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

•LA-ICP-MS via pressed pellets was validated for plant-based foods.•The presented protocol complies with “Green Chemistry” principles.•Milling treatment for particle size reduction and homogenisation was tested.•Sample pretreatment improved considerably signal stability and analysis results.•Optimal analytical parameters were determined for Mn, Ni, Cu, Zn, As, Se and Pb. 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.