Electrochemical synthesis of Ni nanostructures on paper electrode forsimultaneous sensing of dopamine, tryptophan and ascorbic acid

In this work we used a simple strategy for simultaneous determination of dopaminehydrochloride(Dph), tryptophan (Trp) and ascor-bic acid (AA) by electrochemical synthesis ofconductive Ni nanostructures (band gap of 1.0eV) on the surface of multiwalled carbon nanotubenanocomposite modified paper electrode (NiNPs/MWCNT/PE). Scanning electron microscopy(SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differentialpulse vol-tammetry (DPV) were used to characterize the performance and microstructure of thesensor. The diffusion coefficient (D) and the kinetic parameters such as electron transfercoefficient (α) and catalytic rate constant (k) for Dph, Trp and AA were also determined usingelectrochemical approaches [1]. The cyclic voltammetry method showed Dph, Trp and AAoxidation reaction with irreversible characteristics was diffusion-controlled at low scan rates.Under the optimized experimental conditions Dph, Trp and AA give linear response over therange of 0.008 - 70.0 mM, 0.006–50.0 mM and 0.01.0–40.0 mM, respectively.The lower detectionlimits were found to be 0.23 for Dph, 0.10 for Trp and 0.79 nM for AA. The modified electrodeshowed good sensitivity and stability by better response than to other reported papers [2-3].Thepractical application of the modified electrode was demonstrated by measuring the concentrationof Dph, Trp and AA in blood serumand pharmaceutical samples.

کلیدواژه ها:

Electrochemical deposition ، Ni nanostructures ، Dopamine-hydrochloride ، tryptophanand ascorbic acid ، Nanomolar sensor