Simultaneous determination of norepinephrine, acetaminophen and tryptophan using a modified graphene nanosheets paste electrode

The electrooxidation of norepinephrine (NE) at the surface of a modified graphene nanosheet paste electrode was studied using electrochemical approaches. Under the optimized conditions (pH 7.0), the square wave voltammetric (SWV) peak current of NE increased linearly with NE concentration in the range of 8.0 x 10(-8) -6.0 x 10(-4) M. The detection limit was 3.0 x 10(-8) M for NE. This method was also used for the simultaneous determination of NE, acetaminophen (AC) and tryptophan (TRP). Finally, this new sensor was used for determination of NE, AC and TRP in some real samples.