Determination of multi-residue pesticides in dairy products using single-step emulsification/demulsification clean-up strategy combined with low-pressure gas chromatography-tandem mass spectrometry.

ABSTRACT

In this study, a simple, sensitive, and rapid method was developed for the simultaneous determination of 99 kinds of pesticides in fatty milk samples. This novel emulsification-demulsification clean-up approach, coupled with an automatic demulsification-dehydration cartridge, allowed rapid single-step clean-up operation and high throughput. It also achieved effective and selective removal of lipids. The analysis was performed using low-pressure gas chromatography-tandem mass spectrometry (LPGC-MS/MS). Based on the optimal conditions, the targeted pesticides showed good linearity in the range of 5-250 µg/kg, with recoveries of 70-120% at spiking levels of 5, 10, and 20 µg/kg in cow milk, goat milk, and almond milk, respectively. The limit of quantification for most pesticides was 5 µg/kg, and the RSDs were lower than 20%. Analysis of real dairy products obtained from local markets revealed a potential risk in plant-derived almond milk, but no significant risks were found for cow and goat milk.