Sampling and quantification method for the analysis of disinfectant biocide residues on industrial food contact surfaces by liquid chromatography-mass spectrometry.

Abstract

BACKGROUND: Cleaning and disinfection protocols are routinely applied in the agri-food industry to control the microbiological burden of food-contact surfaces and ensure consumer safety. Quaternary ammonium compounds (QACs) and N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine (AMPD) are widely used for this purpose. However, existing methods for the detection of biocide residues on food-contact surfaces rely on colorimetric or spectrophotometric approaches that lack the sensitivity and specificity required for regulatory monitoring. To date, no LC-MS/MS-based surface sampling method covering both QACs and AMPD on stainless steel has been reported. RESULTS: A systematic comparison of sampling vectors, impregnation solvents, and extraction conditions identified the cloth impregnated with an ethanol/water mixture as the optimal approach. Recovery yields ranged from 63 to 90% for QACs, while AMPD showed lower and more condition-dependent recoveries. LC-MS/MS quantification was validated according to NF V03-110 guidelines, with LODs of 1.5 μg L-1 and LOQs of 5 μg L-1 for all analytes. Trueness and precision met the 20% criterion except for the intermediate precision of ADEBAC-C14 at the lowest validation level (26.5%). Recovery of QACs remained comparatively stable across food-soiling conditions, whereas AMPD recovery varied markedly according to the food debris present, highlighting substance-specific sampling constraints. SIGNIFICANCE: This work provides the first LC-MS/MS-based approach covering both QACs and AMPD on food-contact surfaces, combining an experimentally characterized surface-sampling procedure with validated LC-MS/MS quantification. Applied under real-world conditions, the approach identified critical areas prone to residue accumulation and provides a practical and specific analytical tool to support surface hygiene control in the agri-food sector.

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