Single phase of Tb-doped YPO 4 phosphors with xenotime structure were successfully synthesized via a polyacrylamide gel at different annealing temperatures (650–1050 °C). The crystal structure, thermal behavior and optical properties of the as-synthesized samples were investigated by XRD , TG-DTA, FT-IR, PL, and XPS . The effects of heat treatment on the structure and luminescence properties of samples were discussed. The PL spectra results reveal that the annealing temperature plays a key role in the luminescence properties of products. The samples obtained under 650–850 °C exhibit a strong green emission at 546 nm, attributing to the 5 D 4 - 7 F 5 transition of Tb 3+ , while the samples produced above 850 °C emit dominating blue lines at 381 and 415 nm, corresponding to the 5 D 3 - 7 F 6 and 5 D 3 - 7 F 5 transitions, respectively. The XPS results imply that a part of doping Tb 3+ ions may be oxidized to Tb 4+ on the high-temperature thermal treatment process, which could be the reason for the bluish color of Tb-doped YPO 4 phosphors.
Rapid and selective enrichment of phosphopeptides from complex biological samples is essential and challenging in phosphorylated proteomics. We present the direct growth of the ultrathin YPO 4 shell on the surface of polyacrylate capped secondary Fe 3 O 4 microspheres (PA-Fe 3 O 4 @YPO 4 ) for the rapid and selective trapping phosphopeptides from complex samples. The prepared PA-Fe 3 O 4 @YPO 4 could be rapidly harvested in the presence of an applied magnetic field and easily re-dispersed in solutions after removing the external magnet. The ultrathin YPO 4 shell on super-hydrophilic PA-Fe 3 O 4 has the advantages of fast adsorption/desorption dynamics and low non-specific adsorption, thus trapping of phosphopeptides from the tryptic digests mixture of β-casein/BSA with molar ratio of 1/300 is achieved in 20 s adsorption/desorption time. Two phosphopeptides can still be detected with a signal to noise ratio (S/N) over 3 when the amount of β-casein was as low as 8 fmol.
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