Synergistic effect of lacunary polyoxotungstates and carbon nanotubes for extraction of organophosphorus pesticides

In this work, for the first time, a nanocomposite composed of carbon nanotubes and lacunary polyoxotungstates (LPOT/CNT) was synthesized. The nanocomposites were used as a sorbent for the dispersive micro solid-phase extraction (D-mu SPE) of five organophosphorus pesticides (OPPs) (i.e. fenthion, diazinon, fenitrothion, profenofos, and phosalone) from water and fruit juice samples. The extracted OPPs were quantified via gas chromatographyflame ionization detector (GC-FID). The main factors affecting the D-mu SPE of the OPPs, such as the desorption conditions, amount of sorbent, and extraction time, were investigated, in detail. The LPOT/CNT nanocomposite shows a synergistic effect and its extraction efficiency is higher than intact CNTs and LPOTs. Under the optimized conditions, the D-mu SPE-GC-FID method showed linearity from 0.02 to 200 ng mL(-1), limits of detection in the range of 0.007-0.02 ng mL(-1). The precision expressed as relative standard deviations (RSD%) ranged from 3.3 to 4.7%. The D-mu SPE-GC-FID based on LPOT/CNT sorbent was used for the extraction of OPPs in fruit juices (apple juice and peach juice) and real water samples (wastewater and river water) and with relative recovery values of 94.2-99.6%.

Automated summary

In this study, a nanocomposite of LPOT/CNT was synthesized for the first time and used for the dispersive micro solid-phase extraction of organophosphorus pesticides. The LPOT/CNT nanocomposite showed higher extraction efficiency compared to intact CNTs and LPOTs. The method showed good linearity, low detection limits, and high precision, with relative recovery values ranging from 94.2% to 99.6% in fruit juice and water samples.