IMEP-113, determination of total cadmium and lead in baby food : interlaboratory comparison report, December 2011

This report presents the results of the thirteen proficiency test (PT) which focussed on the determination of total Cd and Pb in baby food according to Commission Regulation (EC) No 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs. The test material used in this exercise was baby food formula purchased in a local pharmacy and prepared by the Reference Material Unit of the IRMM for this exercise. Each participant received one bottle containing approximately 15 g of test material. Thirty five laboratories from 26 countries registered to the exercise and all of them reported results. Participants were asked to analyse the measurands in the powder and in the reconstituted form (powder diluted with water, 1:8 fold, to mimic the product as consumed). The assigned value for total Cd was determined by LGC Ltd (UK) and IRMM using direct isotope dilution inductively coupled plasma mass spectrometry. The assigned value for total Pb was determined at IRMM using the same technique as for Cd. The standard deviation for proficiency assessment σ was set at 22 % of the assigned value based on the modified Horwitz equation. Laboratories were rated with z- and ζ-scores (zeta-scores) in accordance with ISO 13528. The outcome of this exercise is clearly influenced by the very low level of Cd and Pb content in the test material which triggered: - a high number of "less than" values; - overestimated values especially for lead very likely due to contamination. Reported results were satisfactory for total cadmium in both forms, (powder and in the reconstituted formula).