示波极谱法测定空气中的痕量镓

Determination of Traces of Gallium in Air by Oscillographic Polarography

作者用10％HNO_3对采集在微孔滤膜上的镓及其化合物在室温下进行浸取,然后用氨水调pH至8～9后过滤,除去大部分共存金属干扰成分。经蒸发浓缩后,在pH6.2的乙酸-乙酸铵缓冲液中,镓与铜铁试剂和二苯胍形成三元络合物,该络合物-1.08伏(vs.SCE)处有一灵敏的吸附催化波,在0.005～0.10μg/ml范围内,波高与镓含量成正比。本法灵敏度为0.005μg。ml,合并变异系数为6.8％,平均回收率为97.8％。

Gallium and its compounds in air col-lected by millipore filter membrane areleached by 10% HNO_3, at room temperaure.After being adjusted with ammonia solntionto pH8-9, the leachate is filtered and thefiltrate is evaporated to dryness on a waterbath. The resdue is dissolved with 2 ml of10%HNO, and then into the solution areadded 0.5 ml of 5% hydroxylamine hydro-chloride solution, 0.20ml of 5% sulfosalicylicacid solution, 0.5ml of NaF solution (1mgF/ml) and 1 drop of methyl red solution.Lat it Stand for 5 min after the color ofthe solution turns orange by addition of1:1 NH_4OH solution. Add 0.20ml of 0.20%cupferron solution, 0.20ml of 0.5% diphe-nyl-guanidine solution (prepared in 95%ethanol) and 0.5ml of acetic acid-ammoni-um aceate buffer (pH 7.0). Then addwater to make the final volume of the testsolution be 10ml and measure the height ofthe second derivative polarographic wave at-1.08Ⅴ(vs.SCE). The sensitivity of themethod is 0.005-0. 10μg/ml, the coefficient ofvariation 6.8%, recovery 97.8%. Within0.005-0.10μg/ml, the wave height is linearwith the concentration of gallium.