{"id":1448,"date":"2024-05-06T23:35:27","date_gmt":"2024-05-06T17:50:27","guid":{"rendered":"https:\/\/microbenotes.com\/?p=1448"},"modified":"2024-05-26T03:20:31","modified_gmt":"2024-05-25T21:35:31","slug":"gas-chromatography","status":"publish","type":"post","link":"https:\/\/microbenotes.com\/gas-chromatography\/","title":{"rendered":"Gas Chromatography: Principle, Parts, Steps, Procedure, Uses"},"content":{"rendered":"\n<p><span style=\"color: #000000;\"><strong>Gas chromatography differs from other forms of <a href=\"https:\/\/microbenotes.com\/chromatography-principle-types-and-applications\/\" target=\"_blank\" rel=\"noopener noreferrer\">chromatography<\/a> in that the mobile phase is a gas and the components are separated as vapors.<\/strong><\/span><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">It is thus used to separate and detect small molecular weight compounds in the gas phase.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The sample is either a gas or a liquid that is vaporized in the injection port. The mobile phase for gas chromatography is a carrier gas, typically helium because of its\u00a0low molecular weight and being chemically inert.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The pressure is applied and the mobile phase moves the analyte through the column. The separation is accomplished using a column coated with a stationary phase.<\/span><\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"420\" src=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/10\/Principle-of-Gas-Chromatography.jpg\" alt=\"Principle of\u00a0Gas Chromatography\" class=\"wp-image-1450\" srcset=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/10\/Principle-of-Gas-Chromatography.jpg 800w, https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/10\/Principle-of-Gas-Chromatography-300x158.jpg 300w, https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/10\/Principle-of-Gas-Chromatography-768x403.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/figure><\/div>\n\n\n<p>Image Source: <a href=\"https:\/\/bitesizebio.com\/28687\/carrying-gas-chromatography\/\" target=\"_blank\" rel=\"noopener noreferrer\">Bitesize Bio<\/a>.<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_69 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title \" >Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #0a0a0a;color:#0a0a0a\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #0a0a0a;color:#0a0a0a\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/microbenotes.com\/gas-chromatography\/#principle-of-gas-chromatography-how-does-gas-chromatography-work\" title=\"Principle of Gas chromatography (how does gas chromatography work)\">Principle of Gas chromatography (how does gas chromatography work)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/microbenotes.com\/gas-chromatography\/#parts-of-gas-chromatography\" title=\"Parts of Gas chromatography\">Parts of Gas chromatography<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/microbenotes.com\/gas-chromatography\/#the-procedure-of-gas-chromatography\" title=\"The procedure of Gas Chromatography\">The procedure of Gas Chromatography<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/microbenotes.com\/gas-chromatography\/#applications\" title=\"Applications\">Applications<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/microbenotes.com\/gas-chromatography\/#advantages\" title=\"Advantages\">Advantages<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/microbenotes.com\/gas-chromatography\/#limitations\" title=\"Limitations\">Limitations<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/microbenotes.com\/gas-chromatography\/#references\" title=\"References\">References<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"principle-of-gas-chromatography-how-does-gas-chromatography-work\"><\/span><span style=\"color: #000000;\"><strong>Principle of Gas chromatography (how does gas chromatography work)<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><span style=\"color: #000000;\">The equilibrium for gas chromatography is partitioning, and the components of the sample will partition (i.e.&nbsp;distribute) between the two phases: the stationary phase and the mobile phase.<\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\">Compounds that have a greater affinity for the stationary phase spend more time in the column and thus elute later and have a longer <strong>retention time (Rt)<\/strong> than samples that have a higher affinity for the mobile phase.<\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\">Affinity for the stationary phase is driven mainly by intermolecular interactions and the polarity of the stationary phase can be chosen to maximize interactions and thus the separation.<\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\">Ideal peaks are Gaussian distributions and symmetrical, because of the random nature of the analyte interactions with the column.<\/span><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">The separation is hence accomplished by partitioning the sample between the gas and a thin layer of a nonvolatile liquid held on a solid support.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">A sample containing the solutes is injected into a heated block where it is immediately vaporized and swept as a plug of vapor by the carrier gas stream into the column inlet.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The solutes are adsorbed by the stationary phase and then desorbed by a fresh carrier gas.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The process is repeated in each plate as the sample is moved toward the outlet.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Each solute will travel at its own rate through the column.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Their bands will separate into distinct zones depending on the partition coefficients, and band spreading.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The solutes are eluted one after another in the increasing order of their kd, and enter into a detector attached to the exit end of the column.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Here they register a series of signals resulting from concentration changes and rates of elution on the recorder as a plot of time versus the composition of carrier gas stream.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The appearance time, height, width, and area of these peaks can be measured to yield quantitative data.<\/span><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"parts-of-gas-chromatography\"><\/span><span style=\"color: #000000;\"><strong>Parts of Gas chromatography<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"700\" height=\"350\" src=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/10\/Instrumentation-of-Gas-Chromatography.jpg\" alt=\"Instrumentation of\u00a0Gas Chromatography\" class=\"wp-image-1449\" srcset=\"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/10\/Instrumentation-of-Gas-Chromatography.jpg 700w, https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/10\/Instrumentation-of-Gas-Chromatography-300x150.jpg 300w\" sizes=\"(max-width: 700px) 100vw, 700px\" \/><\/figure><\/div>\n\n\n<p><span style=\"color: #000000;\">Gas chromatography is mainly composed of the following parts:<\/span><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><span style=\"color: #000000;\"><strong> Carrier gas in a high-pressure cylinder with attendant pressure regulators and flow meters <\/strong><\/span><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">Helium, N<sub>2<\/sub>, H, Argon are used as carrier gases.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Helium is preferred for thermal conductivity detectors because of its high thermal conductivity relative to that of most organic vapors.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">N<sub>2<\/sub> is preferable when a large consumption of carrier gas is employed.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Carrier gas from the tank passes through a toggle valve, a flow meter, (1-1000 ml\/min), capillary restrictors, and a pressure gauge (1-4 atm).<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Flow rate is adjusted by means of a needle valve mounted on the base of the flow meter and controlled by capillary restrictors.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The operating efficiency of the gas chromatograph is directly dependant on the maintenance of constant gas flow.<\/span><\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\" start=\"2\">\n<li><span style=\"color: #000000;\"><strong> Sample injection system <\/strong><\/span><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">Liquid samples are injected by a microsyringe with a needle inserted through a self-scaling, silicon-rubber septum into a heated metal block by a resistance heater.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Gaseous samples are injected by a gas-tight syringe or through a by-pass loop and valves.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Typical sample volumes range from 0.1 to 0.2 ml.<\/span><\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\" start=\"3\">\n<li><span style=\"color: #000000;\"><strong> The separation column <\/strong><\/span><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">The heart of the gas chromatography is the column which is made of metals bent in U shape or coiled into an open spiral or a flat pancake shape.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Copper is useful up to 250<sup>0<\/sup><\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Swege lock fittings make column insertion easy.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Several sizes of columns are used depending upon the requirements.<\/span><\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\" start=\"4\">\n<li><span style=\"color: #000000;\"><strong> Liquid phases <\/strong><\/span><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">An infinite variety of liquid phases are available limited only by their volatility, thermal stability and ability to wet the support.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">No single phase will serve for all separation problems at all temperatures.<\/span><\/li>\n<\/ul>\n\n\n\n<p><span style=\"color: #000000;\"><strong>Non-Polar<\/strong> \u2013 Parafin, squalane, silicone greases, apiezon L, silicone gum rubber. These materials separate the components in order of their boiling points.<\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\"><strong>Intermediate Polarity<\/strong> \u2013 These materials contain a polar or polarizable group on a long non-polar skeleton which can dissolve both polar and non-polar solutes. For example. diethyl hexyl phthalate is used for the separation of high boiling alcohols.<\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\"><strong>Polar <\/strong>\u2013 Carbowaxes \u2013 Liquid phases with a large proportion of polar groups. Separation of polar and non-polar substances.<\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\"><strong>Hydrogen bonding<\/strong> &#8211; Polar liquid phases with high hydrogen bonding e.g. Glycol.<\/span><\/p>\n\n\n\n<p><span style=\"color: #000000;\"><strong>Specific purpose phases<\/strong> \u2013 Relying on a chemical reaction with solute to achieve separations. e.g AgNO3 in glycol separates unsaturated hydrocarbons.<\/span><\/p>\n\n\n\n<ol class=\"wp-block-list\" start=\"5\">\n<li><span style=\"color: #000000;\"><strong> Supports <\/strong><\/span><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">The structure and surface characteristics of the support materials are important parameters, which determine the efficiency of the support and the degree of separation respectively.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The support should be inert but capable of immobilizing a large volume of liquid phase as a thin film over its surface.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The surface area should be large to ensure the rapid attainment of equilibrium between stationary and mobile phases.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Support should be strong enough to resist breakdown in handling and be capable of packed into a uniform bed.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Diatomaceous earth, kieselguhr treated with Na 2CO 3 for 900<sup>0<\/sup> C causes the particle fusion into coarser aggregates.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Glass beads with a low surface area and low porosity can be used to coat up to 3% stationary phases.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Porous polymer beads differing in the degree of cross-linking of styrene with alkyl-vinyl benzene are also used which are stable up to 250<sup>0<\/sup><\/span><\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\" start=\"6\">\n<li><span style=\"color: #000000;\"><strong> Detector<\/strong><\/span><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">Detectors sense the arrival of the separated components and provide a signal.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">These are either concentration-dependent or mass dependant.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The detector should be close to the column exit and the correct temperature to prevent decomposition.<\/span><\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\" start=\"7\">\n<li><span style=\"color: #000000;\"><strong> Recorder <\/strong><\/span><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">The recorder should be generally 10 mv (full scale) fitted with a fast response pen (1 sec or less). The recorder should be connected with a series of good quality resistances connected across the input to attenuate the large signals.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">An integrator may be a good addition.<\/span><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"the-procedure-of-gas-chromatography\"><\/span><span style=\"color: #000000;\"><strong>The procedure of Gas Chromatography<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><span style=\"color: #000000;\"><strong>Step 1: Sample Injection and Vapourization<\/strong><\/span><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">A small amount of liquid sample to be analyzed is drawn up into a syringe.\u00a0<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The syringe needle is positioned in the hot injection port of the gas chromatograph and the sample is injected quickly.\u00a0<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The injection of the sample is considered to be a &#8220;point&#8221; in time, that is, it is assumed that the entire sample enters the gas chromatograph at the same time, so the sample must be injected quickly.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The temperature is set to be higher than the boiling points of the components of the mixture so that the components will vaporize.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The vaporized components then mix with the inert gas mobile phase to be carried to the gas chromatography column to be separated.\u00a0<\/span><\/li>\n<\/ol>\n\n\n\n<p><span style=\"color: #000000;\"><strong>Step 2: Separation in the Column<\/strong><\/span><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">Components in the mixture are separated based on their abilities to adsorb on or bind to, the stationary phase.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">A component that adsorbs most strongly to the stationary phase will spend the most time in the column (will be retained in the column for the longest time) and will, therefore, have the longest retention time (Rt). It will emerge from the gas chromatograph last.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">A component that adsorbs the least strongly to the stationary phase will spend the least time in the column (will be retained in the column for the shortest time) and will, therefore, have the shortest retention time (Rt).\u00a0 It will emerge from the gas chromatograph first.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">If we consider a 2 component mixture in which component A is more\u00a0polar\u00a0than component B then:<\/span><\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">component A will have a<strong> longer retention time<\/strong> in a polar column than component B<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">component A will have a <strong>shorter retention time<\/strong> in a non-polar column than component B<\/span><\/li>\n<\/ol>\n\n\n\n<p><span style=\"color: #000000;\"><strong>Step 3: Detecting and Recording Results<\/strong><\/span><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">The components of the mixture reach the detector at different times due to differences in the time they are retained in the column.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The component that is retained the shortest time in the column is detected first.\u00a0The component that is retained the longest time in the column is detected last.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The detector sends a signal to the chart recorder which results in a peak on the chart paper. The component that is detected first is recorded first.\u00a0 The component that is detected last is recorded last.<\/span><\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"applications\"><\/span><span style=\"color: #000000;\"><strong>Applications<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">GC analysis is used to calculate the content of a chemical product, for example in assuring the quality of products in the chemical industry; or measuring toxic substances in soil, air or water.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Gas chromatography is used in the analysis of:<\/span><\/li>\n<\/ul>\n\n\n\n<p><span style=\"color: #000000;\">(a) air-borne pollutants&nbsp;<\/span><br><span style=\"color: #000000;\">(b) performance-enhancing drugs in athlete&#8217;s urine samples&nbsp;<\/span><br><span style=\"color: #000000;\">(c) oil spills&nbsp;<\/span><br><span style=\"color: #000000;\">(d) essential oils in perfume preparation<\/span><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">GC is very accurate if used properly and can measure\u00a0picomoles\u00a0of a substance in a 1 ml liquid sample, or\u00a0parts-per-billion\u00a0concentrations in gaseous samples.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Gas Chromatography is used extensively in\u00a0forensic science. Disciplines as diverse as solid drug dose (pre-consumption form) identification and quantification, arson investigation, paint chip analysis, and toxicology cases, employ GC to identify and quantify various biological specimens and crime-scene evidence.<\/span><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"advantages\"><\/span><span style=\"color: #000000;\"><strong>Advantages<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">The use of longer columns and higher velocity of carrier gas permits the fast separation in a matter of a few minutes.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Higher working temperatures up to 5000C and the possibility of converting any material into a volatile component make gas chromatography one of the most versatile techniques.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">GC is popular for environmental monitoring and industrial applications because it is very reliable and can be run nearly continuously.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">GC is typically used in applications where small, volatile molecules are detected and with non-aqueous solutions.\u00a0<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">GC is favored for non-polar molecules.<\/span><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"limitations\"><\/span><span style=\"color: #000000;\"><strong>Limitations<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><span style=\"color: #000000;\">Compound to be analyzed should be stable under GC operation conditions.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">They should have a vapor pressure significantly greater than zero.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Typically, the compounds analyzed are less than 1,000 Da, because it is difficult to vaporize larger compounds.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">The samples are also required to be\u00a0salt-free; they should not contain\u00a0ions.<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">Very minute amounts of a substance can be measured, but it is often required that the sample must be measured in comparison to a sample containing the pure, suspected substance known as a\u00a0reference standard.<\/span><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"references\"><\/span><span style=\"color: #000000;\"><strong>References<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><a href=\"https:\/\/nptel.ac.in\/courses\/103108100\/module7\/module7.pdf\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"color: #000000;\">https:\/\/nptel.ac.in\/courses\/103108100\/module7\/module7.pdf<\/span><\/a><\/li>\n\n\n\n<li><span style=\"color: #000000;\">https:\/\/en.wikipedia.org\/wiki\/Gas_chromatography#Carrier_gas_selection_and_flow_rates<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">https:\/\/www.jove.com\/science-education\/10187\/gas-chromatography-gc-with-flame-ionization-detection<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">http:\/\/davisson.nat.uni-magdeburg.de\/Downloads\/Chromatographie.pdf<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">https:\/\/www.whitman.edu\/chemistry\/edusolns_software\/GC_LC_CE_MS_2017\/CH%201%202017.pdf<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">http:\/\/www.ausetute.com.au\/gc.html<\/span><\/li>\n\n\n\n<li><span style=\"color: #000000;\">http:\/\/web.uniplovdiv.bg\/plamenpenchev\/mag\/books\/anchem\/Handbook%20of%20Analytical%20Techniques,%202%20Volume%20Set.pdf<\/span><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>Gas chromatography differs from other forms of chromatography in that the mobile phase is a gas and the components are separated as vapors. Image Source: Bitesize Bio. Principle of Gas &#8230; <a title=\"Gas Chromatography: Principle, Parts, Steps, Procedure, Uses\" class=\"read-more\" href=\"https:\/\/microbenotes.com\/gas-chromatography\/\" aria-label=\"Read more about Gas Chromatography: Principle, Parts, Steps, Procedure, Uses\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":1450,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rank_math_lock_modified_date":false,"footnotes":""},"categories":[2578],"tags":[2596,2918,2924,2923,2926,2928,2920,2925,2927,2929,2919,2921,2922,2930],"class_list":["post-1448","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-instrumentation","tag-chromatography","tag-gas-chromatography","tag-gas-chromatography-advantages","tag-gas-chromatography-applications","tag-gas-chromatography-definition","tag-gas-chromatography-diagram","tag-gas-chromatography-instrumentation","tag-gas-chromatography-limitations","tag-gas-chromatography-machine","tag-gas-chromatography-method","tag-gas-chromatography-principle","tag-gas-chromatography-procedure","tag-gas-chromatography-steps","tag-gas-chromatography-theory"],"custom":{"td_video":"","featured_image":"https:\/\/microbenotes.com\/wp-content\/uploads\/2018\/10\/Principle-of-Gas-Chromatography.jpg","author":{"name":"Sagar Aryal","avatar":"https:\/\/secure.gravatar.com\/avatar\/862472ea06500d4318f1ad82addb608e?s=96&d=mm&r=g"},"categories":[{"term_id":2578,"name":"Instrumentation","slug":"instrumentation","term_group":0,"term_taxonomy_id":2578,"taxonomy":"category","description":"<strong>Instrumentation is a collection of devices and mechanics used to measure, evaluate, and test systems.<\/strong>\r\n<ul>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">In biology, the instrumentation is considered a part of biomedical engineering where the working mechanism and the parts of a system are studies.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Instrumentation in biology or Bioinstrumentation is primarily concentrated on bringing the engineering and medical worlds together.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Different devices like centrifuges and autoclaves that are common in biological laboratories are a part of the instrumentation. Studies done in instrumentations allow the understanding of the parts and working mechanisms of such devices.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Other important techniques include chromatography which is routinely performed in laboratories to separate biological systems, which are also equally important.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Instrumentation is still an emerging discipline with new pieces of machinery still being produced for convenience in laboratories.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">The application of bio-instruments is not only limited to laboratories as modern agriculture makes use of bio-instruments to monitor and evaluate soil and to measure plant growth.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Besides, these instruments can also be used to determine the physiological activities of plants like the carbon dioxide trade rate, net photosynthesis, etc.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Processes like electrophoresis make use of nucleic acids along with biosensors to compare the DNA sequences. This enables genetic testing and diagnosis of various diseases.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Genetic testing is heavily influenced by the progress made in instrumentation as new devices and techniques are discovered which makes the process faster, more accurate, and more reliable.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">As RT-PCR and blotting are considered advanced molecular diagnosis methods, disease diagnosis becomes faster and more accurate than ever.\u00a0<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Determination of radioisotopes and concentration of a solution has been made easier with techniques like spectroscopy and colorimetry.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">As the discipline continues to grow, the main focus of the field remains in the improvements of technology to make the medical processes faster and more efficient.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Instrumentation, thus, is slowly becoming an integral part of all biological fields with new emerging new technology and the discovery of fast and reliable procedures.<\/span><\/li>\r\n<\/ul>","parent":0,"count":64,"filter":"raw","cat_ID":2578,"category_count":64,"category_description":"<strong>Instrumentation is a collection of devices and mechanics used to measure, evaluate, and test systems.<\/strong>\r\n<ul>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">In biology, the instrumentation is considered a part of biomedical engineering where the working mechanism and the parts of a system are studies.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Instrumentation in biology or Bioinstrumentation is primarily concentrated on bringing the engineering and medical worlds together.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Different devices like centrifuges and autoclaves that are common in biological laboratories are a part of the instrumentation. Studies done in instrumentations allow the understanding of the parts and working mechanisms of such devices.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Other important techniques include chromatography which is routinely performed in laboratories to separate biological systems, which are also equally important.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Instrumentation is still an emerging discipline with new pieces of machinery still being produced for convenience in laboratories.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">The application of bio-instruments is not only limited to laboratories as modern agriculture makes use of bio-instruments to monitor and evaluate soil and to measure plant growth.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Besides, these instruments can also be used to determine the physiological activities of plants like the carbon dioxide trade rate, net photosynthesis, etc.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Processes like electrophoresis make use of nucleic acids along with biosensors to compare the DNA sequences. This enables genetic testing and diagnosis of various diseases.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Genetic testing is heavily influenced by the progress made in instrumentation as new devices and techniques are discovered which makes the process faster, more accurate, and more reliable.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">As RT-PCR and blotting are considered advanced molecular diagnosis methods, disease diagnosis becomes faster and more accurate than ever.\u00a0<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Determination of radioisotopes and concentration of a solution has been made easier with techniques like spectroscopy and colorimetry.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">As the discipline continues to grow, the main focus of the field remains in the improvements of technology to make the medical processes faster and more efficient.<\/span><\/li>\r\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Instrumentation, thus, is slowly becoming an integral part of all biological fields with new emerging new technology and the discovery of fast and reliable procedures.<\/span><\/li>\r\n<\/ul>","cat_name":"Instrumentation","category_nicename":"instrumentation","category_parent":0}]},"_links":{"self":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts\/1448"}],"collection":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/comments?post=1448"}],"version-history":[{"count":1,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts\/1448\/revisions"}],"predecessor-version":[{"id":44236,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/posts\/1448\/revisions\/44236"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/media\/1450"}],"wp:attachment":[{"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/media?parent=1448"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/categories?post=1448"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/microbenotes.com\/wp-json\/wp\/v2\/tags?post=1448"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}