This document provides guidance to the food industry, service providers and control laboratories on methodologies to be used for sample preparation, detection, identification and measurement of nano objects in inorganic food additives incorporated in food matrices.
Electron microscopy combined with energy dispersive X-ray spectroscopy (EM-EDX) and inductively coupled plasma mass spectrometry (ICP-MS) operated in single particle mode (spICP-MS) are the selected measurement methodologies to provide information on (i) the chemical composition and (ii) number-based particle size distribution of the nano-objects.
Special attention is given to the sample preparation, including matrix digestion, sample extraction and dilution steps to be used according to the combination of (i) the chemical nature of the food additive, (ii) the type of food matrix and (iii) the analytical technique of choice (EM-EDX or spICP-MS).