Green Emission of Tb-doped Mg-Al Layered Double Hydroxide Response to <Emphasis Type="Bold">L-lysine</Emphasis>

The paper describes a study on the green emission of a Tb-doped Mg-Al layered double hydroxide (Tb-LDH) response to L-lysine (Lys). Fluorescent study was found that the Tb-LDH exhibited strong green emission due to ⁵D₄-⁷F_J (J = 5, 6) transition of Tb³⁺, and the green emission almost quenched while the Tb-LDH was exposed to 0.01, 0.05, 0.1, 0.25, and 0.5 mol·L^?1 Lys solution, respectively. Meanwhile the emission attributed to Lys markedly increased as the Tb-LDH was exposed to 0.01 and 0.05 mol·L^?1 Lys solution, then decreased as the concentration of Lys solution further increased to 0.5 from 0.05 mol·L^?1. The green emission of Tb-LDH optimal response to Lys happened at 0.05 mol·L^?1 of Lys solution. XRD results revealed that no reflections ascribed to Lys appeared in the composites of Tb-LDH and Lys. IR spectra suggested that the IR spectra of Tb-LDH obviously changed after it was exposed to Lys solution. These results indicated that the green emission of Tb-LDH response to Lys was possibly owing to interaction between the Tb-LDH and Lys. Moreover, this interaction between the Tb-LDH and Lys may be resulted from absorption. The green emission of Tb-LDH response to Lys would be potential application in detecting L-lysine.