Determination of organophosphorus pesticides in pakchoi samples by headspace solid-phase microextraction coupled with gas chromatography using home-made fiber

A home-made sol-gel-derived co-poly (hydroxy-terminated silicone divinylbenzene) (OH-TSO/DVB) coating fiber has firstly been applied for headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography (GC)-nitrogen-phosphorus detector (NPD) to determine five organophosphorus pesticides (OPPs) in pakchoi samples. The following parameters influencing on the extraction efficiency of HS-SPME were optimized statistically: extraction temperature, extraction time, ionic strength, constant agitation, effect of sample matrix, desorption temperature, and desorption time. Compared with commercial available fibers and OH-TSO SPME fiber, this fiber showed statistically better enrichment capability for these pesticides. For the developed HS-SPME-GC method, it was found that the linearity was all two orders of magnitude, with the limits of detection (LOD) ranging from 0.007 to 0.07 ng g(-1), and relative standard deviations (RSD) varying between 4.1 and 8.7% (n = 5). Recoveries of spiked pakchoi samples ranged from 80.74 to 101.47% for every pesticide at each investigated concentration. Overall, it indicated that the obtained method is a validated and accurate procedure for determination of OPPs in pakchoi samples.