application of hollow fiber stir bar solid/liquid phase microextraction for determination of chlorpyrifos in water and fruit juice samples

Chlorpyrifos is an organophosphorous insecticide widely used for pest control in agriculture and with minimum degree for indoor applications. this pesticide can affect the human nervous system, so it is considered a toxic species for the human body [1]. layered double hydroxides (ldhs) are a class of 2-dimensional layered materials. ldhs have high anion exchange capacities, with large surface area, and the interlayers having variable sizes. for these reasons, the application of ldhs as sorbents has been actively investigated [2]. in the past decades, the development of new extraction methods that integrate the extraction and stirring element in the same device have been become popular because of some advantages such as simplicity, no loss of analyte and enhancement in the extraction recovery [3]. in this regard, a design of hollow fiber supported liquid membrane so-called hollow fiber stir bar solid/liquid phase microextraction ((hf-sb-s/lpme) has been developed. extraction device for the hf-sb-s/lpme procedure was prepared using a hollow fiber reinforced with acceptor phase and magnetic wire in the hf lumen. in the current study, acceptor phase was fe3o4/mg-al layered double hydroxide dispersed in organic solvent of toluene, which was held in the pores and lumen of a porous polypropylene hollow fiber membrane while a magnetic wire in the hf lumen and applied for preconcentration and determination of chlorpyrifos in water and fruit juice samples. the effective factors on extraction (ph, stirring rate, salt effect, the volume of donor phase and extraction time) were investigated and optimized. at the optimum conditions, the relative standard deviations (rsd) of the method were calculated 5.4% (as intra-day relative standard deviation) and 8.9% (as inter-day relative standard deviation) at 30 µg l−1 concentration level.