SPECTROCHEMICAL DETERMINATION OF TRACE As, Fe, Hg, Mn AND Pb BY ARGON-STABILIZED U-SHAPED DC ARC

摘要

Argon-stabilized U-shaped DC arc with the system for aerosol introduction was used for the determination of As, Fe, Hg, Mn and Pb. By the application of a computer program performing time integration of the registered signals and by optimizing the working conditions of U-shaped arc plasma, the detection capability for As, Fe, Hg, Mn and Pb was improved, which contributed to the lowering of the detection limits. The lowest detection limits for Fe, Mn and Pb were achieved during the integration time of20 s, and for As and Hg during the integration time of 30 s, and their values were 1.1,0.1,0.9,15 and 2.6 ng/mL, respectively. Detection limits obtained by our method with the optimal integration times were compared with the detection limits obtained byother methods: inductively coupled plasma-atomic emission spectrometry (ICP-AES), direct coupled plasma-atomic emission spectrometry (DCP-AES), microwave induced plasma-atomic emission spectrometry (MTP-AES), inductively coupled plasma-mass spectrometry(ICP-MS) and the improved thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS).