Determination of theophylline at a cysteic acid modified glassy carbon electrode

A glassy carbon electrode modified with electrodeposited cysteic acid is proposed for the determination of theophylline. Estimation of the linear range, calibration function and limit of detection, as well as determination in real samples such as medication tablets were performed. According to the results, such a modified electrode appears to be a straightforward alternative to common glassy carbon or other modified electrodes. This thanks to the affinity of cysteic acid to the analyte, the low cost, the simplicity of the modification procedure and the reproducibility of the electrode surface.