# Functionalized Carbon-Based Electrochemical Sensors for Food and Alcoholic Beverages Safety
## 3 Carbon Nanomaterial-Based Electrochemical Sensors
### Graphene
In order to maximize the detection efficiency and accuracy, porous structures such as Co\({}_{3}\)O\({}_{4}\), TiO\({}_{2}\), and MnO\({}_{2}\) were loaded onto the surface of graphene to exhibit greater analytic performance in food and alcohol  
Figure 5: Graphene-based electrochemical sensors for food and alcoholic beverage safety. **(a)** The design of the electrochemical platform. Reprinted with permission from [100]. Copyright Wiley, 2019. **(b)** Schematic display of the steps involved in the preparation and performance of the immunosensor for Sacch. Reprinted with permission from [104]. Copyright Springer, 2018. **(c)** Electrochemical synthesis of po-Gr and treatment of NR with po-Gr. Reprinted with permission from [108]. Copyright Elsevier, 2017. **(d)** Illustration for the fabrication of CS-fre\({}_{2}\)O\({}_{3}\)-ERGO/GCE and its application for the detection of GA in wines. Reprinted with permission from [101]. Copyright Elsevier, 2015. **(e)** Two-dimensional nanocomposite-based electrochemical sensor for rapid determination of trans-resveratrol. Reprinted with permission from [106]. Copyright Elsevier, 2020. **(f)** Schematic illustration of the preparation of LIPG-based electrochemical sensor for the detection of TRA in red wines and grape skins. Reprinted with permission from [105]. Copyright Elsevier, 2020. **(g)** CV curves and the possible electrochemical reaction mechanism of sunset yellow and tartrazine. Reprinted with permission from [109]. Copyright Elsevier, 2013. **(h)** Sketch of the AuNP/RGO/SPCE-modified nanostructured platform and its application for AA determination in milk. Reprinted with permission from [112]. Copyright Elsevier, 2020. **(i)** Raman spectrum and CV curves for different concentrations of AFB1. Reproduced with permission from [113]. Copyright PLOS, 2019.  
safety [119]. For instance, a composite of graphene and mesoporous TiO\({}_{2}\), as a novel voltammetric sensor, was fabricated by a facile one-pot hydrothermal method. The developed sensor exhibited well-defined and separated SWV peaks (i.e., 272 mV) for detecting sunset yellow FCF and tartrazine in several food sample extracts using CV and SWV techniques, as shown in Figure 5g [109]. With the aim of enhancing the sensitivity of the electrochemical apta-sensors, [PERSON] et al. [110] reported gold nanoparticles dotted graphene (GNPs/GR) as an efficient aptamer used for bisphenol A (BPA) detection in milk products. The fabricated electrochemical sensor exhibited a wide range of concentrations and a low limit of BPA detection by analyzing the current change of ferricyanide. Similarly, [PERSON] et al. [111] reported the composite of layer-by-layer films of graphene (Gr)-gold nanoparticles (Au) and molecularly imprinted polymers (MIPs) as an electrochemical sensor used for efficiently detecting trans-resveratrol by taking advantage of their synergistic effects. In addition to the detection of chemical contaminants in foods, it is also important to monitor the quality of nutrients in food. Au nanoparticles decorated reduced graphene oxide flakes as an efficient detector were developed to monitor the quality control and quantitative assessment of vitamin C in infant food by studying L-ascorbic acid (AA) oxidation. As shown in Figure 5h, the oxidation of AA to dehydroascorbic acid showed a good linear relationship in the range of 50-500 uM and a low detection limit of 17 uM [112]. Finally, combining electrochemical sensing technology with other technologies, such as Raman spectroscopy, FT-IR spectroscopy, and mass spectrometry, can further improve the detection accuracy and sensitivity. A new Aflatoxin B1 sensor was developed based on Au nanostructures/graphene nanosheets-modified indium tin oxide (ITO) substrate, which could enhance the Raman effect and the electrochemical conductivity (Figure 5i). The presented sensor was a simple, easy, and sensitive sensor for monitoring the low concentrations of AFB1 with a detection limit of about 6.9 pg mL\({}^{-1}\).