Abstract
In physiological studies, it is well known that most of the bioavailability and toxicity of trace elements strongly depend on the concentration. In view of the dialysate can be used to reflect the extracellular concentration of metal ions, in-vivo microdialysis coupled with suitable on-line instrumental analytical technique has been widely employed to investigate the physiological reactions in a specific micro-area of a living organism. Owing to the extremely low concentration of analytes and complex matrix are always encountered in the conjunction of analytical chemistry and biological researches, an on-line sampling and matrix separation technique dealing with high salt contented samples has been studied in the present work.In this study, a hyphenation technique comprising in-vivo microdialysis and ETV-ICP-MS was developed to monitor the dynamic variation of trace metals in simulated body fluid systems. The sampling system was constructed by a micro-injection pump and 6-way valve equipped with a 20-mL sample loop. The interface between sampling system and ETV-ICP-MS was built up with narrow PTFE tubing where the solution was driven by a peristaltic pump. To solve the salt interference caused by the ringer perfusate and to achieve optimal analytical signal, a mixture of palladium and NH4NO3 was employed as binary chemical modifier in the ETV separation procedure. The effects of pyrolysis and vaporization temperature and the amount of added modifiers on the analyte signal were also explored and optimized. Based on the stability and sensitivity studies, the proposed on-line system coupling microdialysis with ETV-ICP-MS has been proven feasible for the determination of trace elements ( Cu, Zn, Mn, Pb ) in biological samples.