Simultaneous determination of pesticide residues and antioxidants in blended oil using a liquid-liquid extraction combined with dispersive solid phase extraction method

•A method of determination of antioxidants and pesticide residues in blend oil was developed by LEE-dSPE.•A PB design was employed to screen the significant factors in process.•A CCD design was adopted to optimize the amount of PSA and GCB.•Method validation was carried through.

This article developed a method to detect two antioxidants (butylated hydroxyl anisole (BHA), butylated hydroxyl toluene (BHT)) and twelve pesticides (dichlorvos, pirimicarb, prothiofos, fenitrothion, ethoprophos, malathion, beta-Cypermethrin, profenofos, diazinon, propoxur, procymidon, captan) in blended oil samples after their extraction simultaneously. The establishment of the method was based on two-step process of screening and optimization experiment design. With a Plackett-Burman (PB) design, significant parameters were found by screening experiment and single factor experiment accompanied by a central composite design (CCD) experiment were used to make important parameters optimal. The coefficients of determination (r2) was between 0.9931 and 0.9996 while the limits of quantification (LOQs) and limits of detection (LODs) were found in scope of 0.002-0.04 mg·kg−1 and 0.0006-0.0012 mg·kg−1. Recovery values of analytes were above 74%, at the same time the relative standard deviations (RSDs) under 10% at the concentrations ranging from 0.05 mg·kg−1 to 0.20 mg·kg−1. To sum up, this method with shorter time and fewer consumption of reagents could be employed in various occasions to detect antioxidants and pesticides.