Cobalt Oxide/Nickel Cobalt Sulfide/Poly(1,8‐diaminonaphthalene) Electrochemical Sensor‐Based Therapeutic Monitoring of Primaquine in Urine to Combat Low Treatment Adherence in Vivax Malaria Therapy

Patients’ compliance with primaquine treatment is low due to the long 14‐day duration of primaquine and the toxic side effects, including acute hemolytic anemia. This study aimed to develop a cobalt oxide/nickel cobalt sulfide/poly(1,8‐diaminonaphthalene) (Co ₃ O ₄ @NiCo ₂ S ₄ @poly(1,8‐DAN))‐based electrochemical sensor for monitoring primaquine in urine to combat low adherence. The Co ₃ O ₄ @NiCo ₂ S ₄ @poly(1,8‐DAN) nanocomposite was synthesized using hydrothermal and oxidative polymerization and characterized using high‐resolution transmission electron microscopy (HRTEM), energy‐dispersive X‐ray spectroscopy (EDS), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy were used to study the electrochemical properties of the nanocomposite. A 5 μL aliquot of Co ₃ O ₄ @NiCo ₂ S ₄ @poly(1,8‐DAN) was drop‐casted onto the glassy carbon electrode, and DPV was used to evaluate the electrochemical sensor’s performance. A linear calibration response was established over primaquine’s concentration range of 10–50 µM. The study found a detection limit of 2.51 nM with a linear concentration range of 10–50 µM. Real sample analysis in urine demonstrated recovery ranges of 98.3%–101.1%. This study reports, for the first time, the synthesis of the Co ₃ O ₄ @NiCo ₂ S ₄ @poly(1,8‐DAN) ternary nanocomposite and its application for the detection of primaquine.