Professor Hyunwoo Kim of the Chemistry Department and his research team have developed a technique that can easily analyze the optical activity of charged compounds by using nuclear magnetic resonance (NMR) spectroscopy. The research finding entitled “H NMR Chiral Analysis of Charged Molecules via Ion Pairing with Aluminum Complexes” was published online in the October 19th issue of The Journal of the American Chemical Society.
The technique relies on observation of the behavior of optical isomers. Molecules with the same composition that are mirror images of each other are optical isomers. For example, the building blocks of all living organisms, amino acids, are a single optical isomer. In our bodies, optical isomers bring different physiological changes due to their distinct optical activities. Therefore, controlling and analyzing the optical activities are critical when developing a new drug.
High-performance liquid chromatography (HPLC) is the de facto standard of analyzing the optical activity of a compound. However, HPLC is very expensive that many laboratories can’t afford to have. In addition, with the machine, one analysis may take 30 minutes to one hour to complete. It lacks in signal sensitivity and chemical decomposition, and the application is limited to nonpolar compounds.
Usually adopted in analyzing the structure of a chemical compound, NMR spectroscopy requires only one to five minutes per single analysis. Since it is essential for analyzing the molecular structure, many chemistry labs have NMR equipment. However, until this technique was invented, no other research team had reported an effective way of using the NMR spectroscopy to decompose the signal of chiral activity of a compound.
The research team uses negatively-charged metal compounds in NMR spectroscopy. The technique employs negatively-charged metal compounds which bond ionically to positively- and negatively-charged optical compounds. As a result, the NMR spectroscopy can distinguish the signal from chiral activity. Not only can it analyze various chemicals without structural constraints, but it can also be used for both nonpolar and polar solvents.
As many compounds for new drugs have functional groups, which can be charged, this analysis method can be directly employed in the development process of drugs. Professor Kim said, “A revolutionary analysis method has been developed using simple chemical principles. I hope that our method will be applied to the development of new medicine.”
This research was sponsored by the Center for Nanomaterials and Chemical Reactions at the Institute for Basic Science and the Supercomputing Research Center of KAIST.
Picture 1: Separations of NMR Signals of Chemicals due to Interaction with Metal Compounds
Picture 2: Separations of NMR Signals in Different Chemicals
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