The Experts below are selected from a list of 30165 Experts worldwide ranked by ideXlab platform
Thomas Kraemer - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography in combination with a quadrupole time of Flight Instrument with sequential window acquisition of all theoretical fragment ion spectra acquisition validated quantification of 39 antidepressants in whole blood as part of a simultaneous screening and quantification procedure
Analytical Chemistry, 2015Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Thomas KraemerAbstract:Sequential window acquisition of all theoretical fragment ion spectra (SWATH) is a data independent acquisition (DIA) method for very fast scanning quadrupole time-of-Flight (QTOF) Instruments. SWATH repeatedly cycles through 28 consecutive 20 Da precursor isolation windows detecting all precursor ions and fragments MS ALL like and yet fast enough to generate more than 10 data points over the chromatographic peak. It was already shown in previous publications that SWATH, despite its wide Q1 windows, allows the identification of different substances and that SWATH has a higher identification rate than data dependent acquisition approaches. The aim of this study was a proof of concept study whether these same data sets can also enable validated quantification according to international guidelines, exemplified for 39 antidepressants. The validation included recovery, matrix effects, process efficiency, ion suppression, and enhancement of coeluting ions, selectivity, accuracy, precision, and stability. The me...
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liquid chromatography in combination with a quadrupole time of Flight Instrument lc qtof with sequential window acquisition of all theoretical fragment ion spectra swath acquisition systematic studies on its use for screenings in clinical and forensic toxicology and comparison with information dependent acquisition ida
Analytical Chemistry, 2014Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Michael Poetzsch, Thomas KraemerAbstract:Forensic and clinical toxicological screening procedures are employing liquid chromatography–tandem mass spectrometry (LC-MS/MS) techniques with information-dependent acquisition (IDA) approaches more and more often. It is known that the complexity of a sample and the IDA settings might prevent important compounds from being triggered. Therefore, data-independent acquisition (DIA) methods should be more suitable for systematic toxicological analysis (STA). The DIA method sequential window acquisition of all theoretical fragment-ion spectra (SWATH), which uses Q1 windows of 20–35 Da for data-independent fragmentation, was systematically investigated for its suitability for STA. Quality of SWATH-generated mass spectra were evaluated with regard to mass error, relative abundance of the fragments, and library hits. With the Q1 window set to 20–25 Da, several precursors pass Q1 at the same time and are fragmented, thus impairing the library search algorithms to a different extent: forward fit was less affected...
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liquid chromatography in combination with a quadrupole time of Flight Instrument lc qtof with sequential window acquisition of all theoretical fragment ion spectra swath acquisition systematic studies on its use for screenings in clinical and forensic toxicology and comparison with information dependent acquisition ida
Analytical Chemistry, 2014Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Michael Poetzsch, Thomas KraemerAbstract:Forensic and clinical toxicological screening procedures are employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques with information-dependent acquisition (IDA) approaches more and more often. It is known that the complexity of a sample and the IDA settings might prevent important compounds from being triggered. Therefore, data-independent acquisition (DIA) methods should be more suitable for systematic toxicological analysis (STA). The DIA method sequential window acquisition of all theoretical fragment-ion spectra (SWATH), which uses Q1 windows of 20-35 Da for data-independent fragmentation, was systematically investigated for its suitability for STA. Quality of SWATH-generated mass spectra were evaluated with regard to mass error, relative abundance of the fragments, and library hits. With the Q1 window set to 20-25 Da, several precursors pass Q1 at the same time and are fragmented, thus impairing the library search algorithms to a different extent: forward fit was less affected than reverse fit and purity fit. Mass error was not affected. The relative abundance of the fragments was concentration dependent for some analytes and was influenced by cofragmentation, especially of deuterated analogues. Also, the detection rate of IDA compared to SWATH was investigated in a forced coelution experiment (up to 20 analytes coeluting). Even using several different IDA settings, it was observed that IDA failed to trigger relevant compounds. Screening results of 382 authentic forensic cases revealed that SWATH's detection rate was superior to IDA, which failed to trigger ∼10% of the analytes.
Harald Köfeler - One of the best experts on this subject based on the ideXlab platform.
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on the inter Instrument and inter laboratory transferability of a tandem mass spectral reference library 1 results of an austrian multicenter study
Journal of Mass Spectrometry, 2009Co-Authors: Herbert Oberacher, Marion Pavlic, Kathrin Libiseller, Birthe Schubert, Edina Csaszar, Rainer Schuhmacher, Michael Sulyok, Harald KöfelerAbstract:The inter-Instrument and inter-laboratory transferability of a tandem mass spectral reference library originally built on a quadrupole-quadrupole-time-of-Flight Instrument was examined. The library consisted of 3759 MS/MS spectra collected from 402 reference compounds applying several different collision-energy values for fragmentation. In the course of the multicenter study, 22 test compounds were sent to three different laboratories, where 418 tandem mass spectra were acquired using four different Instruments from two manufacturers. The study covered the following types of tandem mass spectrometers: quadrupole-quadrupole-time-of-Flight, quadrupole-quadrupole-linear ion trap, quadrupole-quadrupole-quadrupole, and linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer. In each participating laboratory, optimized Instrumental parameters were gathered solely from routinely applied workflows. No standardization procedure was applied to increase the inter-Instrument comparability of MS/MS spectra. The acquired tandem mass spectra were matched against the established reference library using a sophisticated matching algorithm, which is presented in detail in a companion paper. Correct answers, meaning that the correct compound was retrieved as top hit, were obtained in 98.1% of cases. For the remaining 1.9% of spectra, the correct compound was matched at second rank. The observed high percentage of correct assignments clearly suggests that the developed mass spectral library search approach is to a large extent platform independent. Copyright © 2009 John Wiley & Sons, Ltd.
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on the inter Instrument and inter laboratory transferability of a tandem mass spectral reference library 1 results of an austrian multicenter study
Journal of Mass Spectrometry, 2009Co-Authors: Herbert Oberacher, Marion Pavlic, Kathrin Libiseller, Birthe Schubert, Edina Csaszar, Rainer Schuhmacher, Michael Sulyok, Harald KöfelerAbstract:The inter-Instrument and inter-laboratory transferability of a tandem mass spectral reference library originally built on a quadrupole-quadrupole-time-of-Flight Instrument was examined. The library consisted of 3759 MS/MS spectra collected from 402 reference compounds applying several different collision-energy values for fragmentation. In the course of the multicenter study, 22 test compounds were sent to three different laboratories, where 418 tandem mass spectra were acquired using four different Instruments from two manufacturers. The study covered the following types of tandem mass spectrometers: quadrupole-quadrupole-time-of-Flight, quadrupole-quadrupole-linear ion trap, quadrupole-quadrupole-quadrupole, and linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer. In each participating laboratory, optimized Instrumental parameters were gathered solely from routinely applied workflows. No standardization procedure was applied to increase the inter-Instrument comparability of MS/MS spectra. The acquired tandem mass spectra were matched against the established reference library using a sophisticated matching algorithm, which is presented in detail in a companion paper. Correct answers, meaning that the correct compound was retrieved as top hit, were obtained in 98.1% of cases. For the remaining 1.9% of spectra, the correct compound was matched at second rank. The observed high percentage of correct assignments clearly suggests that the developed mass spectral library search approach is to a large extent platform independent.
Andreas T Roemmelt - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography in combination with a quadrupole time of Flight Instrument with sequential window acquisition of all theoretical fragment ion spectra acquisition validated quantification of 39 antidepressants in whole blood as part of a simultaneous screening and quantification procedure
Analytical Chemistry, 2015Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Thomas KraemerAbstract:Sequential window acquisition of all theoretical fragment ion spectra (SWATH) is a data independent acquisition (DIA) method for very fast scanning quadrupole time-of-Flight (QTOF) Instruments. SWATH repeatedly cycles through 28 consecutive 20 Da precursor isolation windows detecting all precursor ions and fragments MS ALL like and yet fast enough to generate more than 10 data points over the chromatographic peak. It was already shown in previous publications that SWATH, despite its wide Q1 windows, allows the identification of different substances and that SWATH has a higher identification rate than data dependent acquisition approaches. The aim of this study was a proof of concept study whether these same data sets can also enable validated quantification according to international guidelines, exemplified for 39 antidepressants. The validation included recovery, matrix effects, process efficiency, ion suppression, and enhancement of coeluting ions, selectivity, accuracy, precision, and stability. The me...
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liquid chromatography in combination with a quadrupole time of Flight Instrument lc qtof with sequential window acquisition of all theoretical fragment ion spectra swath acquisition systematic studies on its use for screenings in clinical and forensic toxicology and comparison with information dependent acquisition ida
Analytical Chemistry, 2014Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Michael Poetzsch, Thomas KraemerAbstract:Forensic and clinical toxicological screening procedures are employing liquid chromatography–tandem mass spectrometry (LC-MS/MS) techniques with information-dependent acquisition (IDA) approaches more and more often. It is known that the complexity of a sample and the IDA settings might prevent important compounds from being triggered. Therefore, data-independent acquisition (DIA) methods should be more suitable for systematic toxicological analysis (STA). The DIA method sequential window acquisition of all theoretical fragment-ion spectra (SWATH), which uses Q1 windows of 20–35 Da for data-independent fragmentation, was systematically investigated for its suitability for STA. Quality of SWATH-generated mass spectra were evaluated with regard to mass error, relative abundance of the fragments, and library hits. With the Q1 window set to 20–25 Da, several precursors pass Q1 at the same time and are fragmented, thus impairing the library search algorithms to a different extent: forward fit was less affected...
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liquid chromatography in combination with a quadrupole time of Flight Instrument lc qtof with sequential window acquisition of all theoretical fragment ion spectra swath acquisition systematic studies on its use for screenings in clinical and forensic toxicology and comparison with information dependent acquisition ida
Analytical Chemistry, 2014Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Michael Poetzsch, Thomas KraemerAbstract:Forensic and clinical toxicological screening procedures are employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques with information-dependent acquisition (IDA) approaches more and more often. It is known that the complexity of a sample and the IDA settings might prevent important compounds from being triggered. Therefore, data-independent acquisition (DIA) methods should be more suitable for systematic toxicological analysis (STA). The DIA method sequential window acquisition of all theoretical fragment-ion spectra (SWATH), which uses Q1 windows of 20-35 Da for data-independent fragmentation, was systematically investigated for its suitability for STA. Quality of SWATH-generated mass spectra were evaluated with regard to mass error, relative abundance of the fragments, and library hits. With the Q1 window set to 20-25 Da, several precursors pass Q1 at the same time and are fragmented, thus impairing the library search algorithms to a different extent: forward fit was less affected than reverse fit and purity fit. Mass error was not affected. The relative abundance of the fragments was concentration dependent for some analytes and was influenced by cofragmentation, especially of deuterated analogues. Also, the detection rate of IDA compared to SWATH was investigated in a forced coelution experiment (up to 20 analytes coeluting). Even using several different IDA settings, it was observed that IDA failed to trigger relevant compounds. Screening results of 382 authentic forensic cases revealed that SWATH's detection rate was superior to IDA, which failed to trigger ∼10% of the analytes.
Herbert Oberacher - One of the best experts on this subject based on the ideXlab platform.
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on the inter Instrument and inter laboratory transferability of a tandem mass spectral reference library 1 results of an austrian multicenter study
Journal of Mass Spectrometry, 2009Co-Authors: Herbert Oberacher, Marion Pavlic, Kathrin Libiseller, Birthe Schubert, Edina Csaszar, Rainer Schuhmacher, Michael Sulyok, Harald KöfelerAbstract:The inter-Instrument and inter-laboratory transferability of a tandem mass spectral reference library originally built on a quadrupole-quadrupole-time-of-Flight Instrument was examined. The library consisted of 3759 MS/MS spectra collected from 402 reference compounds applying several different collision-energy values for fragmentation. In the course of the multicenter study, 22 test compounds were sent to three different laboratories, where 418 tandem mass spectra were acquired using four different Instruments from two manufacturers. The study covered the following types of tandem mass spectrometers: quadrupole-quadrupole-time-of-Flight, quadrupole-quadrupole-linear ion trap, quadrupole-quadrupole-quadrupole, and linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer. In each participating laboratory, optimized Instrumental parameters were gathered solely from routinely applied workflows. No standardization procedure was applied to increase the inter-Instrument comparability of MS/MS spectra. The acquired tandem mass spectra were matched against the established reference library using a sophisticated matching algorithm, which is presented in detail in a companion paper. Correct answers, meaning that the correct compound was retrieved as top hit, were obtained in 98.1% of cases. For the remaining 1.9% of spectra, the correct compound was matched at second rank. The observed high percentage of correct assignments clearly suggests that the developed mass spectral library search approach is to a large extent platform independent. Copyright © 2009 John Wiley & Sons, Ltd.
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on the inter Instrument and inter laboratory transferability of a tandem mass spectral reference library 1 results of an austrian multicenter study
Journal of Mass Spectrometry, 2009Co-Authors: Herbert Oberacher, Marion Pavlic, Kathrin Libiseller, Birthe Schubert, Edina Csaszar, Rainer Schuhmacher, Michael Sulyok, Harald KöfelerAbstract:The inter-Instrument and inter-laboratory transferability of a tandem mass spectral reference library originally built on a quadrupole-quadrupole-time-of-Flight Instrument was examined. The library consisted of 3759 MS/MS spectra collected from 402 reference compounds applying several different collision-energy values for fragmentation. In the course of the multicenter study, 22 test compounds were sent to three different laboratories, where 418 tandem mass spectra were acquired using four different Instruments from two manufacturers. The study covered the following types of tandem mass spectrometers: quadrupole-quadrupole-time-of-Flight, quadrupole-quadrupole-linear ion trap, quadrupole-quadrupole-quadrupole, and linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer. In each participating laboratory, optimized Instrumental parameters were gathered solely from routinely applied workflows. No standardization procedure was applied to increase the inter-Instrument comparability of MS/MS spectra. The acquired tandem mass spectra were matched against the established reference library using a sophisticated matching algorithm, which is presented in detail in a companion paper. Correct answers, meaning that the correct compound was retrieved as top hit, were obtained in 98.1% of cases. For the remaining 1.9% of spectra, the correct compound was matched at second rank. The observed high percentage of correct assignments clearly suggests that the developed mass spectral library search approach is to a large extent platform independent.
Andrea E Steuer - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography in combination with a quadrupole time of Flight Instrument with sequential window acquisition of all theoretical fragment ion spectra acquisition validated quantification of 39 antidepressants in whole blood as part of a simultaneous screening and quantification procedure
Analytical Chemistry, 2015Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Thomas KraemerAbstract:Sequential window acquisition of all theoretical fragment ion spectra (SWATH) is a data independent acquisition (DIA) method for very fast scanning quadrupole time-of-Flight (QTOF) Instruments. SWATH repeatedly cycles through 28 consecutive 20 Da precursor isolation windows detecting all precursor ions and fragments MS ALL like and yet fast enough to generate more than 10 data points over the chromatographic peak. It was already shown in previous publications that SWATH, despite its wide Q1 windows, allows the identification of different substances and that SWATH has a higher identification rate than data dependent acquisition approaches. The aim of this study was a proof of concept study whether these same data sets can also enable validated quantification according to international guidelines, exemplified for 39 antidepressants. The validation included recovery, matrix effects, process efficiency, ion suppression, and enhancement of coeluting ions, selectivity, accuracy, precision, and stability. The me...
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liquid chromatography in combination with a quadrupole time of Flight Instrument lc qtof with sequential window acquisition of all theoretical fragment ion spectra swath acquisition systematic studies on its use for screenings in clinical and forensic toxicology and comparison with information dependent acquisition ida
Analytical Chemistry, 2014Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Michael Poetzsch, Thomas KraemerAbstract:Forensic and clinical toxicological screening procedures are employing liquid chromatography–tandem mass spectrometry (LC-MS/MS) techniques with information-dependent acquisition (IDA) approaches more and more often. It is known that the complexity of a sample and the IDA settings might prevent important compounds from being triggered. Therefore, data-independent acquisition (DIA) methods should be more suitable for systematic toxicological analysis (STA). The DIA method sequential window acquisition of all theoretical fragment-ion spectra (SWATH), which uses Q1 windows of 20–35 Da for data-independent fragmentation, was systematically investigated for its suitability for STA. Quality of SWATH-generated mass spectra were evaluated with regard to mass error, relative abundance of the fragments, and library hits. With the Q1 window set to 20–25 Da, several precursors pass Q1 at the same time and are fragmented, thus impairing the library search algorithms to a different extent: forward fit was less affected...
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liquid chromatography in combination with a quadrupole time of Flight Instrument lc qtof with sequential window acquisition of all theoretical fragment ion spectra swath acquisition systematic studies on its use for screenings in clinical and forensic toxicology and comparison with information dependent acquisition ida
Analytical Chemistry, 2014Co-Authors: Andreas T Roemmelt, Andrea E Steuer, Michael Poetzsch, Thomas KraemerAbstract:Forensic and clinical toxicological screening procedures are employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques with information-dependent acquisition (IDA) approaches more and more often. It is known that the complexity of a sample and the IDA settings might prevent important compounds from being triggered. Therefore, data-independent acquisition (DIA) methods should be more suitable for systematic toxicological analysis (STA). The DIA method sequential window acquisition of all theoretical fragment-ion spectra (SWATH), which uses Q1 windows of 20-35 Da for data-independent fragmentation, was systematically investigated for its suitability for STA. Quality of SWATH-generated mass spectra were evaluated with regard to mass error, relative abundance of the fragments, and library hits. With the Q1 window set to 20-25 Da, several precursors pass Q1 at the same time and are fragmented, thus impairing the library search algorithms to a different extent: forward fit was less affected than reverse fit and purity fit. Mass error was not affected. The relative abundance of the fragments was concentration dependent for some analytes and was influenced by cofragmentation, especially of deuterated analogues. Also, the detection rate of IDA compared to SWATH was investigated in a forced coelution experiment (up to 20 analytes coeluting). Even using several different IDA settings, it was observed that IDA failed to trigger relevant compounds. Screening results of 382 authentic forensic cases revealed that SWATH's detection rate was superior to IDA, which failed to trigger ∼10% of the analytes.