Topics - Loop

Loop The term loop in chromatography is used in quite a difference sense to its colloquial meanings. It is normally used in conjunction with the term sample i.e. sample loop. In general, samples can be placed on a chromatographic column using one of two procedures. The sample can either be injected onto a column using a micro-syringe through a sealed septum or it can be placed in a length of tubing and the tubing interposed into the mobile phase flow-path to the column and thus, swept onto the column. The length of tube in which the sample is stored prior to injection is called the sample loop. Sample loops can vary in capacities from a few micro-liters in analytical chromatography to many milliliters in preparative chromatography