Monitoring of polar pesticides and contaminants in edible oils and nuts by liquid chromatography-tandem mass spectrometry

A single method was developed for the determination of polar pesticides (fosetyl-Al and its metabolite, phosphonic acid, and ethephon) and environmental contaminants (chlorate and perchlorate) in edible oils and nuts. Two extraction methods based on QuPPe-PO approach (Quick Polar Pesticides Method for products of Plant Origin) were optimized. In oils, a single extraction using water acidified with formic acid (1%) was performed, while in nuts, the clean-up step was modified. C18 was used as sorbent and an extra cleaning step with n-hexane was added. The extracts were analysed by liquid chromatography coupled to a triple quadrupole mass analyser (LC-QqQ-MS/MS). The method was validated and the limit of quantification was 0.01 mg kg(-1) for all analytematrix combination. Recoveries from 70 to 120%, and intra and inter-day precision values <= 20% were obtained. Forty samples of edible oils and nuts were analysed, detecting phosphonic acid in nuts at concentrations up to 4.6 mg kg(-1).

Automated summary

A single method was developed for determining polar pesticides and environmental contaminants in edible oils and nuts. The method included optimized extraction processes, clean-up steps, and analysis using LC-QqQ-MS/MS. The study successfully detected phosphonic acid in nuts at concentrations up to 4.6 mg kg(-1).