3D graphene–carbon nanotubes-based solid-phase extraction technique combined with GC–MS for the determination of organophosphorus pesticides in water samples

Abstract

Three-dimensional graphene–carbon nanotubes were prepared by the chemical reduction of a mixed aqueous solution of carboxylated multiwalled carbon nanotubes (C-MWCNTs) and graphene oxide, followed by freeze-drying. C-MWCNTs were then introduced into a three-dimensional graphene aerogel. The obtained three-dimensional graphene–carbon nanotubes were used as a solid-phase adsorbent for the determination of four organophosphorus pesticides (OPPs) in water using GC–MS. Under the optimal extraction conditions, good linearity was achieved between 0.5 and 500 μg L−1 with a correlation coefficient of 0.9993–0.9998. The limits of detection (S/N = 3) and limits of quantification (S/N = 10) for the OPPs ranged from 0.28 to 0.52 and 0.96 to 1.64 μg L−1, respectively. The accuracy of the proposed method was evaluated by measuring the recovery of spiked samples, which ranged from 94.8 to 103.5%, with relative standard deviations lower than 7.0% (n = 3). This method was applied to the determination of target analytes in wetland water, lake water, and river water, and the results showed that the three-dimensional graphene–carbon nanotubes have great potential for the determination of OPPs in real water samples.