Experiments on the formation of acylium ions from alkenic compounds following chemical ionization with no <sup>+</sup>

Schneider, B.; Budzikiewicz, H.

doi:10.1002/oms.1210260523

Cited by 7 publications

(2 citation statements)

References 11 publications

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“…NCI spectra were recorded without the conversion dynode. Samples were introduced with a modified [13] direct insertion probe (IGT, Much, Germany), For gas chromatography/EI (GC/El) measurements (electron energy 70 eV, emission current 1 mA, pressure 2• to- 3 Fa, temperature 140°C), samples were introduced via a Varian 3700 gas chromatograph (SE-54 fused-silica column).…”

Section: Experimental Instrumentationmentioning

confidence: 99%

Oxidation reactions of dibenzothiophene subjected to negative chemical ionization with oxygen

Drabner

Budzikiewicz

1993

J. Am. Soc. Mass Spectrom.

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Dibenzothiophene (1) suffers surface-catalyzed oxidation under CI(O2) conditions. While in the positive mode M(+) is the only major ion and those of the oxidation products are of minor importance in the negative mode, essentially only ions stemming from oxidized species can be seen, the sulfone ion [M+O2](-) being the most important one. The ion m/z 184 previously attributed to M(-) is actually the anion of 2-sulfobenzoic acid cyclic anhydride. Structures for the various oxidation products are proposed and the mechanisms leading to their formation are discussed.

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Section: Experimental Instrumentationmentioning

confidence: 99%

Oxidation reactions of dibenzothiophene subjected to negative chemical ionization with oxygen

Drabner

Budzikiewicz

1993

J. Am. Soc. Mass Spectrom.

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“…Subsequent to studies by Hunt and Harvey (1), Einhorn (2)(3)(4), and Budzikiewicz (5,6) on the reaction of NO + with olefins, chemical ionization nitric oxide mass spectrometry (CI/NO + /MS) was used for locating double bonds in aliphatic compounds. The purpose of this study was to examine the possible application of CI/NO + /MS for double-bond location in 1-O-monoalkenylglycerols isolated from the liver oil of the shark Centrophorus squamosus, which are glycerol ether lipids as shown in Scheme 1.…”

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Location of deep‐sea shark (Centrophorus squamosus) glycerol ether lipid double bonds by nitric oxide chemical ionization mass spectrometry

Sellier

Bordier

1997

J Americ Oil Chem Soc

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Chemical ionization mass spectrometry with nitric oxide as the reactant gas has proved to be an efficient tool for locating the double bond in monoalkenylglycerols of type HO-CH 2 -CHOH-CH 2 -O-(CH 2 ) n-1 -CH=CH-(CH 2 ) n-2 -CH 3 . These monoalkenylglycerols were extracted from the liver oil of the shark Centrophorus squamosus, which lives at depths ranging from 1000 m and deeper. The presence of characteristic acylium ions R 1 CO + and/or R 2 CO + allowed location of the double-bond position. JAOCS 74, 923-926 (1997). KEY WORDS:Characteristic acylium ions, chemical ionization with NO + , ether di-O-methylglycerols, gas chromatography/mass spectrometry, Glycerol ethers, hexadec-9-enylglycerol, liver oil of shark Centrophorus squamosus, location of double bond in monoalkenylglycerols, octadec-9-enylglycerol, selachyl alcohol. (1), Einhorn (2-4), and Budzikiewicz (5,6) on the reaction of NO + with olefins, chemical ionization nitric oxide mass spectrometry (CI/NO + /MS) was used for locating double bonds in aliphatic compounds. The purpose of this study was to examine the possible application of CI/NO + /MS for double-bond location in 1-O-monoalkenylglycerols isolated from the liver oil of the shark Centrophorus squamosus, which are glycerol ether lipids as shown in Scheme 1. Subsequent to studies by Hunt and HarveyWe recently reported (7) the characterization of fatty acid methyl esters from this liver oil by gas chromatography-mass spectrometry (GC-MS), and the purification of two of them, namely docosahexaenoic acid (DHA or 22:6) and docosamonoenoic acid (DMA or 22:1), by countercurrent chromatography. We then directed our investigations to the unsaponifiable complementary fraction, more particularly to the glycerol ether fraction (8), because of its potential applications in industry.The unsaponifiable matter of this liver oil contains glycerol ethers in addition to squalene. These molecules exhibit bacteriostatic (9) and antiinflammatory properties (10) and hemopoietic effects (11,12); they are also believed to protect against radiation damage (13) and possess antitumor properties (14).Electronic impact (EI) of pure NO in a conventional CI source produces NO + in good yield with lesser amounts of the dimeric ion (NO) 2 +• . In general, three alternative reaction channels (15) are observed and give (M + NO) + , (M − H) + , and M +• ions.Apparently two distinct processes may occur (3,4):Step 1: oxidative cleavage of the double bond and neutral-neutral reaction catalyzed by the source surface : [1] which may be followed by Step 2: hydride ion abstraction, classically observed with NO as reactant gas: [2] The ions R 1 CO + and/or R 2 CO + are acylium diagnostic ions. The most important prerequisites for the formation of these acylium ions are a low ion-source temperature (16) and a small amount of sample at the given NO pressure (3,4). EXPERIMENTAL PROCEDURESShark liver oil was obtained from IS-France Company (Lorient, France). By a procedure already described (8), the oil was saponified and esterified with BF 3 ...

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Analysis of benzannelated thiophene derivatives by negative‐ion chemical ionization using oxygen as a reagent gas

Drabner

Budzikiewicz

1995

J. Mass Spectrom.

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Under the conditions of negative-ion chemical ionization with O2 as a reagent gas [NCI(O,)], thiophene derivatives suffer surface-catalysed oxidative degradation with subsequent ionization of the resulting species. These degradation reactions are to some extent structure specific and thus may be used for the localization of rings and/or substituents. It is advisable, however, to combine NCI(0,) with either electron impact ionization or positive ion CI. The latter ionization methods yield abundant M" ions but hardly any structurespecific fragments, whereas with NCI(0,) the determination of the molecular mass may be difiicult owing to the competing oxidation reactions.

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Experiments on the formation of acylium ions from alkenic compounds following chemical ionization with no ⁺

Abstract: Alkenic compounds when subjected to chemical ionization with NO+ yield two acylium ions by oxidative cleavage of the double bond. Studies on the mechanism of formation of these ions are reported.

Cited by 7 publications

References 11 publications

Oxidation reactions of dibenzothiophene subjected to negative chemical ionization with oxygen

Oxidation reactions of dibenzothiophene subjected to negative chemical ionization with oxygen

Location of deep‐sea shark (Centrophorus squamosus) glycerol ether lipid double bonds by nitric oxide chemical ionization mass spectrometry

Analysis of benzannelated thiophene derivatives by negative‐ion chemical ionization using oxygen as a reagent gas

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Experiments on the formation of acylium ions from alkenic compounds following chemical ionization with no +

Abstract: Alkenic compounds when subjected to chemical ionization with NO+ yield two acylium ions by oxidative cleavage of the double bond. Studies on the mechanism of formation of these ions are reported.

Cited by 7 publications

References 11 publications

Oxidation reactions of dibenzothiophene subjected to negative chemical ionization with oxygen

Oxidation reactions of dibenzothiophene subjected to negative chemical ionization with oxygen

Location of deep‐sea shark (Centrophorus squamosus) glycerol ether lipid double bonds by nitric oxide chemical ionization mass spectrometry

Analysis of benzannelated thiophene derivatives by negative‐ion chemical ionization using oxygen as a reagent gas

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Experiments on the formation of acylium ions from alkenic compounds following chemical ionization with no ⁺