Quick, easy, cheap, effective, rugged and safe method with magnetic graphitized carbon black and primary secondary amine as adsorbent and its application in pesticide residue analysis.

By using magnetic graphitized carbon black and primary secondary amine (GCB/PSA/MNPs) as adsorbent, a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method was proposed for pesticide residue analysis in vegetables. The magnetic adsorbent was fabricated via simple co-mixing method based on an "aggregate warp" mechanism. To achieve the optimum conditions of modified QuEChERS toward target analytes, several parameters, including the composition of analyte protectants and the amount of the adsorbents were investigated. Under the optimized conditions, a simple, rapid and effective method for the determination of 10 pesticide residues in vegetables was established by coupling modified QuEChERS to gas chromatography/mass spectrometry analysis. The detection limits of the proposed method for 10 pesticides ranged from 0.39 to 8.6ng/g. Good linearity (R value≥0.990) was achieved at concentration levels of 10-200ng/g, and acceptable method reproducibility was found as intra- and inter-day precisions, yielding the relative standard deviations less than 10.7% and 13.4%, respectively. The recoveries were in the range of 69.9-125.0% at different concentrations for real samples. Compared with the reported methods for the determination of a large number of samples, the proposed method has the advantage of less time-consuming in clean-up procedure.