Determination of Pesticides in Wheat Flour Using Microextraction on Packed Sorbent Coupled to Ultra-High Performance Liquid Chromatography and Tandem Mass Spectrometry

An ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method for multiclass analysis of pesticide and fungicide residues in wheat flour based is presented. An efficient and rapid cleanup based on microextraction by packed sorbent (MEPS) has been developed in order to have a good enrichment factor together with a low matrix effect. The target analytes were 25 pesticides widely used in wheat, with different physico-chemical characteristics and different mechanism of action: acetylcholinesterase inhibitors such as organophosphorus, carbamates, neonicotinoids, and inhibitors of ergosterol such as imidazoles and triazoles. MEPS was shown to be successful with reduction of the amount of solvent required and possibility of automation of the cleanup procedure. The whole method was then validated according to the SANCO/12571/2013 guidelines, proving its suitability as confirmation method for the selected analytes.