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 mu M. The proposed copper nanoclusters was further applied to determine L-histidine in rat serum after intraperitoneal injection.