Where
Georgia World Congress Center285 Andrew Young International Blvd NW
Room A305
Atlanta, GA 30313
Driving Directions
Taking the Top-Down Approach to Dancing Down a Quadrupole:
Quantitation of Low Abundance Intact Proteins in Biological Samples
Katarina Marakova, Ph.D.
Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX
Faculty of Pharmacy, Comenius University in Bratislava, Bratislava, Slovakia
Proteins are essential biomolecules enabling many cellular functions within biological systems. Their variable expression in biological fluids from normal levels usually correlates with the progression of various diseases. Hence, development of reliable analytical methods for their detection and quantitation in biological samples represent a key interest in biological, medical, and pharmaceutical sciences.
The vast majority of liquid chromatography – mass spectrometry quantitative protein assays, are based on bottom-up methodologies, where protein targets are digested prior to instrumental analysis. Top-down approaches, which bypass enzymatic digestion, have been primarily used for discovery and generally feature high resolution mass spectrometers.
In this talk, the practical possibilities and challenges with development of a top-down quantitative reversed-phase liquid chromatography – triple quadrupole mass spectrometry method for direct analysis of low abundance intact proteins in biological samples will be discussed. The targeted growth factor proteins (MW 5.5 – 26.5kDa; pI 4.6 – 9.9) are known to be differentially expressed in a number of disease states, including multiple cancers.
Specific nuances in optimization of both liquid chromatography and mass spectrometric detection must be addressed to reach suitable analytical figures of merit for a reliable quantitation of low abundance intact proteins in biological samples. Choosing an appropriate sample preparation strategy is also crucial. Matrix effects and the specificity of multiple reaction monitoring (MRM) transitions were assessed for different biological samples and sample preparation strategies. Additionally, a quadrupole – time-of-flight mass spectrometer was used to identify the structure of MRM product ions from the triple quadrupole experiments.Beer for Breakfast: Flavor Profiling and Quality Control of Craft Beer by LC-QTOF-MS
Tiffany Liden, Hailee Anderson, Kevin Schug
Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX USA
The brewing of beer was first documented by ancient Egyptians around 5000 B.C. The beverage, created from only a few ingredients, has a highly complex composition, which is beloved by many. The combination of phenolic and iso--acid compounds influence beer quality characteristics, such as flavor, color, and clarity. They are also key components for stability. Phenolic substances, which play a central role in brewing science and preservation of the flavor, are determined by the raw materials. Iso--acid compounds are responsible for the bitterness and the characteristic flavor of beer. A qualitative profile of broad classes of beers, including IPAs, wheats, blondes, and bocks, were analyzed using a Shimadzu LCMS-9030 quadrupole time of flight (LC-Q-TOF) system. Data dependent acquisition was performed in order to identify phenolic and iso--acid compounds using library functionality. Untargeted compounds were also investigated to further characterize flavor profiles. Different reversed phase separation modes were investigated to most comprehensively fingerprint and compare the composition of different beers.