DETERMINATION OF SULFATE IN BRACKISH WATERS BY LASER RAMAN-SPECTROSCOPY

After recent developments in our Vibrational studies, we can arrive at a new method of determining sulfate in brackish waters. This paper di scusses the recent developments and applications of the new method. Th e first thing is the establishment of a calibration work to the sulfat e solutions of different concentrations using an internal standard by laser Raman spectroscopy. The second is an application of this method to the determination of sulfate in many samples of brackish waters aro und an estuary. The calibration curve of sulfate ion was linear up to the concentration of 0.04 mol/dm(3) in Raman spectroscopy, Sodium chlo ride had no effect on this calibration curve up to the concentration o f 1.0 mol/dm(3). We then applied Raman spectroscopy to determine the s ulfate concentration in brackish waters near an estuary. The concentra tion of sulfate in brackish waters at most of the sample points was hi gher in ebb tide than in flood tide except at some points. Similar ten dency was found for the chloride concentration of sample solutions. Th e concentration ratio of sulfate to chloride was nearly equal to 0.14 at most points in the flood tide. But the ratio was found to be higher in the ebb tide.