Selective Detection of Norepinephrine at Nafion Modified Carbon Fiber Microelectrode in the Presence of Ascorbic Acid

KeyWord:Nafion  carbon fiber electrode  differential pulse voltammetry(DPV)  cyclic voltammetry(CV)  norepinephrine(NE)  ascorbic acid(AA)

Abstract:

      A carbon fiber microelectrode modified with Nafion was fabricated by electrodeposition method on the basis of previous work.The electrochemical behaviour of norepinephrine(NE) and ascorbic acid(AA) at the prepared microelectrodes before and after modification were investigated using cyclic voltammetry(CV) and differential pulse votammetric(DPV) methods.Under the optimum conditions,the Nafion modified-electrode can completely shield the electrochemical response of AA,however,a sensitive response to NE was obtained on the modified electrode.Based on this,the modified electrode can be used to selectively detect NE without interference from high concentration AA.DPV response of NE showed a good linearity(r2=0.991 2) at the modified microelectrode with its concentration in the range of 1.0¡Á10-6-1.0¡Á10-4 mol/L,with a detection limit(S/N=3) of 8.6¡Á10-7 mol/L.The proposed method was applied in the determination of NE in simulation sample with spiked recovery of 101.6%.The modified electrode exhibited almost the same electrochemical behavior after a month,indicating that the modified electrode is pretty stable and has a good reproducibility.The advantages of excellent sensitivity and selectivity made the modified electrode could be used to monitor NE in complex biological environment.