A novel dopamine electrochemical sensor based on La3+/ZnO nanoflower modified graphite screen printed electrode

Somayeh Tajik,Hadi Beitollahi,Mohammad Reza Aflatoonian

doi:10.5599/jese.674

Abstract

Flower-like La3+/ZnO nanocomposite was facile synthesized. A simple and ultrasensitive sensor based on graphite screen printed electrode (SPE) modified by La3+/ZnO nanoflower was developed for the electrochemical determination of dopamine. The electrochemical behavior of dopamine was studied in 0.1 M phosphate buffer solution (PBS) using cyclic voltammetry (CV), chronoamperometry (CA) and differential pulse voltammetry (DPV). Compared with the unmodified graphite screen printed electrode, the modified electrode facilitates the electron transfer of dopamine, since it notably increases the oxidation peak current of dopamine. Also, according to CV results the maximum oxidation of dopamine on La3+/ZnO/SPE occurs at 150 mV which is about 140 mV more negative compared with unmodified SPE. Under optimized conditions, the modified electrode exhibited a linear response over the concentration range from 0.15 to 300.0 μM, with a detection limit of 0.08 μM (S/N = 3). The proposed sensor exhibited a high sensitivity, good stability and was successfully applied for dopamine determination in dopamine ampoule, with high recovery.

Highlights

Dopamine (3,4-dihydroxyphenyl ethylamine), as an excitatory neurotransmitter in mammalian central nervous systems [1], plays an important role in several physiological activity such as mood, attitude and movement [2]
Experiments performed by use of the modified electrode at various pH values ranging from 2.0–9.0, revealed that the best results for electrooxidation of dopamine are obtained at pH 7.0
According to cyclic voltammetry (CV) results, the maximum oxidation of dopamine on La3+/ZnO/screen printed electrode (SPE) occurs at 150 mV which is about 140 mV more negative compared with unmodified SPE

Summary

Introduction

Dopamine (3,4-dihydroxyphenyl ethylamine), as an excitatory neurotransmitter in mammalian central nervous systems [1], plays an important role in several physiological activity such as mood, attitude and movement [2]. Screen-printed electrodes (SPEs), which are fabricated by printing several types of inks on a specific substrate have been considered superior Such SPEs have been recently employed as diagnostic tools for food poisoning, diseases, and environmental pollutants [17,18,19,20,21]. All the chemicals used for the preparation of nano-powders, namely zinc acetate (Zn(CH3COO)2×2H2O), lanthanum nitrate (La(NO3)3×6H2O), thiourea ((NH2)2CS) and ammonia (25 % NH3), were of analytical grade. ZnO nanostructures were prepared by dissolving 0.46 mol of zinc acetate in 80 mL of deionized water, 0.0046 mol of lanthanium nitrate in 80 mL of deionized water, 0.18 mol of thiourea in 80 mL of deionised water and lastly by adding 19.76 mL of ammonia in 80 mL of deionised water. The dopamine content was analyzed by the proposed method using the standard addition method

Result and Discussion

50 This work

Findings

Conclusions