An all-solid-state monohydrogen phosphate sensor based on a macrocyclic ionophore.

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Materials Science

Background:

• Accurate quantification of monohydrogen phosphate ions is crucial in environmental and biological monitoring.
• Development of selective and sensitive ion-selective electrodes (ISEs) is an ongoing area of research.

Purpose of the Study:

• To develop and characterize a novel all-solid-state electrode for the selective determination of monohydrogen phosphate ions.
• To investigate the performance and selectivity of the developed electrode.

Main Methods:

• Synthesis of a chiral A(2)B(2) macrocyclic compound as an ionophore.
• Fabrication of a polyvinyl chloride (PVC)/polyurethane (PU) membrane matrix incorporating the ionophore and nitrophenyl octyl ether plasticizer.
• Electrochemical characterization using potentiometric measurements.

Main Results:

• The optimized electrode exhibited a near-Nernstian slope of 31.0 ± 1.0 mV/decade for HPO(4)(2-) over a wide concentration range (1.0 x 10(-6) to 1.0 x 10(-2)M) at pH 7.4.
• The electrode demonstrated a low detection limit of 8.4 x 10(-7)M and a useful life of six weeks.
• Excellent selectivity for monohydrogen phosphate was observed over various other anions, with the selectivity sequence HPO(4)(2-)>SO(4)(2-)>Ac(-)>NO(3)(-)>ClO(4)(-)>Cl(-)>I(-).

Conclusions:

• The developed all-solid-state electrode, utilizing a novel chiral macrocyclic ionophore, offers a selective and sensitive method for monohydrogen phosphate quantification.
• The electrode's performance, including its near-Nernstian response, low detection limit, and excellent selectivity, makes it suitable for practical applications in ion analysis.