Au-nanoclusters incorporated 3-amino-5-mercapto-1,2,4-triazole film modified electrode for the simultaneous determination of ascorbic acid, dopamine, uric acid and nitrite.

A novel biosensor has been constructed by the electrodeposition of Au-nanoclusters (nano-Au) on poly(3-amino-5-mercapto-1,2,4-triazole) (p-TA) film modified glassy carbon electrode (GCE) and employed for the simultaneous determination of dopamine (DA), ascorbic acid (AA), uric acid (UA) and nitrite (NO(2)(-)). NH(2) and SH groups exposed to the p-TA layer are helpful for the electrodeposition of nano-Au. The combination of nano-Au and p-TA endow the biosensor with large surface area, good biological compatibility, electricity and stability, high selectivity and sensitivity and flexible and controllable electrodeposition process. In the fourfold co-existence system, the linear calibration plots for AA, DA, UA and NO(2)(-) were obtained over the range of 2.1-50.1 μM, 0.6-340.0 μM, 1.6-110.0 μM and 15.9-277.0 μM with detection limits of 1.1×10(-6) M, 5.0×10(-8) M, 8.0×10(-8) M and 8.9×10(-7) M, respectively. In addition, the modified biosensor was applied to the determination of AA, DA, UA and NO(2)(-) in urine and serum samples by using standard adding method with satisfactory results.