Highly selective and sensitive copper membrane electrode based on a new synthesized Schiff base

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Materials Science

Background:

• Development of selective ion-selective electrodes (ISEs) is crucial for accurate metal ion monitoring.
• Schiff bases offer potential as ionophores in ISE membranes due to their coordinating properties.

Purpose of the Study:

• To synthesize and characterize Bis(2-hydroxyacetophenone)butane-2,3-dihydrazone (BHAB) as a novel N-N Schiff base ionophore.
• To construct and evaluate a Cu(II) membrane sensor utilizing BHAB.
• To investigate the sensor's performance, selectivity, and applicability in real samples.

Main Methods:

• Synthesis of BHAB Schiff base.
• Fabrication of a membrane electrode with poly(vinyl chloride) (PVC), o-nitrophenyloctyl ether (NPOE), BHAB, and oleic acid (OA).
• Electrochemical characterization including potentiometric measurements, pH studies, and selectivity tests against various cations.

Main Results:

• The optimized membrane composition (30% PVC, 55% NPOE, 7% BHAB, 8% OA) yielded the best sensor performance.
• The sensor exhibited excellent selectivity and sensitivity for Cu(II) ions over a wide range of interfering cations.
• A Nernstian response with a slope of 29.6 mV/decade was observed over a broad concentration range (5.0x10⁻⁸ to 1.0x10⁻² mol L⁻¹).
• The detection limit was as low as 3.0x10⁻⁸ mol L⁻¹ with a fast response time (<15s).
• The electrode demonstrated stability over 12 weeks within a pH range of 2.8–5.8.

Conclusions:

• BHAB is an effective ion carrier for developing a highly selective and sensitive Cu(II) membrane sensor.
• The developed sensor shows promising performance for copper determination in water samples and potentiometric titrations.