A highly sensitive photoelectrochemical sensor for the detection of theophylline based on the photoelectrocatalytic activity of a nanocomposite of polydopamine nanospheres and gold nanoparticles

(S/N = 3). This sensor exhibited optimal selectivity, prolonged stability, and commendable reproducibility when determining TP. It was successfully applied to measure TP content in various matrices, including tea, biological samples, and blood samples, with acceptable recovery rates ranging from 95.3% to 107.7%.