A new and facile method for preparation of amorphous carbon nanoparticles and their application as an efficient and cheap sorbent for the extraction of some pesticides from fruit juices

In present work, amorphous carbon nanoparticles have been prepared by a facile method and used as an efficient and cheap sorbent in dispersive solid phase extraction coupled with dispersive liquid-liquid microextraction. The proposed method is used as a sample preparation technique for the extraction and preconcentration of some pesticides from different fruit juice samples prior to their determination by gas chromatography-flame ionization detection. In this method, the sample solution containing the analytes is vortexed after adding a few mg of the sorbent. After centrifugation, the solution is discarded and the analytes-loaded sorbent is eluted with iso-propanol. Then to more concentrate the analytes, the obtained eluent is mixed with 1,2-dibromoethane at mu L-level (as a preconcentration solvent) and rapidly injected into deionized water. After centrifugation, the droplets of 1,2-dibromoethane containing the analytes are sedimented at the bottom of test tube. This phase is taken and injected into the separation system for quantitative analysis. The properties of the sorbent were characterized using techniques such as X-ray diffraction, Fourier transform infrared spectrophotometry, and scanning electron microscopy. Under optimum conditions, limits of detection and quantification were achieved in the ranges of 0.83-1.16 and 2.8-4.0 ng mL(-1), respectively. Relative standard deviations were less than 8% for intra- (n = 6) and inter-day (n = 4) precisions at a concentration of 10 ng mL(-1) of each analyte. Extraction recoveries and enrichment factors of the analytes ranged from 61 to 83% and 610-832, respectively.