ABSTRACT
In this paper, the amino acid chiral ionic liquid (AACIL) was prepared with L-phenylalanine and imidazole. It was characterized by CD, FT-IR, 1H NMR, and 13C NMR spectrum. The chiral recognition sensor was constructed with AACIL and Cu(II), which exhibited different chiral visual responses (solubility or color difference) to the enantiomers of glutamine (Gln) and phenylalanine (Phe). The effects of solvent, pH, time, temperature, metal ions, and other amino acids on visual chiral recognition were optimized. The minimum concentrations of Gln and Phe for visual chiral recognition were 0.20 mg/ml and 0.28 mg/ml, respectively. The mechanism of chiral recognition was investigated by FT-IR, TEM, SEM, TG, XPS, and CD. The location of the host-guest inclusion or molecular placement has been conformationally searched based on Gaussian 09 software.
Subject(s)
Amino Acids , Ionic Liquids , Amino Acids/chemistry , Phenylalanine/chemistry , Glutamine , Ionic Liquids/chemistry , Spectroscopy, Fourier Transform Infrared , StereoisomerismABSTRACT
In this work, an "on-off-on" fluorescent probe based on Ni-MOF functionalized Nitrogen-doped carbon quantum dots (Ni-MOF-NCDs) was developed. Ni-MOF-NCDs was characterized by FT-IR, TEM, SEM, and XPS. The presence of Fe (III) will reduce the fluorescence intensity of Ni-MOF-NCDs and "turn off" the fluorescence signal at emission peak of 390 nm, while the signal can be "turn on" after the addition of ascorbic acid (AA). The Ni-MOF-NCDs was established as an "on-off-on" fluorescent probe for the detection of Fe (III) and AA with the linear ranges of 0.029-8.0 µg/mL and 0.263-18.0 µg/mL, respectively. The method has been successfully applied to the detection of water samples and foods with satisfactory recovery. The experimental results showed that Ni-MOF-NCDs not only had the fluorescence properties of NCDs, but also had the adsorption performance of Ni-MOF.
