Detection of chlordanes by positive ion chemical ionization in an ion trap: a comparitive study of the non‐conventional reagents acetonitrile, acrylonitrile and dichloromethane

Zencak, Zdenek; Oehme, Michael; Skopp, Sonja

doi:10.1002/rcm.434

Cited by 7 publications

(6 citation statements)

References 17 publications

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“…Acrylonitrile and dichloromethane have been investigated for their properties as specific reagents for the characterization of isomers of chlordane compounds. 102 These CI reagents reacted principally through a retro-Diels-Alder reaction, followed by HCl elimination in the case of dichloromethane which allows the differentiation of cis/trans isomers. Limits of detection at the pg level were achieved with heptachlor with both CI reagents in the selected ion monitoring mode, while limits of detection proved to be more favorable with acetonitrile compared with acrylonitrile and dichloromethane in the case of chlordane and nonachlor.…”

Section: Acrylonitrile Dichloromethane and Halogenated Reagentsmentioning

confidence: 99%

“…Limits of detection at the pg level were achieved with heptachlor with both CI reagents in the selected ion monitoring mode, while limits of detection proved to be more favorable with acetonitrile compared with acrylonitrile and dichloromethane in the case of chlordane and nonachlor. 102 Ion-molecule reactions between PAHs and selected positive reactant ions of dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, difluoromethane 103 and 1,1-difluoroethane 103,104 have been employed to differentiate series of structural isomers of PAHs. Main product ions resulted from the formation of an adduct ion with the selected ions from the halocarbon precursors and from the elimination of an HX molecule (X = Cl, F) from these adducts.…”

Section: Acrylonitrile Dichloromethane and Halogenated Reagentsmentioning

confidence: 99%

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Low-Pressure Chemical Ionization in Ion Trap Mass Spectrometry

Bouchonnet

Libong

Sablier

2004

Eur J Mass Spectrom (Chichester)

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This article presents the specificities of low pressure chemical ionization in ion trap mass spectrometry. One main feature is the ability to perform chemical ionization with liquid reagents as readily as with "conventional" gases (methane, isobutane and ammonia). The reactivities and analytical applications of gas and liquid reagents are summarized from literature data and are compared when possible.

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Section: Acrylonitrile Dichloromethane and Halogenated Reagentsmentioning

confidence: 99%

Section: Acrylonitrile Dichloromethane and Halogenated Reagentsmentioning

confidence: 99%

Low-Pressure Chemical Ionization in Ion Trap Mass Spectrometry

Bouchonnet

Libong

Sablier

2004

Eur J Mass Spectrom (Chichester)

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“…Recently, there is interest in [M + H] + pathways that are common in electrospray ionization (ESI) and positive chemical ionization (PCI). Chemical ionization (CI) mass spectrometry is a versatile tool for both structural characterization and quantitative analysis that rely on the enhanced [M + H] + peak 1, 2. Even though CI is a more selective form of ionization than EI, fragmentation mechanisms studied by triple‐quadrupole mass spectrometry (QqQ‐MSMS) have been dominated by EI.…”

Section: Introductionmentioning

confidence: 99%

Positive chemical ionization triple‐quadrupole mass spectrometry and ab initio computational studies of the multi‐pathway fragmentation of phthalates

2010

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We report the first positive chemical ionization (PCI) fragmentation mechanisms of phthalates using triple-quadrupole mass spectrometry and ab initio computational studies using density functional theories (DFT). Methane PCI spectra showed abundant [M + H](+), together with [M + C(2)H(5)](+) and [M + C(3)H(5)](+). Fragmentation of [M + H](+), [M + C(2)H(5)](+) and [M + C(3)H(5)](+) involved characteristic ions at m/z 149, 177 and 189, assigned as protonated phthalic anhydride and an adduct of phthalic anhydride with C(2)H(5)(+) and C(3)H(5)(+), respectively. Fragmentation of these ions provided more structural information from the PCI spectra. A multi-pathway fragmentation was proposed for these ions leading to the protonated phthalic anhydride. DFT methods were used to calculate relative free energies and to determine structures of intermediate ions for these pathways. The first step of the fragmentation of [M + C(2)H(5)](+) and [M + C(3)H(5)](+) is the elimination of [R-H] from an ester group. The second ester group undergoes either a McLafferty rearrangement route or a neutral loss elimination of ROH. DFT calculations (B3LYP, B3PW91 and BPW91) using 6-311G(d,p) basis sets showed that McLafferty rearrangement of dibutyl, di(-n-octyl) and di(2-ethyl-n-hexyl) phthalates is an energetically more favorable pathway than loss of an alcohol moiety. Prominent ions in these pathways were confirmed with deuterium labeled phthalates.

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“…Chemical ionization mass spectrometry (MS) is a powerful tool for steric structure identification that often allows differentiation between isomers . In addition, compound selectivity or sensitivity can be increased by choice of reagent gases with different proton affinities and ion−molecule reaction properties.…”

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confidence: 99%

Dichloromethane-Enhanced Negative Ion Chemical Ionization for the Determination of Polychlorinated n-Alkanes

2003

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The use of dichloromethane/methane reagent gas mixtures is described as an alternative to conventional electron capture negative ionization for the determination of polychlorinated n-alkanes (PCAs). A nearly exclusive formation of [M + Cl]- adduct ions was observed suppressing the generation of other fragment ions. The resulting enhanced selectivity and sensitivity lowered quantification limits to 3 ng for a technical PCA mixture and 10.5-13.5 pg for single congeners. Response factors for congeners of different degrees of chlorination varied by not more than a factor of 2. Interferences from other polychlorinated compounds present in environmental samples such as toxaphene or chlordanes were suppressed by a factor of 5 or more. The technique was applied for the determination of the composition of technical PCA mixtures as well as for the analysis of PCAs in North Sea dab liver.

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Detection of chlordanes by positive ion chemical ionization in an ion trap: a comparitive study of the non‐conventional reagents acetonitrile, acrylonitrile and dichloromethane

Cited by 7 publications

References 17 publications

Low-Pressure Chemical Ionization in Ion Trap Mass Spectrometry

Low-Pressure Chemical Ionization in Ion Trap Mass Spectrometry

Positive chemical ionization triple‐quadrupole mass spectrometry and ab initio computational studies of the multi‐pathway fragmentation of phthalates

Dichloromethane-Enhanced Negative Ion Chemical Ionization for the Determination of Polychlorinated n-Alkanes

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