Ultrasonic-Assisted Magnetic Solid-Phase Dispersive Extraction for Determination of Chlorpyrifos and Triclosan in Wastewater Samples prior to Liquid Chromatography Tandem Mass Spectrometry Detection

In the present study, carbon nanodots (CNDs) were successfully anchored on magnetite (Fe3O4) under magnetic stirring and the nanocomposite prepared was assessed as a new adsorbent for ultrasonic-assisted magnetic solid-phase dispersive extraction of chlorpyrifos (CPF) and triclosan (TCS) in water samples. Detection was achieved using ultrahigh performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The prepared magnetic CNDs were characterised by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared and X-ray diffraction. The investigation and optimisation of the main experimental variables having an influence on the analytical response were performed using a multivariate approach. The factors studied were sample pH, mass of adsorbent and extraction time. The selection of desorption solvent and desorption time were examined and optimised univariately. By appropriating the optimum experimental conditions, the developed method was validated for accuracy using real environmental water samples. The average percentage recoveries obtained using influent and effluent spiked wastewater samples ranged between 76-108% and 79-96% for CPF and TCS, respectively. A good linearity (R-2 > 0.995) was established ranging between 5 and 100 mu g L-1. The limit of detection and limit of quantification were in the range of 0.024-0.081 mu g L-1 and 0.057-0.192 mu g L-1, respectively. The repeatability and reproducibility expressed as % relative standard deviation were less than 4.7%. The developed method exhibited good method performance, is rapid, simple, inexpensive and environmentally friendly.