Graphitic carbon nitride supported Gd(OH)3/CuO nano-rods: A high-performance catalyst for electro-catalytic theophylline detection

Background Monitoring the drug components is important to maintain the patient's health. Theophylline (THE) is a drug used to treat asthma, which has serious health consequences if consumed in excess. This drug is also found in food, so the chance of increased consumption must be high. In addition, low levels of medication lead to improper treatment. Therefore, monitoring this type of medication is a crucial factor. Methods Synthesis of an efficient electrocatalyst, combining gadolinium copper oxide with graphitic carbon nitride (GCO-gCN) via facile hydrothermal method. Physical characterizations validated the GCO-gCN composites, prepared well and highly interconnected. Determining THE through analyzing current responses from GCO-gCN/GCE using cyclic voltammetry (CV), and differential pulse voltammetry (DPV) as an electrochemical sensor. The developed technique was effectively applied to determine THE in food and serum samples, yielding satisfactory outcomes. Significant findings Detection parameters such as limit of detection (LOD = 9.6 ng/L), sensitivity (0.716 μA/μM cm²), and limit of quantification (LOQ = 29.32 ng/L), were successfully determined. Additionally, the sensors exhibited exceptional interference resistance, high sensitivity, robust stability, and reliable repeatability and reproducibility (RSD < 5 %). This study underscores the GCO-gCN/GCE composite's potential as a highly efficient material for sensitive and reliable THE detection.