[Study and spectrophotometric determination of trace silver with iodide-Victoria Pure Blue BO system].

Analytical properties and spectra of naphthyl diphenymethane basic dyes and associated complexes of dye with [AgI2]- was studied. A new method for the spectrophotometric determination of trace amount of silver was developed. The method was based on the Victoria Pure Blue BO reacted with [AgI2]- to form blue associated complex in the buffer medium of H3PO4 -NaH2PO4. The spectrophotometric measurements were directly carried out at 574 nm, the apparent molar absorptivity of associated complex was 7.25 x 10(4) L x mol(-1) x cm(-1). The Beer's law was obeyed in the range of 4-250 microg x L(-1). The recoveries were in the range of 97.0%-98.3%. RSD was 2.7%. The method has been used to determination of trace silver in river water with satisfactory results.