Gas Chromatography principle relies on partition based separation of elements. This chromatography is of two forms like gas liquid chromatography GLC and gasoline solid chromatography. Of them GLC is widely used and so our whole discussion would be associated with it. The Principle in gas chromatography entails separation of volatile parts of the sample based on their partition co-efficient. This is ratio of solubility of material between gaseous mobile phase and stationary liquid phase. The parts of the sample which are partitioned into gasoline come out first while some come later. Gas Chromatography runs on the principle of partition chromatography for separation of elements. The stationary phase is a liquid coating supported over a predetermined period while the mobile phase is an inert and stable gas. Thus, the title as Gas-Liquid chromatography.
This type of chromatography was primarily designed to evaluate volatile substances like fatty acids, essential oils, etc. The System is quite costly, cumbersome and has delicate instrumentation. The tools maintenance, and operating costs are extremely high. But Still, gas chromatography is an important instrument in analytical chemistry, particularly in the medicinal field. The Gas is set to flow at a constant rate from the cylinder on to the liquid coating impregnated on a solid support in a column. The sample is injected into the injection point and can be transported by the cell gas to the column. Within the column, the parts become separated from the differential partition between the mobile phase gasoline and stationary phase liquid. The element that partitioned into gas comes from the column and can be detected by the sensor. The one partitioned into liquid stage comes out afterwards and can be also detected. The recordings are displayed on a computer program. From these peaks, one can determine the elements and their concentration.
High performance liquid chromatography has a broader array of uses than conventional gas chromatography. For the analysis of explosives Particularly, gas chromatography is better suited since, the mixture or compound is not required to be converted into a gas phase. You can imagine the need to convert into a gas phase would be inconvenient to say the least for the testing of volatile compounds! There is a specific kind of HPLC that is often utilized in forensic labs. It is known as reversed phase HPLC. This type is used on a daily basis in labs around the world for the analysis of agents used in drug dilution such as sugars and flour, in the analysis of explosives and bomb making materials, in medical toxicology, and in the analysis of drug use.