Nanoparticle-modified electrodes have shown promising results in the sensitive and selective electroanalytical determination of antibiotics. In recent papers, nanomaterials such as carbon nanotubes ^[1][49] and graphene oxide ^[2][50] have been used to modify electrodes, resulting in improved electrocatalytic properties and enhanced sensitivity and selectivity in electrochemical sensors. For example, Feizollahi at al. ^[1][49] developed a new method for detecting sulfamethazine (SMZ) in cow’s milk using a glassy carbon electrode modified with graphene oxide and decorated with Cu-Ag core–shell nanoparticles.

Electrodes modified with nanoparticles could be utilized in multiple electroanalytical applications of a broad range of antibiotics, including chloramphenicol ^[3][51], doxorubicin ^[4][52], pyrazinamide ^[5][53], streptomycin ^[6][54], and amoxicillin ^[7][55]. Some examples of electrode surfaces modified with nanoparticles that have been used in the determination of antibiotics are shown in Table 1.

These are just a few examples of nanoparticle-modified electrode surfaces that have been used for the electroanalytical determination of antibiotics. There are more examples of electrode surfaces modified with nanoparticles for the sensitive and selective electroanalytical determination of antibiotics. For instance, Shun Liu et al. developed a sensor using a nanocomposite of reduced graphene oxide and silver nanoparticles to detect the antibiotic chloramphenicol. This sensor was proved to be reproducible, stable, and selective over similar interfering substances in order to accurately detect chloramphenicol in milk samples ^[13][61]. Cesarino et al. also reported the preparation of a paraffin composite electrode based on multi-walled carbon nanotubes (MWCNT) modified with antimony nanoparticles (SbNPs). The sensor was used to detect two antibiotics, sulfamethoxazole and trimethoprim, using differential pulse voltammetry in natural water samples. The sensor’s structure and electrochemical properties were studied using field emission gun scanning electron microscopy and cyclic voltammetry, respectively ^[19][48].

These examples demonstrate the potential of using nanoparticles to modify electrode surfaces for the sensitive and selective electroanalytical determination of antibiotics, but there are many more. In one study, the development of an electrochemical sensor using platinum nanoparticles on carbon (PtNPs/C) for the detection of tetracycline is described. The sensor was first synthesized and characterized using X-ray diffraction and transmission electron microscopy. The researchers then studied how different experimental conditions, such as the number of platinum nanoparticles and the pH of the solution, affected the sensor’s behavior. They used cyclic voltammetry and differential pulse voltammetry to investigate how tetracycline is electro-oxidized on the sensor and determined that the sensor was able to accurately detect tetracycline over a wide range of concentrations in urine samples. This suggests that the sensor may have the potential for use in clinical analysis and quality control ^[14][62].

In another study, Zhu et al. developed a copper nanoparticle-based film incorporating a cationic surfactant and graphene for determining the presence of gatifloxacin and perflocacin using differential pulse stripping voltammetry. The film’s surface was analyzed using SEM and EDS, and it was found to have improved electrocatalytic properties due to the combination of copper nanoparticles, graphene, and CTAB surfactants. The modified electrode showed good performance in detecting the drugs, with linear responses at concentrations between 0.02–40 µM and 0.04–20 µM and detection limits of 0.0021 µM and 0.0025 µM, respectively. The sensors were also used to detect the drugs in shrimp and animal serum with successful results, suggesting that the film is a promising catalyst for electrocatalysis ^[20][65].

Over the past few decades, various studies have reported on the use of electrochemical methods for accurately measuring the presence of antibiotics. These methods have proven to be effective in detecting these substances in a quantitative manner. Primarily, according to Dai et al. ^[21][66], gold nanoparticles (∼30–60 nm in diameter) were deposited onto the surface of glassy carbon microspheres. Later, Wang et al. ^[22][67] reported the use of a tetracycline sensor, using a molecularly imprinted, polymer-modified carbon nanotube–gold nanoparticles electrode. Moreover, Bagheri Hashkavayi et al. ^[23][68] developed a label-free electrochemical aptasensor for the determination of chloramphenicol based on gold nanocube-modified, screen-printed gold electrodes. Giribabu et al. ^[24][69] developed an electrochemical sensor for chloramphenicol determination, using a glassy carbon electrode modified with dendrite-like Fe₃O₄ nanoparticles, while Prado et al. ^[25][70] prepared an electrochemical sensor modified with ruthenium nanoparticles on reduced graphene oxide for the simultaneous determination of amoxicillin. In addition, M. K. L. Da Silva et al. ^[26][71] synthesized a sensor with reduced graphene oxide, modified with antimony and copper nanoparticles for levofloxacin oxidation. Guaraldo et al. ^[27][72] introduced a glassy carbon (GC) electrode modified with Printex L6 carbon black (PC) and copper (II) phthalocyanine (CuPh) films for the electrochemical determination of the antibiotic trimethoprim. In 2020, Sanz et al. ^[28][73] constructed a multi-walled carbon nanotube (CNT) and gold nanoparticle (AuNP)-modified glassy carbon electrode (GCE) for the sensitive determination of cefadroxil antibiotic, while W. da Silva et al. ^[29][74] developed a poly(methylene green) film on a Fe₂O₃ magnetic nanoparticle-modified electrode in sulfuric acid-doped ethaline deep eutectic solvent for the antibiotics dapsone and Vajdle et al. ^[30][75] used a carbon paste electrode modified with gold nanoparticles for selected macrolide antibiotics determination as standard and in pharmaceutical preparations. Moreover, in 2021, Feizollahi et al. ^[1][49] developed a determination method of sulfamethazine (SMZ) in cow’s milk using a glassy carbon electrode modified with graphene oxide decorated with Cu–Ag core–shell nanoparticles, Olugbenga Osikoya and Poomani Govender ^[31][76] developed a benzene-sourced graphene–gold nanoparticle sensor for the detection of tetracycline. Mahmoudpour et al. ^[32][77] used reduced graphene oxide and a nanogold-functionalized poly(amidoamine) dendrimer for ciprofloxacin determination in real samples, and Zeb et al. ^[33][78] used a magnetic nanoparticles/MIP-based electrochemical sensor for the quantification of tetracycline in milk samples. Table 2 provides a summary of the above-mentioned studies on using nanoparticle-modified electrodes for measuring antibiotic levels in different types of samples.

When using solid electrodes in electrochemical applications, limitations such as a narrow potential range, electrode fouling, low detection limits, poor sensitivity, and reproducibility are often encountered. To address these issues, various strategies have been developed to modify the surfaces of electrodes using different redox-active molecules, perm-selective polymers, and electrode activation methods. These modifications result in improved electrode activity and sensitivity towards the target material, faster electron transfer between the analyte and electrode, increased electrocatalytic activity with a larger surface area, faster diffusion at the electrode surface, less interference, and reduced fouling ^[34][35][79,80].

In addition to their electrocatalytic properties, these nanoparticle-modified electrodes have the advantages of low cost, high sensitivity, and convenient operability, making them very promising to overcome potential interferences from analogs with similar chemical structures and to improve the stability and selectivity of these sensors.

Recently, two-dimensional nanomaterials have received great attention in the field of electrochemical applications because of their outstanding physicochemical properties ^[36][81]. Therefore, vanadium carbide entrapped on graphitic carbon nitride nanosheets (VC/g-CN NSs) was used as a highly efficient electrocatalyst for the determination of furazolidone (FZD) in biological samples. The electrochemical performance of the VC/g-CN NSs-modified glassy carbon electrode (GCE) for FZD detection was studied using cyclic voltammetry and amperometric methods. Thus, the proposed electrode offered active sites with a large electron-transfer rate and a rapid mass transport ability to enhance the electrochemical activity toward FZD detection. Under the optimization conditions, the VC/g-CN NSs modified electrode showed a wide detection range (0.004–141 μM), a very low detection limit (0.5 nM), and excellent selectivity and reproducibility.