Primary-secondary wavelength spectrophotometric determination of trace amounts of silver in wastewater with 2,4-dibromo-6-carboxy-benzenediazoaminoazobenzene

In the presence of Triton X 100 at pH 13 the reaction between silver (Ag+) and chromogenic reagent, 2,4-dibromo-6-carboxy-benzenediazoaminoazo-benzene (DBCBAA) was developed to form a red complex. This reaction was highly sel ective in the presence of disodium ethylene diamine tetracetate (Na(2)EDTA) . Because of the interference of excess of DBCBAA the mw method named Its p rimary-secondary wavelength spectrophotometry (PSWS) was applied instead of the ordinary spectrophotometry for the determination of trace amounts of s ilver in wastewater Results showed that such a method gave out the better p recision and higher accuracy thm the ordinary method By analyzing several w astewater samples, the relative standard deviations were less than 3.69% an d the recovery rate of Ag between 93.5 and 104%.