Copper nanoclusters-modified with papaya juice for fluorescence turn-on detection of serum l-histidine Today four files of proofs was sent to m.saksena@elsevier.com Please check the files

Papaya juice protected copper nanoclusters was depicted for detection of serum l -histidine. The fluorescent probe was synthesized by using a simple “one pot” hydrothermal preparation strategy with papaya juice playing dual roles both as a green reductant and stabilizer. The excitation and emission peaks of the copper nanoclusters were at 400 nm and 490 nm, respectively. The fluorescence was turned-on in addition of l -histidine due to the enhanced surface electron density. The fluorescent intensity increased linearly with l -histidine concentration ranging from 2.0 to 50.0 µM. The proposed copper nanoclusters was further applied to determine l -histidine in rat serum after intraperitoneal injection.