Report of the Seventh Interlaboratory Comparison organized by the European Union - Reference Laboratory for Heavy Metals in Feed and Food. IMEP-107: Total and Inorganic As in Rice.

Abstract

The Institute for Reference Materials and Measurands (IRMM) of the Joint Research Centre (JRC), a Directorate-General of the European Commission, operates the European Union-Reference Laboratory for Heavy Metals in Feed and Food (EU-RL-HM). Two of its core tasks are to provide advice to the Directorate General for Health and Consumers (DG Sanco) on scientific matters and to organise interlaboratory comparisons (ILC) among appointed National Reference Laboratories (NRLs). This report represents the results of the seventh ILC of the EU-RL-HM (former CRL-HM) which focused on the determination of total and inorganic As in rice. The test item used in this exercise is rice purchased in a local supermarket and was provided by the University of Aberdeen. The test item was processed, bottled and labelled at IRMM and dispatched to the participants the first half of December 2009. Each participant received one bottle containing approximately 20 g of test item. Participation in this exercise was not limited to the NRLs but was open to laboratories from all around the world, to be able to judge the state-of-the-art of the determination of total and, exercise, of which 98 reported results for total As and 30 for inorganic As. Twenty-nine of the participants were NRLs of the EU-RL-HM network, 8 out of which reported values for inorganic As. The assigned values for IMEP-107 were provided by a group of laboratories expert in the field: seven for total As and six for inorganic As. The uncertainties of the respective assigned values, uref, were derived from the standard deviation of the means provided by the experts, propagated with a contribution for homogeneity, ubb, and stability, ust. Laboratory results were rated with z-and ¿-scores (zeta-scores) in accordance with ISO 13528. The standard deviation for proficiency assessment (also called target standard deviation) was fixed to 15% by the advisory board of this ILC, on the basis of the outcome of previous ILCs organised by the EU-RL-HL and on the state-of-the-art in this field of analysis. Around 75% of the participants performed satisfactory for total and inorganic As.JRC.DDG.D.6-Food Safety and Qualit