Electrochemical Behavior of 8-Azaguanine at DNA Langmuir - Blodgett Modified Glassy Carbon Electrode and Its Analytical Application

摘要

A highly sensitive electrochemical biosensor for the detection of trace amounts of 8-azaguanine has been designed. Double stranded (ds)DNA molecules are immobilized onto a glassy carbon electrode surface with Langmuir-Blodgett technique. The adsorptive voltammetric behaviors of 8-azaguanine at DNA-modified electrode were explored by means of cyclic voltammetry and square wave voltammetry. Compared with bare glassy carbon electrode (GCE), the Langmuir-Blodgett film modified electrode can greatly improve the measuring sensitivity of 8azaguanine. Under the optimum experimental conditions, the Langmuir - Blodgett film modified electrode in pH 3.0 Britton-Robinson buffer solutions shows a linear voltammetric response in the range of 5.0 x 10~(-8) to 1.0 x 10~(-5) mol L~(-1) with detection limit 9.0 x 10~(-9) mol L~(-1). The method proposed was applied successfully for the determination of 8_azaguanine in diluted human urine with wonderful satisfactory.