Immobilization of DNA on a glassy carbon electrode based on Langmuir–Blodgett technique: application to the detection of epinephrine
A double-stranded (ds) DNA-octadecylamine Langmuir–Blodgett film was attached to the surface of glassy carbon electrode (GCE) to create a novel voltammetric sensor (DNA-LB/GCE) for epinephrine (EP). Atomic force microscopy and electrochemical impedance spectroscopy were employed to study the characteristic of the DNA-LB film. The electrochemical behavior of EP at the modified electrode was investigated in pH 6.0 phosphate buffer solutions by cyclic voltammetry and amperometric methods. Compared with bare GCE, the DNA-LB/GCE sensor demonstrated an electrocatalytic effect on the oxidation of EP. In addition, the sensor shows excellent selectivity for EP detection, being free of interference from excess ascorbic acid and uric acid, and the method was also applied successfully to detect EP in the human urine samples.