Quantification of potentially toxic elements in food material by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) via pressed pellets.

Here, we validated a protocol for the elemental analysis of plant and food materials using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and pressed pellets in compliance with the Green Chemistry principles, i.e. avoiding the use of hazardous reagents. The protocol included sample pre-treatment, preparation of pellets, and LA-ICP-MS optimisation for the food sample matrix using leaf certified reference materials. Sample homogenisation and particle size reduction (∼10 µm) for samples with larger initial particle sizes proved crucial in improving signal stability and analytical results, whereas the raster mode was preferred over spot mode for greater accuracy. The validation of the technique was successful for determination of Mn, Ni, Cu, Zn, As, Se, Cd and Pb (z-score values  ≤2). We propose LA-ICP-MS using pressed pellets as an alternative to ICP-MS in food analysis.