Download application for 2022 Georges Guiochon Student Award sponsored by WCDG
Applications due February 25, 2022 to washchrom@gmail.com. Poster abstracts due to HPLC 2022 meeting by May 6, 2022.

January Meeting

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January 19, 2022
4:00PM (Eastern) Presentation followed by discussion

Ion Source Development for Radiative Association Kinetics Experiments
Leah G. Dodson, Dept. of Chemistry & Biochemistry, University of Maryland College Park

Recent advances in investigating radiative association (RA) reactions by quantum dynamics methods have revealed troubling discrepancies when compared with the reaction rates obtained using statistical methods, sometimes differing by up to four orders of magnitude. Notoriously difficult to measure in the laboratory, RA experiments are necessary to test the application of theoretical models to real systems. A new laboratory effort is being undertaken in the Chemistry Department at UMD to develop the tools necessary to experimentally measure rate constants for RA reactions at temperatures relevant to the interstellar medium (down to 10 K). The instrument combines a cryogenic buffer-gas beam with a cryogenic ion trap in order to investigate ion/molecule RA reactions as a function of temperature. In this talk, I will focus on the description of our glow discharge ion source and the general characteristics of our mass spectrometer. I will also describe our tactics for directly measuring the temperature-dependent reactivities with the immediate goal of measuring the rate constants for a series of RA reactions between magnesium monocations (Mg+) and cyanopolyyne (HC2n+1N, n = 0–3) neutral molecules. These experiments will shed light on disagreement between theoretical RA studies, while also providing experimentally-measured rate constants for reactions that are relevant to astrochemistry.

Bio: Leah grew up in central Pennsylvania. For undergrad she went to Case Western Reserve University in Cleveland, OH where she majored in Chemistry (minor in Physics) and graduated with a BS in 2010. While she was at Case, she studied the photophysical properties of pharmaceutical water pollutants in the research lab of Carlos Crespo-Hernández. Leah obtained her PhD in chemistry in 2016 with Mitchio Okumura at California Institute of Technology in Pasadena, CA. There she studied the spectroscopy and kinetics of radicals that are relevant to atmospheric and combustion chemistry, including several visits to the Advanced Light Source in Berkeley, CA and Sandia National Laboratories in Livermore, CA. After completing her degree, she moved to Boulder, CO where she was a NIST NRC postdoc in the lab of J. Mathias Weber at JILA/the University of Colorado. She carried out experiments using ion spectroscopy and cryogenic systems to obtain detailed structural information about gas phase ions. In Fall 2019, she started her independent group in the Chemistry Department at the University of Maryland in College Park, MD. Her group is focused on using cryogenic tools to study spectroscopy and kinetics of astrophysically-relevant molecules and ions.


February Meeting

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February 15, 2022
3:00-4:30PM Eastern

Recent advances in multi-dimensional liquid chromatography for biopharmaceutical analysis
Dwight Stoll, Gustavus Adolphus College

Selectivity in multi-modal chromatography of bispecific antibodies and the implications on downstream processing
Sid Parasnavis, AstraZeneca

Towards improved methods consistency: artifacts observed during peptide mapping, HPLC fractionation, and the mitigation strategies
Ben Niu, AstraZeneca

Chromatography fractionation followed by peptide mapping is a common workflow for biotherapeutics product understanding, peak ID, CQA assessment. Product integrity going through the fractionation process, however, has been overlooked thus far – notable level of artifact oxidations can be induced by the process. Additionally, in the context of trypsin assisted peptide mapping, we observed significant occurrence of non-tryptic activities, giving dramatically different product digestion profiles. We present our understandings of the cause of these artifact phenomena, and will share our proposed mitigation strategies.

Speaker Biographies:

Dwight Stoll is Professor of Chemistry at Gustavus Adolphus College in St. Peter, MN. He has authored or co-authored more than 80 peer-reviewed publications and five book chapters in separation science, and speaks internationally on the topic. He has also written the monthly “LC Troubleshooting” column for LCGC Magazine since 2017. His primary research focus is on the development of two-dimensional liquid chromatography (2D-LC) for both targeted and untargeted analyses. Within this area he has made contributions on many aspects of the technique including stationary phase characterization, biopharmaceutical analysis, new 2D-LC methodologies and instrumentation, and fundamental aspects including re-equilibration in gradient elution liquid chromatography and analyte focusing. He has taught several short courses on 2D-LC in recent years at venues including Pittcon and the international HPLC20XX series. He is the 2011 recipient of LCGC’s Emerging Leader in Chromatography Award, the 2015 recipient of the American Chemical Society Division of Analytical Chemistry Award for Young Investigators in Separation Science, and in 2017 he received the Georges Guiochon Faculty Fellowship.

Ben Niu is a Senior Scientist in BioPharmaceuticals R&D at AstraZeneca. Ben specializes in biopharmaceutical developments and CMC analytical strategies with strong focuses on mass spectrometry and related assays for method development, product and process characterizations. Ben is an innovative powerplant in the workplace and has facilitated many cross-functional, collaborative works. Ben is also a self-taught coder and programmer. In his free time, Ben likes to hike, play violin, and cook with his wife.


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