十六烷基三甲基溴化胺介质中分光光度法测定微量锗(Ⅳ)

CTMAB Medium Spectrophotometric Determination of Micro Ge(Ⅳ)

研究了在十六烷基三甲基溴化胺（CTMAB）溶液存在下，5-（对羧基苯偶氮）-8-羟基喹哪啶（5-CPAHQD）与微量锗（Ⅳ）发生显色反应的条件，建立了新的测定微量锗（Ⅳ）的高灵敏度分光光度法。实验结果表明，在硼酸钠-氢氧化钠介质中，5-（对羧基苯偶氮）-8-羟基喹哪啶与微量锗（Ⅳ）发生灵敏的显色反应，生成配合比为3∶1的橙红色配合物。配合物的最大吸收峰位于540 nm，表观摩尔吸收系数为2．5×10^ L·mol^-1·cm^-1，在10 mL溶液中，微量锗（Ⅳ）质量在0．03～2．8μg之间符合比耳定律，检出限为0．1 mg/L，并且该显色反应具有较强的抗干扰能力，可用于茶水中微量锗（Ⅳ）的测定，方法的回收率在103．2％～104．1％之间，测得其相对标准偏差（n＝6）≤2．5％，结果与原子吸收光谱法相一致。

The color reaction of chromogenic agent 5-（4-carboxylphenylazo）-8-hydmxylquinoline （5-CPAHQD）with Ge（Ⅳ）was studied in the presence of micromulsion CTMAB.A novel spectrophotometric determination of trace Ge（Ⅳ）with high sensitivity was established.The results showed that in the Na2 B4 O7-NaOH medium of pH 9.80,5-CPAHQD reacted with Ge（Ⅳ）and could form a red stable complex and the molar ratio of reagent/metal was 3∶1 .The maximum absorption peak of the complex was located at 540 nm with the apparent molar absorptivity of 2.5×10^5 L·mol^-1 ·cm^-1 .In 10 mL of solution,0.03-2.8μg of Ge（Ⅳ）obeyed Beer’s law and the detection limit was 0.1 mg/L.The color reaction system could tolerate many interfering ions due to the existence of ammonia.This method was applied to the determination of trace Ge（Ⅳ）in tea,producing results in consistency with the results obtained by AAS method.Recovery was also tested and the values obtained were in the range of 103.2%-104.1% with the RSD（n=6）of lower than 2.5%.