研究表明:以微晶百里酚酞(TMPT)作固相吸附剂可分离微量铋(Ⅲ),其酸度用邻苯二甲酸盐缓冲溶液控制在pH 3.0,在有50 g·L-1 TMPT乙醇溶液0.10 mL,0.10 mol·L-1碘化钾溶液0.80 mL,1.0×10-2mol·L-1十二烷基三甲基溴化铵(DTMAB)溶液0.30 mL存在时,Bi3+与I-的络阴离子与DTMAB+阳离子形成不溶于水的三元缔合物(DTMAB)3［BiI6］,加入溴化钾1.0 g充分振荡后,此缔合物能被定量吸附在微晶百里酚酞上,实现Bi3+与K+、Na+、Ca2+、Mg2+、Zn2+、Fe3+、Co2+、Ni2+、Mn2+、Al3+等离子的定量分离。从下层盐水相中取1.00 mL试液,在CTMAB存在下以5-Br-PADAP作显色剂,用分光光度法于波长555 nm处测量其中的铋含量。方法用于含铋药物的测定,结果与EDTA滴定法相符,测定值的相对标准偏差(n=6)不大于2.0%。

It was found that micro-amounts of bismuth(Ⅲ) could be separated from K+, Na+, Ca2+, Mg2+, Zn2+, Fe3+, Co2+, Ni2+, Mn2+ and Al3+ by adsorption on microcrystalline thymolphthalein (added as 0.10 mL of 50 g·L-1 ethanol solution) in the form of an insoluble ternary ion association complex (DTMAB)3［BiI6］ through reaction in a mixture containing 0.80 mL of 0.10 mol·L-1 KI solution, and 0.30 mL of 1.0×10-2mol·L-1 dodecyltrimethylammonium bromide (DTMAB) solution, buffered to pH 3.0 with phthalate buffer solution, diluted to 10 mL, and thence added with 1.0 g of KBr. After shaking, 1.00 mL of the lower aqueous salt phase was taken and Bi(Ⅲ) in the solution was determined photometrically by the color reaction with 5-Br-PADAP in the presence of CTMAB. Absorbance of the color solution was measured at 555 nm. The proposed method was used for determination of bismuth in drug samples, giving results in consistency with the results found by EDTA titration. Values of RSD′s (n=6) found were ≤2.0%.