A sensitive theophylline sensor based on a single walled carbon nanotube–large mesoporous carbon/Nafion/glassy carbon electrode

A novel theophylline (TP) sensor was developed using a single walled carbon nanotube–large mesoporous carbon/Nafion composite modified glassy carbon electrode (SWCNT–LMC/Nafion/GCE). The morphology of the SWCNT–LMC microstructure was characterized by transmission electron microscopy (TEM) and the surface of the modified electrode was characterized by cyclic voltammetry (CV). The results showed enhanced electrochemical reactivity and voltammetric response of TP. Under the selected conditions the peak current was linear with TP concentration from 0.3 to 38.0 μM with a detection limit of 0.08 μM (S/N = 3), as determined by differential pulse voltammetry (DPV). The SWCNT–LMC/Nafion/GCE was successfully applied for the determination of TP in human blood serum and urine samples with good recoveries.