Alcohol mass spectrometry

Mass Spectrometry The molecular ion peak is usually quite small m the mass spec trum of an alcohol A peak corresponding to loss of water is often evident Alcohols also fragment readily by a pathway m which the molecular ion loses an alkyl group from the... 

Mass Spectrometry Ethers like alcohols lose an alkyl radical from their molecular ion to give an oxygen stabilized cation Thus m/z 73 and m/z 87 are both more abun dant than the molecular ion m the mass spectrum of sec butyl ethyl ether... 

Mass spectral analysis of quaternary ammonium compounds can be achieved by fast-atom bombardment (fab) ms (189,190). This technique rehes on bombarding a solution of the molecule, usually in glycerol [56-81-5] or y -nitroben2yl alcohol [619-25-0], with argon and detecting the parent cation plus a proton (MH ). A more recent technique has been reported (191), in which information on the stmcture of the quaternary compounds is obtained indirectly through cluster-ion formation detected via Hquid secondary ion mass spectrometry (Isims) experiments. 

Mass Spectrometry Ethers, like alcohols, lose an alkyl radical from their- molecular-... 

A large number of silylating agents exist for the introduction of the trimethylsilyl group onto a variety of alcohols. In general, the sterically least hindered alcohols are the most readily silylated, but are also the most labile to hydrolysis with either acid or base. Trimethylsilylation is used extensively for the derivatization of most functional groups to increase their volatility for gas chromatography and mass spectrometry. 

An example of how information from fragmentation patterns can be used to solve structural problems is given in Worked Example 12.1. This example is a simple one, but the principles used are broadly applicable for organic structure determination by mass spectrometry. We ll see in the next section and in later chapters that specific functional groups, such as alcohols, ketones, aldehydes, and amines, show specific kinds of mass spectral fragmentations that can be interpreted to provide structural information. 

DNA sequencing and. 1113 Electrospray ionization (ESI) mass spectrometry, 417-418 Electrostatic potential map, 37 acetaldehyde, 688 acetamide, 791,922 acetate ion. 43. 53, 56, 757 acetic acid. 53. 55 acetic acid dimer, 755 acetic anhydride, 791 acetone, 55, 56. 78 acetone anion, 56 acetyl azide, 830 acetyl chloride, 791 acetylene. 262 acetylide anion, 271 acid anhydride, 791 acid chloride, 791 acyl cation, 558 adenine, 1104 alanine, 1017 alanine zwitterion, 1017 alcohol. 75 alkene, 74, 147 alkyl halide, 75 alkyne. 74... 

Properties of panal (Nakamura etal., 1988a). Purified panal is a colorless, amorphous solid, soluble in alcohols, water, ethyl acetate, and chloroform. The absorption spectrum (Fig. 9.3) shows a single peak (A.max 217nm, e 15,300). Optical rotation [a]D —17° (c 0.9, methanol). Mass spectrometry and NMR analysis showed that panal is a sesquiterpene aldehyde, C15H18O5 (Mr 278.30), with the structure shown below. 

The ion spray liquid chromatography/mass spectrometry (LC-MS) interface coupled via a postsuppressor split with an ion chromatography (IC) has been used in the analysis of alcohol sulfates. The IC-MS readily produces the molecular weight while the tandem mass spectrometric detection IC-MS-MS provides structural information [305]. 

Which bond of the ester is broken, the acyl—O or the alkyl—O bond The answer is found by the use of Hj O. If the acyl—O bond breaks, the labeled oxygen will appear in the acid otherwise it will be in the alcohol (see 10-10). Although neither compound is radioactive, the one that contains 0 can be determined by submitting both to mass spectrometry (MS). In a similar way, deuterium can be used as a label for hydrogen. In this case, it is not necessary to use mass spectrometry (MS), since IR and NMR spectra can be used to determine when deuterium has been substituted... 

Di Corcia A, C Crescenzi, A Marcomini, R Samperi (1998) Liquid-chromatography-electrospray-mass spectrometry as a valuable tool for characterizing biodegradation intermediates of branched alcohol ethoxyl-ate surfactants. Environ Sci Technol 32 711-718. 

Further indirect evidence for the oxidation of the primary alcohol in 5 and the formation of glycoside 6 during the course of the reaction was obtained by electrospray mass spectrometry. Towards this end, excess formaldehyde was added to the reaction mixture after the oxidation of 5 into 6, and the resulting solution stirred for an additional 30 min at ambient temperature to form the instable intermediate 7 (eq 6). The unnatural sugar 5-hydroxymethyl-a-methylglucoside (8) is spontaneously derived from 7 at ambient temperature via a Cannizzarro-like reaction in the presence of excess formaldehyde (eq. 7). 

Sample preparation for the common desorption/ionisation (DI) methods varies greatly. Films of solid inorganic or organic samples may be analysed with DI mass spectrometry, but sample preparation as a solution for LSIMS and FAB is far more common. The sample molecules are dissolved in a low-vapour-pressure liquid solvent - usually glycerol or nitrobenzyl alcohol. Other solvents have also been used for more specialised applications. Key requirements for the solvent matrix are sample solubility, low solvent volatility and muted acid - base or redox reactivity. In FAB and LSIMS, the special art of sample preparation in the selection of a solvent matrix, and then manipulation of the mass spectral data afterwards to minimise its contribution, still predominates. Incident particles in FAB and LSIMS are generated in filament ionisation sources or plasma discharge sources. 

Eudy, L. W. Walla, M. D. Hudson, J. R. Morgan, S. L. Fox, A. Gas chromatography-mass spectrometry studies on the occurrence of acetamide, pro-pionamide, and furfuryl alcohol in pyrolyzates of bacteria, bacterial fractions, and model compounds. I. Anal. Appl. Pyrolysis 1985,7,231-247. 

TPD and static secondary ion mass spectrometry (SSIMS) data suggest that methanol dissociatively adsorbs at Ob-vacs and molecularly at the Ti5c sites [52, 53]. There is also some evidence that methanol also dissociates at other sites apart from Ob-vacs, presumably Tisc sites [53-55]. Similar conclusions have been reached for a series of short-chain (C2-C8) aliphatic alcohols [56-58]. 

Jandera, P., Holcapek, M., Theodoridis, G. (1998). Investigation of chromatographic behavior of alcohol ethoxylate surfactants in normal-phase and reversed-phase systems using high-performance liquid chromatography-mass spectrometry. J. Chromatogr. A 813(2), 299-311. 

Andreu V, Ferrer E, Rubio JL, Font G, Pico Y (2007) Quantitative determination of octylphenol, nonylphenol, alkylphenol ethoxylates and alcohol ethoxylates by pressurized liquid extraction and liquid chromatography-mass spectrometry in soils treated with sewage sludges. Sci Total Environ 378 124—129... 

J.J. Jimenez, J.L. Bemal, S. Aumente, L. Toribio, J. Bernal, Quality assurance of commercial beeswax II. Gas chromatography electron impact ionization mass spectrometry of alcohols and acids, Journal of Chromatography A, 1007, 101 116 (2003). 

Detailed examination of another madder preparation proved that the sample can be premordanted with alum. [ 19] After hydrolysis performed with hydrochloric acid and extraction with M-amyl alcohol, only four colourants are found alizarin, purpurin, and probably lucidin and ruberythric acid. Additionally, signals at m/z 525 and 539 are observed in the mass spectrum. Analysis of the preparation by inductively coupled plasma mass spectrometry (ICP MS) shows that aluminium and calcium are the main inorganic components of the sample. This is why it was suggested that the signal at m/z 539 can be attributed to the complex of aluminium with alizarin, and the second one, observed at m/z 525, to an aluminium-calcium cluster. 

The gold(i)-catalyzed addition of alcohols to alkynes has been investigated in the gas phase by mass spectrometry techniques. While in the condensed phase, an efficient coupling to the corresponding enol ethers has been observed, in the... 

Gas chromatography and gas chromatography-mass spectrometry have also been used to measure fatty alcohol [119], phytol [120], and the several isomers of inositol [121]. 

KATONA, Z.F., SASS, P., MOLNAR-PERL, I., Simultaneous determination of sugars, sugar alcohols, acids, and amino acids in apricots by gas chromatography-mass spectrometry, J. Chromatogr., 1999, 847, 91-102. 

Complexes of N-N bonded dinitrogen dioxide, such as depicted in pathway B of Scheme 5, would appear to be necessary in order to effect the formation of the N-N bond. This has been treated theoretically as a metal promoted reductive coupling of 2 NO to form a hyponitrite complex (79). The Cu Tp112) system was also shown to catalyze NO oxidations of benzyl and isopropyl alcohol to benzaldehyde and acetone (Eq. (37)). Electrospray mass spectrometry indicated that higher... 

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