CTAB functionalized graphene oxide/multiwalled carbon nanotube composite modified electrode for the simultaneous determination of ascorbic acid, dopamine, uric acid and nitrite

We have developed hexadecyl trimethyl ammonium bromide (CTAB) functionalized graphene oxide (GO)/multiwalled carbon nanotubes (MWNTs) modified glassy carbon electrode (CTAB-GO/MWNT) as a novel system for the simultaneous determination of dopamine (DA), ascorbic acid (AA), uric acid (UA) and nitrite (NO2-). The combination of graphene oxide and MWNTs endow the biosensor with large surface area, good biological compatibility, electricity and stability, high selectivity and sensitivity. In the fourfold co-existence system, the linear calibration plots for AA, DA, UA and NO2- were obtained over the range of 5.0-300 mu M, 5.0-500 3.0-60 mu M and 5.0-800 mu M with detection limits of 1.0 mu M, 1.5 mu M, 1.0 mu M and 1.5 mu M, respectively. In addition, the modified biosensor was applied to the determination of AA, DA, UA and NO2- in urine samples by using standard adding method with satisfactory results. (C) 2014 Elsevier B.V. All rights reserved.