Work

Electrical and electrochemical pH sensing technologies: comparative mechanisms, performance, and applications

Year: 2026

Type: article

Abstract: Reliable pH measurement remains central to chemical, biological, and environmental monitoring, yet conventional electrochemical glass electrodes face persistent challenges of fragility, slow response, and limited integrability. This study presents a comparative analysis between a conventional glass-electrode pH meter and a custom-fabricated aluminum interdigitated electrode (Al-IDE) for full-range pH sensing (pH 1–13). The Al-IDE device, fabricated via standard photolithography on thermally oxidized silicon, was evaluated under identical conditions using pure buffer systems. Electrical measurements revealed a distinct U-shaped current response, decreasing from 3107 nA at pH 1 to 1.03 nA near pH 7, before rising to 781 nA at pH 13. This behaviour reflects the amphoteric nature of the Al₂O₃ surface, governed by protonation–deprotonation equilibria that modulate interfacial charge transport. The proposed nonlinear quadratic model achieved strong segmental correlations (R² > 0.89) for both acidic and alkaline regimes. Comparative assessment against the glass electrode yielded a mean absolute deviation of ≈ 0.19 pH units, confirming excellent agreement between the two modalities. While the glass electrode followed a linear Nernstian slope (–58.6 mV pH⁻¹), the Al-IDE offered rapid, reference-free, and mechanically robust operation with repeatability (RSD) ranging up to 3.5%. These findings establish the Al-IDE as a low-cost, CMOS-compatible alternative for portable or embedded pH monitoring and provide foundational insights for hybrid electro-electrical sensing architectures that integrate the precision of electrochemical systems with the real-time responsiveness of electrical transduction.

Source: Journal of Solid State Electrochemistry

DOI: 10.1007/s10008-026-06534-y

Authors: Saroja Rijal, Uda Hashim, M. N. Afnan Uda, M. N. A. Uda, Yuri Pamungkas

Institutions: Universiti of Malaysia Sabah, Universiti Malaysia Perlis, Institut Teknologi Sepuluh Nopember

Language: English

Topic: Analytical Chemistry and Sensors

Subfield: Bioengineering

Field: Chemical Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,790

Funder: Universiti Malaysia Sabah