Determination of toxic trace elements in canned vegetables. The importance of sample preparation

Abstract This manuscript presents the outcome of a proficiency test, named IMEP-118, for the determination of total As, Cd, Pb, Hg, Sn and inorganic As mass fractions in canned vegetables (peas in brine). With this exercise a new approach was followed by the organizers, aimed at the production of a test item identical to those screened in official controls. A total of 127 participants from 36 countries registered to the exercise out of which 123 reported results back. Laboratory results were rated using z- and ζ-scores in accordance with ISO 13528:2005. Due to lack of specific sample preparation protocol for such commodities, the participants used two different approaches. From the analytical point of view the majority of laboratories (more than 74 %) performed satisfactorily. However, several participants (32) characterised the test item as compliant with the respective EU legislation, although it was not.