Application of Gas Chromatography (GC)

1) Pharmaceutical

Chromatography is used by pharmaceutical companies to prepare large amounts of pure materials that are further required in making medicines. Also, it is used to check the presence of any contamination in the manufactured compounds. In the field of organic chemistry and pharmacy, chiral compounds are very close to each other in terms of atomic or molecular weight, element composition, and the physical properties. However, they exist in two different forms, called the enantiomers and optical isomers. Both these compounds though may appear to be same, have very different chemical properties. So, in pharmacy, chromatography becomes crucial to analyze the exact chiral compound so that correct medicines can be manufactured. For instance, a compound called thalidomide has two optical isomers and one of the isomers can cause birth defect if a pregnant women consumes it in early stages of pregnancy. So, it is important to carefully separate the isomers. Chromatography is used as a technique to separate the additives, vitamins, preservatives, proteins and amino acids. Some other uses are in the detection of drugs or medications in the urine and the separation of traces of chemicals in the case of fire in houses or buildings. It is also very popular in forensic science for investigative purposes. 

2) Oleochemicals

Chromatography has developed into one of the principle methods of analysis of oleochemicals. Gas chromatography has been used extensively for the analysis of long-chain fatty acids as well as for the analysis of triglycerides and plant sterols. In recent years, high pressure liquid chromatography (HPLC) has been used for the analysis of triglycerides as well as for other related materials. Specialized gas chromatography columns have been developed for the separation of long-chain fatty acids such as the methyl esters. These columns have generally used high polarity stationary phases which separate fatty acids by degree of unsaturation. A specialized use of these high polarity stationary phases is separation ofcis-trans isomers as well ascis-cis andtrans-trans isomers. In this paper, packed and capillary columns are compared for the separation of thecis-trans isomers of fatty acid methyl esters prepared from a hydrogenated vegetable oil. For HPLC separations, the presence of a double bond is approximately equivalent chromatographically to shortening the alkyl chain by two carbons. The long-chain polyenic acids or ethyl esters thus elute near but are resolved from the short-chain saturated fatty acids or esters. HPLC is the method of choice for relatively complex, high molecular weight, or labile esters, such as those of retinyl or cholesterol. Glyceryl esters are particularly well resolved by HPLC in terms of both total

chain length and degree of unsaturation. This technique is also useful for lipid class separations and for the analysis of modified fatty acid products, such as prostaglandins and related materials. In general, these analyses are conducted with octadecyl bonded phase column packings.

3) Oleochemicalshttp://www.researchgate.net/publication/226004574_Column_types_for_the_chromatographic_analysis_of_oleochemicalsChromatography has developed into one of the principle methods of analysis of oleochemicals.Gas chromatography has been usedextensively for the analysis of long-chain fatty acids as well as for the analysis of triglycerides and plant sterols. Inrecent years, high pressure liquid chromatography (HPLC) has been used for the analysis of triglycerides as well as for otherrelated materials. Specialized gas chromatography columns have been developed for the separation of long-chain fatty acidssuch as the methyl esters. These columns have generally used high polarity stationary phases which separate fatty acids bydegree of unsaturation. A specialized use of these high polarity stationary phases is separation ofcis-trans isomers as well ascis-cis andtrans-trans isomers. In this paper, packed and capillary columns are compared for the separation of thecis-trans isomers of fatty acid methyl esters prepared from a hydrogenated vegetable oil. For HPLC separations, the presence of a doublebond is approximately equivalent chromatographically to shortening the alkyl chain by two carbons. The long-chain polyenicacids or ethyl esters thus elute near but are resolved from the short-chain saturated fatty acids or esters. HPLC is the methodof choice for relatively complex, high molecular weight, or labile esters, such as those of retinyl or cholesterol. Glycerylesters are particularly well resolved by HPLC in terms of both total chain length and degree of unsaturation. This techniqueis also useful for lipid class separations and for the analysis of modified fatty acid products, such as prostaglandins andrelated materials. In general, these analyses are conducted with octadecyl bonded phase column packings.

4) Cosmeticshttp://onlinelibrary.wiley.com/doi/10.1002/jhrc.1240181008/abstract

A gas chromatographic (GC)-mass spectrometric (GC-MS) method has been developed for the routine analysis of 11 fragrance substances in cosmetics: cinnamic alcohol, cinnamic aldehyde, eugenol, hydroxy citronellal, α-amyl cinnamic aldehyde, geraniol, isoeugenol, coumarin, dihydrocoumarin, citronellal and citral. Methods for sample preparation of various types of cosmetic products, prior to GC analysis, have also been developed and proved to be rugged. Detection limits of all of target fragrance substances were approximately 1 ppm. Calibration curves of the target fragrance substances analyzed by GC were found to be linear in the investigated concentration range, 0.005% – 0.50%. The recoveries of the target fragrances from various types of cosmetic products were 80% – 116% and the relative standard deviations of the quantitative analysis of the target fragrance substances were within 5%.