# Functionalized Carbon-Based Electrochemical Sensors for Food and Alcoholic Beverages Safety
## 3 Carbon Nanomaterial-Based Electrochemical Sensors
### CDs
In addition, a Ferrocene (Fc) and \(\beta\)-cyclodextrin(\(\beta\)-CD) host-guest complex was introduced to improve the solubility, electrical stability, and bioavailability. Accordingly, based on the CV and DPV techniques in phosphate buffer solution, this ternary detection system, Fc CD/N-CDs, was found to be a suitable choice for the detection of uric acid via the establishment of a new method. [PERSON] et al. [72] used CDs to interact with \(N\)-(2-aminoethyl)-\(N\),\(N^{\prime}\),\(N^{\prime}\)-tris(pyridine-2-yl-methyl)ethane-1,2-diamine (TPEA) for the detection of Cu\({}^{2+}\). Benefiting from the good conductivity of CDs and the strong complexing ability of TPEA with Cu\({}^{2+}\), the detection of Cu\({}^{2+}\) content in themouse brain was as good as the result of inductively coupled plasma-atomic emission spectrometry (ICP-AES), indicating that this method has good feasibility and application prospects (Figure 3e). [PERSON] and coworkers [73] successfully synthesized the CDs/octahedral Cu\({}_{2}\)O nanocomposites, which exhibited good linear response, low detection limit, high selectivity, and wide detection range toward the electrocatalytic oxidation of glucose and the electrocatalytic reduction of H\({}_{2}\)O\({}_{2}\). [PERSON] et al. [74] prepared an ultra-sensitive sensor of Au NP/CD nanocomposites protected by Fc derivatives and graphene, which can be used for simultaneous detection of vitamin C, DA, UA, and paracetamol. As summarized in Table 1, CDs have been widely used as electrode materials for the detection of chemical substances in bulk food, but their application to alcoholic beverages still needs to be further studied. Modifications such as doping nitrogen, grafting organic molecules, and loading metal nanoparticles can greatly improve the sensitivity, selectivity, durability, and repeatability of CD-based electrochemical sensors. However, the resultant complex electrode systems greatly hinder the exploration of underlying detection mechanisms. Therefore, in the future, more attention should focus on the development of electrode systems with an accurate structure and single components. Figure 3: CD-based electrochemical sensors for food and alcoholic beverage safety. (**a**) Schematic illustration of N-doped CD synthesis and DA detection. Reprinted with permission from [67]. Copyright Elsevier, 2015. (**b**) Schematic illustration of the strategy for DA detection. Reprinted with permission from [68]. Copyright the Royal Society of Chemistry, 2013. (**c**) Hydrothermal approach to CNDs and its TEM image, UV-vis absorption, and PL spectra. Reprinted with permission from [69]. Copyright Elsevier, 2012. (**d**) Schematic illustration of Hb-CNDs-chitosan system and CVs of Hb-CNDs-chitosan/GC electrode in 5 pH 7.4 PBS containing H\({}_{2}\)O\({}_{2}\). Reprinted with permission from [70]. Copyright Elsevier, 2014. (**e**) A schematic illustration of the electrochemical sensor for Cu\({}^{2+}\) detection based on CDs-TPEA. Reprinted with permission from [72], Copyright American Chemical Society, 2012.