Studies on the Determination of Mercury by On-line Solvent Extraction and Non-Aqueous Media Hydride Generation Non-Dispersive Atomic Fluorescence Spectrometry

摘要

A new method for on-line solvent extraction covalent hydride generation in a non-aqueous extraction phase is proposed.Both liquid-liquid extraction and gas-liquid separation steps are accomplished in an online mode and with AFS as detector.Hydride generation is carried out in an aliquot of metal-complex extraction solution by sodium tetrahy-droborate in N,N-dimethylformamide solution and anhydrous acetic acid.An improved U-type gas-liquid separator was used.The working conditions and manifolds scheme of flow injection were optimized.The detection limit attained for mercury was 20 ng L~(-1).The precision of the determination at a concentration level of around 20 times the detection limit was 5.6%.The proposed method gives improved sensitivity and eliminates interference.The method has been applied to the determination of mercury in certified reference materials with good accuracy and precision.