Visual detection of kanamycin with functionalized Au nanoparticles

A simple and rapid colorimetric detection strategy, based on hydrogen bond identification of 6-thioguanine (6-TG) functionalized Au nanoparticles (AuNPs), is proposed for highly selective and sensitive determination of kanamycin (KA). In this strategy, the hydrogen bond interaction between 6-TG and kanamycin induces AuNPs to agglomerate, with a consequent color change of AuNPs from wine red to purple or even blue. The kanamycin concentrations can be quantified by employing UV-vis spectrophotometer. The results display that kanamycin concentrations (0.005 to 18 µM) are linearly related to A₆₂₀/A₅₂₀ (the absorbance ratio of 620 nm and 520 nm) with a LOD of 1.8 nM and a LOQ of 5.9 nM (S/N = 3). This strategy also reveals a high degree of selectivity among a series of common interfering species. Moreover, the strategy can be employed to detect trace amounts of kanamycin in real-life samples, and it shows satisfying results compared with high performance liquid chromatography. In general, this developed strategy is facile and inexpensive without the need for complex processing procedures and expensive instruments. In addition, this work may further exploit detection strategies for other organic contaminants, as well as make a strong contribution to the development of the colorimetric method.