STUDY AND APPLICATION OF SPECTROPHOTOMETRIC DETERMINATION OF MICRO AMOUNTS OF BISMUTH WITH MESO—TETRAKIS—(4—N—TRIMETHYL AMMONIUMPHENYL)PORPHINE

摘要

A new highly sensitive spectrophotometric method has been developed for the determination of micro amounts of bismuth （Ⅲ）, based on the formation of Bi （Ⅲ）—meso—tetrakis—（4—N—trimethylammonium phenyl） porphine [T （4TMAP） P] complex. In the presence of Cd （Ⅱ）, Bi（Ⅲ） reacts almost instantaneously with T （4TMAP）P in a 0. 6 mol/l NaAc—HAC buffer （PH5.8） at room temperature. The composition of the complex is T（4TMAP）P: Bi=1:1. The absorbance complex obeys Beer’s law over the Bi（Ⅲ） concentration range 0.1—1.4 μg/ml. The linear relative coefficient γ is 0.9998. The apparent molar absorptivity was 1.75×105 1. mol-1. cm-1 at 463nm. The relative standard deviation of the method is 1.50％ for Bi（Ⅲ） 7ug/10ml （10 determinations）. The interference of foreign ions has been examined. This simple and rapid method can be applied to the assay of Bi（Ⅲ） in some tablets directly.