Science has developed a lot since the invention of fire by the ancient cavemen. Now a days we use various types of high-tech instruments for the precision of our scientific experiments. Gas Chromatography (GC) is one of the most common procedures used in analytical chemistry. It helps us analyze compounds through evaporation. One of the best features of this process is the compounds are not decomposed. Some of the more expensive GCs also detects the element for us, which later can be used to prepare pure compound from a mixture. Compounds present in a volatile liquid or gaseous solute are isolated after traveling through a coated column based on the substance’s size and intermolecular interactions. When a compound tends to bind to the column through intermolecular interactions, it takes a longer time to emerge than compared with a compound that does not tend to stick onto the column. The level of binding experienced between the substances and the column is determined based on the number and strength of intermolecular interactions between the two species. Substances that pass quickly through the column exhibit fewer intermolecular interactions with the column.
The development of Gas Chromatography first started with the Russians scientist Mikhail Semenovich Tswett in the year 1903.1 Later after many years German scientist Fritz Prior improved the techniques and was able to do solid state Gas Chromatography.2 And years later in 1941 Archer John Porter Martin got noble prize for his work on this field.3 He was also able to produce liquid-gas chromatography. Hence he laid the foundation of GC.
A gas chromatographer is the instrument used in this process. It helps to separate chemicals in a complex sample. The complex sample is passed through a narrow tube in gas stream, they pass depending on their physical and chemical properties and interact with a specific column filling. As all the compounds in that sample reach the end of the tunnel they are identified electronically. The main task of the column is to make the compounds pass through different times depending on their properties, this helps to detect them. In the beginning of this process a micro syringe is used to inject the known volume of the complex compound to be analyzed.
Gas Chromatography helps us to analyze contents of a substance very accurately. For example, it helps to determine the quality of products in chemical industry and determine toxic substances in a mixture. The more expensive GC instruments can measure up to picomoles of a substance in a 1 ml liquid sample.4 Gas Chromatography is used in forensic science, solid drug dose identification, arson investigation, paint chip analysis, toxicology cases, quantify various biological specimens and crime-scene evidence.5 With the expansion of science popular culture has adopted various sides of it. The use of gas chromatography is widely seen on TV shows, movies and books. But often their capabilities is exaggerated. For example, I myself use to watch CSI a lot when I was younger and they portray GC as a magical instrument which can identify any unknown sample within minutes and it would even give all the details of its origin and the day it was used. In real world it takes way longer. And to be more accurate the tests are to be performed quite a few times. Thus after doing the experiment in class I understood it is not at all the way described in the books.
1. Berichte der Deutschen botanischen Gesellschaft, vol. 24, pp. 316’326.
2. Martin, Archer, and Richard Synge. “Theory and Instrumentation If GC.” Theory and Instrumentation of GC Introduction to Gas Chromatography (n.d.): n. pag. CHROMacademy. Crawford Scientific. Web.
3. Lovelock, James. “Archer John Porter Martin CBE. 1 March 1910 – 28 July 2002.” Archer John Porter Martin CBE. 1 March 1910. Royal Society Publishing, 1 Dec. 2004. Web. 18 Apr. 2015.
4. “Biomedical Chromatography”. 2012 Journal Citation Reports. Web of Science (Science ed.). Thomson Reuters. 2013.
5. “How Is Gas Chromatography Used in Forensics?” – May 26 2014 12:00 AM. Chromatorgraphy Today, 25 Apr. 2014. Web. 19 Apr. 2015.
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