Electrochemical Determination of Terazosin at a Poly(Allura Red AC)‐Modified Glassy Carbon Electrode: Mechanistic Study and Application to Pharmaceutical Formulations and Serum Samples

An electrochemical method based on a poly(Allura Red AC)‐modified glassy carbon electrode was developed for the determination of terazosin hydrochloride. The sensing platform was fabricated by electropolymerization, resulting in a stable and electroactive polymer film. The electrochemical behavior of terazosin hydrochloride and its oxidation mechanism were investigated by cyclic voltammetry and differential pulse adsorptive stripping voltammetry. Mechanistic studies based on pH dependence and Laviron analysis indicated a two‐electron, one‐proton oxidation process governed by adsorption‐controlled kinetics. Under optimized conditions, the proposed sensor exhibited a wide linear dynamic range of 0.04–8.0 µM and a low detection limit of 3.48 × 10 ^–3 µM. The method demonstrated high precision, with intraday and inter‐day relative standard deviation values below 1.1%. Its practical applicability was demonstrated by the determination of terazosin hydrochloride in commercial tablet formulations and spiked human serum samples, with recovery values close to 100%. Overall, the results indicate that the poly(Allura Red AC)‐modified electrode offers a straightforward electropolymerization‐based approach with satisfactory analytical performance for terazosin hydrochloride determination in pharmaceutical and biologically relevant samples.