Principles and Practice of Chromatography - Introduction > Page 2

"Thus, the smallest HETP (the highest efficiency) should be obtainable by using very small particles and a high pressure difference across the column".

Despite his recommendations, however, it was nearly four decades before this concept were taken seriously and the predicted high efficiency liquid chromatography columns became a reality. By the mid 1960s the development of all aspects of chromatography were virtually complete and since then, despite the plethora of publications that have appeared on the subject, the vast majority has dealt with applications of the technique and only a minority with fundamental aspects of the subject and novel instrumentation concepts.

Today, chromatography is an extremely versatile technique; it can separate gases, and volatile substances by GC, involatile chemicals and materials of extremely high molecular weight (including biopolymers) by LC and if necessary very inexpensively by TLC. All three techniques, (GC), (LC) and TLC have common features that classify them as chromatography systems.

Chromatography has been defined as follows,

Chromatography is a separation process that is achieved by distributing the components of a mixture between two phases, a stationary phase and a mobile phase. Those components held preferentially in the stationary phase are retained longer in the system than those that are distributed selectively in the mobile phase. As a consequence, solutes are eluted from the system as local concentrations in the mobile phase in the order of their increasing distribution coefficients with respect to the stationary phase; ipso facto a separation is achieved.