C-doped ZnO nanocomposites molecularly imprinted photoelectrochemical sensor for ultrasensitive and selective detection of oxytetracycline in milk

Detection methods for antibiotics in wastewater: a review

Antibiotics are widely used as fungicides because of their antibacterial and bactericidal effects. However, it is necessary to control their dosage. If the amount of antbiotics is too much, it cannot be completely metabolized and absorbed, will pollute the environment, and have a great impact on human health. Many antibiotics usually left in factory or aquaculture wastewater pollute the environment, so it is vital to detect the content of antibiotics in wastewater. This article summarizes several common methods of antibiotic detection and pretreatment steps. The detection methods of antibiotics in wastewater mainly include immunoassay, instrumental analysis method, and sensor. Studies have shown that immunoassay can detect deficient concentrations of antibiotics, but it is affected by external factors leading to errors. The detection speed of the instrumental analysis method is fast, but the repeatability is poor, the price is high, and the operation is complicated. The sensor is a method that is currently increasingly studied, including electrochemical sensors, optical sensors, biosensors, photoelectrochemical sensors, and surface plasmon resonance sensors. It has the advantages of fast detection speed, high accuracy, and strong sensitivity. However, the reproducibility and stability of the sensor are poor. At present, there is no method that can comprehensively integrate the advantages. This paper aims to review the enrichment and detection methods of antibiotics in wastewater from 2020 to the present. It also aims to provide some ideas for future research directions in this field.

Highly electroactive Co-ZnO/GO nanocomposite: Electrochemical sensing platform for oxytetracycline determination

Antimicrobial residues in animal-derived foods have become a major source of concern around the world. Oxytetracycline (OTC), one of these antibiotics that belongs to the tetracycline family should be detected in these matrices. Nanostructured metal oxides have attracted a lot of scientific attention due to their special characteristics that can be exploited for creating innovative nanodevices. Therefore, in the present study, we report the fabrication of cobalt-doped ZnO/GO nanocomposites for OTC sensors using a simple and environmentally friendly method that does not require toxic solvents. Contact angle measurements, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV-Vis were used to confirm the successful fabrication of the Co-ZnO/GO nanocomposite and to determine the surface area, Structural, morphological features, chemical composition and purity of the nanocomposite. The electrochemical and electrocatalytic properties were recorded using cyclic voltammetry (CV), electrochemical impedance spectroscopy, and differential pulse voltammetry (DPV). Optimizing parameters such as scan rate, pH value, deposition time, and deposition potential, we achieve a wide linear concentration range from 10-12 M to 10-7 M, with an impressive detection limit of 1.6 10-13 M.Notably, our sensor exhibits remarkable selectivity, demonstrating its usefulness for the detection of oxytetracycline traces in real milk samples. These results emphasize the novelty and practical significance of our work and provide a promising avenue for the development of sensitive and selective electrochemical sensing platforms in various fields.

A perovskite-based electrochemiluminescence aptasensor for tetracycline screening

Tetracyclines are currently the most commonly used class of antibiotics, and their residue issue significantly impacts public health safety. In this study, a surface modification of perovskite with cetyltrimethylammonium bromide led to the generation of stable electrochemiluminescence (ECL) emitters in aqueous systems and improved the biocompatibility of perovskite. A perovskite quantum dot-based ECL sensing strategy was developed. Utilizing the corresponding aptamer of the antibiotics, strain displacement reactions were triggered, disrupting the ECL quenching system composed of perovskite and Ag nanoclusters (Ag NCs) on the electrode surface, generating a signal to achieve quantitative detection of several common tetracycline antibiotics. The perovskite quantum dot provided a strong and stable initial signal, while the efficient catalytic activity of the silver cluster enhanced the recognition sensitivity. Tetracycline, chlortetracycline, and oxytetracycline were used as examples to demonstrate the differentiation and quantitative detection through this method. In addition, the aptasensor exhibited analytical performance with the linear range (0.1-10 μM OTC) and good recovery rates of 94.7% to 101.6% in real samples. This approach has the potential to become a sensitive and practical approach for assessing antibiotic residues.

Zinc Oxide-Loaded Cellulose-Based Carbon Gas Sensor for Selective Detection of Ammonia

Cellulose-based carbon (CBC) is widely known for its porous structure and high specific surface area and is liable to adsorb gas molecules and macromolecular pollutants. However, the application of CBC in gas sensing has been little studied. In this paper, a ZnO/CBC heterojunction was formed by means of simple co-precipitation and high-temperature carbonization. As a new ammonia sensor, the prepared ZnO/CBC sensor can detect ammonia that the previous pure ZnO ammonia sensor cannot at room temperature. It has a great gas sensing response, stability, and selectivity to an ammonia concentration of 200 ppm. This study provides a new idea for the design and synthesis of biomass carbon-metal oxide composites.