Electrochemical investigation of p-Dimethyl amino antipyrine using ZrO₂/halloysite nano clay modified CPE

p-Dimethyl amino Antipyrine (p-DAAP) is an additive used in cocaine samples, and it is carcinogenic. Hence, its determination at the trace level is necessary. The voltammetric study has been developed for the determination of trace amounts of p-DAAP using a newly developed sensor material called Zr-halloysite nano clay composite at a carbon paste electrode (ZrO₂/HNC@CPE). The characterisation studies, like Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy confirm the formation of monoclinic structure for ZrO2 with crystalline size of 23.57 nm. The modified electrode exhibited significantly enhanced electrocatalytic activity, as evidenced by a higher exchange current density (i₀) of 355.8 µA compared with the carbon paste electrode (CPE), which showed a lower i₀ value of 172.5 µA, as determined from electrochemical impedance spectroscopy. Among the various buffer solutions used in the study, the phosphate buffer with a pH of 6.0 yielded the best results. The redox behaviour of the p-DAAP was investigated by cyclic voltammetry with the potential range between 0.1 and 0.6 V, and analytical applications have been studied through square wave voltammetric techniques using ZrO2/HNC@CPE as a working electrode in the linear range of 1 × 10–5 to 1 × 10–7 M. The ZrO2/HNC@CPE provided superior sensitivity and stability. Further, the limit of detection and limit of quantification were found to be 4.39 nM and 14.64 nM, respectively. This innovative approach has been applied to investigate the p-DAAP in biological and various water samples.