Ultraviolet absorbance titration for the determination of conditional stability constants of Hg(Ⅱ) and dissolved organic matter

作     者：BAI Yingchen WU Fengchang WAN Guojing LIU Congqiang FU Pingqing LI Wen 

作者机构：The State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Graduate School of Chinese Academy of Sciences Beijing 100039 China 

出 版 物：《Chinese Journal Of Geochemistry》 (中国地球化学学报)

年 卷 期：2008年第27卷第1期

页      面：46-52页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：the National Natural Science Foundation of China(Grant Nos.40525011,40632011) the International Cooperation Project of the Chinese Academy of Sciences 

主　　题：紫外线 稳定性 汞 有机物 

摘      要：Strong interaction between natural dissolved organic matter (DOM) and Hg(Ⅱ) may influence the trans- port, conversion, toxicity and bio-validity of mercury in the environment. In this paper ultraviolet (UV) absorbance titration was employed for the first time for the determination of the conditional stability constants of Hg(Ⅱ) and (DOM). With increasing Hg(Ⅱ) concentrations, the UV absorbance of fulvic acid, humic acid, and DOM in river increases progressively. By linear and non-linear model fitting, the conditional stability constants (lgK) of Hg(Ⅱ) and DOM were worked out to be 3.54?4.93 and 3.64?4.85, respectively. The results are consistent with those acquired by the typical fluorescence quenching titration method, with the maximum relative error of lgK being 2.6% and the average relative error being 0.2%. The UV absorbance titration method has the advantages of rapid determination, simple performance, and it will probably become a new approach to studying interactions between DOM and trace metallic ions.