| A dispersive solid-phase microextraction method based on magnetic carbon nano-onions (MCNOs) was
developed for the extraction and preconcentration of some pesticides from water and vegetable
samples. For more cleanup and preconcentration, a dispersive liquid–liquid microextraction (DLLME)
method was employed after performing the first step. In this method, firstly, MCNOs were prepared and
then used for adsorption of the analytes from the sample solution. After that, the adsorbed analytes were
eluted with an appropriate water-miscible organic solvent and used as a dispersive solvent in the
following DLLME procedure. The extracted analytes were quantified by gas chromatography-mass
spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Various factors affecting the method
efficiency such as sorbent weight, salt effect, pH, temperature, and type and volume of eluent and
extraction solvent were optimized. This method showed wide linear ranges with a coefficient of
determination $ 0.994, and low limits of detection (0.001–0.005 ng mL1) and quantification (0.003–
0.019 ng mL1) under optimal conditions. Also, a good precision (relative standard deviation # 8.6%) for
five replicates and a satisfactory accuracy (mean relative recoveries between 82 and 99%) were obtained.
It can be considered as an efficient and environment friendly method for the extraction of analytes from
vegetable and fruit juices and water samples. |