新银盐光度法测定化学试剂中微量砷

Determination of Microamount Arsenic in Chemical Reagent by a New Silver Salt Spectrophotometry

提出了测定化学试剂中微量砷的新方法。在酒石酸介质中，用硼氢化钾发生砷化氢，用硝酸银－聚乙烯醇－乙醇吸收砷化氢，形成黄色银溶胶，在４１０ｕｍ测定吸光度。方法操作简便，分析速度快，灵敏度高。对几种化学试剂中微量砷的分析，相对标准偏差小于１０％，回收率为９２％－１０３％。运用正交试验考察了新银盐光度法发生砷化氢的条件，研究了发生效率和吸收效率，讨论了吸收显色液用量对砷化氢吸收的影响及共存离子的影响。

he arsenic is reduced into arsine by KBH. in a tartaric acid medium. The arsine is absorbed by an absorbing solution of silver nitrate--polyvinylol--ethanol. The color developed due to the reaction between arsine and silver nitrate is photometrically measured at 410urn. The advantages of this method are simple operation,less time--consuming and high sensitivity. Determination of arsenic in chemical reagents shows that the relative standard deviation is less than 10%,the recovery tatio is 92 %--103 %. The conditions of the hydride generation are investigated by orthogonal test. The yeild of the hydride generation and the absorption are studied. The influence of the volume of absorbing solution and coexistence ion on this method are discussed.