Purpose
Quantitative determination of antioxidants.
Brief description of the method
HPLC (High Perfomance Liquid Chromatography) has been developed from column chromatography to enable mixtures of substances to be separated better and more rapidly. The separation performance has been improved considerably through the use of sorbents (stationary phase) whose particles are considerably smaller (approximately 5-10 µm) than those used in column chromatography. The use of these sorbents necessarily increases the pressure that is needed to drive the eluent (mobile phase).
After the sample has been injected the eluent is forced through the separation column under pressure. The separation of the mixture results from interactions between the various constituents and the sorbent and eluent. The individual substances are identified by a suitable detector (e.g. an ultraviolet or refractive index detector situated at the end of the column). A connected recorder registers the substances as signals in the form of Gauss curves (peaks). The individual peaks provide qualitative and quantitative information concerning the investigated mixtures. The chromatogram – which contains all peaks – is evaluated quantitatively on a computer.