Studies on Hydroxyfluoran and Its Derivatives as Organic Reagents. XVI. Spectrophotometric Determination of Ag [I], CN^-, I^- and S₂O₃^2- with 3, 4, 5, 6-Tetrachloro 3', 4', 5', 6'-Tetrahydroxyfluoran Methyl Ester and 1, 10-Phenanthroline

Abstract

3, 4, 5, 6-Tetrachloro-3', 4', 5', 6'-tetrahydroxyfluoran methyl ester (I) formed a blue complex with silver (I) in the presence of excess 1, 10-phenpthroline (II) and polyvinylpyrolidone (PVP) in a neutral solution. The color was applied for spectrophotometric determination of Ag [I], CN^-, I^-, and S₂O₃^2-. The absorbance of I-II-Ag [I] solution was measured at 630 on or 650 nm against I-II solution for the determination of Ag [I]. The difference in the absorbance of I-II-Ag [I] solution and of I^-, CN^-, or S₂O₃^2- solution was measured at 630 nm against water for the determination of CN^-, I^-, and S₂O₃^2-. Linear calibration curves were obtained for 0 to 2.8 μg of Ag [I], 0 to 3.0 μg of CN^-, 1.0 to 7.5 μg of I^-, and 0 to 6.5 μg of S₂O₃^2- using I and II.