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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]
Because it is commonly recrystallized from chloroform, the complex is often supplied as the adduct [Pd 2 (dba) 3 ·CHCl 3]. [1] The purity of samples can be variable. [3] In [Pd 2 (dba) 3], the pair of Pd atoms are separated by 320 pm but are tied together by dba units. [4] The Pd(0) centres are bound to the alkene parts of the dba ligands.
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]
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]
MS is an experiment that must take place in gas phase and under vacuum (1.33 * 10 −2 to 1.33 * 10 −6 pascal). Therefore, the development of devices facilitating the transition from samples at higher pressure and in condensed phase (solid or liquid) into a vacuum system has been essential to develop MS as a potent tool for identification and ...
An example total ion current chromatogram from an LC-MS analysis. The total ion current chromatogram (TICC) represents the summed intensity across the entire range of masses being detected at every point in the analysis. [2] [3] The range is typically several hundred mass-to-charge units or more. In complex samples, the TICC often provides ...
In enzymology, formate C-acetyltransferase (pyruvate formate lyase) (EC 2.3.1.54) is an enzyme. Pyruvate formate lyase is found in Escherichia coli [1] and other organisms. It helps regulate anaerobic glucose metabolism. Using radical non-redox chemistry, it catalyzes the reversible conversion of pyruvate and coenzyme-A into formate and acetyl ...
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 ...