离子色谱电感耦合等离子体质谱研究痕量氯金酸在弱碱性体系中金(Ⅲ)的形态  

A study of Trace Gold Chloride and Hydroxide Speciation in Weak Alkaline Solution by Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry

作　　者：刘德晔[1] 朱醇[1] 马永建[1] 

机构地区：[1]江苏省疾病预防控制中心,南京210009

出　　处：《分析化学》2012年第6期945-949,共5页Chinese Journal of Analytical Chemistry

摘　　要：采用离子色谱电感耦合等离子体质谱联用方法研究弱碱性体系下痕量氯金酸中Au(Ⅲ)的形态。结果表明:在弱碱性条件下,总金含量在4.0～30 ng之间,Au(Ⅲ)主要以[AuCl2(OH)2]μ和[AuCl(OH)3]μ的形式存在。与较高含量的氯金酸溶液相比,痕量氯金酸溶液中的[AuCl2(OH)2]μ至少可以在pH 7.0～10.0范围内存在。溶液外加的Cl-可使[AuCl2(OH)2]-含量升高同时降低[AuCl(OH)3]μ含量;当pH=7.0或Clμ浓度高于0.050 mol/L,会产生不随色谱流出的金络合物,根据水解过程推断该络合物为[AuCl3(OH)]μ。在pH 8.0～10.0,Cl-浓度在0.000～0.020 mol/L时,[AuCl2(OH)2]μ+OHμ幑幐[AuCl(OH)3]μ+Clμ的水解平衡常数为不定值,说明痕量氯金酸的水解不仅受pH值和Clμ浓度影响,还受其它因素影响。A method based on ion chromatography-inductively coupled plasma mass spectrometry（IC-ICPMS） was developed to study trace gold chloride and hydroxide speciation in weak alkaline solution.The results revealed that,the main compounds in weak alkaline solution were [AuCl 2（OH） 2 ] - and [AuCl（OH） 3] - when the total Au mass was between 4.0-30 ng.Unlike high HAuCl 4.4H 2 O concentration,trace [AuCl 2（OH） 2 ] - could exist between pH 7.0 to 10.0,at least.Additional chloride brought promotion to [AuCl 2（OH） 2 ] - and reduction to [AuCl（OH） 3 ] -.When pH was 7.0 or chloride concentration was above 0.050 mol / L,Au would generate a compound which could not be flushed out of chromatography system.According to hydrolysis process,that compound was deduced as [AuCl 3（OH） ] -.The equilibrium constant K 3 of [AuCl 2（OH） 2 ] - ＋OH  - [AuCl（OH） 3 ] - ＋Cl - always changed with pH values and chloride concentrations.Therefore,there might exist other factor to influence the trace Au？ hydrolysis.

关 键 词：离子色谱-电感耦合等离子体质谱 金形态 平衡常数 

分 类 号：O614.123[理学—无机化学] O657.63[理学—化学]