Ternary Metal (W–Ni–Sr) Oxide@Polypyrrole Nanotubes: A New Frontier in the Electrochemical Detection of Promethazine Hydrochloride (PMHC)

Promethazine hydrochloride (PMHC) is a vital drug that is used as an anticholinergic, antipsychotic, antihistaminic, analgesic, sedative, and neuroleptic. However, the overdosage of PMHC also causes reproductive variations, cardiac changes, hypotension, and endocrinal variations. Hence, the detection of PMHC is crucial. Therefore, in this work an electrochemical method for the detection of PMHC is reported. The fabrication for the modified electrode is built with tungsten (W), nickel (N), and strontium (S) ternary oxide (tWNSO). To the best of our knowledge, this tWNSO ternary oxide preparation is reported for the first time in the literature. The prepared ternary oxide is deposited on the polypyrrole nanotubes, and this nanocomposite that is formed is confirmed by various physical characterizations like XRD, SEM, TEM, UV-vis spectroscopy, FTIR spectroscopy, and also DFT studies for PMHC. Thus, the nanocomposite obtained is used as a working electrode for the detection of PMHC. The fabricated tWNSO/PPyNTs/GCE has an effective surface area of 0.0436 cm². Also, no fouling was observed. The limit of detection of the analyte PMHC is 3.66 nM, the limit of quantification is 11.10 nM, and the sensitivity of the fabricated electrode in identifying the analyte is found to be 20.10 μA μM^-1 cm^-2. Thus, the modified working electrode effectively detects the analyte PMHC while demonstrating excellent stability and reproducibility.