The Experts below are selected from a list of 31305 Experts worldwide ranked by ideXlab platform
Ron M A Heeren - One of the best experts on this subject based on the ideXlab platform.
-
ultra high mass Resolving Power mass accuracy and dynamic range maldi mass spectrometry imaging by 21 t ft icr ms
Analytical Chemistry, 2020Co-Authors: Andrew P Bowman, Ron M A Heeren, Greg T Blakney, Christopher L Hendrickson, Shane R Ellis, Donald F SmithAbstract:Detailed characterization of complex biological surfaces by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) requires instrumentation that is capable of high mass Resolving Power, mass accuracy, and dynamic range. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) offers the highest mass spectral performance for MALDI MSI experiments, and often reveals molecular features that are unresolved on lower performance instrumentation. Higher magnetic field strength improves all performance characteristics of FT-ICR; mass Resolving Power improves linearly, while mass accuracy and dynamic range improve quadratically with magnetic field strength. Here, MALDI MSI at 21T is demonstrated for the first time: mass Resolving Power in excess of 1 600 000 (at m/z 400), root-mean-square mass measurement accuracy below 100 ppb, and dynamic range per pixel over 500:1 were obtained from the direct analysis of biological tissue sections. Molecular features with m/z differences as small as 1.79 mDa were resolved and identified with high mass accuracy. These features allow for the separation and identification of lipids to the underlying structures of tissues. The unique molecular detail, accuracy, sensitivity, and dynamic range combined in a 21T MALDI FT-ICR MSI experiment enable researchers to visualize molecular structures in complex tissues that have remained hidden until now. The instrument described allows for future innovative, such as high-end studies to unravel the complexity of biological, geological, and engineered organic material surfaces with an unsurpassed detail.
-
laser post ionisation combined with a high Resolving Power orbitrap mass spectrometer for enhanced maldi ms imaging of lipids
Chemical Communications, 2017Co-Authors: Shane R Ellis, J Soltwisch, Martin R L Paine, K Dreisewerd, Ron M A HeerenAbstract:Coupling laser post-ionisation with a high Resolving Power MALDI Orbitrap mass spectrometer has realised an up to ∼100-fold increase in the sensitivity and enhanced the chemical coverage for MALDI-MS imaging of lipids relative to conventional MALDI. This could constitute a major breakthrough for biomedical research.
-
the composition of poly ethylene terephthalate pet surface precipitates determined at high Resolving Power by tandem mass spectrometry imaging
Microscopy and Microanalysis, 2017Co-Authors: Gregory L Fisher, John S Hammond, Scott R Bryan, Paul E Larson, Ron M A HeerenAbstract:We present the first demonstration of a general method for the chemical characterization of small surface features at high magnification via simultaneous collection of mass spectrometry (MS) imaging and tandem MS imaging data. High lateral resolution tandem secondary ion MS imaging is employed to determine the composition of surface features on poly(ethylene terephthalate) (PET) that precipitate during heat treatment. The surface features, probed at a lateral Resolving Power of<200 nm using a surface-sensitive ion beam, are found to be comprised of ethylene terephthalate trimer at a greater abundance than is observed in the surrounding polymer matrix. This is the first chemical identification of PET surface precipitates made without either an extraction step or the use of a reference material. The new capability employed for this study achieves the highest practical lateral resolution ever reported for tandem MS imaging.
-
high mass accuracy and high mass Resolving Power ft icr secondary ion mass spectrometry for biological tissue imaging
arXiv: Instrumentation and Detectors, 2013Co-Authors: Donald F Smith, Andras Kiss, Franklin E Leach, Errol W Robinson, Ljiljana Pasatolic, Ron M A HeerenAbstract:Biological tissue imaging by secondary ion mass spectrometry has seen rapid development with the commercial availability of polyatomic primary ion sources. Endogenous lipids and other small bio-molecules can now be routinely mapped on the sub-micrometer scale. Such experiments are typically performed on time-of-flight mass spectrometers for high sensitivity and high repetition rate imaging. However, such mass analyzers lack the mass Resolving Power to ensure separation of isobaric ions and the mass accuracy for elemental formula assignment based on exact mass measurement. We have recently reported a secondary ion mass spectrometer with the combination of a C60 primary ion gun with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) for high mass Resolving Power, high mass measurement accuracy and tandem mass spectrometry capabilities. In this work, high specificity and high sensitivity secondary ion FT-ICR MS was applied to chemical imaging of biological tissue. An entire rat brain tissue was measured with 150 um spatial resolution (75 um primary ion spot size) with mass Resolving Power (m/{\Delta}m50%) of 67,500 (at m/z 750) and root-mean-square measurement accuracy less than two parts-per-million for intact phospholipids, small molecules and fragments. For the first time, ultra-high mass Resolving Power SIMS has been demonstrated, with m/{\Delta}m50% > 3,000,000. Higher spatial resolution capabilities of the platform were tested at a spatial resolution of 20 um. The results represent order of magnitude improvements in mass Resolving Power and mass measurement accuracy for SIMS imaging and the promise of the platform for ultra-high mass Resolving Power and high spatial resolution imaging.
-
high mass accuracy and high mass Resolving Power ft icr secondary ion mass spectrometry for biological tissue imaging
Analytical and Bioanalytical Chemistry, 2013Co-Authors: Donald F Smith, Andras Kiss, Franklin E Leach, Errol W Robinson, Ljiljana Pasatolic, Ron M A HeerenAbstract:Biological tissue imaging by secondary ion mass spectrometry has seen rapid development with the commercial availability of polyatomic primary ion sources. Endogenous lipids and other small bio-molecules can now be routinely mapped on the sub-micrometer scale. Such experiments are typically performed on time-of-flight mass spectrometers for high sensitivity and high repetition rate imaging. However, such mass analyzers lack the mass Resolving Power to ensure separation of isobaric ions and the mass accuracy for elemental formula assignment based on exact mass measurement. We have recently reported a secondary ion mass spectrometer with the combination of a C60 primary ion gun with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) for high mass Resolving Power, high mass measurement accuracy, and tandem mass spectrometry capabilities. In this work, high specificity and high sensitivity secondary ion FT-ICR MS was applied to chemical imaging of biological tissue. An entire rat brain tissue was measured with 150 μm spatial resolution (75 μm primary ion spot size) with mass Resolving Power (m/Δm50%) of 67,500 (at m/z 750) and root-mean-square measurement accuracy less than two parts-per-million for intact phospholipids, small molecules and fragments. For the first time, ultra-high mass Resolving Power SIMS has been demonstrated, with m/Δm50% > 3,000,000. Higher spatial resolution capabilities of the platform were tested at a spatial resolution of 20 μm. The results represent order of magnitude improvements in mass Resolving Power and mass measurement accuracy for SIMS imaging and the promise of the platform for ultra-high mass Resolving Power and high spatial resolution imaging.
John A. Mclean - One of the best experts on this subject based on the ideXlab platform.
-
correlating Resolving Power resolution and collision cross section unifying cross platform assessment of separation efficiency in ion mobility spectrometry
Analytical Chemistry, 2017Co-Authors: James N Dodds, John A. McleanAbstract:Here we examine the relationship among Resolving Power (Rp), resolution (Rpp), and collision cross section (CCS) for compounds analyzed in previous ion mobility (IM) experiments representing a wide variety of instrument platforms and IM techniques. Our previous work indicated these three variables effectively describe and predict separation efficiency for drift tube ion mobility spectrometry experiments. In this work, we seek to determine if our previous findings are a general reflection of IM behavior that can be applied to various instrument platforms and mobility techniques. Results suggest IM distributions are well characterized by a Gaussian model and separation efficiency can be predicted on the basis of the empirical difference in the gas-phase CCS and a CCS-based Resolving Power definition (CCS/ΔCCS). Notably traveling wave (TWIMS) was found to operate at resolutions substantially higher than a single-peak Resolving Power suggested. When a CCS-based Rp definition was utilized, TWIMS was found to o...
-
correlating Resolving Power resolution and collision cross section unifying cross platform assessment of separation efficiency in ion mobility spectrometry
Analytical Chemistry, 2017Co-Authors: James N Dodds, Jody C May, John A. McleanAbstract:Here we examine the relationship among Resolving Power (Rp), resolution (Rpp), and collision cross section (CCS) for compounds analyzed in previous ion mobility (IM) experiments representing a wide variety of instrument platforms and IM techniques. Our previous work indicated these three variables effectively describe and predict separation efficiency for drift tube ion mobility spectrometry experiments. In this work, we seek to determine if our previous findings are a general reflection of IM behavior that can be applied to various instrument platforms and mobility techniques. Results suggest IM distributions are well characterized by a Gaussian model and separation efficiency can be predicted on the basis of the empirical difference in the gas-phase CCS and a CCS-based Resolving Power definition (CCS/ΔCCS). Notably traveling wave (TWIMS) was found to operate at resolutions substantially higher than a single-peak Resolving Power suggested. When a CCS-based Rp definition was utilized, TWIMS was found to operate at a Resolving Power between 40 and 50, confirming the previous observations by Giles and co-workers. After the separation axis (and corresponding Resolving Power) is converted to cross section space, it is possible to effectively predict separation behavior for all mobility techniques evaluated (i.e., uniform field, trapped ion mobility, traveling wave, cyclic, and overtone instruments) using the equations described in this work. Finally, we are able to establish for the first time that the current state-of-the-art ion mobility separations benchmark at a CCS-based Resolving Power of >300 that is sufficient to differentiate analyte ions with CCS differences as small as 0.5%.
-
broadscale Resolving Power performance of a high precision uniform field ion mobility mass spectrometer
Analyst, 2015Co-Authors: Jody C May, James N Dodds, Ruwan T. Kurulugama, George C Stafford, John Fjeldsted, John A. McleanAbstract:An extensive study of two current ion mobility Resolving Power theories ("conditional" and "semi-empirical") was undertaken using a recently developed drift tube ion mobility-mass spectrometer. The current study investigates the quantitative agreement between experiment and theory at reduced pressure (4 Torr) for a wide range of initial ion gate widths (100 to 500 μs), and ion mobility values (K0 from 0.50 to 3.0 cm(2) V(-1) s(-1)) representing measurements obtained in helium, nitrogen, and carbon dioxide drift gas. Results suggest that the conditional Resolving Power theory deviates from experimental results for low mobility ions (e.g., high mass analytes) and for initial ion gate widths beyond 200 μs. A semi-empirical Resolving Power theory provided close-correlation of predicted Resolving Powers to experimental results across the full range of mobilities and gate widths investigated. Interpreting the results from the semi-empirical theory, the performance of the current instrumentation was found to be highly linear for a wide range of analytes, with optimal Resolving Powers being accessible for a narrow range of drift fields between 14 and 17 V cm(-1). While developed using singly-charged ion mobility data, preliminary results suggest that the semi-empirical theory has broader applicability to higher-charge state systems.
Donald F Smith - One of the best experts on this subject based on the ideXlab platform.
-
ultra high mass Resolving Power mass accuracy and dynamic range maldi mass spectrometry imaging by 21 t ft icr ms
Analytical Chemistry, 2020Co-Authors: Andrew P Bowman, Ron M A Heeren, Greg T Blakney, Christopher L Hendrickson, Shane R Ellis, Donald F SmithAbstract:Detailed characterization of complex biological surfaces by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) requires instrumentation that is capable of high mass Resolving Power, mass accuracy, and dynamic range. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) offers the highest mass spectral performance for MALDI MSI experiments, and often reveals molecular features that are unresolved on lower performance instrumentation. Higher magnetic field strength improves all performance characteristics of FT-ICR; mass Resolving Power improves linearly, while mass accuracy and dynamic range improve quadratically with magnetic field strength. Here, MALDI MSI at 21T is demonstrated for the first time: mass Resolving Power in excess of 1 600 000 (at m/z 400), root-mean-square mass measurement accuracy below 100 ppb, and dynamic range per pixel over 500:1 were obtained from the direct analysis of biological tissue sections. Molecular features with m/z differences as small as 1.79 mDa were resolved and identified with high mass accuracy. These features allow for the separation and identification of lipids to the underlying structures of tissues. The unique molecular detail, accuracy, sensitivity, and dynamic range combined in a 21T MALDI FT-ICR MSI experiment enable researchers to visualize molecular structures in complex tissues that have remained hidden until now. The instrument described allows for future innovative, such as high-end studies to unravel the complexity of biological, geological, and engineered organic material surfaces with an unsurpassed detail.
-
high mass accuracy and high mass Resolving Power ft icr secondary ion mass spectrometry for biological tissue imaging
arXiv: Instrumentation and Detectors, 2013Co-Authors: Donald F Smith, Andras Kiss, Franklin E Leach, Errol W Robinson, Ljiljana Pasatolic, Ron M A HeerenAbstract:Biological tissue imaging by secondary ion mass spectrometry has seen rapid development with the commercial availability of polyatomic primary ion sources. Endogenous lipids and other small bio-molecules can now be routinely mapped on the sub-micrometer scale. Such experiments are typically performed on time-of-flight mass spectrometers for high sensitivity and high repetition rate imaging. However, such mass analyzers lack the mass Resolving Power to ensure separation of isobaric ions and the mass accuracy for elemental formula assignment based on exact mass measurement. We have recently reported a secondary ion mass spectrometer with the combination of a C60 primary ion gun with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) for high mass Resolving Power, high mass measurement accuracy and tandem mass spectrometry capabilities. In this work, high specificity and high sensitivity secondary ion FT-ICR MS was applied to chemical imaging of biological tissue. An entire rat brain tissue was measured with 150 um spatial resolution (75 um primary ion spot size) with mass Resolving Power (m/{\Delta}m50%) of 67,500 (at m/z 750) and root-mean-square measurement accuracy less than two parts-per-million for intact phospholipids, small molecules and fragments. For the first time, ultra-high mass Resolving Power SIMS has been demonstrated, with m/{\Delta}m50% > 3,000,000. Higher spatial resolution capabilities of the platform were tested at a spatial resolution of 20 um. The results represent order of magnitude improvements in mass Resolving Power and mass measurement accuracy for SIMS imaging and the promise of the platform for ultra-high mass Resolving Power and high spatial resolution imaging.
-
high mass accuracy and high mass Resolving Power ft icr secondary ion mass spectrometry for biological tissue imaging
Analytical and Bioanalytical Chemistry, 2013Co-Authors: Donald F Smith, Andras Kiss, Franklin E Leach, Errol W Robinson, Ljiljana Pasatolic, Ron M A HeerenAbstract:Biological tissue imaging by secondary ion mass spectrometry has seen rapid development with the commercial availability of polyatomic primary ion sources. Endogenous lipids and other small bio-molecules can now be routinely mapped on the sub-micrometer scale. Such experiments are typically performed on time-of-flight mass spectrometers for high sensitivity and high repetition rate imaging. However, such mass analyzers lack the mass Resolving Power to ensure separation of isobaric ions and the mass accuracy for elemental formula assignment based on exact mass measurement. We have recently reported a secondary ion mass spectrometer with the combination of a C60 primary ion gun with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) for high mass Resolving Power, high mass measurement accuracy, and tandem mass spectrometry capabilities. In this work, high specificity and high sensitivity secondary ion FT-ICR MS was applied to chemical imaging of biological tissue. An entire rat brain tissue was measured with 150 μm spatial resolution (75 μm primary ion spot size) with mass Resolving Power (m/Δm50%) of 67,500 (at m/z 750) and root-mean-square measurement accuracy less than two parts-per-million for intact phospholipids, small molecules and fragments. For the first time, ultra-high mass Resolving Power SIMS has been demonstrated, with m/Δm50% > 3,000,000. Higher spatial resolution capabilities of the platform were tested at a spatial resolution of 20 μm. The results represent order of magnitude improvements in mass Resolving Power and mass measurement accuracy for SIMS imaging and the promise of the platform for ultra-high mass Resolving Power and high spatial resolution imaging.
James N Dodds - One of the best experts on this subject based on the ideXlab platform.
-
correlating Resolving Power resolution and collision cross section unifying cross platform assessment of separation efficiency in ion mobility spectrometry
Analytical Chemistry, 2017Co-Authors: James N Dodds, John A. McleanAbstract:Here we examine the relationship among Resolving Power (Rp), resolution (Rpp), and collision cross section (CCS) for compounds analyzed in previous ion mobility (IM) experiments representing a wide variety of instrument platforms and IM techniques. Our previous work indicated these three variables effectively describe and predict separation efficiency for drift tube ion mobility spectrometry experiments. In this work, we seek to determine if our previous findings are a general reflection of IM behavior that can be applied to various instrument platforms and mobility techniques. Results suggest IM distributions are well characterized by a Gaussian model and separation efficiency can be predicted on the basis of the empirical difference in the gas-phase CCS and a CCS-based Resolving Power definition (CCS/ΔCCS). Notably traveling wave (TWIMS) was found to operate at resolutions substantially higher than a single-peak Resolving Power suggested. When a CCS-based Rp definition was utilized, TWIMS was found to o...
-
correlating Resolving Power resolution and collision cross section unifying cross platform assessment of separation efficiency in ion mobility spectrometry
Analytical Chemistry, 2017Co-Authors: James N Dodds, Jody C May, John A. McleanAbstract:Here we examine the relationship among Resolving Power (Rp), resolution (Rpp), and collision cross section (CCS) for compounds analyzed in previous ion mobility (IM) experiments representing a wide variety of instrument platforms and IM techniques. Our previous work indicated these three variables effectively describe and predict separation efficiency for drift tube ion mobility spectrometry experiments. In this work, we seek to determine if our previous findings are a general reflection of IM behavior that can be applied to various instrument platforms and mobility techniques. Results suggest IM distributions are well characterized by a Gaussian model and separation efficiency can be predicted on the basis of the empirical difference in the gas-phase CCS and a CCS-based Resolving Power definition (CCS/ΔCCS). Notably traveling wave (TWIMS) was found to operate at resolutions substantially higher than a single-peak Resolving Power suggested. When a CCS-based Rp definition was utilized, TWIMS was found to operate at a Resolving Power between 40 and 50, confirming the previous observations by Giles and co-workers. After the separation axis (and corresponding Resolving Power) is converted to cross section space, it is possible to effectively predict separation behavior for all mobility techniques evaluated (i.e., uniform field, trapped ion mobility, traveling wave, cyclic, and overtone instruments) using the equations described in this work. Finally, we are able to establish for the first time that the current state-of-the-art ion mobility separations benchmark at a CCS-based Resolving Power of >300 that is sufficient to differentiate analyte ions with CCS differences as small as 0.5%.
-
broadscale Resolving Power performance of a high precision uniform field ion mobility mass spectrometer
Analyst, 2015Co-Authors: Jody C May, James N Dodds, Ruwan T. Kurulugama, George C Stafford, John Fjeldsted, John A. McleanAbstract:An extensive study of two current ion mobility Resolving Power theories ("conditional" and "semi-empirical") was undertaken using a recently developed drift tube ion mobility-mass spectrometer. The current study investigates the quantitative agreement between experiment and theory at reduced pressure (4 Torr) for a wide range of initial ion gate widths (100 to 500 μs), and ion mobility values (K0 from 0.50 to 3.0 cm(2) V(-1) s(-1)) representing measurements obtained in helium, nitrogen, and carbon dioxide drift gas. Results suggest that the conditional Resolving Power theory deviates from experimental results for low mobility ions (e.g., high mass analytes) and for initial ion gate widths beyond 200 μs. A semi-empirical Resolving Power theory provided close-correlation of predicted Resolving Powers to experimental results across the full range of mobilities and gate widths investigated. Interpreting the results from the semi-empirical theory, the performance of the current instrumentation was found to be highly linear for a wide range of analytes, with optimal Resolving Powers being accessible for a narrow range of drift fields between 14 and 17 V cm(-1). While developed using singly-charged ion mobility data, preliminary results suggest that the semi-empirical theory has broader applicability to higher-charge state systems.
Richard D Smith - One of the best experts on this subject based on the ideXlab platform.
-
dynamic time warping correction for shifts in ultrahigh Resolving Power ion mobility spectrometry and structures for lossless ion manipulations
Journal of the American Society for Mass Spectrometry, 2021Co-Authors: Adam L Hollerbach, Richard D Smith, Christopher R Conant, Gabe Nagy, Matthew E Monroe, Khushboo Gupta, Micah Donor, Cameron M Giberson, Sandilya V B Garimella, Yehia M IbrahimAbstract:Detection of arrival time shifts between ion mobility spectrometry (IMS) separations can limit achievable Resolving Power (Rp), particularly when multiple separations are summed or averaged, as commonly practiced in IMS. Such variations can be apparent in higher Rp measurements and are particularly evident in long path length traveling wave structures for lossless ion manipulations (SLIM) IMS due to their typically much longer separation times. Here, we explore data processing approaches employing single value alignment (SVA) and nonlinear dynamic time warping (DTW) to correct for variations between IMS separations, such as due to pressure fluctuations, to enable more effective spectrum summation for improving Rp and detection of low-intensity species. For multipass SLIM IMS separations, where narrow mobility range measurements have arrival times that can extend to several seconds, the SVA approach effectively corrected for such variations and significantly improved Rp for summed separations. However, SVA was much less effective for broad mobility range separations, such as obtained with multilevel SLIM IMS. Changes in ions' arrival times were observed to be correlated with small pressure changes, with approximately 0.6% relative arrival time shifts being common, sufficient to result in a loss of Rp for summed separations. Comparison of the approaches showed that DTW alignment performed similarly to SVA when used over a narrow mobility range but was significantly better (providing narrower peaks and higher signal intensities) for wide mobility range data. We found that the DTW approach increased Rp by as much as 115% for measurements in which 50 IMS separations over 2 s were summed. We conclude that DTW is superior to SVA for ultra-high-resolution broad mobility range SLIM IMS separations and leads to a large improvement in effective Rp, correcting for ion arrival time shifts regardless of the cause, as well as improving the detectability of low-abundance species. Our tool is publicly available for use with universal ion mobility format (.UIMF) and text (.txt) files.
-
high definition differential ion mobility spectrometry with Resolving Power up to 500
Journal of the American Society for Mass Spectrometry, 2013Co-Authors: Alexandre A Shvartsburg, Randolph V. Norheim, Ronald J Moore, Thomas A Seim, William F Danielson, Gordon A Anderson, Richard D SmithAbstract:As the resolution of analytical methods improves, further progress tends to be increasingly limited by instrumental parameter instabilities that were previously inconsequential. This is now the case with differential ion mobility spectrometry (FAIMS), where fluctuations of the voltages and gas pressure have become critical. A new high-definition generator for FAIMS compensation voltage reported here provides a stable and accurate output than can be scanned with negligible steps. This reduces the spectral drift and peak width, thus improving the Resolving Power (R) and resolution. The gain for multiply-charged peptides that have narrowest peaks is up to ~40 %, and R ~400–500 is achievable using He/N2 or H2/N2 gas mixtures.
-
scaling of the Resolving Power and sensitivity for planar faims and mobility based discrimination in flow and field driven analyzers
Journal of the American Society for Mass Spectrometry, 2007Co-Authors: Alexandre A Shvartsburg, Richard D SmithAbstract:Continuing development of the technology and applications of field asymmetric waveform ion mobility spectrometry (FAIMS) calls for better understanding of its limitations and factors that govern them. While key performance metrics such as resolution and ion transmission have been calculated for specific cases employing numerical simulations, the underlying physical trends remained obscure. Here we determine that the Resolving Power of planar FAIMS scales as the square root of separation time and sensitivity drops exponentially at the rate controlled by absolute ion mobility and several instrument parameters. A strong dependence of ion transmission on mobility severely discriminates against species with higher mobility, presenting particular problems for analyses of complex mixtures. While the time evolution of resolution and sensitivity is virtually identical in existing FAIMS systems using gas flow and proposed devices driven by electric field, the distributions of separation times are not. The inverse correlation between mobility (and thus diffusion speed) and residence time for ions in field-driven FAIMS greatly reduces the mobility-based discrimination and provides much more uniform separations. Under typical operating conditions, the spread of elimination rates for commonly analyzed ions is reduced from >5 times in flow-driven to 1.6 times in field-driven FAIMS while the difference in Resolving Power decreases from ∼60% to ∼15%.
