A Surfactant-Electropolymer modified dual sensor for the monitoring of norepinephrine at nanomolar levels in biological samples and pharmaceutical formulations

Abstract

This paper focuses on the surface modification of a Glassy carbon electrode (GCE) using poly-terephthalic acid and poly-4-amino-3-hydroxy-1-naphthalenesulfonic acid (poly-(TERE-AHNSA)/GCE) by simultaneous electropolymerization of respective monomers for the first time from the best of our knowledge, which is a simple and cost-effective method. FTIR, AFM, and SEM-EDX examinations were used to confirm the developed electrode. The adapted electrode is then used for the monitoring and determination of clinically significant norepinephrine (NE) using electroanalytical techniques such as differential pulse and cyclic voltammetry. The electrooxidation of NE on poly-(TERE-AHNSA)/GCE occurred at a potential of +0.216 V in phosphate buffer solution (PB) of pH 6.0 and showed a higher current response compared to electrodes developed with separate electropolymers. This enhanced response is likely due to the synergistic effect of both polymer layers obtained through electropolymerization, which increases the surface area. The developed sensor exhibits favorable characteristics, including a lowest detection limit (LOD) of 2.08 nM, a linear range spanning from 5.0 nM to 1600.0 μM which is the widest range ever reported, as well as improved sensitivity and selectivity, surpassing previous reports. The linearity analysis was also performed utilizing a screen-printed electrode (SPE), yielding linear ranges of 100.0 nM–600.0 μM. With a recovery rate ranging from 98 to 105%, the developed sensor shows great potential as a reliable tool for electroanalysis of NE in blood, urine, and pharmaceutical samples.