Highly sensitive amoxicillin immunosensor based on aqueous vanadium disulphide quantum dots

Abstract

Abstract Antibiotic detection is necessary to monitor and control the usage and thereby to curtail the side effects. Amoxicillin (Am) is one of the most frequently used antibiotics for animals, and human health worldwide causes tremendous side effects. Herein, a composite of chitosan (CH) and thioglycolic acid capped vanadium sulfide quantum dots (TGA-VS2QDs) was hydrothermally synthesized and used to develop an electrochemical immunosensor to detect Am. TGA helps in making water-soluble and stable VS2QDs. To attain functional groups and to improve the film-forming capacity of TGA-VS2QDs, a composite formed with CH with the support of EDC- NHS chemistry. The composite formation was verified by Fourier-Transform Infrared Spectroscopy (FTIR) and electrochemical techniques. A uniform and stable film of CH-TGA-VS2QDs was constructed on glass substrate coating with indium tin oxide (ITO) to form CH-TGA-VS2QDs/ITO electrodes, and the monoclonal antibody of Am was immobilized. This immunosensor showed a specific and selective interaction towards Am among different antibiotics. This immunoelectrode showed linearity within the range of 10-3 – 5 x 104 nM with a limit of detection of 1.65 pM and sensitivity as 6.31 µA nM-1 cm-2, which is better than previous reports. Efforts were also made to test the Am in spiked fish samples and found satisfactory results.