Proficiency test on the determination of 3-MCPD esters in edible oil

The Institute for Reference Materials and Measurements (IRMM) of the European Commission's Joint Research Centre (JRC) was requested by the Directorate General Health and Consumers (DG SANCO) to organise a proficiency test on the determination of 3-MCPD esters in edible oils. The aim of this test was to evaluate the comparability of analysis results gained by European laboratories. The organisation of the study as well as the evaluation of the results was done in accordance with "The International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories" and ISO standard 43. Altogether 41 laboratories from 11 EU Member States, Switzerland and Macedonia subscribed for participation in the study. The participants were asked to determine the 3-MCPD esters content of the test samples by application of their in-house analysis methods. In total, 34 sets of results were reported to the organisers of the study. The performance of laboratories for the oil samples was expressed by z-scores and by relative bias for the 3-MCPD standard solution in sodium chloride. The percentage of successful laboratories in the determination of the 3-MCPD esters in contaminated palm oil sample was 56 % and in spiked sample of extra virgin oil 85 %. The study revealed that the application of a particular analysis procedure might lead to strong positive bias.