Electrochemical determination of 8-azaguanine in human urine at a multi-carbon nanotubes modified electrode

Abstract

A novel carbon nanotubes modified glassy carbon electrode was simply and conveniently fabricated. The electrochemical properties of 8-azaguanine at a carbon nanotubes modified electrode were investigated by cyclic voltammetry, and an anodic peak was observed at approximately 0.86 V (vs. SCE). Based on this, an ultrasensitive electrochemical method was proposed for the determination of 8-azaguanine. The oxidation peak current is linear to the concentration of 8-azaguanine over the range from 2.5×10−8 to 1.0×10−5 M, and the limit of detection is 1.0×10−8 M at 2 min open-circuit accumulation. The relative standard deviation at 2.0×10−7 M 8-azaguanine was approximately 5.3% (n=10). The analysis method is demonstrated by using human urine samples obtained from cancer patients following intravenous administration of 8-azaguanine.