An electrically compensated trap designed to eighth order for FT-ICR mass spectrometry

Brustkern, Adam M.; Rempel, Don L.; Gross, Michael L.

doi:10.1016/j.jasms.2008.05.016

Cited by 47 publications

(47 citation statements)

References 25 publications

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“…1. [11][12][13][14] The Tolmachev cell extends an original Gabrielse idea of multiple axial segments to which different dc voltages are applied to produce a nearly quadrupolar trapping potential.…”

Section: Icr Trapped Ion Cell Con Gurationmentioning

confidence: 99%

Mass Resolution and Mass Accuracy: How Much Is Enough?

et al. 2013

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Accurate mass measurement requires the highest possible mass resolution, to ensure that only a single elemental composition contributes to the mass spectral peak in question. Although mass resolution is conventionally defined as the closest distinguishable separation between two peaks of equal height and width, the required mass resolving power can be ∼10× higher for equal width peaks whose peak height ratio is 100 : 1. Ergo, minimum resolving power requires specification of maximum dynamic range, and is thus 10-100× higher than the conventional definition. Mass resolving power also depends on massto-charge ratio. Mass accuracy depends on mass spectral signal-to-noise ratio and digital resolution. Finally, the reliability of elemental composition assignment can be improved by resolution of isotopic fine structure. Thus, the answer to the question of "how much is enough mass resolving power" requires that one first specify S/N ratio, dynamic range, digital resolution, mass-to-charge ratio, and (if available) isotopic fine structure. The highest available broadband mass resolving power and mass accuracy is from Fourier transform ion cyclotron resonance mass spectrometry. Over the past five years, FT-ICR MS mass accuracy has improved by about an order of magnitude, based on higher magnetic field strength, conditional averaging of time-domain transients, better mass calibration (spectral segmentation; inclusion of a space charge term); radially dispersed excitation; phase correction to yield absorption-mode display; and new ICR cell segmentation designs.

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Section: Icr Trapped Ion Cell Con Gurationmentioning

confidence: 99%

Mass Resolution and Mass Accuracy: How Much Is Enough?

et al. 2013

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“…Resistors R4 and R6 set the AC signal gain of this main stage to 19, while the 3-dB bandwidth f 3dB (high frequency cut-off), which can be calculated by Eq. (12), is limited by the capacitor C6 together with the feedback resistor R6 to 10 MHz. Bypass capacitors are placed as close as possible to the AD8099 chip, as suggested by the data sheet, 35 for optimum distortion and power supply rejection performance.…”

Section: A Circuit Designmentioning

confidence: 99%

“…Both frequency poles can be estimated by Eq. (12). It is to be noted that the resistance of R1 was chosen to be large due to required large transimpedance.…”

Section: B Bandwidth and Computer Simulationmentioning

confidence: 99%

“…In the 90s, different ICR cell designs were conceived to reduce the perturbation caused by the imperfect electrostatic trapping potential to improve performance. 11 In recent years, cell design research remains active; a few modern designs have been reported to optimize the in-cell electric field [12][13][14][15][16][17] to push the FT-ICR MS performance close to its theoretical limit. Ion packets experience an imperfect, non-hyperbolic electric field and axial magnetic field inhomogeneity when a) Electronic mail: p.oconnor@warwick.ac.uk.…”

Section: Introductionmentioning

confidence: 99%

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A gain and bandwidth enhanced transimpedance preamplifier for Fourier-transform ion cyclotron resonance mass spectrometry

Lin

Green

O’Connor

2011

Review of Scientific Instruments

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The nature of the ion signal from a 12-T Fourier-transform ion cyclotron resonance mass spectrometer and the electronic noise were studied to further understand the electronic detection limit. At minimal cost, a new transimpedance preamplifier was designed, computer simulated, built, and tested. The preamplifier design pushes the electronic signal-to-noise performance at room temperature to the limit, because of its enhanced tolerance of the capacitance of the detection device, lower intrinsic noise, and larger flat mid-band gain (input current noise spectral density of around 1 pA/ √ Hz when the transimpedance is about 85 dB ). The designed preamplifier has a bandwidth of ∼3 kHz to 10 MHz, which corresponds to the mass-to-charge ratio, m/z, of approximately 18 to 61 k at 12 T. The transimpedance and the bandwidth can be easily adjusted by changing the value of passive components. The feedback limitation of the circuit is discussed. With the maximum possible transimpedance of 5.3 M when using an 0402 surface mount resistor, the preamplifier was estimated to be able to detect ∼110 charges in a single scan.

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“…The cylinder mantle electrodes are used for radio frequency (rf) excitation of the ions and for image current detection in order to perform mass spectrometric analysis. In some Bcompensatedĉ ylindrical ICR cells [13][14][15][16], DC voltages are applied to additional cylindrical segments in order to compensate for and to smooth the anharmonicity effect of the trapping voltages, which causes distortion of cyclotron motion synchronization and loss of resolving power.…”

mentioning

confidence: 99%

Tracking the Magnetron Motion in FT-ICR Mass Spectrometry

Jertz

Friеdrich

Kriete

et al. 2015

J. Am. Soc. Mass Spectrom.

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Abstract. In Fourier transform ion cyclotron resonance spectrometry (FT-ICR MS) the ion magnetron motion is not usually directly measured, yet its contribution to the performance of the FT-ICR cell is important. Its presence is manifested primarily by the appearance of even-numbered harmonics in the spectra. In this work, the relationship between the ion magnetron motion in the ICR cell and the intensities of the second harmonic signal and its sideband peak in the FT-ICR spectrum is studied. Ion motion simulations show that during a cyclotron motion excitation of ions which are offset to the cell axis, a position-dependent radial drift of the cyclotron center takes place. This radial drift can be directed outwards if the ion is initially offset towards one of the detection electrodes, or it can be directed inwards if the ion is initially offset towards one of the excitation electrodes. Consequently, a magnetron orbit diameter can increase or decrease during a resonant cyclotron excitation. A method has been developed to study this behavior of the magnetron motion by acquiring a series of FT-ICR spectra using varied post-capture delay (PCD) time intervals. PCD is the delay time after the capture of the ions in the cell before the cyclotron excitation of the ion is started. Plotting the relative intensity of the second harmonic sideband peak versus the PCD in each mass spectrum leads to an oscillating BPCD curve". The position and height of minima and maxima of this curve can be used to interpret the size and the position of the magnetron orbit. Ion motion simulations show that an off-axis magnetron orbit generates even-numbered harmonic peaks with sidebands at a distance of one magnetron frequency and multiples of it. This magnetron offset is due to a radial offset of the electric field axis versus the geometric cell axis. In this work, we also show how this offset of the radial electric field center can be corrected by applying appropriate DC correction voltages to the mantle electrodes of the ICR cell while observing the signals of the second harmonic peak group. The field correction leads to a definite performance increase in terms of resolving power and mass accuracy, and the mass spectrum contains intensity-minimized even-numbered harmonics. This is very important in the case of high performance cells, particularly the dynamically harmonized cell, since the magnetron motion can severely impair the averaging effect for dynamic harmonization and can therefore reduce the resolving power.

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An electrically compensated trap designed to eighth order for FT-ICR mass spectrometry

Cited by 47 publications

References 25 publications

Mass Resolution and Mass Accuracy: How Much Is Enough?

Mass Resolution and Mass Accuracy: How Much Is Enough?

A gain and bandwidth enhanced transimpedance preamplifier for Fourier-transform ion cyclotron resonance mass spectrometry

Tracking the Magnetron Motion in FT-ICR Mass Spectrometry

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