Element determinations in aqueous and acetonitrile containing solutions by atomic emission spectrometry using a microwave plasma torch

摘要

The analytical performance of the microwave plasma torch (MPT) as a radiation source for atomic emission spectrometry in the case of sample introduction of liquids by pneumatic nebulization using a Legere nebulizer was investigated. Aerosol loading by either water or acetonitrile (AcN) did not disturb the plasma discharge stability. The addition of Cs or AcN to aqueous solutions leads to a signal suppression in the case of Cd, Cr and Pb and a signal enhancement in the case of Li for concomitant concentrations of about 50 mu g ml(-1) onwards. For aqueous solutions, the limits of detection of Cr, Cd and Pb are on the order of 0.1-1 mu g ml(-1) and 5-20 ng ml(-1) for Li. For Cr, dissolved as ammonium pyrrolidinedithiocarbamate (APDC) complex in an AcN/H2O mixture (2:1), the detection limit is 0.1 mu g ml(-1). When AcN is present in the aerosol, spectral background records show that the wavelength range in which atomic emission lines are free from interferences is limited as a result of strong molecular band emission spectra, especially between 350 and 430 nm. (C) 1998 Elsevier Science B.V. All rights reserved. [References: 29]