Report of the Second Interlaboratory Comparison Organised by the Community Reference Laboratory for Heavy Metals in Feed and Food: Total Cd, Pb and Hg in Mineral Water

摘要

The Institute for Reference Materials and Measurements (IRMM) of the EuropeanCommission's Directorate-General Joint Research Centre holds the CommunityReference Laboratory for Heavy Metals in Feed and Food (CRL-HM). One of thecore tasks is to organise interlaboratory comparisons (ILCs) among appointedNational Reference Laboratories (NRLs). This report presents the results of thesecond ILC of the CRL-HM which focused on the determination of the total Cd, Pband Hg content in mineral water.The test material used in this exercise was a commercial mineral waterpurchased in Belgium at a local supermarket. The material was spiked with Cd,Pb and Hg, rebottled and dispatched by the Reference Material Unit of the IRMM.The samples were dispatched on the first half of May 2007. Each participantreceived two sets of samples containing one bottle per set. Each bottle containedapproximately 100 mL of test material. Twenty participants from 17 countriesregistered to the exercise of which 20 submitted results for Cd and Pb and 19 forHg.The assigned values were those obtained from the gravimetric measurementsused to spike the material. The homogeneity and stability studies weresubcontracted to the University of Natural Resources and Applied Life Sciences(BOKU) in Vienna.The uncertainty of the assigned values was calculated combining the uncertaintyof the spiking procedure with a contribution for the between-bottle homogeneityand for long-term stability of the test material. Participants were invited to reportthe uncertainty on their measurements. This was done by all them.Laboratory results were rated with z and zeta scores in accordance with ISO135281. Standard deviation for proficiency assessment (also called targetstandard deviation) for Cd, Pb and Hg was 10% of the assigned value.