Low Parts per Billion Determination of Sulfide by Coulometric Argentometry

Present methods for the determination of sulfide in wastewater are hindered by poor detection limits and extensive sample pretreatment. A less problematic method has been developed with a method detection limit of 2.5 μg L-1. With this technique, sparged hydrogen sulfide is precipitated in an acetate-supporting electrolyte by electrogenerated silver ions. Analysis of basepreserved samples was performed with no pretreatment other than volumetric dilution. Metals, halides, and nitrogen-base salts were studied as possible interferences to the method. Direct comparisons with the standard methylene blue method were made for both municipal and industrial wastewaters. The present method was found to be far less inhibited by sample turbidity.