Synthesis and characterization of bipyridine cobalt(ii) complex modified graphite screen printed electrode: an electrochemical sensor for simultaneous detection of acetaminophen and naproxen

The new Co(II) compound [Co(5,5′-dmbpy)2(NCS)2] (a1) was prepared by reacting Co(NO3)2·6H2O, 5,5′-dimethyl-2,2′-bipyridine ligand, and Na(SCN). The nano-scale size of [Co(5,5′-dmbpy)2(NCS)2] (a1) was synthesized using sonochemical process. The size of the nanoparticles (a2) was ∼13 ± 2 nm. We have also provided a new platform of electrochemical sensing for simultaneous detection of acetaminophen and naproxen using (a2) surface modified graphite screen printed electrode (SPE) in 0.1 M phosphate buffer solution (PBS, pH 7.0). In contrast to bare SPE, the modified SPE could significantly improve the electrooxidation activity of acetaminophen along with the rise in the current of an anodic peak. The peak currents acquired using differential pulse voltammetry (DPV) raised linearly with the raising of acetaminophen concentration and the sensor had a detection range over the concentration range of 0.009–325.0 μM, with a detection limit of 5.0 nM (S/N = 3). In the case of naproxen peak, currents of naproxen oxidation at the modified SPE were linearly dependent on the naproxen amounts in the range of 1.0–500.0 μM. The detection limit (S/N = 3) was calculated to be 0.03 μM. The DPV responses show that the peaks of acetaminophen and naproxen oxidation were vividly separated from one other with a potential difference of 410 mV between them. The low detection limit, high sensitivity, and stability made the relevant electrode applicable for the analysis of acetaminophen and naproxen in real samples. Further, its practical applicability was reliable and desirable in the analysis of pharmaceutical compounds and biological fluids. The benefits of using this modified electrode for the determination of analytes are compared with other works in the manuscript.