A highly sensitive electrochemical sensor for theophylline based on dopamine-melanin nanosphere (DMN)-gold nanoparticles (AuNPs)-modified electrode

Herein, a facile electrochemical sensor was proposed for accurate determination of theophylline (TP) based on dopamine-melanin nanosphere (DMN)-gold nanoparticles (AuNPs) nanocomposite-modified glass carbon electrode. The dopamine-melanin nanospheres (DMNs) were prepared facilely by a chemical route. The well-dispersed Au nanoparticles were anchored on the surface of DMNs via in situ reduction of Au precursor. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were adopted to investigate the electrochemical oxidation behavior of TP at the DMN-AuNPs-modified electrode. In 0.1 M H2SO4 medium, the developed electrochemical sensor displayed excellent electrocatalytic activity toward the oxidation of TP. The sensor showed high sensitivity for the determination of TP under the optimized conditions. The oxidation peak current of TP exhibited good linear relationship with its concentration in the range from 50 nM to 2 mu M with detection limit of 9.6 nM (S/N = 3). The modified electrode showed excellent selectivity, long-term stability, and good repeatability for the determination of TP. This proposed method was successfully applied to determine the content of TP in tea and biological samples with acceptable recoveries.

Automated summary

A facile electrochemical sensor based on dopamine-melanin nanosphere (DMN)-gold nanoparticles (AuNPs) nanocomposite-modified electrode was developed for accurate determination of theophylline (TP). The sensor showed high sensitivity and selectivity, suitable for the determination of TP content in tea and biological samples.