A graphene-coated magnetic nanocomposite for the enrichment of fourteen pesticides in tomato and rape samples prior to their determination by gas chromatography-mass spectrometry

摘要

A graphene-based magnetic nanocomposite (Fe3O4@SiO2–G) was synthesized and used as the adsorbent for the extraction of fourteen pesticides in tomato and rape samples prior to their gas chromatography-mass spectrometry (GC-MS) detection. Various experimental parameters affecting the extraction efficiencies, such as the amount of Fe3O4@SiO2–G, extraction time, the pH and salt concentration of the sample solution and desorption conditions were investigated. Under optimized experimental conditions, good linearity existed in the range of 1.0–100.0 ng g?1 for all the analytes with the correlation coefficients (r) ranging from 0.9972 to 0.9996. The limits of detection (S/N = 3) of the method for the compounds were between 0.005 and 0.030 ng g?1 for the vegetable samples. Good reproducibilities were obtained with the relative standard deviations (RSDs) below 12.5% (n = 5). The recoveries of the method were in the range between 83.2% and 110.3%...