A simple and sensitive colorimetric sensor for determination of gentamicin in milk based on lysine functionalized gold nanoparticles

The residue of gentamicin (GEN) in food is a serious threat to human health. Therefore, it is urgent to develop a simple and highly sensitive method for effectively detecting GEN in food. In this study we proposed a lysine-functionalized gold nanoparticles (AuNPs) colorimetric sensor to detect GEN simply and quickly. The detection mechanism as follows: The interaction between lysine and AuNPs causes lysine to adsorb on the surface of AuNPs. After the addition of GEN, the strong hydrogen bond between GEN and lysine promotes the aggregation of AuNPs. The color of AuNPs changed from wine red to blue, which produced obvious color change. UV–vis spectrometer was used to detect it. The results showed that the colorimetric sensor had high selectivity and sensitivity for the detection of GEN, and the linear range and limit of detection were 5–60 nM and 1.22 nM, respectively. In addition, this method has been successfully applied to the quantitative detection of GEN in milk, and the accuracy and recovery were satisfied.