等色染料离子对浮选光度法测定铟的研究

用pH=5.5的醋酸与醋酸钠缓冲溶液,解析溴铟酸与罗丹明6G(R6G)形成的三元络合物R6G.InBr4,加入四溴荧光素(TBF)与游离出的R6G形成等色染料离子对R6G.TBF,离子对同时被甲苯浮选,将浮选物溶于丙酮.由于2种染料颜色相近,同时参与铟的测定,使本方法具有较高的灵敏度,灵敏度较R6G.InBr4萃取光度法测定铟提高5倍.摩尔吸光系数ε=2.0×105L/(mol.cm),铟的质量浓度在0~0.5 mg/L内遵从比耳定律,用于粗铜中微量铟的测定,回收率为98.5%~102.3%,6次平行测定相对标准偏差为2.6%~3.2%,结果满意.

Studies on Flotation Spectrophotomentric Determination of Indium with Isochromatic Dye Ion-pair

The flotation spectrophotometric method for the determination of indium with isochromatic dye ion-pair is described.An anionic rhodamine 6G and a cationic indium were produced and entered into aqueous phase when pH=5.5,HAc-NaAc buffer solution had been added in R6G·InBr-4 solution;so R6G anion and indium cation can be reacted with tetrabromfluorescein(TBF) that,an isochromatic dye ion-pair,i.e.a ternary complex system was formed,which can be flotated by toluene.The float products were dissolved in acetone and absorbance of the solution was measured at 530 nm. The sensitivity was raised because of the two dye's((n(In)∶)(n(R6G))∶n(TBF)=1∶1∶1)reinforced effect.The molar absorptivity of this method is 2.0×(10~5 L/(mol·cm)).Beer′s law was obeyed in the range of 0 ～ 0.5 mg/L with a relative standard deviation of 2.6 %～(3.2 %) and the recoveries was 98.5 % ～ 102.3 %.The method was applied satisfactorily to the determination of indium in crude copper samples.