Analysis

LC is a chromatographic analysis method. CD can be used as both a stationary phase and a component of the mobile phase in LC. Research has focused more on the use of CD as a bonded chiral stationary phase (CSP) in high-performance liquid chromatography (HPLC). CDs bonded to silica gel have been successfully used to analyze some difficult-to-separate diastereomers and structural isomers. Native β-CD served as a bonded CSP that has been successfully used to separate and analyze enantiomers of amines, amino acids, alkaloids, and other compounds. Furthermore, derivatized β-CDs can be used as bonded CSPs, which are suitable for reverse-phase and normal-phase HPLC analysis.

• Instance

Substituted β-CD-CSPs with different phenylcarbamate substituents and derivatized β-CD-CSPs with different spacer lengths have been prepared for liquid chromatographic analysis of several series of enantiomers ^[1,2].

GC is also an analytical method where CD is mainly used as a GC stationary phase. Native CD molecules have many intramolecular hydrogen bonds, high melting points, poor coating, and film-forming properties, which makes them unsuitable for use as GC stationary phases. Notably, the melting points of CDs are lowered, and coatings and films can be formed more easily after derivatization. Therefore, CD derivatives are good GC stationary phases that are suitable for separating volatile and stable chiral compounds. It is worth noting that CD derivatives should meet thermal stability requirements when used as stationary phases in GC.

• Instance

β-CD derivatives were used as CSPs for capillary column GC analysis. They separated more than 30 enantiomers of halogenated hydrocarbons, epoxy compounds, ketones, amines, alcohols, amino acids and other compounds, showing good enantiomeric separation selectivity ^[3].

TLC is a chromatography analysis technique that separates components in non-volatile mixtures using a thin stationary phase supported by an inert backing. CD and its derivatives can be used as components in the mobile phase and stationary phase of TLC, especially in the mobile phase. Compared with traditional organic solvents, CD solution has many advantages as a mobile phase in TLC, including increasing selectivity for chromatographic separations of polar and nonpolar substances, reducing solubility-related problems, and avoiding possible detection limit reductions. Therefore, the involvement of CD facilitates the TLC analysis.

• Instance

A substituted-β-CD was studied as a mobile phase layer in TLC analysis. It enhanced the migration of coumarin, rhodamine and bismane laser dyes on TLC, thus facilitating good separation of these components on commonly used silica gel plates ^[4].