Abstract
A flow injection on-line matrix separation system coupled with inductively coupled plasma mass spectrometry was developed for the determination of trace elements in the microdialysis samples consist of high salt content samples. In view of avoiding the influence causing by the swelling and shrinking of resin, a commercial available iminodiacetate resin, named Muromac A-1, was packed into a homemade micro-column (1.5 mm id.× 3.5 mm). The manifold of on-line separation/ preconcentration flow injection system was constructed by two 10-ways and one 6-ways valves. In order to achieve the optimized analytical performance, the effects of the composition of the condition solution, variation of the sample pH, amount of the buffer, and composition of the eluent, carrier flow rate and the resulted peaks of analytes were investigated.Under the optimized conditions, a microdialysis sample (adjusted to pH 6.0~7.0) pass through the micro-column conditioned with 1M ammonium acetate, after washing the column with water, the adsorbed metals were subsequently eluted into the ICP-MS with 10 % HNO3. Overall operation time of on-line matrix separation could be accomplished within 10 min only. Detection limits of the trace metals in the microdialysis samples were several hundreds ng L－1 below except Ni. The validity of the method developed was confirmed by the good agreement of results obtained both with FI-micro column-ICP-MS system after microdialysis sampling and graphite furnace atomic absorption spectrometry (GFAAS) and ICP-MS directly. According to our experimental results, the method could be successfully applied to the determination of Cd, Cu, Mn, Ni, Pt and Zn down to the sub-μg L－1 level in the microdialysis samples with just 20μL sample volume.