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Formate is a common C-1 source in living systems. It is formed from many precursors including choline, serine, and sarcosine. It provides a C-1 source in the biosynthesis of some nucleic acids. Formate (or formic acid) is invoked as a leaving group in the demethylation of some sterols. [2]
Atmospheric pressure chemical ionization chamber cross section. Atmospheric pressure chemical ionization (APCI) is an ionization method used in mass spectrometry which utilizes gas-phase ion-molecule reactions at atmospheric pressure (10 5 Pa), [1] [2] commonly coupled with high-performance liquid chromatography (HPLC). [3]
Ammonium formate can be used as a mobile phase additive in high performance liquid chromatography (HPLC), and is suitable for use with liquid chromatography-mass spectrometry (LC/MS). The p K a values of formic acid and the ammonium ion are 3.8 and 9.2, respectively.
Scheme of a Direct-EI, LC-MS interface. A direct electron ionization liquid chromatography–mass spectrometry interface (Direct-EI LC-MS interface) is a technique for coupling liquid chromatography and mass spectrometry based on the direct introduction of the liquid effluent into an electron ionization (EI) source. [1]
A good example is the formation of adducts between the Lewis acid borane and the oxygen atom in the Lewis bases, tetrahydrofuran (THF): BH 3 ·O(CH 2) 4 or diethyl ether: BH 3 ·O(CH 3 CH 2) 2. Many Lewis acids and Lewis bases reacting in the gas phase or in non-aqueous solvents to form adducts have been examined in the ECW model . [ 3 ]
Ion suppression in LC-MS and LC-MS/MS refers to reduced detector response, or signal:noise as a manifested effect of competition for ionisation efficiency in the ionisation source, between the analyte(s) of interest and other endogenous or exogenous (e.g. plasticisers extracted from plastic tubes, [1] mobile phase additives) species which have not been removed from the sample matrix during ...
This format was officially released at the 2008 American Society for Mass Spectrometry Meeting, and is since then relatively stable with very few updates. On 1 June 2009, mzML 1.1.0 was released. On 1 June 2009, mzML 1.1.0 was released.
Liquid chromatography–mass spectrometry (LC–MS) is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography (or HPLC) with the mass analysis capabilities of mass spectrometry (MS). Coupled chromatography – MS systems are popular in chemical analysis because the individual capabilities ...