Preparation of Molecularly Imprinted Metoprolol Sensor from Poly(aniline-co-p-toluene sulfonic acid)

In this study, the metoprolol (MTP), which is a beta blocker class molecule used in the hypertension treatment, was prepared by modifying the glassy carbon electrode (GCE) with molecular imprinting technique. Firstly, p-toluene sulfonic acid (PTSA) and aniline (AN) were coelectropolymerized in the presence of MTP as a template molecule on GCE and MTP contained poly(aniline-co-p-toluene sulfonic acid) (p(AN-co-PTSA)) film was obtained. Then, the template metoprolol molecule was desorbed from the conductive p(AN-co-PTSA) film structure on the GCE surface using hydrochloric acid. Obtained molecularly imprinted electrodes were used to determine MTP by square wave voltammetry (SWV) method. The modifed electrodes obtained showed a correlation coefficient (R²) of 0.9995 in the 40-1500 µM MTP concentration range. The limit of detection (LOD) and the limit of quantification (LOQ) of the p(AN-co-PTSA) film modifed MTP electrodes were 37.9 µM and 126.3 µM, respectively. The standard deviation of 1.33% was observed for the first three replicates with the same modified electrode. For the ten replicated electrodes, stable reproducibility was achieved between the first electrode result and the tenth electrode result. For the modifed MTP electrode, the relative standard deviation (RSD%) value was calculated to be 2.53%. As results, the molecular imprinted electrodes prepared with p(AN-co-PTSA) film have low response time, high reproducibility, good stability and high selectivity for the determination of MTP.