Automation of a modular method (EN 1528) for analysis of GC-amenable pesticides in food of animal origin

Current manual multi-methods for analysis of pesticides are limited due to their complexity and scope of pesticides, high demand for time and solvent or unsuitability for broad types of food of animal origin. The following research presents a novel automated sample preparation and purification method for various food matrices of animal origin, including milk, raw milk, dairy products, cheese, eggs, fish, fish products, and offal. The Ultra-Turrax® Tube Drive System enables quick fat extraction using a solvent mixture of cyclohexane/ethyl acetate/acetonitrile. From the resulting fat extract one aliquot is taken for clean-up and another aliquot for fat content determination, applicable to products with fat contents ranging from 1% to 30%. The automated clean-up, using gel permeation chromatography and solid-phase extraction (primary secondary amine and C18 cartridge), was successfully validated for more than 40 gas chromatography-amenable pesticides relevant to food of animal origin at a level of 10 µg/kg across each matrix. Additionally, 70% of analytes in milk (28 out of 40), 80% in cheese (34 out of 40), 82% in dairy products (38 out of 40), 82% in eggs (46 out of 56), and 85% in fish and offal (48 out of 56) were validated even at a lower level of 0.5 µg/kg. The spectrum of pesticides was expanded by employing a more comprehensive mix containing 196 gas chromatography-amenable analytes, spiked at a level of 10 µg/kg. Compared to the modified EN 1528 method, the quantification of analytes increased by 40%, representing an increase from 90 to 150 analytes out of 196 in each matrix. In conclusion, this automated analytical method can be directly implemented as a routine monitoring system for residual pesticide analysis in various matrices of animal origin, providing a robust tool for ensuring food safety.