ABSTRACT
Chloride is one of the most commonly occurring anions in the environment. It can be analyzed using several different methods, some of which are listed below: mercuric nitrate titrimetric method, argentometric titrimetric method, automated ferricyanide colorimetric method, gravimetric determination, ion-selective electrode method and ion chromatography. Mercuric nitrate titrimetric method and automated ferricyanide colorimetric method are Environmental Protection Agency (EPA) approved for chloride determination in wastewater. Chloride standards are prepared in the concentration range 1-250 mg/L from the stock standard solution. Chloride reacts with mercuric nitrate to form soluble mercuric chloride. Gravimetric analysis for chloride in wastewaters does not give accurate results at concentrations below 100 mg/L. This method is rarely applied in routine environmental analysis because it is lengthy and rigorous. This method is based on the fact that AgNO3 reacts with the chloride anions in the solution, thus precipitating out AgCl.
