Application of Graphene-Based Materials for Detection of Nitrate and Nitrite in Water—A Review

Abstract

Nitrite and nitrate are widely found in various water environments but the potential toxicity of nitrite and nitrate poses a great threat to human health. Recently, many methods have been developed to detect nitrate and nitrite in water. One of them is to use graphene-based materials. Graphene is a two-dimensional carbon nano-material with sp 2 hybrid orbital, which has a large surface area and excellent conductivity and electron transfer ability. It is widely used for modifying electrodes for electrochemical sensors. Graphene based electrochemical sensors have the advantages of being low cost, effective and efficient for nitrite and nitrate detection. This paper reviews the application of graphene-based nanomaterials for electrochemical detection of nitrate and nitrite in water. The properties and advantages of the electrodes were modified by graphene, graphene oxide and reduced graphene oxide nanocomposite in the development of nitrite sensors are discussed in detail. Based on the review, the paper summarizes the working conditions and performance of different sensors, including working potential, pH, detection range, detection limit, sensitivity, reproducibility, repeatability and long-term stability. Furthermore, the challenges and suggestions for future research on the application of graphene-based nanocomposite electrochemical sensors for nitrite detection are also highlighted.Sensors 2020, 20, 54 2 of 35 deaths. Nitrite in drinking water can irreversibly convert hemoglobin into methemoglobin, which results in a decrease in oxygen carrying capacity in the blood [5]. It can react with secondary amines to produce n-nitrosamines, which are likely to lead to gastric cancer [6]. Since nitrate is converted into nitrite in the digestive tract, it also very harmful to the human body [7]. It can also lead to the unnatural reproduction of aquatic plants and algae, leading to "red tides" and the death of fish [8,9]. The United States (U.S.) Environmental Protection Agency has limited the nitrite and nitrate content in drinking water to 1 mg/L and 10 mg/L [10] and other countries have made similar regulations. The concentration of nitrate and nitrite in water has become one of the indexes for evaluating water quality. Therefore, the detection of nitrate and nitrite in water samples at low concentrations has been the focus of research [11].So far, many methods have been used to detect nitrate and nitrite, such as spectrophotometry [12][13][14], chemiluminescence [15,16], chromatography [17], fluorescence [18,19] and electrochemical methods [20][21][22]. Among them, the electrochemical method is one of the most commonly used detection methods because of its advantages of being low cost, fast, direct and high efficiency [23]. However, the sensitivity and accuracy of the electrodes are reduced because of disturbance by other substances. Bare electrodes need higher applied potential, which limits the application of bare electrodes [24]. Therefore, electrochemical techniques based on modified electrodes have been extensively...

Graphene-Oxide-Based Electrochemical Sensors for the Sensitive Detection of Pharmaceutical Drug Naproxen

“…These data can be then applied to design and tune the specific catalytic activity of GO-based nanomaterials for sensing and environmental applications [21][22][23]. In addition, over the last decade, heteroatom-doped GO materials have been extensively studied to tune the structural and electronic properties of GO for applications in energy storage and catalytic sensing [24][25][26][27].The purpose of this study was three-fold: (i) to develop an advanced electrochemical sensor for the detection of naproxen; (ii) to compare the performance of various GO-based sensors and rationalize the effects of oxygenated functional groups; and (iii) to investigate the effects of dopants on the performance of the GO-based electrochemical sensors.…”

“…These data can be then applied to design and tune the specific catalytic activity of GO-based nanomaterials for sensing and environmental applications [21][22][23]. In addition, over the last decade, heteroatom-doped GO materials have been extensively studied to tune the structural and electronic properties of GO for applications in energy storage and catalytic sensing [24][25][26][27].…”

Application of Microfluidic Chip Technology in Food Safety Sensing

“…The LOD of sunset yellow and tartrazine in grape juice and orange juice were 10 −5 mol/L and 10 −4 mol/L, respectively. Nitrite, as a kind of food additive, is often used in the production of meat products to increase the freshness of meat, inhibit microorganisms, and help to maintain the structure and nutritional value of meat products, but excessive intake may cause poisoning or death [106,107]. Jayawardane et al [90] developed a disposable microfluidic paper-based analytical device based on inkjet printing for the determination of nitrite and nitrate.…”

Structure, Properties, and Electrochemical Sensing Applications of Graphene‐Based Materials

“…Heavy metals, agrochemicals, metabolic substances, and other environmental contaminants should be monitored and quantified because of their contamination potential, high toxicity, and concentration-dependent bioaccumulation. [135][136][137][138] Graphene-based materials can interact with and promote the adsorption of substances, improve the immobilization of different species, and therefore, provide new functionalities that can be used to decontaminate and monitor hazardous compounds. [139] Electrochemical sensors are simple and miniaturized devices that can be used to detect small amounts of widely spread environmental pollutants.…”

“…[1,133] Herein, we emphasize several studies that have described the environmental applications of graphene, GO, and rGO for monitoring water quality [142] and detecting food colorants, toxic substances, [143] and hazardous ions. [137,144] These studies have emphasized the importance of the electronic/structural characteristics of graphene and its derivatives for the improvement of the electroanalytical figures.…”