Solid-contact Hg(II)-selective electrode based on a carbon-epoxy composite containing a new dithiophosphate-based...

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Materials Science

Background:

• Ion-selective electrodes (ISEs) are crucial for detecting specific ions in various matrices.
• Developing highly selective and stable electrodes for heavy metal ions like mercury (II) remains a significant challenge.
• Existing mercury (II) sensors often suffer from interference and limited operational stability.

Purpose of the Study:

• To develop and characterize a novel ion-selective electrode for mercury (II) detection.
• To evaluate the electrode's selectivity, Nernstian response, and detection limits.
• To assess the electrode's long-term stability and applicability in potentiometric titrations.

Main Methods:

• Fabrication of an ion-selective electrode with an inner solid contact utilizing a new ligand: O,O'-(2,2'-biphenylene)dithiophosphate pentyl (PenDTF).
• Electrochemical characterization including Nernstian response, selectivity testing against divalent ions, and determination of detection limits.
• Evaluation of electrode stability through repeated use and testing across a pH range (0-5).
• Application of the electrode as an indicator in the potentiometric titration of mercury (II) with EDTA.

Main Results:

• The novel PenDTF-based electrode demonstrated high selectivity for mercury (II) ions, even in the presence of other divalent ions.
• A good Nernstian response to Hg(II) (33.7±1.0 mV decade(-1)) was observed over a concentration range of 5.3×10(-7) to 1.0×10(-2) mol L(-1).
• The electrode achieved a low detection limit of (6.1±1.7)×10(-7) mol L(-1) and showed good stability with a variation coefficient of 3% after surface renewal.
• The electrode performed satisfactorily as an indicating electrode in potentiometric titrations of Hg(II) with EDTA.

Conclusions:

• The developed ion-selective electrode offers a promising, selective, and stable platform for mercury (II) ion determination.
• The electrode's robust design and reliable performance make it suitable for practical analytical applications, including titrations.
• This novel sensor contributes to advancements in electrochemical sensing for environmental and industrial monitoring of mercury.