Determination of Ag, Bi, Cd, Hg, Pb, Tl, and Zn by inductively coupled plasma mass spectrometry combined with vapor generation assisted by solution anode glow discharge - A preliminary study.

ABSTRACT

A new technique of vapor generation assisted by a microplasma was proposed for an inductively coupled plasma mass spectrometry (ICP MS). It was found that, by replacing a traditional pneumatic nebulizer with a microplasma (solution anode glow discharge, SAGD), analytical signals of Ag, Bi, Cd, Hg, Pb, Tl, and Zn were improved 8, 4, 13, 13, 9, 10, and 7 times, respectively. The main factor contributing to boosted analytical signal intensities was the higher analyte flux produced by the novel microplasma system. The measurement precision in SAGD-ICP MS was comparable to that achievable for ICP MS (with pneumatic nebulization), and it did not exceed 2%. The detection limits of Ag, Bi, Cd, Hg, Pb, Tl, and Zn in SAGD-ICP MS were 5, 2, 6, 5, 4, 10, and 20 ng L-1, respectively. The analytical performance of this method may be further improved if the observed memory effects could be minimized. To validate the trueness of the novel method, certified reference materials of lobster hepatopancreas (TORT-2), cormorant tissue (MODAS-4), and wastewater (ERM CA-713) were analyzed to determine traces of Cd, Hg, and Pb. Recoveries of certified values for these analytes were ranged from 91 to 111%, which indicated that the studied microplasma system in combination with ICP MS can be successfully used for very sensitive determinations of selected hazardous elements in environmental samples.