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PVC(聚氯乙烯)基体和液膜电极直接电位法测定金(Ⅲ)已得到了发展,将膜同硝酸灵四氯金酸盐(Ⅲ)结合作为电活性物质,能迅速响应浓度范围10~(-5)—0.1M的金(Ⅲ),得到的响应斜率为52.8—55.2毫伏/组(十个一组),在许多阴阳离子存在的情况下,pH值为2—5时,电极对金(Ⅲ)有较好的选择性,PVC膜电极具有选择性较好(Cr~(3+)、Mn~(2+)和ClO_4~-除外)和热稳定性较高的优点,与PVC膜电极相比,液膜电极响应斜率高、响应时间短。在2微克/毫升—2毫克/毫升的测定范围内,AuCl_4~-的平均回收率为98.5％,平均值的标准偏差为1.0％,测定某些金合金(含金58.3—99.9％)和药品制剂中的金,平均回收率为99.4％,平均值的标准偏差为0.7％,该方法的测定结果可与孔雀绿分光光度法和美国药典重量法的测定结果相媲美。
Determination of gold (Ⅲ) by direct potentiometry with PVC (polyvinyl chloride) matrix and liquid membrane electrode has been developed. The combination of membrane and tetrachloroaurate (Ⅲ) with nitrite as electroactive substance can rapidly respond to the concentration range of 10 ~ (-5) -0.1M of gold (III), the resulting response slope of 52.8-55.2 mV / group (a group of ten), in many cases of anion and cation, the pH value of 2-5, the electrode The selectivity to gold (Ⅲ) is better. The PVC membrane electrode has the better selectivity (excluding Cr 3+, Mn 2+ and ClO 4 -) and the higher thermal stability. Compared with PVC membrane electrode, liquid membrane electrode has high response slope and short response time. The average recoveries of AuCl_4 ~ - in the range of 2 μg / ml to 2 mg / ml were 98.5% and the average standard deviations were 1.0%. Some gold alloys (58.3-99.9% gold) The gold in the formulation had an average recovery of 99.4% and a mean standard deviation of 0.7%. The assay of this method is comparable to that of malachite green spectrophotometry and the U.S. Pharmacopoeia gravimetric assay.