Fluorescence probe for sensitive and selective screening of kanamycin using Co²⁺ ions quenched gold nanoclusters

The turn "off-on" fluorescence (FL) probe was developed for screening of kanamycin (KAN) in food and beverages in the present work. Due to dynamic quenching, the FL signal of glutathione protected gold nanoclusters (GSH-AuNCs) was quenched by using cobalt (Co²⁺) ions. GSH-AuNCs acted as "turn-off" due to Co²⁺ ions. The FL intensity quenched by Co²⁺ ions was regained using KAN due to KAN triggered aggregation induced enhancement (AIEE) of GSH-AuNCs, and GSH-AuNCs-Co²⁺ acted as a "turn-on" probe. The probe GSH-AuNCs-Co²⁺ was used for KAN screening for the first time, and it has an extended linear range of 1-30 μM with a detection limit of 0.5 μM. The probe successfully detected KAN in NFC mango juice, yoghurt, and tomatoes with a good 92.73-108.45% recovery range. The wide detection platform with improved sensitivity and real-world utilization for screening KAN was established by the current work.