Microwave-assisted sample preparation for screening of heavy metal elements in food additives by ICP-MS

The screening of heavy metals in food additives is important for public health due to their probable critical effects, induced by excessive intakes, and difficulties in tracing in food matrix. This study aimed to assess the applicability of microwave (MW)-based digestion and inductively coupled plasma-mass spectrometry (ICP-MS) for quantification of heavy metals in food additives. MW-assisted diluted acid digestion (1550 W at 220 °C, 0.79 mol/L of HNO₃ solution) was applied as a pretreatment and ICP-MS was used for 19 different heavy metals at different concentrations, up to 20 ng/g. The optimized protocol was validated by spiking heavy metals to glycerin and applied to 18 food additives. The method was linear for 14 heavy metals (R² > 0.990). For 11 heavy metals, both intra- and inter-day accuracies in glycerin were estimated to 88.5%–123.7%, with intra- and inter-day precisions of less than 5.5% and 4.9%, respectively, and their contents in food additives were discussed. The findings in this work provide an alternative analytical method for regulatory compliance and quality control in food industries.