High performance liquid chromatography is a type of column chromatography which uses columns, 1-3 mm in diameter with adsorbent particles in the size range of 10-20 n m while the solvent is pumped under pressure at a high rate of flow.
The column is made of thick stainless steel tubing 10-20 cm in length. In contrast to conventional Column chromatography which is hampered by low column efficiency and a long separation time High Performance liquid chromatography is about 100 times faster and much more efficient. While gas liquid chromatography (GLC discussed under Gas chromatography) is extremely useful in analysing mixtures with very small amounts or trace concentrations of substances, it fails in the case of compounds which have low vapour pressure or are unstable at higher temperatures.
Such compounds can be effectively separated and analysed by high performance liquid chromatography which is ideal for detection of chlorinated hydrocarbon pesticides, polyaromatic hydrocarbons, caffeine, steroids etc. in food samples.