käänteisfaasi

Käänteisfaasi, also known as reverse phase, is a common technique in chromatography, particularly in high-performance liquid chromatography (HPLC). It is characterized by the use of a stationary phase that is nonpolar and a mobile phase that is polar. This is the opposite of normal-phase chromatography, where the stationary phase is polar and the mobile phase is nonpolar.

In käänteisfaasi chromatography, separation occurs based on the hydrophobic interactions between the analytes and the stationary phase. Nonpolar compounds will interact more strongly with the nonpolar stationary phase and elute later, while polar compounds will interact less strongly and elute earlier with the polar mobile phase. Common stationary phases include silica gel modified with alkyl chains, such as C18 (octadecylsilane) or C8 (octylsilane). The mobile phase typically consists of a mixture of water and an organic solvent like methanol or acetonitrile. The ratio of these solvents can be adjusted to optimize separation. Käänteisfaasi chromatography is widely used for the separation of a broad range of compounds, including pharmaceuticals, environmental pollutants, and biological molecules, due to its versatility and compatibility with aqueous samples.