title: Simultaneous determination of trace cadmium and mercury in Chinese herbal medicine by non-dispersive atomic fluorescence spectrometry using intermittent flow vapor generator.
abstract: A method was proposed for the simultaneous determination of trace cadmium and mercury by vapor generation non-dispersive atomic fluorescence spectrometry using an intermittent flow system. The effects of the parameters on the performance were studied systematically. The parameters such as acid concentration of the reaction medium, flow rate of the carrier gas and shield gas, the observation height and the atomizer temperature, etc. which affected the sensitivity, were optimized. Ascorbic acid, cobalt ion and thiourea were used as enhancement reagents or masking agents to enhance the generation efficiency of the volatile species of Cd and Hg. The mechanisms of their effects on vapor generation were investigated. In the presence of thiourea and ascorbic acid, the influences of some coexisting elements on the determination of cadmium and mercury were investigated. The detection limits (3sigma) were 0.010 microg l(-1) for Cd and 0.019 microg l(-1) for Hg, respectively. The relative standard deviations for Cd and Hg at 1.00 microg l(-1) were 2.6% and 0.97% (n = 11), respectively. The proposed method has been satisfactorily applied to the determination of trace cadmium and mercury in Chinese herbal medicine.
authors.affiliation: Key Laboratory of Analytical Science of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, Hebei Province, China. hanwen@mail.hbu.edu.cn
authors.forename: Hanwen
authors.initials: H
authors.lastname: Sun
authors.forename: Ran
authors.initials: R
authors.lastname: Suo
authors.forename: Yunkai
authors.initials: Y
authors.lastname: Lü
mesh_terms: D001205:Ascorbic Acid; D002104:Cadmium / Q000032:analysis*; D003035:Cobalt; D004340:Drug Contamination; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000032:analysis*; D009330:Nebulizers and Vaporizers; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000295:instrumentation* / Q000379:methods*; D013696:Temperature; D013890:Thiourea; D014835:Volatilization
chemical_list: D004365:Drugs, Chinese Herbal; D002104:Cadmium; D003035:Cobalt; D008628:Mercury; D013890:Thiourea; D001205:Ascorbic Acid