Titania immobilized polypropylene hollow fiber as a disposable coating for stir bar sorptive extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometry speciation of arsenic in chicken tissues

摘要

The bottleneck of applying stir bar sorptive extraction (SBSE) to elemental speciation analysis is lack of suitable extraction phases with good affinities to different elemental species. In this paper, a newly high polar extraction phase of titania immobilized polypropylene hollow fiber (TiO_2-PPHF) was prepared by sol-gel immersion and low temperature hydrothermal process and the obtained TiO_2-PPHF inherits the adsorption properties of TiO_2 and the toughness of PPHF. With a suitable size of stainless steel magnetic bar inserted into the prepared TiO_2-PPHF, a disposable TiO_2-PPHF coating stir bar was obtained. The prepared TiO_2-PPHF was characterized by X-ray diffraction spectrometry and scanning electron microscopy and the significant parameters affecting the extraction efficiency of different arsenic species were studied. Based on the above facts, a new method of SBSE combined with high performance liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) was developed for the speciation of phenyl arsenic compounds and their possible transformation products in chicken tissues. Under the optimal conditions, limits of detection (LODs) of the developed method for eight target arsenic species were in the range of 11.4-64.6ngL~(-1) with enrichment factors of 8.5-22.3 (theory enrichment factor was 50), and the relative standard deviations (RSDs) were varying from 6.3 to 12.6% (cAsIII/V=5μgL~(-1), cMMA,DMA,p-ASA,4-OH,3-NHPAA,PA,4-NPAA=10μgL~(-1), n=7). The proposed method was successfully applied to the speciation of arsenic in chicken meat/liver samples and the recoveries for the spiked samples were in the range of 78.5-120.4%. In order to validate the accuracy of the proposed method, a certified reference material of BCR-627 tuna fish tissue was analyzed and the determined values were in good agreement with the certified values. The TiO_2-PPHF was demonstrated to be a highly selective coating for the target arsenic species, and could be easily prepared in batches with low cost. In addition, with the disposable coating, the carry-over effect commonly encountered in conventional SBSE was avoided.