Elimination of axial ejection during excitation with a capacitively coupled open trapped-ion cell for Fourier transform ion cyclotron resonance mass spectrometry

Beu, Steven C.; Laude, David A.

doi:10.1021/ac00026a016

Cited by 105 publications

(77 citation statements)

References 28 publications

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“…In this region, ions will experience some axial excitation, which could lead to unintended axial ejection. This approach to avoiding fringe field effects is similar to that utilized in FTICR cell design for reducing undesirable axial ejection [21]. A similar distortion also occurs to the quadrupolar trapping potential at the end of the single section device.…”

Section: Methodsmentioning

confidence: 90%

A two-dimensional quadrupole ion trap mass spectrometer

Schwartz

Senko

Syka

2002

J. Am. Soc. Mass Spectrom.

683

718

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The use of a linear or two-dimensional (2-D) quadrupole ion trap as a high performance mass spectrometer is demonstrated. Mass analysis is performed by ejecting ions out a slot in one of the rods using the mass selective instability mode of operation. Resonance ejection and excitation are utilized to enhance mass analysis and to allow isolation and activation of ions for MS n capability. Improved trapping efficiency and increased ion capacity are observed relative to a three-dimensional (3-D) ion trap with similar mass range. Mass resolution comparable to 3-D traps is readily achieved, including high resolution at slower scan rates, although adequate mechanical tolerance of the trap structure is a requirement. [8 -11], and standard three-dimensional (3-D) ion trap mass spectrometers [12,13]. Several of the quadrupole based 2-D ion traps are capable of mass selective isolation and activation of ions including MS 3 analysis [7,9 -11]. Syka and Fies have described the theoretical advantages of 2-D versus 3-D quadrupole ion traps for Fourier transform mass spectrometry [14]. These advantages include reduced space charge effects due to the increased ion storage volume, and enhanced sensitivity for externally injected ions due to higher trapping efficiencies. Bier and Syka described several forms of linear and circular 2-D ion traps with larger ion capacity to be used as mass spectrometers [15] using the mass selective instability mode of operation [16] similar to that used in all commercial 3-D quadrupole ion trap instruments.Despite the previously described advantages and the recent progress with 2-D ion traps in hybrid instruments, only a few examples have appeared using these traps as stand-alone mass spectrometers. Senko et al. recently demonstrated image current detection with FT analysis in a 2-D ion trap which utilized independent detection electrodes between the quadrupole rods [17]. Although promising results were presented, space charge effects were found to limit this configuration's ultimate performance as the motion of the ions is largely restricted to one of the symmetry planes of the device. The relative insensitivity of the image current ion detection scheme precluded the use of lower numbers of trapped ions to avoid such space charge effects.Welling et al. demonstrated two variations of mass selective instability in a stand-alone 2-D quadrupole ion trap [18]. The first method, referred to as "q-scanning", exploited the field penetration of the detector between the quadrupole rods to allow for ion extraction using a downward ramp of the RF voltage. This allowed relatively quick scanning of a broad mass range (1 second scan from 20 -1000 m/z), but produced mass spectral resolution of only five to six. The second method, referred to as "secular scanning", used frequency swept parametric excitation to eject ions between the quadrupole rods. Although the scan rate was 100x slower than the q-scan, a resolution of 800 at m/z 130 was obtained.Lammert et al. have presented preliminary results using a toroida...

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Section: Methodsmentioning

confidence: 90%

A two-dimensional quadrupole ion trap mass spectrometer

Schwartz

Senko

Syka

2002

J. Am. Soc. Mass Spectrom.

683

718

View full text Add to dashboard Cite

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“…Within the trapped-ion cell, each measurement cycle requires ion injection, excitation, and acquisition of the induced ion signal (i.e., ion transient detection). Historically, closed orthorhombic cells, predominant in early FT-ICR mass spectrometers, were replaced by cylindrical cells with either capacitive coupling open configuration or so-called infinity cell layout, i.e., a closed cell with trapping plates that have excitation circuitry that emulates axially-infinite distribution of the excitation field [11][12][13][14].…”

mentioning

confidence: 99%

Trapped-ion cell with improved dc potential harmonicity for FT-ICR MS

Tolmachev

Robinson

et al. 2008

J. Am. Soc. Mass Spectrom.

103

137

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The trapped-ion cell is a key component critical for optimal performance in Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS). To extend the performance of FT-ICR MS, we have developed a new cell design that is capable of generating a DC trapping potential which closely approaches that of an ideal Penning trap, i.e., a 3D axial quadrupolar potential distribution. The new cell design was built upon an open cylindrical geometry, supplemented with two pairs of cylindrical compensation segments. Electric potential calculations for trial cell geometries were aimed at minimizing spatial variations of the radial electric field divided by radius. The resulting cell proportions and compensation voltages delivered practically constant effective ion cyclotron frequency that was independent of ion radial and axial positions. Our customized 12 tesla FT-ICR instrument was upgraded with the new cell, and the performance was characterized for a range of ion excitation power and ion populations. Operating the compensated cell at increased postexcitation radii, ϳ0.7 of the cell inner radius, resulted in improved mass measurement accuracy together with increased signal intensity. Under these same operating conditions the noncompensated open cell configuration exhibited peak splitting and reduced signal life time. Mass accuracy tests using 11 calibrants covering a wide m/z range reproducibly produced under 0.05 ppm RMS precision of the internal calibration for reduced ion populations and the optimal excitation radius. Conditions of increased ion population resulted in a twofold improvement in mass accuracy compared with the noncompensated cell, due to the larger achievable excitation radii and correspondingly lower space charge related perturbations of the calibration law. (J

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“…21 cylindrical open ICR cell. 22,23 Ions were excited by broadband frequency chirp excitation and detected before a single zero-fill, Gaussian apodization, and Fourier transform. An AWG3 workflow-based data station is used for experiment control, data acquisition, and analysis.…”

Section: Methodsmentioning

confidence: 99%

Vacuum compatible sample positioning device for matrix assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry imaging

Aizikov

Smith

Chargin

et al. 2011

Review of Scientific Instruments

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The high mass accuracy and resolving power of Fourier transform ion cyclotron resonance mass spectrometers (FT-ICR MS) make them ideal mass detectors for mass spectrometry imaging (MSI), promising to provide unmatched molecular resolution capabilities. The intrinsic low tolerance of FT-ICR MS to RF interference, however, along with typically vertical positioning of the sample, and MSI acquisition speed requirements present numerous engineering challenges in creating robotics capable of achieving the spatial resolution to match. This work discusses a two-dimensional positioning stage designed to address these issues. The stage is capable of operating in ∼1 × 10 -8 mbar vacuum. The range of motion is set to 100 mm × 100 mm to accommodate large samples, while the positioning accuracy is demonstrated to be less than 0.4 micron in both directions under vertical load over the entire range. This device was integrated into three different matrix assisted laser desorption/ionization (MALDI) FT-ICR instruments and showed no detectable RF noise. The "oversampling" MALDI-MSI experiments, under which the sample is completely ablated at each position, followed by the target movement of the distance smaller than the laser beam, conducted on the custom-built 7T FT-ICR MS demonstrate the stability and positional accuracy of the stage robotics which delivers high spatial resolution mass spectral images at a fraction of the laser spot diameter.

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Elimination of axial ejection during excitation with a capacitively coupled open trapped-ion cell for Fourier transform ion cyclotron resonance mass spectrometry

Cited by 105 publications

References 28 publications

A two-dimensional quadrupole ion trap mass spectrometer

A two-dimensional quadrupole ion trap mass spectrometer

Trapped-ion cell with improved dc potential harmonicity for FT-ICR MS

Vacuum compatible sample positioning device for matrix assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry imaging

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