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Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, or separating the different components of a mixture. [ 1 ]
The method uses headspace gas injected into a gas chromatographic column (GC) to determine the original concentration in a water sample. [9] A sample of water is collected in the field in a vial without headspace and capped with a Teflon septum or crimp top to minimize the escape of volatile gases. It is beneficial to store the bottles upside ...
Unresolved complex mixture (UCM), or hump, is a feature frequently observed in gas chromatographic (GC) data of crude oils and extracts from organisms exposed to oil. [1] The reason for the UCM hump appearance is that GC cannot resolve and identify a significant part of the hydrocarbons in crude oils. The resolved components appear as peaks ...
Gas chromatography–mass spectrometry (GC–MS) is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. [1] Applications of GC–MS include drug detection, fire investigation, environmental analysis, explosives investigation, food and flavor analysis ...
Pyrolysis GC/MS chromatogram of mahogany wood analyzed with OpenChrom. Pyrolysis–gas chromatography–mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry. [1] [2]
In engineering and physics, g c is a unit conversion factor used to convert mass to force or vice versa. [1] It is defined as = In unit systems where force is a derived unit, like in SI units, g c is equal to 1.
Analytical thermal desorption, known within the analytical chemistry community simply as "thermal desorption" (TD), is a technique that concentrates volatile organic compounds (VOCs) in gas streams prior to injection into a gas chromatograph (GC). It can be used to lower the detection limits of GC methods, and can improve chromatographic ...
Calibration curves are obtained by plotting measured isotope ratios in the prepared blends against the known ratio of the sample mass to the mass of the spike solution in each blend. Isotope dilution calibration plots sometimes show nonlinear relationships and in practice polynomial fitting is often performed to empirically describe such curves ...