Abstract
A novel magnetic C3N5 framework material (Fe3O4/C3N5) was developed as a high selectivity extractant for La (III) determination in food samples. The Fe3O4/C3N5 material was synthesized by thermal deammoniation method and has larger surface area (100.3 m(2) g(-1)) and more effective adsorption sites compared with that of individual C3N5 material (19.4 m(2) g(-1)). It was proved that Fe3O4/C3N5 material displayed excellent selectivity and adsorption capacity for La(III). In addition, adsorption isotherm and kinetic data indicated that La(III) adsorption based on Fe3O4/C3N5 material is a monolayer adsorption which is compatible with Langmuir model and follows a pseudo-second-order kinetic equation. By using Fe3O4/C3N5 material as extractant, an analytical method was established with low limits of detection (3 sigma, n = 6) of 10.4 mu g L-1, reasonable recoveries ranged from 86% to 106% and good precision with the RSD less than 10.7%. The analytical method was further applied to the determination of trace La(III) in food sample. It evinced that the concentration of La(III) in sea fish is 13.2 mu g kg(-1) and the content of La-138 is 0.138 mu g kg(-1), which is 1.03% of total La(III).

KeyWords Plus:RARE-EARTH-ELEMENTS; SOLID-PHASE EXTRACTION; PLASMA-MASS SPECTROMETRY; PRECONCENTRATION; NANOPARTICLES; ADSORPTION; WATER; IONS; SEPARATION; NANOTUBES

Published in TALANTA，Volume 225；10.1016/j.talanta.2021.122086，APR 1 2021