Facile preparation of nitrogen-doped amorphous carbon nanocomposite as an efficient sorbent in dispersive solid phase extraction

摘要

In this study, a hyphenated sample pretreatment method based on coupling dispersive solid phase extraction and dispersive liquid-liquid microextraction has been employed for the extraction of some pesticides (chlorpyrifos, clodinafop-propargyl, diniconazole, fenpropathrin, oxadiazon, penconazole and tebuconazole) from fruit juice samples before their quantification by gas chromatography-flame ionisation detection. For this purpose, first a nitrogen-doped amorphous carbon nanocomposite is prepared from L-cysteine and sorbitol using an economically affordable and fast procedure and then it is used as an efficient sorbent for the analytes extraction from the samples in dispersive solid phase extraction step. After that acetonitrile is used to desorb the adsorbed analytes from the sorbent. In the next step, to more concentrate the analytes, the acetonitrile phase is taken and mixed with 1,2-dibromoethane at mu L-level. The mixture is applied in the following dispersive liquid-liquid microextraction. Validation data indicated that the developed method provided high enrichment factors (719-867) and extraction recoveries (72-87), low limits of detection (0.49-0.98 mu g L-1) and quantification (1.6-3.3 mu g L-1), and an acceptable repeatability (relative standard deviations <= 5.4 and 6.4 for intra - and inter-day precisions, respectively).