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Stephan Walker

Observed names: S. Hunter Walker, S. Walker, Walker, Stephan
Institution: Kanton Zürich
ORCID: 0000-0002-7557-264X
Observed ORCID: 0000-0002-7557-264X
OpenAlex ID: A5072717461
Comprehensive comparison of liquid chromatography selectivity as provided by two types of liquid chromatography detectors (high resolution mass spectrometry and tandem mass spectrometry): “Where is the crossover point?”
2010 · A. Kaufmann, P. Butcher, et al. · Analytica Chimica Acta · 188
Development of an improved high resolution mass spectrometry based multi-residue method for veterinary drugs in various food matrices
2010 · A. Kaufmann, P. Butcher, et al. · Analytica Chimica Acta · 153
Determination of nitrofuran and chloramphenicol residues by high resolution mass spectrometry versus tandem quadrupole mass spectrometry
2014 · A. Kaufmann, P. Butcher, et al. · Analytica Chimica Acta · 112
Quantitative and confirmative performance of liquid chromatography coupled to high‐resolution mass spectrometry compared to tandem mass spectrometry
2011 · Anton Kaufmann, Patrick Butcher, et al. · Rapid Communications in Mass Spectrometry · 100
Quantification of anthelmintic drug residues in milk and muscle tissues by liquid chromatography coupled to Orbitrap and liquid chromatography coupled to tandem mass spectrometry
2011 · A. Kaufmann, P. Butcher, et al. · Talanta · 71
Multi-residue quantification of veterinary drugs in milk with a novel extraction and cleanup technique: Salting out supported liquid extraction (SOSLE)
2014 · A. Kaufmann, P. Butcher, et al. · Analytica Chimica Acta · 61
Reliability of veterinary drug residue confirmation: High resolution mass spectrometry versus tandem mass spectrometry
2014 · A. Kaufmann, P. Butcher, et al. · Analytica Chimica Acta · 52
Semi-targeted residue screening in complex matrices with liquid chromatography coupled to high resolution mass spectrometry: current possibilities and limitations
2011 · Anton Kaufmann, Patrick Butcher, et al. · The Analyst · 52
Accuracy of relative isotopic abundance and mass measurements in a single‐stage orbitrap mass spectrometer
2012 · A. Kaufmann, S. Walker · Rapid Communications in Mass Spectrometry · 50
Comparison of linear intrascan and interscan dynamic ranges of Orbitrap and ion‐mobility time‐of‐flight mass spectrometers
2017 · Anton Kaufmann, Stephan Walker · Rapid Communications in Mass Spectrometry · 46
Simplifying Nontargeted Analysis of PFAS in Complex Food Matrixes
2022 · Anton Kaufmann, Patrick Butcher, et al. · Journal of AOAC International · 43
Study of High-Resolution Mass Spectrometry Technology as a Replacement for Tandem Mass Spectrometry in the Field of Quantitative Pesticide Residue Analysis
2012 · Anton Kaufmann, Veronika Dvorak, et al. · Journal of AOAC International · 42
Post-run target screening strategy for ultra high performance liquid chromatography coupled to Orbitrap based veterinary drug residue analysis in animal urine
2012 · A. Kaufmann, S. Walker · Journal of Chromatography A · 31
Improving the QuEChERS Liquid/Liquid Extraction of Analytes With Widely Varying Physicochemical Properties: Example of 201 Veterinary Drugs in Milk
2022 · Anton Kaufmann, Patrick Butcher, et al. · Journal of AOAC International · 27
Using In Silico Fragmentation to Improve Routine Residue Screening in Complex Matrices
2017 · Anton Kaufmann, Patrick Butcher, et al. · Journal of the American Society for Mass Spectrometry · 27
Does the ion mobility resolving power as provided by commercially available ion mobility quadrupole time-of-flight mass spectrometry instruments permit the unambiguous identification of small molecules in complex matrices?
2020 · A. Kaufmann, P. Butcher, et al. · Analytica Chimica Acta · 24
Extension of the Q Orbitrap intrascan dynamic range by using a dedicated customized scan
2016 · A. Kaufmann, S. Walker · Rapid Communications in Mass Spectrometry · 23
Dissociative Photoionization Study of Neopentane: A Path to an Accurate Heat of Formation of the t-Butyl Ion, t-Butyl Iodide, and t-Butyl Hydroperoxide
2009 · William R. Stevens, S. Hunter Walker, et al. · The Journal of Physical Chemistry A · 21
High-resolution mass spectrometry–based multi-residue method covering relevant steroids, stilbenes and resorcylic acid lactones in a variety of animal-based matrices
2018 · A. Kaufmann, P. Butcher, et al. · Analytica Chimica Acta · 19
Analysis of a variety of inorganic and organic additives in food products by ion-pairing liquid chromatography coupled to high-resolution mass spectrometry
2018 · Anton Kaufmann, Mirjam Widmer, et al. · Analytical and Bioanalytical Chemistry · 18
Coalescence and self‐bunching observed in commercial high‐resolution mass spectrometry instrumentation
2018 · Anton Kaufmann, Stephan Walker · Rapid Communications in Mass Spectrometry · 18
Practical application of in silico fragmentation based residue screening with ion mobility high‐resolution mass spectrometry
2017 · Anton Kaufmann, Patrick Butcher, et al. · Rapid Communications in Mass Spectrometry · 18
Assessment and validation of the p-QuEChERS sample preparation methodology for the analysis of >200 veterinary drugs in various animal-based food matrices
2023 · Anton Kaufmann, Patrick Butcher, et al. · Food Additives & Contaminants Part A · 17
Evaluation of the interrelationship between mass resolving power and mass error tolerances for targeted bioanalysis using liquid chromatography coupled to high‐resolution mass spectrometry
2012 · A. Kaufmann, S. Walker · Rapid Communications in Mass Spectrometry · 16
Improved method robustness and ruggedness in liquid chromatography–mass spectrometry by increasing the acid content of the mobile phase
2024 · Anton Kaufmann, Patrick Butcher, et al. · Journal of Chromatography A · 12
Works count: 33
Citation count: 1,290
H-index: 19
I10-index: 27
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