VAPOR GENERATION OF NONMETALS COUPLED TO MICROWAVE PLASMA-TORCH MASS-SPECTROMETRY

A chemical vapor-generation (CVG) method is compared with solution nebulization for determination of nonmetals by microwave plasma-torch mass spectrometry (MPT-MS). In contrast to solution nebulization, the CVG approach produces volatile species that are more efficiently transported to the plasma and influence the discharge to a lesser extent; furthermore, it enables analyte species to be separated from the sample matrix and solvent, so the Likelihood of spectral interferences is lessened. The optimal operating conditions for generating sulfur, chlorine, bromine and iodine vapors have been determined, and several analytical characteristics (including linear dynamic range, detection limits and matrix effects) have been evaluated.;The detection limits for several nonmetal elements are in the range from low ng ml(-1) to high pg ml(-1), between one and three orders of magnitude better than those for the same elements obtained with an inductively coupled plasma on the same mass spectrometer. The linear dynamic range is between four and five orders of magnitude.