Inter-laboratory studies were performed to evaluate the performance of the analytical methods of cadmium (Cd), lead (Pb) and zinc (Zn) in food contact materials. Participants from over 17 laboratories determined the metal levels twice for each sample. All data were statistically analyzed, and performance parameters such as trueness, repeatability (RSDr), and reproducibility (RSDR) were evaluated. In these studies, we set the target value range for trueness to be 80%–110% and the upper limit for RSDr and RSDR to be 10%, and 25%, respectively. First, we evaluated the fluctuations in measurements of metal levels in food simulants using atomic absorption spectroscopy (AAS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and ICP-mass spectrometry (ICP-MS). All calculated values of trueness, RSDr, and RSDR were within the target value ranges (see Table), suggesting that there were no significant differences between the laboratories or the techniques used to determine analyte levels. Then, to evaluate the analytical methods for the determination of the residual levels of Cd and Pb, we compared the performance parameters obtained by two pretreatment methods—wet ashing and microwave digestion—using polyvinyl chloride pellets as samples. Although all estimated parameters fell within the target value ranges, those estimated following microwave digestion had higher accuracy. Finally, we evaluated the analytical methods for the determination of migration levels of Zn using two types of rubber gloves as samples. The estimated RSDr and RSDR values were in the range of 3.2%–8.2% and 7.9%–20.0%, respectively. These results also suggested that the variability in the determination of migration levels was mainly due to the steps performed to prepare the migration testing solutions.

Performance evaluation for the analytical methods of metals in food contact materials

254th National Meeting (2017)

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