DETERMINATION OF TRACE Cr IN PLATING WASTEWATER BY ABSORPTIOMETRY of ECR-CTMAB ETHYL ALCOHOL SYSTEM
Using hydroxylamine hydrochloride as reducer, mixed solution of ECR-CTMAB ethyl alcohol as sensitivity increasing developer, and reagent blank as reference, the extinction of this blue solution is determined with model 72 spectrophotometer at 600 mμ, in a oolormetric cell of one centimeter. It can be used to determine Cr which is in accord with the Beer' law within the range of 0-10μg/25mL. This process is characterized for its reagent stability, high sensitivity, good developing effect and reperoducibility. Besides, it is easy to operate and can directly determine the total Cr and trivalent Cr. therefore, it is considered to be an ideal method for the determination of trace chromium in plating wastewater.