An ultrasensitive electrochemical sensor for xanthine and hypoxanthine based on the enhancement effect of acetylene black
Insoluble acetylene black (AB) nanoparticles were readily dispersed into N,N-dimethylformamide (DMF), and then used to modify the surface of a glassy carbon electrode (GCE) by solvent evaporation. Scanning electron microscopy (SEM) characterization indicates that the GCE surface was covered with a uniform AB film composed of a porous structure. The fabricated AB sensing film exhibits remarkably enhanced current signals for the oxidation of xanthine (XA) and hypoxanthine (HXA) compared to the bare glassy carbon electrode (GCE). The influences of pH value, the amount of AB, accumulation potential and the time on the signal enhancement of XA and HXA were studied. Based on the significant enhancement effect of acetylene black nanoparticles, a simple electrochemical sensing platform with high sensitivity was developed for the simultaneous detection of XA and HXA. Under the optimal conditions, the detection limits (S/N = 3) of XA and HXA were estimated to be as low as 2.5 nM and 5 nM, respectively. Moreover, the proposed electrochemical method was successfully used to detect a real blood sample.