Highly sensitive determination of neomycin residues in milk samples using a fast, simple competitive carbon dot-linked immunosorbent assay (CDs-LISA)

Abstract

Contaminants from antibiotic residues in milk are a potential concern for the global dairy market. We needed rapid, simple, sensitive, and selective analytical methods to ensure the safety of raw milk and milk products for customers. Here, we developed a rapid and simple competitive carbon dot-linked immunosorbent assay (CDs-LISA) using a CDs-conjugated antibody as an effective fluorescent reporter for sensitive neomycin detection in milk. Under the optimum conditions, the detection time of the proposed assay was completed in 30 min and exhibited a wide working range of 0.02–2 ng mL⁻¹ , a low detection limit (0.01 ng mL⁻¹), high precision (%RSD 2.6), and good selectivity in neomycin detection. Using this assay, neomycin levels in milk samples were easily measured in a range from 0.23 to 1.44 µg kg⁻¹, and the recovery rates were determined to be in the range of 84.7 %–113.2 % with an acceptable RSD (3.36–10.67 %). The competitive CDs-LISA demonstrated greater analytical performance than standard immunoassays using horseradish peroxidase and showed significant promise for simple and rapid detection immunoassays, indicating the utility of this analytical method for monitoring antibiotic contamination in milk and its application to dairy food control.