Graphene-based Magnetic Solid Phase Extraction Dispersive Liquid-Liquid Microextraction Combined with Gas Chromatographic Method for Determination of Five Acetanilide Herbicides in Water and Green Tea Samples
Abstract A novel analytical method was developed for the extraction and determination of five chloroacetanilide herbicides (alachlor, acetochlor, metolachlor, butachlor and pretilachlor) in water and green tea samples by graphene-based magnetic solid phase extraction and dispersive liquid-liquid microextraction followed by gas chromatography-flame ionization detection (GC-FID). Some important experimental parameters that could influence the extraction efficiency were investigated. Under the optimum conditions, as high as 3399 to 4002 fold enrichment factors for the herbicides were achieved. A good linearity was obtained in the range of 0.1–50.0 μg L−1 for all the five herbicides with the correlation coefficients (r) varying from 0.9973 to 0.9993. The limits of detection ranged from 0.01 to 0.03μg L−1. The method was applied to the analysis of the chloroacetanilide herbicides in environmental water and green tea samples with a satisfactory result. The recoveries of the method for the analytes were in the range from 80.2% to 105.3%, and the relative standard deviations were between 3.8% and 5.8%.