Analysis of chloride, nitrite and nitrate in processed meat using microwave extraction and two-dimensional ion chromatography

A novel two dimensional ion chromatography (2D-IC) method employing suppressed conductivity (chloride) and UV (nitrite and nitrate) detection was developed, validated, and applied for the simultaneous detection and analysis of these compounds at trace levels in processed meats. Samples were extracted by microwave-assisted aqueous digestion, combined with automated inline solid phase extraction (SPE) to enhance sample preparation sensitivity and effectiveness while reducing costs. Mean recoveries for all analytes exceeded 91 %, with a mean coefficient of variation below 1.5 %. Analysis of processed meats from four major Irish retailers revealed chloride levels range from 5.2 to 35.6 g/kg, with nitrite and nitrate levels up to 39 mg/kg and 252 mg/kg, respectively, in samples above the LOQ. However, 19 % of processed meats showed salt accuracy discrepancies above 120 %, indicating a mismatch between reported salt content and chloride-based estimates. Overall, this validated method shows potential as a monitoring tool for nitrite and nitrate compliance and as a verification tool for labelled salt content in meat products. This method can also support the formulation of new processed meat products with reduced nitrite, nitrate, and salt content. • A novel two-dimensional ion chromatography method for analysing chloride, nitrite, and nitrate in meat. • The method automates sample preparation and reduces analytical interferences from manual laboratory operations. • The proposed method proved suitable for detecting salt, nitrite and nitrate at low and high mg/kg levels in meat. • The proposed method was applied to different commercial processed meats in Ireland..