Synthesis of zinc incorporated in the hydroxyapatite through a solid-state reaction process for electrochemical detection of amoxicillin using ultraviolet radiation (UV) as step catalytic

In this work, a carbon paste electrode modified with zinc integrated into the hydroxyapatite (HAP) Zn-NPh-CPE was developed for the amoxicillin (AMX) electrochemical detection. Notably, the method included a preliminary activation step of AMX before electrochemical detection using ultraviolet radiation (UV). The zinc incorporated into natural phosphate Zn-NPh was synthesized through a solid-state reaction process carried out at different temperatures, ranging from 200 degrees C to 900 degrees C for 14 h in the kiln using natural phosphate and zinc sulfate hexahydrate. It was characterized by (XRD), (FT-IR), (SEM) and (EDX) for structural and morphological details. This result showed that at high temperatures zinc was effectively integrated into the hexagonal structure of hydroxyapatite (HAP). Additionally, the influence of UV radiation on the activation of AMX was investigated using a variety of electrochemical techniques, such as differential pulse voltammetry (DPV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Hence, the results affirm that applying UV radiation catalyzes the oxidation of AMX. A linear correlation was found between the oxidation peak current and the AMX concentration, within two linear ranges from 4.0 x 10 -7 mol L -1 to 1.0 x 10 -5 mol L -1 (R 2 = 0.99) and 1.0 x 10 -5 mol L -1 to 1.0 x 10 -4 mol L -1 (R 2 = 0.989). Using the slope of the lowest concentrations, the detection limit (LOD) was found to be 1.58 x 10 -7 mol L -1 . The designed sensing platform showed excellent repeatability, estimated in terms of relative standard deviation to be (RSD = 2.78 %), for n = 8. Furthermore, this highly sensitive method was successfully applied to detect AMX in actual water samples, including tap water and wastewater samples.