FIELD: analytical methods. SUBSTANCE: 20- ml sample is placed in conical flask. Simultaneously, 0.4 to 0.5 g of silver sulfate and 0.1 to 0.08 g of zirconium dioxide are added. Mixture is stirred, while 50 ml of potassium bichromate in concentrated sulfuric acid is gently added. Mixture is further stirred and allowed to stand for 10 min to complete reaction, after which mixture is cooled and concentration of bichromate ions is determined using coulometric titration technique with potentiometric or biamperometric indication. Method is fit for estimating water quality and can be used for water monitoring at water treatment stations or to control water condition in water reservoirs. EFFECT: increased accuracy of analysis. 4 cl, 4 tbl
