The Importance of Chromatography as an Analytical Technique
Chromatography is the most versatile and widespread technique employed in modern analytical chemistry and there are a number of reasons for this. Firstly, very sensitive methods of detection are available to all types of chromatography and. thus. very small quantities of material can be separated, identified and assayed. It follows, that only a few microgram of sample (at the extreme, even less than a nanogram) may be necessary to ensure the required accuracy. Secondly, chromatographic separations are usually relatively fast and an analysis can be completed in a few minutes and possibly in a few seconds. Another advantage of chromatography is its relative simplicity and ease of operation compared with other instrumental techniques. Finally, if the established procedure is well controlled and the apparatus well maintained, good accuracy and precision can be achieved. However, if the established analytical protocol is not carefully adhered to, there is evidence that analytical reproducibility between different laboratories can vary and can sometimes be very poor.
Quantitative chromatographic analysis is used extensively in all areas of chemical analysis but examples are too numerous to discuss individually. Due to the high sensitivities available, the techniques are invaluable for the analysis of environmental samples (soil and water contamination and atmospheric pollution), for forensic purposes (such as testing for drug residues in blood and urine, for flammable materials in arson samples and traces of poisons or toxic materials) and for clinical studies. The technique is extensively used by the pharmaceutical industry for both research purposes and for quality control. Similarly, the biochemical and biotechnology industries widely use chromatographic techniques and in many cases alternative methods are not available [10]. More recently, applications involving chiral separations and the resolution of biopolymers [11] have become important, where the individual solutes are very similar and demand the high resolving power available from modern columns, the selectivity of unique chiral stationary phases and high detector sensitivity. The technique is also used extensively in the agrochemical industry, not merely for raw material analysis and quality control, but for soil analysis and water purity.
