Triphosphate Ion-Selective Electrode Based on Zr-Porphyrin Complex

Area of Science:

• Analytical Chemistry
• Inorganic Chemistry

Background:

• Developing selective ion-selective electrodes (ISEs) is crucial for accurate anion detection.
• Porphyrin complexes offer potential as selective ionophores in ISEs.
• Understanding the complexation behavior of zirconium(IV) with anions is key for sensor design.

Purpose of the Study:

• To develop a highly selective ion-selective electrode for triphosphate (TP) detection.
• To investigate the complexation mechanism between zirconium(IV) porphyrin complexes and triphosphate.
• To evaluate the electrode's performance in monitoring TP hydrolysis.

Main Methods:

• Synthesis and characterization of zirconium(IV) complexes with octaethylporphin (H2oep) and tetraphenylporphin.
• Fabrication and electrochemical evaluation of ion-selective electrodes using these complexes.
• Spectroscopic and structural analysis to identify electroactive species.
• Monitoring of triphosphate hydrolysis using the developed electrode.

Main Results:

• The zirconium(IV)-octaethylporphin complex exhibited high selectivity for triphosphate over other hydrophilic anions.
• The electroactive species [(Zr4(oep)4(Htp)2] with a TP/Zr ratio of 0.5 was identified, featuring a unique binding structure.
• The zirconium(IV)-tetraphenylporphin complex showed higher Lewis acidity, leading to precipitation and loss of electroactivity at higher TP concentrations.
• The developed electrode successfully monitored the hydrolysis of triphosphate into diphosphate and phosphate.

Conclusions:

• A novel zirconium(IV) porphyrin-based ion-selective electrode provides a selective method for triphosphate detection.
• The unique coordination environment within the zirconium(IV)-octaethylporphin complex is responsible for its high TP selectivity.
• This electrode system is a viable tool for studying biochemical processes involving triphosphate hydrolysis.