Dispersive solid-phase extraction using polyaniline-modified zeolite NaY as a new sorbent for multiresidue analysis of pesticides in food and environmental samples.

The applicability of polyaniline (PANI)-modified zeolite NaY as a sorbent for multi-class pesticides extraction was investigated. The sorbent had a sorption capacity of 833mgkg-1 sorbent and preconcentration factor of 42 in the mixture of twenty pesticides. The PANI-coated zeolite NaY was successfully created via oxidative polymerization of aniline onto the surface of the zeolite. The sorbent was applied for dispersive solid phase extraction (DSPE) of commonly used pesticides belonging to five different chemical groups, involving carbamate, organophosphate, sulfonylurea, pyrethroid and neonicotinoid. The coupling of DSPE and HPLC-PDA resulted in an efficient method for multiresidue analysis of pesticides. The proposed method gave LODs and LOQs in the ranges of 0.001-1.00mgL-1 and 0.005-2.50mgL-1 , respectively. The method was applied for determination of pesticide residues in environmental and food samples including drinking water, pond waters, soils, honey, cabbages, cucumbers, tomatoes and strawberries which were collected in Khon Kaen Province, Thailand. Recoveries of the target pesticides were in the range of 64-128% with RSDs less than 12% using matrix matched calibration for all sample matrices. Eight pesticides were found in fruit and vegetable samples at concentrations of 0.003-0.033mgkg-1 whereas a few compounds in contaminated pond waters have concentrations of 0.046-0.092mgL-1 . The occurrence of high concentration of up to 1.26mgkg-1 in the soil samples is noteworthy.