Type IV Chiral Stationary Phases

Chiral ligand exchange chromatography is based on the formation of diastereomeric ternary complexes that involve a transition metal ion (M), chiral ligand (L), and the enantiomers of the racemic solute (R and S). Of all the transition metals examined [Cu(II), Ni(II), Zn(II), Hg(II), Co(III), Fe(III), etc.], Cu(II) forms the most stable complexes, and cyclic amino acids such as l-proline and l-hydroxyproline are the best chiral selectors, when bound to a polymer or silica support. The diastereomeric mixed chelate complexes formed in this system are represented by the formulas L-M-R and L-M-S. When these complexes have different stabilities, the less stable complex is eluted first, and the enantiomeric solutes are separated. The enantiomers resolved include amino acids, amino acid derivatives, 2-amino alcohols, barbiturates and hydantoins.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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