Fluorescent Detection of Phosphate in Aqueous Solution Based on Near Infrared Emission Ag 2 S QDs/Metal - Organic Shell Composite.

A novel fluorescence method for sensitive and selective detection of phosphate was developed based on near infrared emission Ag2 S QDs/ Metal - Organic Shell Composite via the deposition of metal-organic (zinc-nitrogen) coordination shell around Ag2 S QDs . Under optimal conditions described, the fluorescence intensity of the composite was decreased at 685 nm in the presence of phosphate, which was linearly related to the concentration of phosphate in the range of 0. 7 to 4.2 μM and 11.2 to 88.2 μM with the relative correlation coefficient of R2  = 0.998 and 0.987 respectively and detection limit as low as 6 nM. In addition, the proposed method was successfully utilized in serum samples, tap water and Yangtze River water samples with the recoveries ranged from 94.76 to 100.86 %, which presaged more opportunities for application in related bioassay and water sample researches.