FI-HG-AFS for Determination of Trace Amount of Cadmium in Natural Water

FI-HG-AFS by using knotted reactors(KR)was applied to the determination of trace amount of cadmium in natural water.The sample was on-line mixed with ammonia(aq.)-ammonium chloride buffer solution,and the precipitate of cadmium was collected on the inner walls of the knotted reactor.The removal of the residual solution from KR was achieved by introduction of air flow,and the precipitate was dissolved by HCl(3+97)solution.The solution obtained was mixed with KBH4 solution and used for HG-AFS detection.Under the optimal experimental conditions,an enrichment factor of 14 was obtained with sample consumption of 15.6 mL.The detection limit(3S/N)of the method found was 2.9 ng·L-1 and RSD(n=11)found was 3.4%.The proposed method was used for analysis of standard reference materials and natural water samples,the results of determination obtained was in agreement with the standard values,and values of recovery of Cd in natural water samples were ranged from 91.5% to 107.5%.