Electrochemical Determination of Nitrite by Au Nanoparticle/Graphene-Chitosan Modified Electrode.

Rijian Mo,Chengyong Li,Yanting Feng,Xiemin Yan,Pengzhi Hong,Zhe Wang,Chunxia Zhou,Tiantian Su,Shengli Sun,Qiong Yuan,Xuehua Wang,Lulu Lv

doi:10.3390/s18071986

Abstract

A highly sensitive nitrite (NO2−) electrochemical sensor is fabricated using glassy carbon electrode modified with Au nanoparticle and grapheme oxide. Briefly, this electrochemical sensor was prepared by drop-coating graphene oxide-chitosan mixed film on the surface of the electrode and then electrodepositing a layer of Au nanoparticle using cyclic voltammetry. The electrochemical behavior of NO2− on the sensor was investigated by cyclic voltammetry and amperometric i-t curve. The results showed that the sensor exhibited better electrocatalytic activity for NO2− in 0.1 mol/L phosphate buffer solution (PBS) (pH 5.0). The oxidation peak current was positively correlated with NO2− concentration in the ranges of 0.9 µM to 18.9 µM. The detection limit was estimated to be 0.3 µM. In addition, the interference of some common ions (e.g., NO3−, CO32−, SO42−, Cl−, Ca2+ and Mg2+) and oxidizable compound including sodium sulfite and ascorbic acid in the detection of nitrite was also studied. The results show that this sensor is more sensitive and selective to NO2−. Therefore, this electrochemical sensor provided an effective tool for the detection of NO2−.

Highlights

Nitrite has been used diffusely in the food industry and other fields [1,2,3]
An Ag/AgCl electrode was used as a reference electrode, a platinum (Pt) electrode was used as an auxiliary electrode, and a glassy carbon electrode was used as a working electrode to constitute a three-electrode system
The scanning electron microscopy (SEM) of graphene oxide oxide (GO) is shown in Figure 1a, unveiling the representative wrinkled and puckery graphene lamellate structure

Summary

Introduction

Nitrite has been used diffusely in the food industry and other fields [1,2,3]. Nitrite is detrimental to human health [4,5,6,7]. When its concentration is high in the blood, it can combine with hemoglobin. In this case, the oxygen delivery capacity of hemoglobin will be severe restricted [1,8,9]. Lethal concentrations of NO2 − intake proposed by the World Health Organization (WHO) are in the range of 8.7 × 10−6 –2.83 × 10−5 mol/L [2]. It is critical to create a simple, rapid and sensitive way to detect NO2 −

Methods

Results

Conclusion