In this study, the preparation of a glassy carbon (GC) electrode modified with chitosan/NH2-ionic liquid/manganese oxide nanoparticles (Chit/NH2-IL/MnOx) was described for electro catalytic detection of theophylline (TP). First, chitosan hydrogel (Chit) was electrodeposited on the GC electrode surface ata constant potential (−1.5 V) in acidic solution. Then, the previously synthesized amine-terminated 1-(3-Aminopropyl)-3-methylimidazolium bromide ionic liquid (NH2-IL) was covalently attached to the modified electrode via glutaraldehyde (GA) as linking agent. Finally, manganese oxide (MnOx) nanopar-ticles were electrodeposited onto the Chit/NH2-IL film by potential cycling between −1.0 and 1.7 V inMn(CH3COO)2•4H2O neutral aqueous solution. Electrochemical behavior of the modified electrode was evaluated by cyclic voltammetry (CV) technique. The charge transfer coefficient (˛) and electron transfer rate constant (ks) for MnOOH/MnO2redox couple were calculated to be 0.35 and 1.62 s−1, respectively. The resulting system brings new capabilities for electrochemical sensing through combining the advantages of IL and MnOxnanoparticles. The differential pulse voltammetric (DPV) results indicated the highability of GC/Chit/NH2-IL/MnOx modified electrode to catalyze the oxidation of TP. DPV determination of TP in acetate buffer solution (pH 5) gave linear responses over the concentration range up to 120 M with the detection limit of 50 nM and sensitivity of 804 nA M−1. Furthermore, the applicability of the sensor for TP analysis in pharmaceutical samples has been successfully demonstrated.
