Ratiometric Fluorescent Detection of Phosphate in
Aqueous Solution Based on Near Infrared Fluorescent Silver Nanoclusters/Metal–Organic
Shell Composite
- Publication date
- Publisher
Abstract
Synthesis of near-infrared (NIR)
fluorescent AgNCs with high quantum yield and stability is challenging
but important for sensing and bioimaging application. Here, we report
the fabrication of AgNCs/metal–organic shell composite via
the deposition of metal–organic (zinc–nitrogen) coordination
shell around AgNCs for ratiometric detection of phosphate. The composite
exhibits NIR emission at 720 nm with 30 nm red-shift in comparison
to bare AgNCs and a weak emission at 510 nm from the shell. The absolute
quantum yield of NIR fluorescence of the composite is 15%, owing to
FRET from the shell to the AgNCs core under the excitation at 430
nm. Besides, the composite is stable due to the protection of the
shell. On the basis of the composite, a novel ratiometric fluorescence
probe for the detection of phosphate in aqueous solution with good
sensitivity and selectivity was developed. The limit of detection
(3<i>s</i>) is 0.06 μM, and the relative standard
deviation for 10 replicate detections of 10 μM phosphate was
0.6%. The recoveries of spiked phosphate in water, human urine, and
serum samples ranged from 94.1% to 103.4%