PNNL

Adam is a chemist at Pacific Northwest National Laboratory specializing in the design, construction, and development of novel ion mobility and mass spectrometry (IMS-MS) instrumentation.  His current research focuses on analyzing complex biological mixtures with highly sensitive and ultrahigh resolution IMS-MS systems.  As a scientist at PNNL, his early efforts were spent developing an ultralong path length IMS platform using structures for lossless ion manipulations (SLIM).  His research provided significant enhancements to the sensitivity and resolution of SLIM that his team now employs in new SLIM designs.  Adam and his team have developed SLIM systems with high commercial value, such as a miniature multilevel SLIM that provides higher quality separations than commercially available systems.  His research was featured on the front cover of Analytical Chemistry in February 2022, and he was later awarded the 2022 Biological Sciences Division BESTie award for his efforts.  Adam also has extensive experience studying the fundamentals of electrospray ionization (ESI) and how ESI generated ions behave at atmospheric pressure, which he uses to optimize the sensitivity of IMS-MS systems.  Adam is a coauthor of 13 peer-reviewed publications and coinventor of 4 patents in the fields of mass spectrometry and ion mobility spectrometry.  Adam has led two successful internally funded projects at PNNL during fiscal years 2021 and 2022 and is currently the principal investigator on an LDRD sponsored project that uses ultrahigh resolution ion mobility-mass spectrometry to identify unknown ions without having to use reference standards.

• Analytical instrumentation development
• Ion mobility spectrometry
• Mass spectrometry
• Electrospray ionization
• Ion manipulation at atmospheric pressure
• Ion trajectory simulations

• PhD in Analytical Chemistry, Purdue University, 2018
• BS in Chemistry, University of Utah, 2011

• The American Society for Mass Spectrometry
• Metabolomics Society

• 2022 BESTie Award for paper of the year, Biological Sciences Division, PNNL
• 2014 W. Brooks Fortune Fellowship, Purdue University

2024

• Hollerbach A.L., V.S. Lin, Y.M. Ibrahim, R.G. Ewing, T.O. Metz, and K.E. Rodda. 2024. "Elucidating the Gas-Phase Behavior of Nitazene Analog Protomers using Structures for Lossless Ion Manipulations Ion Mobility-Orbitrap Mass Spectrometry." Journal of the American Society for Mass Spectrometry 35, no. 7:1609-1621. PNNL-SA-198305. doi:10.1021/jasms.4c00200
• Hollerbach A.L., Y.M. Ibrahim, R.V. Norheim, G.A. Anderson, A.G. Ryan, and J.M. Lindquist. 2024. Enabling Ultralow Volume Analysis with a High-Resolution Ion Mobility Mass Spectrometry Platform. PNNL-36741. Richland, WA: Pacific Northwest National Laboratory. Enabling Ultralow Volume Analysis with a High-Resolution Ion Mobility Mass Spectrometry Platform
• Hollerbach A.L., Y.M. Ibrahim, V.S. Lin, K.J. Schultz, A.P. Huntley, P.B. Armentrout, and T.O. Metz, et al. 2024. "Identification of Unique Fragmentation Patterns of Fentanyl Analog Protomers using Structures for Lossless Ion Manipulations Ion Mobility-Orbitrap Mass Spectrometry." Journal of the American Society for Mass Spectrometry 35, no. 4:793-803. PNNL-SA-192943. doi:10.1021/jasms.4c00049
• Huntley A.P., A.L. Hollerbach, R.V. Norheim, A.M. Hamid, G.A. Anderson, V. Garimella, and Y.M. Ibrahim. 2024. "A Cyclable Variable Path Length Multilevel Structures for Lossless Ion Manipulations (SLIM) Platform for Enhanced Ion Mobility Separations." Analytical Chemistry 96, no. 7:3160-3167. PNNL-SA-192944. doi:10.1021/acs.analchem.3c05594
• Johnson S.J., V.B. Garimella, M.D. Baer, and A.L. Hollerbach. 2024. Computational Methods for Modeling Electrospray Microdroplet Chemistry for Improved Quantitative Mass Spectrometry. PNNL-37215. Richland, WA: Pacific Northwest National Laboratory. Computational Methods for Modeling Electrospray Microdroplet Chemistry for Improved Quantitative Mass Spectrometry
• Kwantwi-Barima P., A.L. Hollerbach, I.K. Attah, R.V. Norheim, and Y.M. Ibrahim. 2024. "Ion Mobility Separations Using Cocentric Architecture." Journal of the American Society for Mass Spectrometry 35, no. 7:1576-1583. PNNL-SA-197448. doi:10.1021/jasms.4c00163
• Ross D.H., J. Lee, Y. Gao, A.L. Hollerbach, A. Bilbao, T. Shi, and Y.M. Ibrahim, et al. 2024. "Evaluation of a Reference-Free Collision Cross Section Calibration Strategy for Proteomics Using SLIM-based High-Resolution Ion Mobility Spectrometry- Mass Spectrometry." Journal of the American Society for Mass Spectrometry 35, no. 7:1539-1549. PNNL-SA-197876. doi:10.1021/jasms.4c00141

2023

• Hollerbach, A. L.; Ibrahim, Y. M.; Meras, V.; Norheim, R. V.; Huntley, A. P.; Anderson, G. A.; Metz, T. O.; Ewing, R. G.; Smith, R. D. A Dual-Gated Structures for Lossless Ion Manipulations-Ion Mobility Orbitrap Mass Spectrometry Platform for Combined Ultra-High-Resolution Molecular Analysis, Anal. Chem. 2023.
• Huntley, A. P.; Hollerbach, A. L.; Prabhakaran, A.; Garimella, S. V. B.; Giberson, C. M.; Norheim, R. V.; Smith, R. D.; Ibrahim, Y. M. Development of a Structure for Lossless Ion Manipulations (SLIM) High Charge Capacity Array of Traps, Anal. Chem. 2023, 95, 4446-4453.
• Ibrahim Y.M., A.L. Hollerbach, and P. Kwantwi-Barima. 2023. High resolution mobility spectrometry in a co-axial platform. PNNL-34864. Richland, WA: Pacific Northwest National Laboratory. High resolution mobility spectrometry in a co-axial platform

2022

• Hollerbach A.L., C.R. Conant, G. Nagy, and Y.M. Ibrahim. 2022. "Implementation of Ion Mobility Spectrometry-Based Separations in Structures for Lossless Ion Manipulations (SLIM)." In Biomedical Engineering Technologies. Methods in Molecular Biology, edited by A. Rasooly, H. Baker and M.R. Ossandon. 453-469. New York, New York:Humana Press. PNNL-SA-146735. doi:10.1007/978-1-0716-1811-0_23
• Hollerbach, A. L.; Norheim, R. V.; Kwantwi-Barima, P.; Smith, R. D.; Ibrahim, Y. M. A Miniature Multilevel Structures for Lossless Ion Manipulations Ion Mobility Spectrometer with Wide Mobility Range Separation Capabilities, Anal. Chem. 2022, 94, 2180-2188.
• Hollerbach, A. L.; Ibrahim, Y. M.; Norheim, R. V.; Metz, T. O.; Ewing, R. G. Focusing ions at atmospheric pressure using nonlinear DC voltage sequences applied to a stacked ring ion guide, Int. J. Mass spectrom. 2022, 482, 116948.
• Hollerbach A.L., Y.M. Ibrahim, R.V. Norheim, T.O. Metz, and R.G. Ewing. 2022. Focusing Ions at Atmospheric Pressure Using Nonlinear DC Voltage Sequences Applied to a Stacked Ring Ion Guide. PNNL-33229. Richland, WA: Pacific Northwest National Laboratory. Focusing Ions at Atmospheric Pressure Using Nonlinear DC Voltage Sequences Applied to a Stacked Ring Ion Guide

2021

• Hollerbach, A. L.; Giberson, C. M.; Lee, J.-Y.; Huntley, A. P.; Smith, R. D.; Ibrahim, Y. M. Improving Signal to Noise Ratios in Ion Mobility Spectrometry and Structures for Lossless Ion Manipulations (SLIM) using a High Dynamic Range Analog-to-Digital Converter, J. Am. Soc. Mass. Spectrom. 2021, 32, 2698-2706.
• Hollerbach, A. L.; Conant, C. R.; Nagy, G.; Monroe, M. E.; Gupta, K.; Donor, M.; Giberson, C. M.; Garimella, S. V. B.; Smith, R. D.; Ibrahim, Y. M. Dynamic Time-Warping Correction for Shifts in Ultrahigh Resolving Power Ion Mobility Spectrometry and Structures for Lossless Ion Manipulations, J. Am. Soc. Mass. Spectrom. 2021, 32, 996-1007.

2020

• Hollerbach, A. L.; Li, A.; Prabhakaran, A.; Nagy, G.; Harrilal, C. P.; Conant, C. R.; Norheim, R. V.; Schimelfenig, C. E.; Anderson, G. A.; Garimella, S. V. B.; Smith, R. D.; Ibrahim, Y. M. Ultra-High-Resolution Ion Mobility Separations Over Extended Path Lengths and Mobility Ranges Achieved using a Multilevel Structures for Lossless Ion Manipulations Module, Anal. Chem. 2020, 92, 7972-7979.
• Li, A.; Nagy, G.; Conant, C. R.; Norheim, R. V.; Lee, J. Y.; Giberson, C.; Hollerbach, A. L.; Prabhakaran, V.; Attah, I. K.; Chouinard, C. D.; Prabhakaran, A.; Smith, R. D.; Ibrahim, Y. M.; Garimella, S. V. B. Ion Mobility Spectrometry with High Ion Utilization Efficiency Using Traveling Wave-Based Structures for Lossless Ion Manipulations, Anal. Chem. 2020, 92, 14930-14938.

2019

• Wojcik, R.; Nagy, G.; Attah, I. K.; Webb, I. K.; Garimella, S. V. B.; Weitz, K. K.; Hollerbach, A.; Monroe, M. E.; Ligare, M. R.; Nielson, F. F.; Norheim, R. V.; Renslow, R. S.; Metz, T. O.; Ibrahim, Y. M.; Smith, R. D. SLIM Ultrahigh Resolution Ion Mobility Spectrometry Separations of Isotopologues and Isotopomers Reveal Mobility Shifts due to Mass Distribution Changes, Anal. Chem. 2019, 91, 11952-11962.