Analytical Sciences

Potentiometric Response of a Neutral-carrier-based Membrane to Aqueous Mercury in Cl^--rich Media

Yunmi KIM,* Jongwon KIM,** Kyoung Nam KIM,*** Suk-Kyu CHANG,*** and Taek Dong CHUNG*

*Department of Chemistry, Seoul National University, Seoul 151-747, Korea
**Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763, Korea
***Department of Chemistry, Chung-Ang University, Seoul 156-756, Korea

The unique potentiometric response of mercury sensors was investigated in aqueous Cl^--rich media, which are often encountered in natural, especially biological samples. The conventional neutral-carrier-based Hg(II)-ISEs are not practically useful because the Cl^- concentrations in natural aqueous samples are normally too high for mercury to be present in the form of Hg²⁺. Negative potentiometric slopes, which are the opposite behavior of the previously reported Hg(II)-ISEs, were experimentally confirmed and quantitatively reasoned based on the aqueous solution equilibrium of Hg²⁺.

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