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 nondispersive 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 (3σ) were 0.010 µg l -1 for Cd and 0.019 µg l -1 for Hg, respectively. The relative standard deviations for Cd and Hg at 1.00 µg 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.

Simultaneous determination of mercury and arsenic species in natural freshwater by liquid chromatography with on-line UV irradiation, generation of hydrides and cold vapor and tandem atomic fluorescence detection

“…More recently, a commercial multichannel AFS detector has been developed by Beihing Haiguang Instrument Company (China), which enables simultaneous multielemental analysis [23,24]. At the present a coupling based on the join of two AFS in series has been developed in our laboratory.…”

Determination of cadmium in water samples by fast pyrolysis–chemical vapor generation atomic fluorescence spectrometry

“…Based on the basis of the system of thiourea-NaBH 4 -Cd 2+ in aqueous solution [16], we suggested the following mechanism for Py-CVG: The thiourea enable the Cd 2+ and Cu 2+ to form metal ions-thiourea complex through covalent attachment, Cd 2+ -thiourea complexes may influence the rate of reaction between Cd 2+ and sodium formate . The Cu 2+ -thiourea…”

Atomic spectrometry update. Advances in atomic emission, absorption and fluorescence spectrometry and related techniques

“…Sun et al 239 determined Cd and Hg simultaneously by vapour generation non-dispersive AFS. Ascorbic acid, cobalt and thiourea were used as enhancement reagents or masking agents to enhance the generation efficiency of the volatile species of Cd and Hg, which are probably a mixture of free atoms (Hg) and unstable hydride (Cd).…”

“…They also analyzed soil extracts, obtaining results comparable to those of obtained by ETAAS and FAAS. Chinese researchers, Sun et al, 239 rose to the challenge of the simultaneous determination of trace Cd and Hg in Chinese herbal medicine by non-dispersive AFS with an intermittent flow vapor generator. Ascorbic acid, cobalt and thiourea were used as enhancement reagents or masking agents to enhance the generation efficiency of the volatile species of Cd and Hg.…”