LOW PARTS-PER-BILLION DETERMINATION OF SULFIDE BY COULOMETRIC ARGENTOMETRY

Present methods for the determination of sulfide in wastewater are hin dered by poor detection limits and extensive sample pretreatment A les s problematic method has been developed with a method detection limit of 2.5 mu g L-1. With this technique, sparged hydrogen sulfide is prec ipitated in an acetate-supporting electrolyte by electrogenerated silv er ions. Analysis of base-preserved samples was performed with no pret reatment other than volumetric dilution. Metals, halides, and nitrogen -base salts were studied as possible interferences to the method. Dire ct comparisons with the standard methylene blue method were made for b oth municipal and industrial wastewaters. The present method was found to be far less inhibited by sample turbidity.