TECHNICAL SESSIONS - NOBCCHE
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2021 NOBCChE National Conference September 18, 2021
TECHNICAL
SESSIONS
Analytical Chemistry
11:15 AM - 12:15 PM
Probing specific chemical interactions between emerging contaminants
and surface functional groups using gravimetric and solvatochromic
techniques (31)
Philomena Oluwatosin Olaniyan, Graduate Assistant, Chemistry, Ba State Universit
Emerging contaminants (ECs) such as pharmaceuticals interact with natural organic matter, soil, and
colloidal microplastic surfaces present in the aquatic environment. The fate and transport of ECs in the
environmental waters can be in uenced by their adsorption onto these chemical interfaces. The objective
of this study has been to investigate the type of speci c interactions pharmaceutical contaminants can
have with di erent functional groups that characterize these surfaces. We conducted solvatochromic and
binding studies of two widely detected pharmaceuticals - amlodipine (AMP) and carbamazepine (CBZ).
Quartz crystal microbalance (QCM), a gravimetric sensing tool has been used to investigate the kinetics
and adsorption equilibrium of these compounds from aqueous phase. We have fabricated self-assembled
monolayer of speci c functional groups- phenyl, amine, and carboxyl to study the preferential binding of
these contaminants for a particular substrate. For instance, our results reveal that AMP has a higher
proclivity for the phenyl substrate but CBZ does not. Moreover, solvatochromic studies based on UV-Vis
absorption spectroscopy indicate that AMP and CBZ do not show a linear correlation between
absorption wavenumber and polarizability. The implication is that these molecules are prone to speci c
(e.g., H-bonding, hydrophobic, pi-pi) interactions. We have examined spectrophotometric data of these
molecules in neat and binary media and employed the Kamlet-Taft analysis. These results and the Gibbs
free energy of adsorption (in the range of -35 to -45 kJ/mol) based on QCM binding studies outline the
extent of speci c interactions AMP and CBZ exhibit with chemical moieties available in the aquatic
environment. From our investigations, these compounds possess distinct surface interaction behavior
representative of their molecular structure. Hence, our ndings contribute to the understanding of fate
and transport of these ECs vital for environmental remediation
Technical Sessions Analytical Chemistry 1
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Key Words: Emerging Contaminants, Natural Organic Matter, Surface Chemistry, Quartz Crystal
Microbalance, Fate and Transport
A High-throughput and Robust Automated Plasma Proteomics
Workflow (62)
Ms. Nekesa Oliver, Research Assistant II, Department of Chemistry, Vanderbilt Universit
Bottom-up proteomics using mass spectrometry is essential in clinical applications such as biomarker
discovery and veri cation. However, it often su ers from reproducibility issues in large cohorts (N > 96)
due to numerous sample incubation and liquid transfer steps required for protein denaturation, alkylation,
digestion, chemical labeling, and sample cleanup. Automation of sample preparation on a robotic liquid
handler workstation can increase reproducibility and provide more accurate and reliable data for
comparisons of plasma samples in large cohorts. Herein, we assessed analytical gures of merit in a full
96-well plate of human plasma standards prepared with an automated proteomics work ow. Tandem mass
tagging was incorporated to generate six batches with TMT-Pro 16-plex reagents and resulting peptides
were measured using a Fusion Lumos Tribrid mass spectrometer. This presentation will cover
reproducibility of quanti cation of plasma peptides across sample wells, labeling batches, signal
intensities, dynamic range, and number of identi ed and quanti ed peptides. Overall, sample automation
is highly valuable for ensuring robust plasma proteomics in large clinical studies
Key Words: Proteomics, Mass Spectrometry, clinical, proteins
Reduced ambiguity in the analysis of spectral reaction progress
monitoring data using modified sub-space identification (87)
Dr. Sharon Neal, Associate Professor, Chemistry & Biochemistry, University of Delawar
Research and industrial interest in reaction progress monitoring is increasing due to advances such as the
success of the Process Analytical Technology Initiative in the pharmaceutical industry. The advantages of
this strategy include reduced sample disturbance and contamination and more thorough system
examination. Reaction monitoring using multichannel spectral acquisition, in which the system is
monitored at several wavelengths simultaneously, enables simultaneous analysis of multiple system
components using multivariate data analysis tools. However, there are fundamental limitations in
resolving overlapped spectra from matrix-formatted (two-way) process/reaction monitoring data.
Alternatively, monitoring using linear second-order spectral methods produces three-way reaction
progress data, which can be unambiguously resolved into component factors, in spite of spectral overlap,
if the data are of su cient quality. Unfortunately, there are few inherently second-order spectroscopic
measurements that can be collected on time scales suitable for useful reactions. Consequently, a
numerical strategy to construct three-way data sets from two-way spectral measurements would expand
the utility of this numerical strategy to a wider range of measurement and reaction types
Technical Sessions Analytical Chemistry 2
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In this report, a multiple wavelength implementation of the classical Ho-Kalman method for system
identi cation of linear time-invariant (LTI) systems is used to construct a three-way reaction progress
data set from simulated or experimental matrix-formatted (two-way) process/reaction monitoring data.
The Ho-Kalman method uses state space representations to describe the evolution of linear time
invariant systems, which include spectral signals that obey Beer’s law and exhibit rst, or pseudo- rst,
order kinetics. Method performance is evaluated using simulated and measured sensitizer
photodegradation data monitored using time-resolved, multichannel UV-Visible absorbance or
uorescence spectroscopy. Component factors are unambiguously resolved from high signal-to-noise ratio
data , but even 5% error degraded algorithm performance on overlapped components
Key Words: reaction progress monitoring, system identi cation, optical electronic spectroscopy
12:15 PM - 1:15 PM
3-Dimentional Structural Determination of Epidermal Growth Factor-
Like Repeat 27 from Mouse NOTCH1 using Nuclear Magnetic
Resonance Spectroscopy (27)
Mr. Justin Grenne , PhD Candidate, Chemistry, LS
Notch receptors have large extracellular domains containing up to 36 tandem epidermal growth factor-like
(EGF) repeats, which facilitate cell signaling by binding ligands on neighboring cells. Notch receptors play
major roles in a variety of developmental processes by controlling cell fate decisions. Each EGF repeat
consists of about 40 amino acids with 3 conserved disul de bonds. Many of the EGF repeats are modi ed
by O-linked fucose glycans, and more than half have calcium-binding sites, but the sequences of the EGF
repeats vary giving distinct roles to each repeat. EGF repeat 27 (EGF27) from mouse NOTCH1 is
modi ed with O-fucose and is 1 of 7 repeats that is di erentially modi ed by speci c Fringe enzymes,
which are known to regulate NOTCH1 activation and ligand binding. To better understand the role of
EGF27 in NOTCH1 function and regulation, the 3-dimensional structures of EGF27 and its glycoforms
are being pursued using Nuclear Magnetic Resonance (NMR) spectroscopy. Here, I report complete
backbone and side-chain resonance assignment (1H, 15N, and 13C) of the EGF27 protein, the predicted
secondary structure using the assigned chemical shifts, and preliminary 3D structure for EGF27
Key Words:
Localized cell-surface sampling using dual-functionalized beads (30)
Tammi van Neel, Research Assistant, Chemistry, University of Washingto
BACKGROUND: Chemical signals including cytokines, chemokines, and growth factors are critical
mediators in cell communication during many biological processes like the immune response. Identifying
the role of chemical signals during these biological processes can be challenging though due to their short
Technical Sessions Analytical Chemistry 3
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half-lives in signaling microenvironments. Current quanti cation methods for chemical signals relies on
bulk uid (i.e., cell culture supernatant samples) analysis using a variety of traditional (liquid
chromatography, well plate-based immunoassays, etc.) or specialized (e.g., micro uidic devices)
approaches. However, key short-lived chemical signals are often missing or markedly diminished in bulk
uid samples due to degradation, sequestration, or conversion before analysis can be performed, resulting
in an incomplete snapshot of the microenvironment.
OBJECTIVE: Our goal was to create a method which captured chemical signals before their removal
from signaling microenvironments
METHODS: We created a customizable, dual-functionalized bead-based method which enables localized
cell-surface sampling in live cell cultures by simultaneously tethering beads to a cell’s surface and collects
its cell-secreted chemical signal in real-time. On the surface of magnetic, uorescent beads are two
di erent antibodies; one antibody binds to a cell surface receptor (serving as a tether for the bead to “sit”
on the cell surface during culture) while the other antibody captures the cell-secreted chemical signal.
RESULTS: To test our beads, we captured a cell-secreted signal (hepatocyte growth factor; HGF) in situ
in the presence and absence of an added neutralizing factor (c-Met antibodies). Our method captured
similar signal levels in the two conditions while a traditional method showed a signi cant decrease with
the neutralizing factor
CONCLUSIONS: Future work will involve expanding our bead system to include di erent bead-surface
functionalization for sampling in multicellular systems (i.e., cell cultures containing two or more di erent
cell types) to easily “listen” to cellular communication without needing to modify existing protocols or
setups
Key Words: immunoassay, cell culture, method, soluble factor, sampling, cell communication
Support Effects in Boron Catalyzed Propane Oxidative
Dehydrogenation (97)
Mr. Theodore Agbi, Graduate Student Researcher, Chemical and Biological Engineering,
University of Wisconsin-Madiso
Boron based catalysts show unprecedented reactivity and selectivity for the oxidative dehydrogenation of
propane to propylene (ODH), which is a potentially energy and cost-saving process alternative for the
production of light ole ns—essential petrochemical building blocks. Bulk catalysts like hBN show
superior activity, but are less practical than supported materials, which also for new structure activity
relationships. Herein, I use isopropanol as an adsorption probe molecule to study the adsorption
mechanism of the activated oxidized boron layer, proposed to be the active phase, on supported boron
catalysts (Carbon, SiO2, SiC). Di erentiation between weakly and strongly bound surface isopropoxide
species via in situ Di use Re ectance Infrared Fourier Transform Spectroscopy (DRIFTs) o er new
insights into how boron-support interactions alter the observed activity of the catalyst surface. Further,
the product distribution from the temperature programed desorption via online MS o ers insight into
Technical Sessions Analytical Chemistry 4
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whether the boron surface exhibit redox-active or acid/base dehydration characteristics. Preliminary data
show that B/SiO2 exhibits redox products under oxidative environments and dehydration sites under
inert environments. The mechanistic switch in the presence of oxygen has prompted further investigation
and the other supported materials are currently being analyzed. Previously designed B/SiO2 were active
and it was proposed that interactions between surface silanol groups and reactive intermediates were
responsible for observed lower selectivity — although this was never formally studied. Our recently
published B/C show superior reactivity attributed to B-O-C connectivity, and although it was stable the
bare carbon supports present some impracticality under oxidative environments. Therefore, SiC is of
particular interest in this study as an informational bridge. Preliminary reactivity data show that the
activity of B/SiC catalysts can be tuned by facially tuning the support surface to enrich B-O-C
connectivity and reduce the concentration of silanol groups and the SiO2 type features, but appear to
show intermediate selectivity between B/C and B/SiO2
Key Words: Light Ole ns; Oxidative Dehydrogenation of Propane; Boron
Technical Sessions Analytical Chemistry 5
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