Abstract
In this study, the potential of packed column with nonfunctionalized polyvinylchloride (PVC) beads in the automated lab-on-valve on-line sample pretreatment system for matrix elimination and analyte preconcentration prior to ICP-MS measurement. The adsorbed molecule ions were presumably dominated by Lewis acid/base interactions, which facilitated the formation of metal-PVC complexes. Comparing with traditional SPE methods, this on-line automated system could reduce contamination during sample pretreatment in the off-line or batch mode analysis, which might constitute an important source of error. Furthermore, it was not necessary to wash and condition the packing column for each analysis, which prevented additional reagent blank and enhanced throughput in the procedures. Under the optimized condition, the detection limits obtained for the analysis of Mn(II), As(V), Mo(VI) ions and methylmercury (MeHg) were in the range from 3.9 to 24.4 ng L-1. Validations of the proposed method were performed by analyzing the standard reference material─NIST 1640a (nature water) and 2672a (human urine). Eventually, this on-line system comprising microdialysis sampling technology was also applied to monitor in-vivo dynamic changes in the concentration of the MoO42-，As(III)，As(V)， MMA， DMA in the brain extracellular fluid of anesthetized rats after intra-peritoneal dosing.