Fast Multidimensional (3D and 4D) MS 2 and MS 3 Scans in a High-Transmission Pentaquadrupole Mass Spectrometer

An in-depth study of the fragmentation pathway of guanosine was conducted by using an in-source collision-induced dissociation high-mass accuracy tandem mass spectrometry experiment. The equivalent of MS 4 data, a level of information normally achieved on ion trap instruments, was obtained on a Q-TOF mass spectrometer. The combination of the features of high-resolution, accuracy, and in-source CID permitted the unambiguous elucidation of the different fragmentation pathways. Furthermore the elemental compositions of the product ions generated were assigned and their mutual genealogical relationships established. Formerly proposed dissociation pathways of guanosine were revisited and elaborated on more deeply. Furthermore, the presence of H 2 O in the collision cell of several tandem MS instruments was demonstrated and its effect on the product ion spectra investigated. The neutral gain of H 2 O by particular fragments of guanosine was experimentally proven by using argon, saturated with H 2 18 O, as the collision gas. Data indicating the occurrence of more complex reactions in the collision cell as a result of the presence of H 2 O were produced, specifically relating to neutral gain/neutral loss sequences. In silico calculations supported the experimental observation of neutral gain by guanosine fragments and predicted a similar behavior for adenosine. The latter was subsequently experimentally confirmed. , and nucleoside levels in urine have the potential to act as cancer biomarkers [2][3][4][5]. As their occurrence is both ubiquitous and quantitatively varying [6,7] their unequivocal characterization is crucial.For guanine alone over 20 natural variants are known to occur in RNA [6], which makes structural identification a challenging task. In our earlier LC-ESI-MS/MS experiments of urinary nucleosides [8], unexpected product ions of guanosine and its methylated derivatives were detected. The presence of these ions prompted us to perform additional mass spectrometric studies since their origin was not straightforward. This report provides an in-depth study of the fragmentation behavior of guanosine under lowenergy CID conditions, revealing H 2 O addition to specific fragments.We also wish to demonstrate the use of a Q-TOF mass spectrometer in the collection of the equivalent of MS 4 data, a level of information normally acquired only in ion trap-or FT-MS n experiments [9,10]. This was achieved by making optimal use of "in

supporting

confidence: 67%

Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H₂O Adduct Formation and Gas-Phase Reactions in the Collision Cell

Tuytten

Lemière

Dongen

et al. 2005

“…The MS 2 and MS 3 experiments [6] were performed using an Extrel [Pittsburgh, PA] pentaquadrupole (QqQqQ) mass spectrometer [7]. The QqQqQ consists of three mass-analyzing quadrupoles (Q1, Q3, Q5) in which ion mass-selection and mass-analysis are performed, and two radio-frequency-only reaction quadrupoles (q2, q4).…”

Section: Methodsmentioning

confidence: 99%

Distonoid ions

Tomazela

Sabino

Sparrapan

et al. 2006

Self Cite

Radom's definition, distonic radical ions are those formally arising by ionization of diradicals or zwitterionic molecules (including ylides). These ions differ, therefore, from conventional radical ions by displaying the charge site and unpaired electron site (spin) localized mandatorily on separate atoms or group of atoms; that is, these sites are separated in all of their major resonance forms. Many conventional radical ions with a major resonance form in which charge and spin sites reside formally on the same atom or group of atoms display, however, high degree of discretionary (non-mandatory) charge-spin separation. By analogy with the metal/metalloid terminology, we propose that these distonic-like radical ions be classified as distonoid ions. Radical ions would, therefore, be divided into three sub-classes: conventional, distonic, and distonoid ions. B3LYP/6-311 ϩ G(d,p) calculations for a proof-of-principle set of radical cations are used to demonstrate the existence of many types of distonoid ions with a high degree of discretionary charge-spin separation. Reliable calculations are indispensable for probing distonoid ions, since an ion that was expected to be distonoid (by the analysis of its resonance forms) is shown by the calculations to display a characteristic conventional-ion electronic distribution. Similarly to many distonic radical ions, and in sharp contrast to a conventional radical ion (ionized 1,4-dioxane), the gas-phase intrinsic bimolecular reactivity with selective neutrals of a representative distonoid ion, ionized 2-methylene 1,3-dioxolane, is found to include dual ion-radical type reactions. (J Am

“…MS 2 and MS 3 experiments were performed on an Extrel (Pittsburgh, PA, USA) mass spectrometer, denoted as Q 1 q 2 Q 3 q 4 Q 5 , which is described in detail elsewhere [29]. The instrument is composed of a sequential arrangement of three mass analyzing quadrupoles (Q 1 , Q 3 , Q 5 ) and two "rf-only" ion focusing reaction quadrupoles (q 2 , q 4 ).…”

Section: Methodsmentioning

confidence: 99%

Absolute assignment of constitutional isomers via structurally diagnostic fragment ions: The challenging case of α- and β-acyl naphthalenes

Benassi

Eberlin

2010

Self Cite

A general mass spectrometric method is described for the absolute assignment of ␣-or ␤-acyl naphthalenes, via which the gaseous ␣-and ␤-naphthoyl cations of m/z 155 are used as structurally diagnostic fragment ions (SDFI). These stable acylium ions are common and normally abundant fragment ions of acylnaphthalenes in general. Using a pentaquadrupole mass spectrometer, CID experiments with argon and ion/molecule reactions with 2-methyl-1,3-dioxolane, isoprene, acetonitrile and propionitrile were performed but failed to distinguish the two SDFI. Reactions with ethyl vinyl ether and several homologues as well as ethyl vinyl thioether were, however, successful. In reactions with ethyl vinyl ether, the ␣-SDFI form a pair of diagnostic product ions of m/z 165 and m/z 181, which are absent in the corresponding spectrum of the ␤-SDFI. Methyl 4-(1-naphthyl)-2,4-dioxobutanoate was used as a test molecule for this class of constitutional isomers and absolute structural assignment as an ␣-acyl naphthalene was correctly performed via the characterization of its ␣-SDFI. (J Am Soc Mass Spectrom