Monday, January 16th, 2017

Meetings

January 2017 Meeting

Speaker: Alexandre Shvartsburg, Wichita State University

Topic: High-Definition FAIMS for Proteomics, Metabolomics, and Structural Characterization Using Isotopologic Shifts

Date: Monday, January 23, 2017

Time: 6:15 pm Dinner, 7:15 pm: Presentation

Location: Shimadzu Scientific Instrument, Inc. Training Center 7100 Riverwood Drive, Columbia, MD 21046 (Directions)

Dinner: Please RSVP to Katherine Fiedler (Katherine.L.Fiedler@fda.hhs.gov) before January 23 if you will be attending the dinner or are a presenting as a vendor.

Abstract: With all the power of modern MS, most biological and environmental samples require substantial prior separations. The traditional chromatography and electrophoresis are now increasingly complemented by ion mobility spectrometry (IMS) in gases. The nonlinear method of differential or field asymmetric waveform IMS (FAIMS) based on the difference between mobilities at high and low electric fields is much more orthogonal to MS than linear IMS based on absolute mobility, which enables exceptionally specific isomer separations.

We will review the prerequisites for high-resolution FAIMS/MS and its exemplary applications. A major topic in proteomics is the localization of post-translational modifications in mixtures of isomeric proteoforms (variants), where MS/MS is limited by the lack of unique fragments. Mixtures of variants up to ~6 kDa with various PTMs are effectively disentangled by FAIMS using synthetic standards and downstream ETD. All D-amino acid containing peptides (DAACP) are likewise resolved from L-analogs. A similar challenge in metabolomics is elucidating the isomeric diversity of lipids that comprises multiple isomer types including transacylation, double bond position, and cis/trans geometry. High-definition FAIMS developed in our lab generally resolves over ~80% of lipid isomers across types, and more in conjunction with OzID for double bond localization. Finally, FAIMS can resolve isotopic isomers (isotopomers) and isotopologues with peak shifts dependent on the geometry. That is conceptually parallel to NMR, enabling a fundamentally new approach to molecular structure characterization based on gas-phase isotopic shifts.

http://heartlandmassspec.weebly.com/

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Chemical Residue Workshop: call for abstracts

Date: June 23-26, 2017

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December 2016 Meeting

Speaker: Alexei Gapeev, Millis Scientific

Topic: Through the Looking Glass of Mass Spectrometry: Tales of Impurity Profiles

Date: Monday, December 19, 2016

Time: 6:15 pm Dinner, 7:15 pm: Presentation

Location: Shimadzu Scientific Instrument, Inc. Training Center 7100 Riverwood Drive, Columbia, MD 21046 (Directions)

Dinner: Please RSVP to Katherine Fiedler (Katherine.L.Fiedler@fda.hhs.gov) before November 21 if you will be attending the dinner or are a presenting as a vendor.

Abstract: Molecular archaeology constitutes a small but the most exciting segment of work we have done over the years. It aims to uncover a story an artifact may tell. Just as conventional archaeologists we sort through overburden looking for pertinent artifacts, study them at their current state, and strive to relate the present to the past.

A molecular archaeologist studies molecules, rather than tangible objects.
A contemporary LC- or GC-MS system with dynamic range spanning ten orders of magnitude is an indispensable tool to study artifacts, which are often present at trace level.

The objective of this presentation is to present the audience several case studies when we focused at impurity profiles to differentiate and source samples.

Type and origin of an explosive is one the most important questions to be addressed in a bombing investigation. We’ll explore one avenue to characterize nitramine explosives via their impurities and degradation products profile using LC-MS. This study may pave a road to development of a method to determine the manufacturing route and to estimate time of manufacture.

Assessing the likelihood of pregnancy might not sound like something relating to mass spectrometry or impurities profile. We’ll consider a situation when this indeed the case.

Oftentimes a product liability or outright consumer fraud case becomes a molecular archaeology’s poster child: A forensic scientist is asked to shine light on how an article in question was manufactured and how this relates to alleged maleficence.

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