Metastable ion characteristics.  XXII.  Collisional activation spectra of organic ions

McLafferty, Fred W.; Bente, P. F.; Kornfeld, Richard; Tsai, Susan; Howe, Ian

doi:10.1021/ja00788a007

Cited by 329 publications

(74 citation statements)

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“…Nevertheless, the obtained tandem mass spectra can look remarkably different. Although the structure elucidation potential of CID was early recognized [19], the setup of ESI-MS/MS libraries was hampered by lacking reproducibility. This article provides comparable ion trap and triple quadrupole MS/MS data of all discussed substances.…”

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confidence: 99%

Electrospray tandem mass spectrometric investigations of morphinans

Raith

Neubert

Poeaknapo

et al. 2003

J. Am. Soc. Mass Spectrom.

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In this study positive ESI tandem mass spectra of the [M ϩ H] ϩ ions of morphinan alkaloids obtained using an ion trap MS were compared with those from a triple quadrupole MS. This allows to assess the differences of the tandem-in-time versus the tandem-in-space principle, often hampering the development of ESI MS/MS libraries. Fragmentation pathways and possible fragment ion structures were discussed. In order to obtain elemental composition, accurate mass measurements were performed. According to the MS/MS fragmentation pathway, the investigated compounds can be grouped into 4 subsets: (1) morphine and codeine, (2) morphinone, codeinone, and neopinone, (3) thebaine and oripavine, (4) -7] or CE/ESI-MS [8,9], mostly from a forensic point of view. Frequently fragmentation by CID is described and applied as LC/MS/MS. Two reviews highlight the field [10,11]. Some systematic approaches to the setup of libraries have been undertaken, including data for morphine and codeine [12][13][14]. However, none of these studies compared data of ion trap and triple quad systems. Most of the morphinan type substances have been investigated before by electron impact ionization MS [15][16][17]. Tandem MS instrumentation and the principles of operation have been extensively discussed in the literature [18]. In contrast to magnetic sector instruments, triple quadrupole, quadrupole ion trap, and quadrupole time-of-flight are all considered to perform low collision energy fragmentation. Nevertheless, the obtained tandem mass spectra can look remarkably different. Although the structure elucidation potential of CID was early recognized [19], the setup of ESI-MS/MS libraries was hampered by lacking reproducibility. This article provides comparable ion trap and triple quadrupole MS/MS data of all discussed substances. Accurate mass data of selected morphinans were obtained by quadrupole time-of-flight and FT-ICR mass spectrometry, respectively.

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confidence: 99%

Electrospray tandem mass spectrometric investigations of morphinans

Raith

Neubert

Poeaknapo

et al. 2003

J. Am. Soc. Mass Spectrom.

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“…It has been claimed [5] that a unique advantage of CID spectra for structure determination is their virtual insensitivity to ion internal energy, if the peaks resulting from low activation energy pathways are ignored. The CID spectra of precursor ions of the same structure formed with different internal energies will have the same relative abundances within statistical error, if that assumption is valid.…”

Section: Fragmentation Efficiency/he-cidmentioning

confidence: 99%

“…There are limited publications on the role of precollisional internal energy on CID spectra and they show conflicting results. Some studies indicate that precursor ion internal energy has a negligible effect on the CID spectrum, except for product ions formed through processes with the lowest activation energy [5][6][7][8]. In contrast, other studies indicate that CID spectra can be highly dependent on initial energy of the precursor ion and/or angular momentum [9 -12].…”

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confidence: 99%

“…In contrast, other studies indicate that CID spectra can be highly dependent on initial energy of the precursor ion and/or angular momentum [9 -12]. The effect of internal energy on the relative rates of the reactions competing in high-energy (HE) CID processes has been studied by varying the electron energy in electron ionization (EI) [5]. According to the results, precursor ion internal energy has a negligible effect on the CID spectrum, except for product ions formed through the processes of lowest activation energy.…”

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Internal energy deposition in chemical ionization/tandem mass spectrometry

Ospina

Powell

Yost

2003

J. Am. Soc. Mass Spectrom.

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The efficiency of the collision-induced dissociation (CID) process as a function of the internal energy deposited into the ion during the ionization event was evaluated. (M ϩ H) ϩ ions of pyrrole, pyrrolidine, pyridine and piperidine (five and six-membered ring heterocyclics) were generated by chemical ionization (CI). The internal energy of the ions was varied by using different reagent gases. Both high-energy (keV) and low-energy (eV) CID were performed on these ions. The experiments showed that the (M ϩ H) ϩ ions of the five-membered ring compounds, pyrrole and pyrrolidine, have higher fragmentation efficiencies than the sixmembered ring compounds, pyridine and piperidine. Fragmentation efficiencies in highenergy CID clearly correlate with the internal energy deposited by the ionization technique. Experiments showed that the low-energy CID process is more sensitive than high-energy CID to changes in internal energy. C hemical ionization is one of the most widespread ionization techniques used in mass spectrometry. In chemical ionization, collisions between reagent gas ions and sample molecules produce abundant pseudo-molecular ions characteristic of the sample [1]. Ionization in CI can occur by different mechanisms such as charge exchange, electrophilic addition, proton transfer, hydride abstraction, or other anion abstraction mechanism [1][2][3]. Proton transfer from a reagent gas ion (B ϩ H) ϩ to a sample molecule M is the most common process and is represented by the equation:The internal energy (⌬H) of the (M ϩ H) ϩ ion produced by proton transfer depends on the proton affinities (PA) of the species involved and is described by the equation:Fragmentation of the (M ϩ H) ϩ ion in CI spectra depends on its internal energy, which can be controlled by varying the reagent gas. In general, fragmentation increases when the exothermicity of the proton transfer reaction increases. It is possible to predict which proton transfer reactions will occur in a particular system, since values of PA of a large number of compounds are tabulated [4]. CI spectra are often simple, frequently giving only molecular weight information; therefore, activation techniques such as collision with a neutral gas are commonly used to increase the internal energy of the ion and promote fragmentation. It is well known that fragmentation observed in collision-induced dissociation depends upon the internal energy present in the ions prior to collision as well as the energy deposited during collisional activation. There are limited publications on the role of precollisional internal energy on CID spectra and they show conflicting results. Some studies indicate that precursor ion internal energy has a negligible effect on the CID spectrum, except for product ions formed through processes with the lowest activation energy [5][6][7][8]. In contrast, other studies indicate that CID spectra can be highly dependent on initial energy of the precursor ion and/or angular momentum [9 -12]. The effect of internal energy on the relative rates of the reacti...

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“…11 A subsequent survey of the 70 and 12 eV electron impact (EI) ionisation mass spectra of numerous alkenyl ethers C m H 2m -1 OCH 3 (m = 3-6) indicated that several mechanisms operate for alkyl radical elimination from these C n H 2n O +• • species. 12 Extension of this work to encompass determination of the structure of the fragment ions produced by alkyl radical loss by analysis of collision-induced dissociation (CID) 13 mass spectra established that hydrogen transfers and occasional skeletal isomerisations allow groups attached to either carbon atom of the double bond to be lost. 14 15 because it terminates at a radical centre of a DI, followed by γ-cleavage of the resultant ionised enol ether.…”

Section: Introductionmentioning

confidence: 99%

The mechanism of alkyl radical elimination from ionised γγ-disubstituted alkenyl methyl ethers

Bowen

Clifford

Gallagher

1996

Eur. J. Mass Spectrom.

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The mechanism of alkyl radical loss from ionised alkenyl methyl ethers containing two γ-alkyl substituents, R 1 R 2 C=CHCH 2 OCH 3 +• • , has been studied by investigating the collision-induced dissociation spectra of the resultant C n H 2n-1 O + oxonium ions (n = 5-7). Comparison of these spectra with one another and those of reference ions generated by dissociative ionisation of secondary allylic alkenyl methyl ethers indicates that expulsion of a γ-alkyl group occurs without isomerisation of the heavy atom skeleton via an allylic rearrangement.

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Metastable ion characteristics. XXII. Collisional activation spectra of organic ions

Cited by 329 publications

References 1 publication

Electrospray tandem mass spectrometric investigations of morphinans

Electrospray tandem mass spectrometric investigations of morphinans

Internal energy deposition in chemical ionization/tandem mass spectrometry

The mechanism of alkyl radical elimination from ionised γγ-disubstituted alkenyl methyl ethers

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