DETERMINATION OF SULFITE AND SULFATE IN SOLIDS BY TIME-RESOLVED MOLECULAR-EMISSION SPECTROMETRY

A technique for simultaneously determining SO32- and SO42-in solids is proposed. Solid samples are placed in a small, quartz-lined cavity at the end of a stainless steel rod which is rotated into a low temperature flame to a fixed position in line with the entrance slit of a monochromator. The resulting molecular emission of sulfur at 383.6 nm is linearly related to absolute amounts of sulfur between at least 10-5 to 10-7 g. Nanogram amounts of sulfite and sulfate are readily detected, but quantitation is hindered at these low levels by inhomogeneous standards. Excessive salt content and entrapment of the sulfur anion within a refractory matrix represent potential interferences. Standard flame emission instruments may be readily adapted to this technique by the addition of a simple, easily fabricated sample introduction device. © 1979, American Chemical Society. All rights reserved.