- 28 jaanuar 2013
4 EU marker PAHs in chocolate and cocoa butter
Proficiency Test on the determination of 4 EU marker PAHs in chocolate and cocoa butter
The European Union Reference Laboratory for Pylycyclic Aromatic Hydrocarbons organises a proficiency test on the determination of 4 EU marker PAHs in cocoa products.
The objective of this study is to evaluate the capabilities of EU food control laboratories in the determination of 4 EU marker PAHs in chocolate and cocoa butter.
Only national reference laboratories (NRLs) for PAHs and EU official food control laboratories (OCLs) can participate in the study.
Participation is admitted to maximum 40 official food control laboratories, which will be accepted in the order of registration.
Participation is free of charge for NRLs for PAHs. The participation fee for other official food control laboratories, which do not have national reference laboratory status, isEUR 250 (two hundred fifty) per registration! Participation fees are due with the delivery of the test samples.
Test material and analytes
The test materials are commercial chocolate and cocoa butter samples containing the target analytes (see Table 1). One amber glass screw cap vial containing about 30 g of chocolate powder and one amber glass vial containing about 30 g of cocoa butter will be sent to the participants begin of July. In addition participants will get an ampoule with a solution of target PAHs with disclosed analyte content, in which - depending on their preference - either acetonitrile or toluene, will allow the participants verifying instrument calibration against an independent standard. Results do not have to be reporter for the standard solution.
The measurands are the 4 EU marker PAHs as listed in Table 1.
Results have to be reported for the contents of the individual analytes as well as for the sum of the four PAHs. Additional the analyte contents of the chocolate sample have to be expressed both on product and on fat basis. All results have to be reported corrected for recovery, and have to accompanied by the respective measurement uncertainty.
Table 1: measurands
|benz[a]anthracene (BAA)||benzo[a]pyrene (BAP)|
|benzo[b]fluoranthene (BFF)||chrysene (CHR)|
Participants are requested to perform three independent analysis of each sample using a method of their choice. The analyses shall be performed on the same day.
The performance of the participants in the determination of PAHs in the two test samples will be rated by z-scores and zeta-scores.
The standard deviations for proficiency assessment will be derived: - for all four analytes from the fitness-for-purpose function given in Commission Regulation (EU) no 836/2011 assuming a value of 0.3 µ/kg for the limit of detection
- for the sum parameter by propagating the individual standard deviations for proficiency assessment of the four analytes applying the law of error propagation.
|Reporting of results:||deadline 14/09/2012|
|Reporting to participants:||December 2012|
|Sample dispatch:||Begin of July 2012|