Improved Collisionally Activated Dissociation Efficiency and Mass Resolution on a Triple Quadrupole Mass Spectrometer System

Thomson, Bruce A.; Douglas, D. J.; Corr, Jay J.; Hager, James W.; Jolliffe, Charles L.

doi:10.1021/ac00106a008

Cited by 79 publications

(74 citation statements)

References 14 publications

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“…The fragmentation efficiencies for both the linear and flat gradients (at 35 V) are plotted in Figure 5. A maximum fragmentation efficiency of ϳ30% was observed for both gradients, which is comparable with the efficiencies observed in triple quadrupole mass spectrometers [35,36]. Comparable efficiencies were retained for most of the ions at different drift times using the linear gradient.…”

Section: Resultssupporting

confidence: 76%

Simultaneous fragmentation of multiple ions using IMS drift time dependent collision energies

Baker

Tang

Danielson

et al. 2008

J. Am. Soc. Mass Spectrom.

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Ion mobility spectrometry coupled with mass spectrometry (IMS-MS) was utilized to evaluate an ion collision energy ramping technique that simultaneously fragments a variety of species. To evaluate this technique, the fragmentation patterns of a mixture of ions ranging in mass, charge state, and drift time were analyzed to determine their optimal fragmentation conditions. The precursor ions were pulsed into the IMS-MS instrument and separated in the IMS drift cell based on mobility differences. Two differentially pumped short quadrupoles were used to focus the ions exiting the drift cell, and fragmentation was induced by collision induced dissociation (CID) between the conductance limiting orifice behind the second short quadrupole and before the first octopole in the mass spectrometer. To explore the fragmentation spectrum of each precursor ion, the bias voltages for the short quadrupoles and conductance limiting orifices were increased from 0 to 50 V above nonfragmentation voltage settings. An approximately linear correlation was observed between the optimal fragmentation voltage for each ion and its specific drift time, so a linear voltage gradient was employed to supply less collision energy to high mobility ions (e.g., small conformations or higher charge state ions) and more to low mobility ions. Fragmentation efficiencies were found to be similar for different ions when the fragmentation voltage was linearly ramped with drift time, but varied drastically when only a single voltage was used. [7,8] and carbohydrates. [9, 10] While tandem MS has successfully been applied to a range of difficult sequence and structural problems, [11,12] its application to highly complex samples has been limited by the general need for the selection of specific precursor species for each fragmentation experiment. This allows the fragment ions to be correctly assigned to their corresponding precursor ion in a mixture, but creates a severe MS "under sampling" problem in untargeted analyses especially for online liquid chromatography (LC)-MS examinations of small-volume samples. Developing methods to simultaneously fragment all ions in a complex sample is very appealing; however, difficulties arise because distinct species generally require differing amounts of collisional excitation depending on their mass, [13] charge state [14], and structure [15,16].Typically, if only one collision energy is utilized, both under-fragmentation and over-fragmentation (which corresponds to the sequential dissociation of the initial higher m/z dissociation products to yield often less informative lower m/z products) contribute excessively in the acquired spectrum.Multiplexed MS/MS approaches, which dissociate multiple ions simultaneously, have been studied to increase the throughput of LC-MS/MS analyses. Currently, these approaches either use a single collision energy for fragmentation [17,18] or alternate between a low and high collision energy (MS E ) [19]. Since both fragmentation approaches are unable to optimize the collision energy of the d...

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Section: Resultssupporting

confidence: 76%

Simultaneous fragmentation of multiple ions using IMS drift time dependent collision energies

Baker

Tang

Danielson

et al. 2008

J. Am. Soc. Mass Spectrom.

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“…At 0.05 Torr, the collision gas thickness (the product of gas density and the cell length) is 3.2 x 10 15 cm -2 , close to the value of 4 x 10 15 cm -2 established as optimum for a cell with a 15 cm long conventional ion guide [50]. This result suggests that the optimum collision gas thickness may be universal, even when the cell length and pressure are changed by an order of magnitude.…”

Section: Collision Cellsupporting

confidence: 64%

“…From the area of the peak in Fig. 6, which gives the total number of ion counts resulting from 1 pg of verapamil in solution, the probability of detection is 2 x 10 -5 at m/z 165, within the range of values reported for conventional instruments [50,56].…”

Section: Coupling To Liquid Chromatographymentioning

confidence: 52%

See 1 more Smart Citation

A Microelectromechanical Systems-Enabled, Miniature Triple Quadrupole Mass Spectrometer

Wright¹,

Malcolm²,

Wright³

et al. 2015

Anal. Chem.

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Miniaturized mass spectrometers are becoming increasingly capable, enabling the development of many novel field and laboratory applications. However, to date, triple quadrupole tandem mass spectrometers, the workhorses of quantitative analysis, have not been significantly reduced in size. Here, the basis of a field-deployable triple quadrupole is described. The key development is a highly miniaturized ion optical assembly in which a train of six microengineered components are employed to generate ions at atmospheric pressure, provide a vacuum interface, effect ion guiding, and perform pre-filtering, fragmentation and mass analysis. Despite its small dimensions, the collision cell efficiently fragments precursor ions and yields product ion spectra that are very similar to those recorded using conventional instruments. The instrument has been used to detect Thiabendazole, a common pesticide, in apple pulp at a level of 10 ppb.3

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“…Although a precise ion current measurement has not been taken to confirm the totality of this transfer there are no obvious sources of loss. The loss of ions in MS/MS mode through this ion path has been well characterized for this compound [27]. Accounting for these losses and with a measurement of 150,000 ions arriving at the detector the number of ions entering Q0 can then be estimated at ϳ1.2 ϫ 10 7 .…”

Section: Electrospray Versus Maldimentioning

confidence: 99%

Design considerations for high speed quantitative mass spectrometry with MALDI ionization

Corr¹,

Kovarik²,

Schneider³

et al. 2006

J. Am. Soc. Mass Spectrom.

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A MALDI ion source on a triple quadrupole mass spectrometer constructed for the purpose of obtaining high speed quantitative measurements on drugs and other low molecular weight compounds is described. Particular attention is given to the ion generation and transport phenomena that affect analysis speed, throughput, and practical instrument robustness. In this regard parameters that affect desorption speed, beam spreading, ion flight times, sensitivity, signal-to-noise, ion fragmentation, sample carry-over, and instrument contamination are examined and experimental results are provided. MALDI and electrospray sensitivity is compared, to provide a practical frame of reference. . One interesting configuration is MALDI on a triple quadrupole (QqQ) designed for the express purpose of acquiring rapid quantitative measurements on drug entities and other low molecular weight compounds dried and arrayed on microtiter plates. The concept is analogous to plate readers used in high throughput screening albeit these optical based systems derive their speed from parallel measurements. In the case of a mass spectrometer the analysis is inherently serial in nature but could be operated at rates that would approach the throughputs of the optical systems. Assessments of the general utility of MALDI TOF for small molecule quantitative and qualitative analyses have been reported [2] and reviewed [3]. Studies of the practicality of the triple quadrupole approach for various applications have begun to appear in the literature using prototype triple quadrupole instruments [4,5], which have examined in detail the quantitative figures of merit of the technique in biological samples, emphasizing the importance of the use of internal standards. In a sister publication to this work [4], issues important to quantitation and general analytical utility such as chemical diversity, background produced by blank measurements, and s/n are covered in detail. The focus of this work are the characteristics of the instrumentation.The reasons why a triple quadrupole is a logical choice for a MALDI based high speed quantitation tool will be elaborated on in this paper but can be summarized as follows. MALDI on a triple quadruple decouples the synchronization of the desorption event with the mass analysis, similar to orthogonal MALDI TOF, but quite distinct from traditional low-pressure MALDI TOF. The mass spectrometer performance is thus independent from the sample morphology. This allows target preparation to be a noncritical issue so inhomogeneities in the sample, as would be expected in any high throughput methodology, will have no effect on the mass spectrometer mass resolution or accuracy. High-pressure operation of the source and the preanalyzer RF optics is readily accommodated in a QqQ. Collisional cooling of the ion beam is achieved at higher pressures, which reduces ion fragmentation and allows a broader range of laser energy to be utilized. With low-pressure operation on TOF instruments the laser energy must be kept low, near the ionization ...

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Improved Collisionally Activated Dissociation Efficiency and Mass Resolution on a Triple Quadrupole Mass Spectrometer System

Cited by 79 publications

References 14 publications

Simultaneous fragmentation of multiple ions using IMS drift time dependent collision energies

Simultaneous fragmentation of multiple ions using IMS drift time dependent collision energies

A Microelectromechanical Systems-Enabled, Miniature Triple Quadrupole Mass Spectrometer

Design considerations for high speed quantitative mass spectrometry with MALDI ionization

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