Quantitative determination of sulfur by high-resolution graphite furnace molecular absorption spectrometry

In this paper a new procedure for quantitative determination of sulfur, which is based on the molecular absorption of tin sulfide at a wavelength of 271.578 nm, is described. For that purpose a commercially available high-resolution continuum source atomic absorption spectrometer with a transversely heated graphite tube furnace is used. The temperature program is optimized and the measurements are accomplished with a Zr-coated graphite tube without platform. A limit of detection of 0.16 ng S absolute is achieved. Furthermore, the accuracy of the procedure is verified by the recovery rate of both an inorganic and an organic compound. Several water samples from rivers and ponds, three mineral waters with a concentration range from 3 to 370 mg/L S. and one certified reference material are analyzed, too. The results are consistent with the measured values of ion chromatography and gravimetric analysis. The non-spectral interelement effect of Ni has displayed a signal loss. With a 1:1 relation of metal to analyte a loss of 11% of the absorption signal has appeared. This effect is very seldom in natural environment, so the procedure is robust and there are no spectral interelement effects. In addition, this procedure is faster and more easy-to-handle than other methods at this point of time, and resulting in the improved limit of detection. (C) 2012 Elsevier B.V. All rights reserved.