对由溴化十六烷基吡啶(CPB)、辛基苯基聚氧乙烯醚(OP)、正丁醇、正庚烷和水组成的微乳溶液存在下,4-(6-甲氧基-8-喹啉偶氮)-间苯三酚与镓(Ⅲ)的显色反应,进行了研究并提出了分光光度法测定痕量镓(Ⅲ)的方法.结果表明:在pH 9.80的硼砂-氢氧化钠缓冲溶液中,镓(Ⅲ)与试剂形成1∶2的红色络合物,络合物的最大吸收峰在525 nm波长处,表观摩尔吸光率为1.6×105L·mol-1·cm-1 .镓(Ⅲ)量在7~800 μg·L-1范围内符合比耳定律,检出限(3S/N)为1 μg·L-1.方法用于煤和矿石中微量镓的测定,测得结果与原子吸收光谱法的结果相符,测定值的相对标准偏差(n=6)均小于5%.在两实样的基础上用标准加入法做回收试验,测得其平均回收率为102.7%.

A new spectrophotometric method for determination of trace amounts of gallium(Ⅲ) was proposed,base on its reaction with 4-(6-methoxy-8-quinolylazo)-phloroglucinol (MOQAPG) in a microemulsoid composed of CPB,OP,n-butanol,n-heptane and water.It was found that in the microemulsoid with its mass ratio of m(CPB/OP)∶m(n-butanol)∶m(n-heptane)∶m(H2O)=0.25∶3.3∶0.8∶89.9,and buffered at pH 9.80 with borate buffer solution,a red colored complex was formed by the reaction of Ga(Ⅲ) with MOQAPG in the mole ratio of 1 to 2,having its absorption maximum at the wavelength of 525 nm and its apparent molar absorptivity (ε525) of 1.6×105L·mol-1·cm-1.Beer′s law was kept in the range of 7-800 μg of Ga(Ⅲ) per 1 L of solution.Detection limit (3S/N) of the method was found to be 1 μg·L-1.The proposed method was applied to determine contents of gallium in samples of coal and ore,giving results in consistency with the results obtained by AAS,and values of RSD′s (n=6) less than 5%.Test for recovery was made by standard addition method,and value of average recovery found was 102.7%.