mission is to provide EU policies with independent, evidence-based scientific and technical support throughout the whole policy cycle. Working in close cooperation with policy Directorates-General, the JRC addresses key societal challenges while stimulating innovation through developing new standards, methods and tools, and sharing and transferring its know-how to the Member States and international community. Key policy areas include: environment and climate change; energy and transport; agriculture and food security; health and consumer protection; information society and digital agenda; safety and security including nuclear; all supported through a cross-cutting and multi-disciplinary approach.

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doi:10.2788/6263 ISBN 978-92-79-35268-3 (pdf)

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