Analytical Chemistry

"Analytical chemistry is the science of obtaining, processing, and communicating information about the composition and structure of matter."

American Chemical Society

Analytical sessions have been scheduled for Monday Afternoon and Tuesday Morning.

If you find any errors in our listing please let us know at chemistrybuffalogss@gmail.com

Monday Afternoon

Session 2A - Room NSC 222 - Moderator: Konstantinos Plakas

1:10 p.m. - 1:30 p.m.

Characterizing Surface Interactions Between Synthesized Thin Films and Perfluorooctanoic Acid

Abby Snyder, Joseph A. Gardella Jr.

The State University of New York at Buffalo, Department of Chemistry

Perfluorooctanoic acid (PFOA) is an emerging contaminant flagged by the EPA as a developmental disrupter and potential carcinogen in humans. With recent studies showing evidence of PFOA in drinking water across the country, the relationship between PFOA and plastics in the environment is even more important to understand. Using films of different, commonly used polymers, we determined through FTIR and ToF-SIMS analyses whether or not PFOA will sorb onto the surface of plastics in an aquatic environment. Our preliminary ToF-SIMS studies show evidence of peaks characteristic to PFOA on the surface of multiple thin films, which gives us hope for future work in quantifying the sorbing of this contaminant to not only to synthetic samples but also samples from freshwater sources, especially microplastics.

1:30 p.m. - 1:50 p.m.

Drought Metabolomics of Susceptible and Tolerant Soybean Cultivars

Kevin Zemaitis, Philip Lindhorst, Troy D. Wood

The State University of New York at Buffalo, Department of Chemistry

Water deficiency is a devastating agricultural stressor responsible for losses up to fifty percent in crops such as soybean. Plant introductions (PI) of exotic and wild cultivar with positive genetic traits for tolerance have been demonstrated to improve yields under water deficient conditions. Due to the multifaceted nature of drought stress upon the many stages of plant life, mass spectrometric exploration of the plant’s metabolome is key to understanding the positive responses exuded. Herein described is the exploration of the metabolome of a drought tolerant and susceptible cultivar of soybean, PI 567731 and Pana, respectively studied by Fourier Transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Soybeans grown at the University of Missouri (latitude 38.895305, longitude -92.205917) by Dr. Henry T. Nguyen, were collected at two physiological ages, 1 week and 2 to 3 weeks old. Drought treatment consisted of no irrigation or rainfall for 3 weeks and control conditions were within irrigated plots. The two cultivar primarily exhibited differential levels of phytochemicals and chlorophyll-a related catabolites that have been of noted in previous solvent extractions of soybean leaves in our lab. Collision induced dissociation (CID) of the multiple catabolites resulted in characteristic neutral loss of the phytyl group (C20H38; 278.29amu) along with other functional groups on the porphyrin ring. Further reinforcing an unknown connection into the porphyrin metabolism, which warrants further study. Principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) was used for non-targeted screening of all other spectral peaks, statistically significant metabolites were annotated.

1:50 p.m. - 2:10 p.m.

A New Microstrip Half-Wave Resonator for Accelerated Inline Microwave-Assisted Proteolysis

Maria Rivera, Steven J. Ray

The State University of New York at Buffalo, Department of Chemistry

Enzymatic digestion of proteins is an important step in bottom-up mass spectrometric proteomics used to generate specific peptide fragments from the larger biopolymers, which then allows identification of protein sequence. While proteolysis is a widely-used process, it does suffer some drawbacks: it is time consuming, not often amenable to coupling with chromatographic separations, prone to enzymatic autolysis, and often requires post-digestion cleaning processes which can lead to loss of analyte material. Microwave radiation (e.g. 2.45GHz) is well known in heating applications, and also widely used to accelerate a wide range of chemical reactions. The dielectric heating effect induced by microwave radiation is an efficient alternative to the thermal convection strategies. Recently, our laboratory has developed methods to exploit the unique mechanisms of microwave heating for accelerating the enzymatic digestion of proteins. Here, we introduce a microwave microstrip heating cavity designed for in-line proteolytic digestion of biological samples intended for analysis by mass spectrometry (MS). This design is advantageous because in-solution digestion can be directly sprayed from a nano electrospray tip emitter, decreasing sample loss due to handling and allowing direct characterization via MS. The experimental inline setup allows the digestion and characterization of the peptides in a more straightforward and rapid manner than the time consuming conventional protocols.

2:10 pm - 2:30 p.m.

An Analysis of the Targeted Extraction of Stercobilin from Excrement

Emily R. Sekera, Heather L. Rudolph, Troy D. Wood

The State University of New York at Buffalo, Department of Chemistry

Cases of autism spectrum disorders (ASD) are on the rise, yet at this point in time there are no clinical biomarkers for its diagnosis. Emerging evidence has shown that the microbiome of individuals with ASD can have notable differences from controls. Metabolites are the language and currency of microbial communities and therefore due to the differences seen in the microbiome, a potential metabolic biomarker may be observable in the excrement of those with ASD. In studies from our lab, the levels of stercobilin, a metabolite produced by the microbial activity in the colon, is depleted in the fecal material of a transgenic murine model of ASD (48%, p < 0.001). Also observed was the depletion of the precursor of stercobilin, stercobilinogen (51%, p=0.07). Herein, we describe the optimization of extraction procedures for stercobilin to analyze the fecal material of a prenatal immune activation model of autism in which the altered gut microbiome induces offspring exhibiting traits of ASD. We will further discuss the validity of stercobilin across multiple mouse models of autism as well as the hypothesis that the depletion of stercobilin may be affected by the microbial colonies within the microbiome. To conclude, we will discuss the translation of the methodology of extraction from fecal material to the analysis of human urine.

2:30 p.m. - 2:50 p.m.

Electrospray Ionization Zoom Time-of-Flight Mass Spectrometry

Christopher Brais, Steven J. Ray

The State University of New York at Buffalo, Department of Chemistry

Zoom time-of-flight mass spectrometry (Zoom-TOFMS) is a new, velocity-based mass separation technique that serves as a complement to conventional time-of-flight mass spectrometry (TOFMS). Zoom-TOFMS improves mass resolving power and signal-to-noise ratios for a small mass-to-charge (m/z) range by isolating and analyzing only that specific m/z range (focus window). The technique is particularly interesting because it can be easily retrofit to existing TOFMS instruments, with only a few instrument modifications required. Zoom-TOFMS employs a short electrostatic pulse to impart an equivalent momentum to all ions in constant momentum acceleration (CMA). As Zoom-TOFMS and TOFMS share the same instrument architecture, both modalities can be combined in a single instrument; the two modes of operation selected as required. For example, a complete mass spectrum can be collected in the TOFMS mode while the Zoom-TOFMS mode can be used to collect spectra over any small, targeted m/z range. Energy filtering is utilized to isolate the focus window improving measurement fidelity. Here, a commercial TOFMS has been retrofit for Zoom-TOFMS. Ion flight simulations were made using computer simulation to investigate the focusing capabilities of CMA coupled with electrospray ionization (ESI). The practical experimental capabilities of the ESI-Zoom-TOFMS are examined here and current instrument performance evaluated using several commonly studied protein standards and molecular compounds.

Tuesday Morning

Session 4A - Room NSC 222 - Moderator: Ari Darlow

9:30 a.m. - 9:50 a.m.

Using a Digital Micromirror Array for Temporal Gating and Spatial Filtering in Laser Induced Breakdown Spectroscopy and Laser Ablation Molecular Isotopic Spectrometry

Kelsey Williams, George C.-Y. Chan, Steven J. Ray

The State University of New York at Buffalo, Department of Chemistry

Laser induced breakdown spectroscopy (LIBS) and laser ablation molecular isotopic spectrometry (LAMIS) are laser-induced plasma methods for elemental and isotopic analysis, respectively. In these techniques, a laser pulse is focused onto the surface of the sample, generating a plasma and subsequent atomic emission from the elements composing the sample. It is well known that the emission from the laser-induced plasma is dominated by broadband spectral background during the first few microseconds after the laser pulse, resulting in poor signal-to-noise ratios (S/N). However, by delaying detection of emission by 1 to 10 µs after the laser pulse, the S/N of the analysis can be substantially improved. Here, we demonstrate the use of a digital micromirror array (DMMA) as a means of temporal gating and spatial integrating the detection of emission from laser plasmas. The DMMA is a MEMS device composed of over 1 million micro-scale mirrors, each capable of tilting ±12° from a flat, parked position. The DMMA is used here as a mask, allowing for light to be collected and directed towards or away from the detector after a set delay time. The operating principles and current capabilities of this new instrument will be presented.

9:50 a.m. - 10:10 a.m.

Improving Resolving Power in Distance-of-Flight Mass Spectrometry

Eric Jensen, Christopher J. Brais, Steven J. Ray

The State University of New York at Buffalo, Department of Chemistry

Distance-of-flight mass spectrometry (DOFMS) is a novel velocity-based mass separation method that is a complement to traditional time-of-flight mass spectrometry (TOFMS). Where TOFMS measures the time required for an ion to traverse a flight distance, DOFMS spatially separates ions according to m/z (mass-to-charge ratio) and measures the m/z of each ion based on the distance traveled. Here, a home-built DOFMS was used to analyze ions created by a direct current, reduced-pressure argon glow discharge. Ions are extracted into the mass spectrometer and then accelerated to a constant momentum. Ions are then passed through a linear-field reflectron and into an DOFMS detection region, where the flight distance is measured by imaging the ions on a phosphor screen. The mass resolving power attained in DOFMS is influenced by the fact that ions of the same m/z will possess a range of initial energies at the start of this experiment. If left uncorrected, differences in initial energy will lead to different flight distances, degrading mass resolving power. To overcome this problem, an ion reflectron is used to compensate for these initial ion energy differences. In this work, a new multi-stage reflectron is investigated as a means to improve energy compensation, and thus increase mass resolving power in DOFMS. Operating principles, ion optic design simulations, and the experimental performance of this new approach will be presented.

10:10 a.m. - 10:30 a.m.

Biocompatibility of Perfluoropolyether Hydroxyethyl Methacrylate Hydrogels

Lauren Lubecki, Shohini Sen-Britain, Joseph A. Gardella Jr., Wesley L. Hicks Jr.

The State University of New York at Buffalo, Department of Chemistry

Perfluoropolyether-Hydroxyethyl Methacrylate (PFPE-HEMA) Hydrogels are an up and coming drug delivery system capable of delivering proteins in a controlled manner to wound sites. Hydrogels are three-dimensional, hydrophilic, polymeric networks taking up and delivering biomolecules. The fluorocarbon layer controls the uptake and release of biomolecules. However, the potential adsorption and denaturation of these proteins of interest on this layer of these systems has been largely understudied. Bovine Serum Albumin (BSA) is widely studied as a model globular protein (66.5 kDa) and has been used to model the interaction between the hydrogel and the wound matrix. Using surface techniques, adsorption and conformational/orientational changes in BSA on each layer of the hydrogel system has been addressed.

We have utilized ATR-FTIR Spectroscopy to determine how the conformation of BSA changes in contact with the fluorocarbon side as well as the HEMA side of this dual layer hydrogel over time. Additionally, we are utilizing X-Ray Photoelectron Spectroscopy to calculate surface concentrations of BSA adsorbing on the HEMA and fluorocarbon layers over time. This information is helpful in recognizing that the fluorocarbon is inert, and will not cause a change in the protein’s secondary structure.

10:30 a.m. - 10:50 a.m.

The Use of Graphene as a Substrate for Traditional Matrices in MALDI MS

Kayla Mascaro, Troy D. Wood

The State University of New York at Buffalo, Department of Chemistry

Matrix-assisted laser desorption ionization (MALDI) imaging mass spectrometry (IMS) is a useful technique for many types of analysis including pathology and disease biomarkers, but a major limitation is the spatial resolution. In recent years, graphene, a single layer of carbon atoms, has emerged as a possible MALDI matrix capable of combating this limitation. Previous work in our group has shown that graphene has low background noise from salt adducts and matrix clusters found in typical MALDI matrices. In this study, graphene is used in imaging studies as a matrix in conjunction with traditional MALDI matrices to improve homogeneity across samples. The samples are analyzed using Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry. The co-crystallization of the matrix and analyte was significantly improved in the samples deposited on graphene. Calibration curves were also created in an attempt to use MALDI as a quantitative technique. In the future, we plan to explore the use of multiple layers of graphene as a matrix as well as alternative sources of graphene. After performing those studies, we aim to apply the information learned to use graphene with traditional MALDI matrices on tissue samples.

10:50 a.m. - 11:10 a.m.

Metallic Nanoparticle analysis by Solution-Cathode Glow Discharge

Nicholas Hazel, Steven A. Ray

The State University of New York at Buffalo, Department of Chemistry

The Solution-Cathode Glow Discharge (SCGD) is a novel, low cost plasma source that has been under investigation for several years. This source consists of a miniature glow discharge formed between a tungsten anode and a cathode consisting of solution flowing through a glass capillary.

The SCGD has previously been used for the analysis of metals in solution, brine, ores, and peptides. In this experiment, we describe the use of the discharge for the analysis of metallic nanoparticles (NPs). NPs are increasingly seen as a subject of concern as they are increasingly manufactured, used and released into the environment. Accurately determining the presence and concentration of these species is crucial due to their expected further increase in production and use. Currently, ICP is commonly used in analysis of NP solutions, thus, it would be beneficial to demonstrate that the SCGD is capable of analyzing NP samples with similar merit. In this experiment the emission intensity of Ag, CuO, Fe2O3, and Au, NP solutions were compared to emission from sample solutions containing the equivalent metal concentration in dissolved salt form. Recovery percentages for NP solutions were prepared vs concentration and NP size. It was seen that metallic nanoparticle solutions showed decreased recovery rates relative to solutions of free ion, pointing toward incomplete atomization and excitation of the dispersed nanoparticles.

11:10 a.m. - 11:30 a.m.

ToF-SIMS analysis of Polycyclic Aromatic Hydrocarbons for

Source Apportionment in the Tonawanda Coke Soil Study

Kaitlin Ordiway, Joseph A. Gardella Jr.

The State University of New York at Buffalo, Department of Chemistry

Polycyclic aromatic hydrocarbons (PAHs) are a class of compound composed of a series of fused aromatic rings. PAHs found in the environment are a result of anthropogenic pollution sources such as combustion and industrial emissions. The aromaticity stabilizes these compounds making them resistant to degradation and susceptible to local and long-range deposition. PAHs are of particular concern due to their carcinogenicity and their ability to intercalate into human DNA. PAHs have been used as indicators of specific sources of pollution. The correlation between emission source and the PAHs produced make it possible to attribute emission source based on the PAHs present in the area of interest. However, traditional source apportionment methods rely only on the EPA’s priority PAHs limiting the number of variables assessed when determining dissimilarities between source emission profiles. Many sources have sufficient energy to produce low mass PAHs, while higher mass PAHs can only be produced under specific conditions. Time of flight secondary ion mass spectrometry (ToF-SIMS) allows us to look at a high mass range in order assess the higher mass PAHs that are often excluded from traditional mass spectrometry methods. Standards of PAHs and soil sample extracts were analyzed using ToF-SIMS. Data collected will allow for the assessment of PAH pollution in the surrounding community as part of the Tonawanda Coke Soil Study.