EXTRACTION, SEPARATION AND SPECTROPHOTOMETRIC DETERMINATION OF BISMUTH(III) USING 1(4'-BROMOPHENYL) 4,4,6-TRIMETHYL (1H,4H)-PYRIMIDINE-2-THIOL

The operating conditions for the spectrophotometric determination of b ismuth(III) with 1-(4'-bromophenyl)-4.4.6-trimethyl-(1H, 4H)-pyrimidin e-2-thiol (4' bromo PTPT) as a ligand by a liquid-liquid extraction te chnique are presented. In acidic conditions bismuth(III) forms a yello w complex with the ligand which can be extracted in chloroform with an absorption maxima at 410 nm. The molar absorptivity is 1.5 x 10(4) l mole(-1) cm(-1) and Sandell's sensitivity is 14.3 ng cm(-2). The diffe rence in the absorbance between the chloroform blank and bismuth(III) sample increases linearly in the concentration range 2-14 ppm at 0.3 M hydrochloric acid. The proposed method is extremely sensitive, rapid, reproducible and has been satisfactorily applied to the determination of trace amounts of bismuth(III) in synthetic mixtures, alloys and ph armaceutical formulations and also provides binary separation of bismu th(III) from selenium, tellurium, lead, antimony, copper and gold. The overall process of extraction and determination takes about 15 to 20 min.