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Chemistry and Biochemistry Publications

Circular dichroism

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Full-Text Articles in Physical Sciences and Mathematics

L-Tryptophan Adsorption Differentially Changes The Optical Behaviour Of Pseudo-Enantiomeric Cysteine-Functionalized Quantum Dots: Towards Chiral Fluorescent Biosensors, Faezeh Askari, Abbas Rahdar, John F. Trant Feb 2019

L-Tryptophan Adsorption Differentially Changes The Optical Behaviour Of Pseudo-Enantiomeric Cysteine-Functionalized Quantum Dots: Towards Chiral Fluorescent Biosensors, Faezeh Askari, Abbas Rahdar, John F. Trant

Chemistry and Biochemistry Publications

Water-soluble chiral graphene quantum dots (GQDs) with a strong blue emission were synthesized by covalently immobilizing l-cysteine or d-cysteine onto the GQDs. Either the amine or the thiol group of cysteine was used to make the bond through amide coupling or thiol-ene click chemistry respectively. The functionalized chiral GQDs were the characterized by FT-IR and UV–vis. The enantiomeric pairs exhibit equal but opposite bands in circular dichroism spectra suggesting that there is no difference in the efficacy of conjugation. The fluorescent response of these chiral GQDs when exposed to l-tryptophan was then studied. The fluorescence of the amide-conjugated GQDs was …


Vitamin E Circular Dichroism Studies: Insights Into Conformational Changes Induced By The Solvent’S Polarity, Drew Marquardt, Brad J. Van Oosten, Mikel Ghelfi, Jeffrey Atkinson, Thad A. Harroun Dec 2016

Vitamin E Circular Dichroism Studies: Insights Into Conformational Changes Induced By The Solvent’S Polarity, Drew Marquardt, Brad J. Van Oosten, Mikel Ghelfi, Jeffrey Atkinson, Thad A. Harroun

Chemistry and Biochemistry Publications

We used circular dichroism (CD) to study differences in CD spectra between α-, δ-, and methylated-α-tocopherol in solvents with different polarities. CD spectra of the different tocopherol structures differ from each other in intensity and peak locations, which can be attributed to chromanol substitution and the ability to form hydrogen bonds. In addition, each structure was examined in different polarity solvents using the Reichardt index—a measure of the solvent’s ionizing ability, and a direct measurement of solvent–solute interactions. Differences across solvents indicate that hydrogen bonding is a key contributor to CD spectra at 200 nm. These results are a first …