Sol-gel fabrication and performance evaluation of graphene-based hydrophobic solid-phase microextraction fibers for multi-residue analysis of pesticides in water samples.

Widespread use of organophosphorus pesticides poses serious environmental threats, and hence calls for effective analysis methods for these classes of compounds. In this study, a lab-made graphene-based solid-phase microextraction (SPME) fiber was fabricated by the sol-gel method and combined with a gas chromatography-flame photometry detector (GC-FPD) to realize the detection of trace OPPs in water samples. Compared to the commercial fiber coatings, the new sol-gel graphene fiber coatings showed advantages of good durability and solvent resistance, which were attributed to the hydrophobic and antibacterial properties of the functionalized graphene and 3-(trimethoxysilyl)propyldimethyloctadecylammonium chloride (QAS). A headspace SPME method in combination with a GC-FPD was established to evaluate the performance of the novel fibers. The proposed method showed a good linear relationship for the eight OPPs (R≥ 0.9957) in the concentration range of 1 to 1000 μg L, with limits of quantification of 0.11-3.37 μg L and limits of detection of 0.03-1.01 μg L. Furthermore, the developed method also exhibited good recoveries for the analysis of OPPs both in rainwater and lake water, which demonstrates that this method is an alternative choice for multi-residue analysis of OPPs, and it has the potential for broader applications in the future.