Liquid chromatography is the most versatile of all the chromatography techniques and about 65% of all chromatographic analyses employ LC techniques. It is used to separate biopolymers including the polypeptides, proteins, carbohydrates, lipids etc. and, in fact, biotechnology is one of its most popular fields of application. As opposed to GC, LC can separate substances on the basis of ionic interactions and, in addition, LC can separate molecules on the basis of size by, exclusion techniques. In fact, LC can separate many substances that are normally separated by GLC, but, perhaps, less efficiently and less rapidly.

TLC is the cost effective relation of LC. Separations that are possible by LC can often be separated on a thin layer plate. Solutes separated on a thin layer plate, however, are strongly dispersed, even on high efficiency plates, and thus, efficiencies realized with TLC are much less than those obtained from an LC. Nevertheless, due to the unique method of development, which results from a form of frontal analysis by the solvent system as it moves along the plate, TLC can be highly selective providing the sample is not a multi-component mixture. This solvent effect tends to compensate for the poor plate efficiency. The big disadvantage of TLC is its poor quantitative accuracy and precision compared with that of LC. Thus, the less expensive, simple procedure is realized by tolerating relatively poor quantitative accuracy and precision.

Capillary electro chromatography (CEC) in principle is similar to LC but the mobile phase is driven through the column by electro-osmotic flow and not by hydraulic pressure. Thus, the sample should be soluble in an electrolyte and usually aqueous which is necessary for electro-osmotic flow. The capillary has a very small diameter and, as the tube diameter usually constitutes the path length of the sensor (UV adsorption), the detector is relatively insensitive. Thus, high concentrations of solute are necessary and, consequently, the dynamic range of the detector is small. CEC, although heralded by enthusiasts, has yet to be established as a versatile form of chromatography with a wide field of application. Very small samples can be used, but the sampling technique requires a significant amount of material to place the small sample on the column. The areas of application are still not clearly defined and, to date, there are a limited number of publications that give a clear indication of the accuracy and precision that can be expected from the technique.