High-performance liquid chromatography

High-performance liquid chromatography (HPLC) separates and analyzes sample components by pumping a liquid mobile phase through a packed stationary phase under high pressure.

Reversed-phase chromatography: A liquid chromatography mode in which a nonpolar stationary phase retains analytes according to hydrophobic interactions. Its nonpolar packing and aqueous-organic solvents make it HPLC’s most widely used mode.
Chromatography: A family of separation methods that distribute mixture components between a mobile phase and a stationary phase. HPLC is a high-pressure liquid-based member of this broad separation family.
Pharmaceutical analysis: The measurement of identity, strength, purity, and performance of pharmaceutical substances and products. HPLC assays drug ingredients and detects impurities in medicines.
Gas chromatography: A chromatographic method that uses a gas as the mobile phase to separate volatile compounds. Unlike HPLC, it requires analytes that can be vaporized without decomposition.
Normal-phase chromatography: A liquid chromatography mode using a polar stationary phase and a relatively nonpolar mobile phase. It separates compounds by polarity through a retention pattern opposite to reversed-phase HPLC.
Stationary phase: The phase in chromatography that remains fixed while the mobile phase carries sample components past it. Its surface chemistry determines how strongly HPLC analytes are retained.
Drug metabolism: The chemical transformation of drugs by organisms, especially through enzymatic processes. HPLC separates drug metabolites in biological samples before their identification or quantification.
Thin-layer chromatography: A planar chromatographic method in which solvent carries a sample across a coated plate. It uses a flat layer and capillary flow instead of a pressurized packed column.
Isocratic elution: A chromatographic separation in which mobile-phase composition remains constant throughout the run. It suits HPLC separations whose components elute adequately under one solvent composition.
Mobile phase: The fluid that carries analytes through a chromatographic system. Its composition and flow control analyte transport and elution in HPLC.

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