LAUSR

Abstract In present work, a ball milling procedure has been used for chemical synthesis–free and facile preparation of magnetized polycaprolactone composite in which the natural iron oxide obtained from sand, which is easy–accessible and low cost, was used as the magnetic core. The prepared composite was employed for the extraction of some pesticides (diazinon, metalaxyl, oxadiazon, bromopropylate, and fenazaquin) from fruit juice and herbal distillate samples in the developed method named stirring–dependent magnetic dispersive solid phase extraction. In the following, a dispersive liquid–liquid microextraction method was done to enrich the extracted pesticides and obtain high sensitivity. To do the extraction procedure, a few mg of the composite is added into an aqueous phase containing the analytes and stirred at high rate. By this action the particles of composite are dispersed in whole parts of the sample solution and adsorb the analytes. After a few minutes the agitation is stopped and the composite particles are collected on the magnetic stir bar which is taken and eluted with methanol to desorb the analytes. Then the eluent is taken, mixed with 1,1,2-trichloroethane at µL–level, and rapidly injected into deionized water. The obtained cloudy solution is centrifuged and an aliquot of the sedimented phase containing the extracted analytes is injected into gas chromatography–flame ionization detection. Under optimized conditions, the introduced method provided high enrichment factors (2280–2840), and low limits of detection (0.10–0.25 ng mL−1) and quantification (0.34–0.83 ng mL−1).