Abstract
In the present paper, a simple and rapid method for simultaneously measuring norepinephrine (NE) and acetaminophen (AC) that uses manganese dioxide particle decorated chemically reduced graphene oxide sheet nanocomposite electrodes is presented. The morphology and composition of CRGO-MnO2 nanocomposites are characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectral techniques. The resultant CRGO-MnO2 modified GCE exhibited excellent electrocatalytic redox activities toward NE. The experimental parameters for preparation of the CRGO-MnO2 modified GCE also included variables related to the simultaneous determination of NE and AC under optimized conditions, at the same time, using square wave voltammetry (SWV). In particular, the peak potential separation between NE and AC at the CRGO-MnO2 modified GCE was as high as 190 mV, much larger than that at the CRGO/GCE. Using square wave voltammetry, calibration curves for NE and AC were obtained in the range of 2 x 10(-7) to 8 x 10(-4) M and 4 x 10(-6) to 8 x 10(-3) with detection limits of 2.0 x 10(-9) and 4.0 x 10(-7) M, respectively. The proposed method was successfully applied to determine NE and AC in samples with good results. In addition, the CRGO-MnO2 modified GCE has good reproducibility and high stability.