Electrochemical Analysis: Highly Selective Determination of Tenoxicam in Pharmaceutical and Environmental Samples Using a Molecularly Imprinted Polymer-Based Potentiometric Electrochemical Sensor

A highly selective potentiometric method for the determination of tenoxicam (TEX) was developed based on molecularly imprinted polymer (MIP) membrane electrodes. This study contributes to the field of analytical chemistry by designing advanced electrochemical sensors for pharmaceutical analysis. The tenoxicam-imprinted polymers (TEX-MIPs) were synthesized using tenoxicam as the template molecule, allyl chloride as the functional monomer, trimethylolpropane triacrylate (TMPTA) as the cross-linking agent, and benzoyl peroxide (BP) as the radical initiator. Poly(vinyl chloride) (PVC)-based membranes were fabricated incorporating various plasticizers, namely oleic acid (O.A), paraffin (PRF), tri-butyl phosphate (TBP), and di-butyl sebacate (DBS), and subsequently employed to construct potentiometric electrochemical sensors. The fabricated TEX-MIP electrodes exhibited near-Nernstian slopes of 42.6-52.7 mV per decade over a linear concentration range of 1.0 × 10⁻⁵ to 1.0 × 10⁻¹ M. These analytical characteristics demonstrate the suitability of the proposed electrochemical sensing platform for quantitative analysis in modern analytical chemistry. The sensors demonstrated stable and reproducible responses within a wide pH range (3–9). Selectivity studies conducted in the presence of common pharmaceutical excipients, including benzoic acid, sodium benzoate, methyl paraben, and glucose, confirmed the high selectivity of the proposed electrodes toward tenoxicam. The obtained results indicate that TEX-MIP-based membrane electrodes provide a reliable, sensitive, and selective electrochemical analytical platform for the potentiometric determination of tenoxicam in pharmaceutical formulations and environmental samples.