氨水分离-电感耦合等离子体质谱法测定化探样品中的银  

Determination of Silver in Samples for Geochemical Exploration by Inductively Coupled Plasma-Mass Spectrometry after Ammonia Complexation

作　　者：孙朝阳 戴雪峰 代小吕 陈斌[2] 郑存江 

机构地区：[1]浙江省地质矿产研究所,浙江杭州310007 [2]中国环境监测总站,北京100012

出　　处：《岩矿测试》2015年第3期292-296,共5页Rock and Mineral Analysis

基　　金：国家重大科学仪器设备开发专项(2011YQ06010009)

摘　　要：应用电感耦合等离子体质谱法（ICP-MS）测定化探样品中的Ag时,两个同位素107Ag和109Ag分别受90Zr16O1H、91Zr16O和92Zr16O1H、93Nb16O等的干扰,即使采用干扰系数法校正,测定结果误差仍较大。本文采用硝酸-氢氟酸-高氯酸封闭分解样品,氨水沉淀分离干扰元素Zr后以103Rh为内标用ICP-MS测定,溶液中残留Zr对107Ag的测定干扰采用干扰系数法进行校正。方法检出限（3σ）为4.1 ng/g,相对标准偏差（n=12）为2.5%~7.8%。经53个地球化学标准物质验证,溶液中的Ag未见损失。本方法是在氨性介质中Ag与氨形成稳定的络合离子,而Zr则生成氢氧化物沉淀,实现了Ag和Zr的分离,大大减小了Zr对Ag的测定干扰;采用封闭分解样品,减少用酸量,降低了样品空白值,操作方法比高压密闭分解和P507萃淋树脂分离方法更简便快速。Isobaric ions interfere with two isotopes of Ag during determination by Inductively Coupled Plasma-Mass Spectrometry（ ICP-MS）,i. e.,90Zr16O1 H and91Zr16O on107 Ag,and92Zr16O1H and93Nb16 O on109Ag. Although an interference correction coefficient method was used for the calibration of the analytical results,the analytical errors remain serious. In the proposed method,samples were closed decomposed by nitric acid,hydrofluoric acid,and perchloric acid. Ammonia was used to precipitate Zr and the purified Ag was determined by ICP-MS using103 Rh as the internal standard. The interference caused by the residual Zr was calibrated by the interference coefficient method. The method has a detection limit（ 3σ） of 4. 1 ng / g and relative standard deviation（ n = 12） ranging from2. 5% to 7. 8%. Determination of Ag in 53 primary certified materials of geochemical exploration indicates no loss of Ag. Using ammonium as the reagent,separation of Zr and Ag was successfully achieved due to the formation of the stable Ag-ammonium complex and Zr-hydroxide precipitate. The separation of Ag from Zr has reduced the interferences of Zr on Ag. Compared with the high-pressure sealed decomposition method and the P507 extraction resin separation method,the closed sample decomposition method is much simpler with less acid used and a lower blank.

关 键 词：化探样品 银 氨水 封闭溶样 电感耦合等离子体质谱法 

分 类 号：O614.122[理学—无机化学] O657.63[理学—化学]