Solid-Liquid Separation after Liquid-Liquid Extraction. -Spectrophotometric Determination of Bismuth after Extraction of Its 2-mercaptobenzothiazole Complex with Molten Naphthalene-

摘要

A new reagent, 2-mercaptobenzothiazole,sodium salt is describedfor the spectrophotometric determination of bismuth(II) after extractionof bismuth complex with molten naphthalene. This reagentreacts with bismuth(II) to form a water-insoluble complex.The complex is insoluble in chloroform or benzene, but easily soluble inmolten naphthalene. The extracted mixture of bismuth complex andnaphthalene is dissolved in dimethylformamide and the trace amountsof bismuth are determined spectrophotometrically. The linearity betweenthe absorbance and bismuth concentration is held for 10 - 200μgof bismuth in 10 ml of dimethylformamide. The molar absorptivity wascalculated to be 1.1 x 10 4 l.mol-l･cm-l , the sensitivity 0.020 μg ofbismuth per cm2 for the absorbance of 0.001 and the relative standarddeviation 0.76 % for ten times determinations.