Xenon tetroxide is a chemical compound of xenon and oxygen with molecular formula XeO4, remarkable for being a relatively stable compound of a noble gas. It is a yellow crystalline solid that is stable below −35.9 °C; above that temperature it is very prone to exploding and decomposing into elemental xenon and oxygen (O2).
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. Applications of GC–MS include drug detection, fire investigation, environmental analysis, explosives investigation, food and flavor analysis, and identification of unknown samples, including that of material samples obtained from planet Mars during probe missions as early as the 1970s. GC–MS can also be used in airport security to detect substances in luggage or on human beings. Additionally, it can identify trace elements in materials that were previously thought to have disintegrated beyond identification. Like liquid chromatography–mass spectrometry, it allows analysis and detection even of tiny amounts of a substance.
![<span class="mw-page-title-main">Chemical ionization</span> Ionization technique used in mass [[spectroscopy]]](https://upload.wikimedia.org/wikipedia/commons/thumb/7/7b/Chemical_Ionization.png/320px-Chemical_Ionization.png)
Chemical ionization (CI) is a soft ionization technique used in mass spectrometry. This was first introduced by Burnaby Munson and Frank H. Field in 1966. This technique is a branch of gaseous ion-molecule chemistry. Reagent gas molecules are ionized by electron ionization to form reagent ions, which subsequently react with analyte molecules in the gas phase to create analyte ions for analysis by mass spectrometry. Negative chemical ionization (NCI), charge-exchange chemical ionization, atmospheric-pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) are some of the common variants of the technique. CI mass spectrometry finds general application in the identification, structure elucidation and quantitation of organic compounds as well as some utility in biochemical analysis. Samples to be analyzed must be in vapour form, or else, must be vapourized before introduction into the source.
Liquid chromatography–mass spectrometry (LC–MS) is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography with the mass analysis capabilities of mass spectrometry (MS). Coupled chromatography – MS systems are popular in chemical analysis because the individual capabilities of each technique are enhanced synergistically. While liquid chromatography separates mixtures with multiple components, mass spectrometry provides spectral information that may help to identify each separated component. MS is not only sensitive, but provides selective detection, relieving the need for complete chromatographic separation. LC–MS is also appropriate for metabolomics because of its good coverage of a wide range of chemicals. This tandem technique can be used to analyze biochemical, organic, and inorganic compounds commonly found in complex samples of environmental and biological origin. Therefore, LC–MS may be applied in a wide range of sectors including biotechnology, environment monitoring, food processing, and pharmaceutical, agrochemical, and cosmetic industries. Since the early 2000s, LC–MS has also begun to be used in clinical applications.
Ion mobility spectrometry (IMS) It is a method of conducting analytical research that separates and identifies ionized molecules present in the gas phase based on the mobility of the molecules in a carrier buffer gas. Even though it is used extensively for military or security objectives, such as detecting drugs and explosives, the technology also has many applications in laboratory analysis, including studying small and big biomolecules. IMS instruments are extremely sensitive stand-alone devices, but are often coupled with mass spectrometry, gas chromatography or high-performance liquid chromatography in order to achieve a multi-dimensional separation. They come in various sizes, ranging from a few millimeters to several meters depending on the specific application, and are capable of operating under a broad range of conditions. IMS instruments such as microscale high-field asymmetric-waveform ion mobility spectrometry can be palm-portable for use in a range of applications including volatile organic compound (VOC) monitoring, biological sample analysis, medical diagnosis and food quality monitoring. Systems operated at higher pressure are often accompanied by elevated temperature, while lower pressure systems (1–20 hPa) do not require heating.
Atmospheric pressure chemical ionization (APCI) is an ionization method used in mass spectrometry which utilizes gas-phase ion-molecule reactions at atmospheric pressure (105 Pa), commonly coupled with high-performance liquid chromatography (HPLC). APCI is a soft ionization method similar to chemical ionization where primary ions are produced on a solvent spray. The main usage of APCI is for polar and relatively less polar thermally stable compounds with molecular weight less than 1500 Da. The application of APCI with HPLC has gained a large popularity in trace analysis detection such as steroids, pesticides and also in pharmacology for drug metabolites.
Isoamyl alcohol is a colorless liquid with the formula C
5H
12O, specifically (H3C–)2CH–CH2–CH2–OH. It is one of several isomers of amyl alcohol (pentanol). It is also known as isopentyl alcohol, isopentanol, or (in the IUPAC recommended nomenclature) 3-methyl-butan-1-ol. An obsolete name for it was isobutyl carbinol.
tert-Amyl alcohol (TAA) or 2-methylbutan-2-ol (2M2B), is a branched pentanol.
3-Pentanol is one of the eight isomers of amyl alcohol. It is found naturally and has a role as a pheromone.
In mass spectrometry, resolution is a measure of the ability to distinguish two peaks of slightly different mass-to-charge ratios ΔM, in a mass spectrum.
2-Methyl-1-butanol (IUPAC name, also called active amyl alcohol) is an organic compound with the formula CH3CH2CH(CH3)CH2OH. It is one of several isomers of amyl alcohol. This colorless liquid occurs naturally in trace amounts and has attracted some attention as a potential biofuel, exploiting its hydrophobic (gasoline-like) and branched structure. It is chiral.
3-Methyl-1-pentanol is an organic chemical compound. It occurs naturally in Capsicum frutescens, the tabasco pepper.
2-Methyl-1-pentanol is an organic chemical compound. It is used as a solvent and an intermediate in the manufacture of other chemicals.
Isohexanol is an organic chemical compound. It is found in longan fruit.
2-Methyl-2-pentanol is an organic chemical compound. It can be added to a gas chromatograph to help distinguish between branched compounds, especially alcohols. Its presence in urine can be used to test for exposure to 2-methylpentane. As with many other short-chain alcohols, 2-methyl-2-pentanol can produce intoxication and sedative effects similar to those of ethanol, though it is more irritating to mucous membranes and generally more toxic to the body.
3-Methyl-2-pentanol is an organic chemical compound. It has been identified as a component of hops. Its presence in urine can be used to test for exposure to 3-methylpentane.
4-Methyl-2-pentanol or methyl isobutyl carbinol (MIBC) is an organic chemical compound used primarily as a frother in mineral flotation and in the production of lubricant oil additives such as Zinc dithiophosphate. It is also used as a solvent, in organic synthesis, and in the manufacture of brake fluid and as a precursor to some plasticizers. It is an acetone derivative in liquid state, with limited solubility in water but generally miscible with most organic solvents.
2-Methyl-3-pentanol is an organic chemical compound. It is a secondary alcohol that is used as a fuel.
3-Methyl-3-pentanol is an organic chemical compound and a tertiary hexanol. It is used in the synthesis of the tranquilizer emylcamate, and has similar sedative and anticonvulsant actions itself.
3-Methyl-2-butanol is an organic chemical compound. It is used as a solvent and an intermediate in the manufacture of other chemicals.
