2008 Anachem/SAS Symposium
Abstracts for the 2008 Symposium are available
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The 2008 Anachem Symposium will be held on Wednesday, October 29th at the Burton Manor in Livonia. (see map). The preliminary program is listed below. More information about the meeting will be posted here as it becomes available Meeting registration includes the meeting sessions, instrument exhibit, workshops, lunch and a post-meeting reception.
You do not have to be an Anachem Member to attend the
Anyone wishing to present a poster should contact Patsy Coleman at
pcoleman@chem.wayne.edu. The deadline for submission of titles and abstracts
(up to a 250 words) is due Oct 3, 2008.
SYMPOSIUM PROGRAM
Exhibitors
Morning Sessions
Afternoon Sessions MORNING SESSION, 8:30 - 10:30,
ANACHEM AWARD SESSION, Room 3 8:30 AM Rapid Electrophoresis in Parallel for High Throughput Analysis Robert T. Kennedy, University of Michigan, Ann Arbor, MI 9:00 AM Title TDB, Brandon J. Aragona, University of Michigan, Ann Arbor, MI
9:30 AM Laser-Assisted Single-Molecule Refolding, David Rueda, Wayne
State University, 10:00 AM Large-scale Profiling of Specialized Metabolites using LC/TOF MS with Multiplexed Collision Induced Dissociation, A. Daniel Jones, Michigan State University, East Lansing, MI
MASS SPECTROMETRY, Room 2 8:30 AM The Binding Parameter Model: A Quantitative Elucidation of the Fundamental Interactions that Determine the Strength and Specificity of Cation-p Interactions, Nuwan Hallowita, Wayne State University, Detroit, MI 8:50 AM An Ionic Cross-Linking Reagent for Mapping Structural Interactions within Proteins and Multi-Protein Complexes, Yali Lu, Michigan State University, East Lansing, MI 9:10 AM Rapid LC/TOF MS Profiling of Biochemical Responses of Cancer Cells to Chemotherapeutic Agents, Ruth Udey, Michigan State University, East Lansing, MI 9:30 AM Mass Spectrometry Strategies to Identify Lipid Biomarkers of Diabetic Complications, Todd Lydic, Michigan State University, East Lansing, MI 9:50 AM Endogenous metabolites excreted through the skin screened by Geometry Independent Desorption Electrospray Ionization, Andre Venter, Western Michigan University, Kalamazoo, MI 10:10 AM Discovery and Rapid Quantification of a Neutral Lipid Activator of a CAR Variant using ESI and UPLC-MS/MS, Mike Stagliano, Michigan State University, East Lansing, MI
WORKSHOP Room 1 The workshop will cover thermal characterization techniques that can be used to determine material properties. Techniques to be covered include: Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Various aspects of TGA, in particular high temperature TGA, high pressure TGA, and sorption/desorption of moisture or solvents will be detailed. Generally, this technique can be used to characterize materials that exhibit weight loss or gain due to decomposition, oxidation, or dehydration. Alternately, DSC measures endothermic and exothermic transitions in a material and can be used in the identification of amorphous and crystalline materials, identification of phase transitions and changes of state, measurements of specific heat capacity, hears of fusion and reaction, oxidative/thermal stability and reaction kinetics. The details of data analysis and method development will also be covered.
Who should attend
Biography
10:30 - 11:30 AM COFFEE BREAK
PLENARY LECTURE
11:30 AM New Directions in Spectroscopy: Novel NIR Dyes
and Spectroscopy has been a fundamental component of my research since the beginning of my academic career more than 30 years ago. More recently, this research has begun to focus on the development of new dyes, many of which fluoresce in the near infrared (NIR) region of the electromagnetic spectrum. In addition, we have recently developed an approach to the preparation of novel fluorescent nanoparticles with capability for variable spectral properties. This talk will focus on discussions of these two expanding areas of my research in spectroscopy.
12:30 - 1:30 PM LUNCH EXHIBIT AREA
1:30 PM Consumer Product Testing in Today's Safety Conscious Society, Timothy Ruppel, PerkinElmer LAS
2:00 PM Testing consumer products for organic emissions using sorbent-based
technologies, 2:30 PM A Rapid Method for the Determination and Confirmation of Over 400 Pesticide Residues in Food, Stuart Oehrle, Waters Corporation
3:00 PM Determination of Melamine in Liquid Milk and Milk Powder using
Solid Phase
Voltammetric Analysis of Catechols, Katherine L. Logan, Francis Maina,
Tiffany A. Mathews* Classification of wall-coated open-tubular columns at intermediate temperatures for Gas Chromatography, Department of Chemistry, Wayne State University, Detroit, MI 48202
Practical Aspects of High Sensitivity in vivo Detection of Neuropeptides
by
Lipidome Profiling with Ion Mobility Spectrometry-Mass Spectrometry, Sarah
Trimpin1,
Chemical Identification of Gunshot Residue in Decomposing Tissue and Blowfly
IDLs and MDLs: Principles and application of confidence band calibration statistics to trace quantitative analysis, Paul R. Loconto, Michigan Department of Community Health, Bureau of Laboratories, Lansing, Michigan.
The presentation will outline developments associated with obtaining molecular weight and molecular weight distributions for macromolecular materials (i.e. synthetic and biopolymers) using GPC/SEC. Data on a wide range of new technologies (columns, detectors and software) will be presented and how they are being used to speed up data collection and analysis in traditional, high speed and online GPC/SEC analysis. The principles and practice of these new approaches will be presented and discussed.
Who Should Attend
Biography
POSTER SESSION and WINE and CHEESE RECEPTION,
Exhibit Area Development of a bio-analytical lab: Voltammetric Analysis of Catechols , Katherine L. Logan, Francis Maina, Tiffany A. Mathews*, Department of Chemistry, Wayne State University, Detroit MI 48202
Characterization of Dopamine D2/D3 Receptors in the Mouse Nucleus Accumbens
and
Modeling Metal Cation-Phosphate Interactions in Nucleic Acids in the Gas
Phase:
The Development of a New Approach to Tandem Mass Spectrometry Based Upon
Structure and sequential binding energies of Zn+(imidazole)x, x = 1-4, Ravichander Rao Peesara and M. T. Rodgers*, Department of Chemistry, Wayne State University, Detroit, MI 48202, USA IRMPD Action Spectroscopy of Sodiated and Protonated Diethyl and Triethyl Phosphate Esters, B. S. Fales1, Nathaniel O. Fujamade1, Chunhai Ruan1, J. Oomens2, and M. T. Rodgers1*, 1Department of Chemistry, Wayne State University, Detroit, MI 48202, USA, 2FOM Institut for Plasma Physics "Rijnhuizen", Nieuwegein, The Netherlands Noncovalent Interactions of Cu+ with Flavonoids (Catechol, 1,4-Benzoquinone, and Dopamine): Collision-Induced Dissociation and Theoretical Studies, Y. Nei, N. Rannulu, and M.T. Rodgers*, Department of Chemistry, Wayne State University, Detroit, MI 48202
Identification of Chemical Constituents in Salvia Divinorum using Gas
Chromatography- Mass Spectrometry, Melissa A. Bodnar1, Ruth Waddell Smith1,2,
Victoria L. McGuffin1 Testing Pre-treatment Methods for Nondestructive Radiocarbon Dating of Textiles, Deidre Hardemon, Christina Phillips, Ruth Ann Armitage, Department of Chemistry, Eastern Michigan University, Ypsilanti, MI 48197
Detection of DDT in the Environment: Water Analyses Using Solid-Phase
Extraction and Chiral HPLC/SFC Prep Purification: Robust Collection of Enantiomer Peaks Using the +/- Derivative of an Advanced Laser Polarimeter Signal, Gary W. Yanik, PDR-Chiral Inc., Lake Park, FL 33403
The Health Necessity for Tertiary Treatment of Water and Wastewater,
Pardhiva Gogineni,
Identification of Antidegradants in Rubber using Multi-functional pyrolyzer
with GC/MS
2008 ANACHEM/SAS SYMPOSIUM ABSTRACTS
Anachem Award
ANACHEM Award Session honoring Isaiah Warner:
Bioanalytical Chemistry
Rapid Electrophoresis in Parallel for High Throughput Analysis, The throughput of electrophoretic analysis has typically been improved using two main approaches. Miniaturization of electrophoresis channels allows application of high electric fields over short distances to reduce separations times to a few seconds or less. This approach has been mostly used for "sensing" applications where concentration of separated and detected substances is monitored over time. Advances in fabrication and detection technology have also allowed development of systems with parallel channels for improved throughput. This latter technology has mostly been applied to genetic analysis. We have combined rapid separations on microchips with parallel architectures (up to 48 channels) for a substantial improvement in overall throughput, up to ~17,000 assays/hour. This high throughput allows a variety of new applications. In one example, 36 individual enzymatic reactions are monitored at 10 s intervals using rapid, serial electrophoresis in parallel. This system allows, for example, optimization of enzymatic conditions or determining rate constants in a single experiment. Another application is to monitor cellular secretions from discrete tissue samples over time in parallel. We have shown the utility of a 15-channel system for monitoring insulin secretion from 15 individual islets of Langerhans. Both of these cases monitor concentration changes that are generated within sample chambers on the chip. A more difficult problem is introducing discrete samples to a chip for high-throughput analysis. We are exploring use of segmented flows, where aqueous samples are manipulated as droplets within an immiscible carrier fluid, as a method of preparing and introducing discrete samples to electrophoretic channels. Such a system would allow samples to be pumped into the chip for injection with minimal carry-over for continuous introduction and separation of discrete samples. This system may have application to high-throughput screening. Novel Neurochemical Consequences of Cocaine Intake Revealed by 'Real-time' Dopamine Measurements, Brandon J. Aragona, University of Michigan, Ann Arbor, MI A critical aspect of cocaine reward is preferential enhancement of dopamine transmission within a specific subregion of the striatum, the nucleus accumbens (NAc) shell. This effect is controversial because it is well established that cocaine acts via binding to dopamine transporters (DAT) and DAT expression is significantly lower in the NAc shell compared to other regions of the striatum. It has been suggested that this paradox may be explained by an increased number of dopamine release events within the shell following cocaine administration. However, this hypothesis cannot be confirmed using microdialysis because it measures general increases in dopamine concentration ([DA]) without resolving specific transmission processes, such as release and uptake. Here, fast-scan cyclic voltammetry (FSCV) was used to examine specific transmission processes underlying cocaine-evoked increases in dopamine transmission within the NAc core and shell. Initially, altered terminal dopamine concentrations were examined following global autoreceptor blockade that provided characterization of specific components of dopamine neurotransmission. Comparison of increased dopamine signaling evoked by autoreceptor blockade and cocaine administration allowed robust resolution between increased frequency, concentration, and duration of phasic dopamine release events following cocaine delivery. The current study provides the first evidence that cocaine causes a direct increase in the number phasic release events specifically within the NAc shell. Thus, application of electrochemical measurement technology to studies of cocaine reward allowed identification of a novel neurochemical consequence following cocaine intake that is important for understanding drug addiction. Laser-Assisted Single-Molecule Refolding, David Rueda, Wayne State University In vivo, many RNA molecules can adopt multiple conformations depending on their biological context. For example, an RNA molecule initially in a stable hairpin conformation may later interact with a second RNA molecule, thus triggering a dimerization reaction. This is the case of the HIV Dimerization Initiation Sequence (DIS) and the DsrA RNA in bacteria. It is quite common that the initial interaction between the two RNAs takes place via complementary unpaired regions, forming a so-called kissing complex. However, the exact kinetic mechanism by which the two RNA molecules reach the dimerized state is still not well understood. To investigate the refolding energy surface of RNA molecules, we have developed new technology based on the combination of single molecule spectroscopy with laser induced temperature jump kinetics, called Laser Assisted Single-molecule Refolding (LASR). LASR enables us to induce folding reactions of otherwise kinetically trapped RNAs at the single molecule level, and to characterize their folding landscape. Single molecule time trajectories show that we can drive the dimerization reaction between two trapped kissing RNA hairpins with LASR and use this data to calculate folding enthalpies and entropies. Our LASR experiments indicate that the RNA kissing complex is a stable intermediate state that facilitates the dimerization reaction. LASR provides an exciting new approach to study molecular memory effects and kinetically trapped RNAs in general. LASR is readily applicable to study DNA and protein folding as well.
Large-scale Profiling of Specialized Metabolites using LC/TOF MS with Multiplexed Collision Induced Dissociation, A. Daniel Jones, Department of Biochemistry & Molecular Biology and Department of Chemistry, Michigan State University, East Lansing, MI The plant kingdom is estimated to produce hundreds of thousands of specialized metabolites. The emergence of new approaches for controlling gene expression and establishment of an enormous number of mutant genotypes offers powerful resources for gene function discovery. Taking advantage of these resources will require large-scale quantitative screens that can discriminate plants based on cellular chemistry. Fast and high-resolution liquid chromatography/mass spectrometry (LC/MS) analyses yield accurate mass measurements with great potential to meet these needs. Our efforts in this area have employed reverse genetic screening of Arabidopsis mutants, forward genetic screens of mutants and breeding lines of tomato and its relatives, and reef-building corals collected from marine ecosystems. Initial screens are performed with short fused-core HPLC columns and multiplexing of different collision-induced dissociation of all ions during a single analysis. Over the past three years, we have used this approach to screen thousands of genetic variants and different environmental treatments to establish how genetics and environment influence metabolic variations. I will present results that demonstrate how these results are being used to guide improved plant breeding efforts, natural product discovery, and in studies of responses of reef-building corals to environmental stress.
Arranged by Ravi Amunugama, NextGen Sciences, Inc., Ann Arbor, MI, for the Michigan Mass Spectrometry Discussion Group (MMSDG) The Binding Parameter Model: A Quantitative Elucidation of the Fundamental Interactions that Determine the Strength and Specificity of Cation-p Interactions, N. Hallowita, R. Amunugama, C. Ruan, E. Udonkang, H. Huang, and M. T. Rodgers*, Department of Chemistry, Wayne State University, Detroit, MI 48202, USA Over a little more than the last decade, cation-p interactions have come to be appreciated as important noncovalent binding forces that play key roles in determining the structure and mediating the functions of many biological macromolecules. To better understand cation-p interactions and elucidate the contributions that various fundamental interactions contribute to the strength and specificity of binding, a large number of fundamental studies of cation-p interactions have been reported. In most of these studies, the structures and energetics of binding in a variety of model complexes that bind via cation-p interaction were probed by various experimental and theoretical techniques. As a result, accurate absolute bond dissociation energies (BDEs) are now available for hundreds of complexes that bind via cation-p interaction. Complementary computational estimates for the BDEs of these cation-p complexes are also available, and often at several different levels of theory. In the present work, we describe a relatively simple binding parameter model that describes the binding in cation-p complexes as being highly electrostatic in nature and as arising from contributions from ion-quadrupole, ion-dipole, and ion-induced dipole interactions. Our results indicate that this model is quite robust in that it accurately describes the binding for all of the cation-p complexes investigated to date. An advantageous sidelight of the binding parameter model is that it also provides estimates for the quadrupole moments of the p ligands studied, which in most cases cannot be experimentally determined. In addition, the estimated quadrupole moments extracted from this model for the model p ligands investigated exhibit good agreement with semi-quantitative predictions of the influence of the various substituents present on the p electron density of the aromatic ring. An Ionic Cross-Linking Reagent for Mapping Structural Interactions within Proteins and Multi-Protein Complexes, Yali Lu1, Marina Tanasova1, Babak Borhan1 and Gavin E. Reid1,2, 1Department of Chemistry, 2Department of Biochemistry and Molecular Biology. Michigan State University, East Lansing, Michigan 48824 Chemical cross-linking combined with proteolytic digestion and mass spectrometry (MS) is a promising approach to provide inter- and intramolecular distance constraints for the structural characterization of protein topologies and functional multi-protein complexes. Despite the relative straightforwardness of these methodologies, the identification and characterization of cross-linked proteins presents a significant analytical challenge, due to the complexity of the resultant peptide mixtures, as well the array of inter-, intra- or “dead-end”- cross-linked peptides that may be generated from a single cross-linking experiment. To address these issues, we describe the synthesis, characterization and initial evaluation of a novel “fixed charge” sulfonium ion containing cross-linking reagent, S-methyl 5,5’-thiodipentanoylhydroxysuccinimide. The peptide products obtained by reaction with this reagent are all shown to fragment exclusively via facile cleavage of the C-S bond directly adjacent to the fixed charge during CID-MS/MS, resulting in the formation of characteristic products ions that enable the presence and type (i.e., inter-, intra- or dead-end) of the cross-linked products to be readily determined, independently of the “proton mobility” of the precursor ion. Further dissociation of these products provides additional structural information required for identification of the peptide sequences involved in the cross-linking reactions, as well as for characterization of the specific site(s) at which cross-linking has occurred. The specificity of these gas-phase fragmentation reactions, as well as the solubility and stability of the cross-linking reagent under aqueous conditions, suggest that this strategy holds great promise for use in future studies aimed at the structural analysis of large proteins or multi-protein assemblies. Rapid LC/TOF MS Profiling of Biochemical Responses of Cancer Cells to Chemotherapeutic Agents,Ruth N. Udey1; Chrysoula Vasileiou1, Babak Borhan1, A. Daniel Jones1,2,1Department of Chemistry and 2Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI Improvements in cancer chemotherapy drugs will benefit from improved understanding of cellular responses to these agents. Advances in this area will depend upon rapid and information-rich analytical methods capable of profiling a broad range of metabolic responses. In this study, breast, prostate, and lung cancer cell lines were dosed with a novel anticancer drug, mucoxin, and several known anticancer agents. Treated and control cells were collected at multiple time points up to 7 days past dose, and metabolites were extracted with acetonitrile/2-propanol/water (3:3:2). Extracts were analyzed using a 12 minute gradient with a C18 column, negative mode electrospray ionization (ESI), and mass analysis using an LCT Premier oa-TOF mass spectrometer. Mass spectra were collected using multiplexed collision induced dissociation by rapid switching of the Aperture 1 lens potentials of 15, 30, 45, 60, and 75 V in a single analysis. Quantitative comparisons of metabolite profiles were performed using automated peak integration and alignment, Principal Components Analysis (PCA), and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA). More than 1000 signals were extracted from each dataset. Most detected metabolites were assigned as lipids based on mass defects and fragment ions. Phospholipid profiles showed noticeable differences between treated and untreated cells, as well as between mucoxin-treated and other drug-treated cells. Free fatty acids, including eicosanoids, and lysophospholipids involved in many essential biochemical signaling pathways differentiated treatments as well. Identification of biochemical pathways modulated by anticancer drugs can propel discoveries of new lead compounds that effectively treat cancer. Mass Spectrometry Strategies to Identify Lipid Biomarkers of Diabetic Complications, Todd A. Lydic1, Julia V. Busik1 , and Gavin E. Reid2,3, Department of Physiology1, Department of Chemistry2, Department of Biochemistry and Molecular Biology3, Michigan State University. East Lansing, MI, 48824. There is an increasing recognition of the important role that cellular lipids play in the regulation of normal cell function, and of the role of aberrant lipid metabolism in the onset and progression of several diseases, including diabetic complications. However, the enormous diversity of lipid structures provides a significant analytical challenge to the development of robust high throughput mass spectrometry based strategies to characterize the global lipid compositions of normal cells or tissues, or to identify and quantify the changes in lipid profiles and modification states that occur as a function of the onset and progression of disease. This presentation will describe results from our recent studies aimed at the development and application of a comprehensive ‘shotgun’ tandem mass spectrometry (MS/MS) based lipidomics approach using complementary lipid class-specific precursor ion and neutral loss scan mode experiments in a triple quadrupole mass spectrometer. The application of this approach to identify and quantify temporal changes in lipid profiles associated with the onset of diabetic retinopathy in a streptozotocin induced rat model of type 1 diabetes will be discussed. Endogenous Metabolytes Excreted through the Skin Screened by Geometry Independent Desorption Electrospray Ionization, Andre Venter #, Ayanna Jackson*, R. Graham Cooks*, # Department of Chemistry, Western Michigan University. Kalamazoo, MI 49006, * Department of Chemistry, Purdue University, West Lafayette, IN 47907. Desorption electrospray ionization (DESI), a technique that uses electrohydrodynamic nebulization of solvent to desorb and ionize samples directly from surfaces in the ambient environment is simplified by surrounding the ESI sprayer, sample-surface and MS-inlet in a small pressure tight enclosure. This variation to the standard DESI technique removes the need to re-optimize the geometry for different sample surface textures and curvatures. Geometry independent DESI (GI-DESI) allows for high throughput screening of endogenous and xenobiotic metabolytes from skin for unique, time-resolved chemical fingerprints. GI-DESI allows for stable placement of the index finger of human subjects while maintaining reproducible signal intensity. Here GI-DESI is used to determine whether individuals have unique and time-invariant chemical fingerprints and the degree to which these are diagnostic. This method will contribute towards the ultimate goal of using DESI for in-vivo analysis in medicine. Participants volunteered information on diet, supplements and pharmaceuticals taken before the analysis. For each individual, analyses were repeated in the morning and afternoon for three consecutive days. Initial analysis of the data has revealed several peaks common to all the subjects and also a number of peaks unique to specific individuals. In the negative ion mode a series of phosphorilated compounds, lipids and fatty acids were identified. The positive ion mode yielded interesting data in the m/z 100 to 400 range that will be analyzed in detail for known endogenous metabolytes, surfactants, and metabolytes of medication and supplements. Tandem mass spectrometry data was collected for the most abundant ions to aid in identification. Discovery and Rapid Quantification of a Neutral Lipid Activator of a CAR Variant using ESI and UPLC-MS/MS, Michael C. Stagliano1,2; Joshua G. DeKeyser3; Curtis J. Omiecinski3; A. Daniel Jones2,4,1Department of Chemistry, The Pennsylvania State University, University Park, PA; 2Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI; 3Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA; 4Department of Chemistry, Michigan State University, E Lansing, MI; Human constitutive androstane receptor (CAR) regulates gene expression in the liver, controlling metabolism of xenobiotics and drugs. The activity of CAR can be modulated through binding of small molecules to a ligand binding pocket, but our knowledge of the molecules capable of activating CAR remains limited. Previous experiments suggest a compound in the neutral lipid fraction of fetal bovine serum (FBS) activates a splice variant of CAR. Bioassay-directed fractionation and LC/time of flight mass spectrometry suggested a molecular formula of C24H38O4, and ion fragmentation was consistent with dioctyl phthalate or an isomer. A cell-based reporter assay was used to test two isomers, and indicated that di-2-ethylhexyl phthalate (DEHP) was active at low micromolar concentrations but di-n-octyl phthalate (DNOP) was inactive. A rapid UPLC-MS/MS method was developed for distinguishing and quantifying DEHP and DNOP in serum extracts. The method involves a binary gradient of 10 mM aqueous ammonium acetate and methanol, and enabled separation of isomeric phthalates in under 3 minutes, with total analysis time of 5 minutes/sample. The common transition from [M+H]+ (m/z 391) to the dominant fragment ion at m/z 149 was monitored. Monitoring isomer-selective transitions such as m/z 391 à m/z 279 or m/z 167 enable selective detection of DEHP. These discoveries suggest that a common plasticizer has potential to regulate xenobiotic metabolism, and provide rapid screening tools needed to establish the presence or absence of a CAR activator in biological samples.
New Directions in Spectroscopy: Novel NIR Dyes and New Nanotechnology
Directions, Spectroscopy has been a fundamental component of my research since the beginning of my academic career more than 30 years ago. More recently, this research has begun to focus on the development of new dyes, many of which fluoresce in the near infrared (NIR) region of the electromagnetic spectrum. In addition, we have recently developed an approach to the preparation of novel florescent nanoparticles with capability for variable spectral properties. This talk will focus on discussions of these two expanding areas of my research in spectroscopy.
Consumer Product Testing in Today’s Safety Conscious Society, Timothy Ruppel, PerkinElmer LAS My goal is to show you how wide spread are some of the applications in chemistry. These applications include chemicals that we, as analytical chemists, test for and that we, as inhabitants of this planet earth, are exposed during our every day lives. Topics will include:
• Pharmaceutical OVI’s Concern over organic emissions from consumer products has reached global proportions. For many pollutants, the average indoor concentration is much greater than the outdoor concentration and thus, they represent a potentially serious health hazard. Most testing protocols utilize sorbents to collect and concentrate the organic compounds of interest. The material being tested can serve as the source (e.g., automotive out-gassing within the vehicle) or the item being characterized can be placed in an environmental chamber. In both scenarios, vapors from the source pass through a sorbent. The adsorbed organic compounds are removed using either solvents or heat. This work will describe two techniques used to characterize the organic vapors emanating from an array of consumer products. In both techniques, an inert gas flows across the material being characterized. The first approach involves “packing” a known amount of material in a stainless steel or glass tube. An inert gas flows through the material and the entrained organics are then adsorbed on a suitable sorbent. The organics are thermally desorbed. They are separated, identified and quantitated using GC/MS. This technique will be used to characterize an odor detected in polystyrene. The second technique requires the use of an environmental chamber. This work utilizes a micro-chamber interfaced directly to a thermal desorption-GC/MS system. Multiple samples can be evaluated simultaneously. This system facilitates the determination of pollutants from virtually any consumer product and complements work being performed in large environmental chambers. A number of different materials normally associated with automotive interiors – carpet, leather, trim, adhesives, etc. will be examined. The relative amounts of the JAMA monitored compounds will be reported. A Rapid Method for the Determination & Confirmation of over 400 Pesticide Residues in Food, Stuart Oehrle, Waters Corporation Currently, there are over 1,000 pesticides in use and there is increasing pressure to broaden the range of pesticides determined in a single analysis over a shortened run time. Most countries have strict regulations governing pesticides with legislation that imposes Maximum Residue Limits (MRLs) for pesticide residues in food products requiring analytical techniques that are sensitive, selective and robust. Multi-residue pesticide analysis is challenging due to the low levels present, the wide variety of pesticides and the very different chemical classes they represent. Main challenges facing food safety testing laboratories today are the need to meet mandated detection limits, develop generic sample preparation techniques for complex matrices and the desire to increase sample throughput. A single multi-residue method per instrument can dramatically improve return on investment by removing the need to change method parameters. Using UltraPerformance Liquid Chromatography (UPLC™) and tandem quadropole mass spectrometry (UPLC/MS/MS), one can effectively screen for many pesticides in a single run with analysis times under 10 minutes. The Determination of Melamine in Liquid Milk and Milk Powder using Solid Phase Extraction (SPE) and Tandem Mass Spectrometry, John George, Kurt Thaxton, Varian Standard quality control tests for food products estimate protein levels by measuring the nitrogen content. Melamine is an additive that is typically used as a modifying agent for plastics, paints and coatings. Recently, there have been incidences where food manufacturers or suppliers in China have added Melamine to food or feed in order to deceive quality control analyses. The Food and Drug Administration (FDA) determined that Melamine caused widespread pet illness and/or death when illicitly added to pet food last year. Even more recently, a wave of illness among Chinese infants was attributed to Melamine-tainted infant formula. The FDA found that Melamine binds easily with isocyanuric acid to generate a crystalline polymer, which is toxic to humans. A simple, rapid, cost-effective, and robust method for melamine that is free of matrix interference is essential for quantitative analysis. An SPE cleanup with Bond Elut ™ Plexa PCX in combination with tandem mass spectrometry provides a complete solution for melamine analysis in complex matrices. Both LC/MS/MS and GC/MS/MS data is presented.
Advances in Academic
Research Voltammetric Analysis of Catechols, Katherine L. Logan, Francis Maina, Tiffany A. Mathews*, Department of Chemistry, Wayne State Univ., Detroit MI 48202 Redox reactions are important to many biological systems. The objective is to develop an upper-level chemistry lab to demonstrate how electrochemistry is being applied to detect and monitor neurochemicals. This lab focuses on measuring catecholamine neurotransmitters such as dopamine (DA), dihydroxyphenylacetic acid (DOPAC), and catechol using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and rotating disk electrode voltammetry (RDE). Catecholamines are an important class of neurotransmitters, and neuroscientists are especially interested in monitoring the neurotransmitter DA. DA is a key neurotransmitter because it involved with addiction, Parkinson’s disease, schizophrenia, and attention deficit hyperactivity (ADHD). Two commercially electrochemical instruments were used the BAS-100 electrochemical analyzer (capable of performing CV, LSV, and RDE experiments) and CH electrochemical system (capable of performing CV and LSV). Both systems used a three electrode set up which included a Ag/AgCl reference, Pt auxiliary, and working glassy carbon electrode. The potential range to observe the oxidation of DA and DOPAC was set to 100 – 1000 mV at a scan rate of 600 V/s. The oxidation potential of DA was determined to be in the range of 620 - 680 mV versus a Ag/AgCl reference electrode. DOPAC has a slightly higher oxidation potential range of 630 – 705 mV versus a Ag/AgCl reference electrode. Future experiments will characterizing the parent compound catechol and apply this system to biological samples. Classification of Wall-coated Open-tubular Columns at Intermediate Temperatures for Gas Chromatography, Sanka N. Atapattu, Colin F. Poole, Department of Chemistry, Wayne State University, Detroit, MI 48202 An iteration procedure is used to optimize the solute descriptors for 93 compounds suitable for characterizing the retention properties of open-tubular columns for gas chromatography in the intermediate temperature range of 150-250°C. These solute descriptors are used to calculate the system constants of the solvation parameter model for thirteen open-tubular columns (Rxi-17, Rtx-TNT1, Rtx-TNT2, Rxi-5Sil, SPB-Octyl, HP-5, Rtx-440, Rxi-50, Rtx-OPP, DB-1701, DB-225, HP-Innowax, and HP-88) at increments of 20°C from 160 to 240°C. The optimized descriptor values afford a two- to three-fold improvement in the fit to the retention model compared with literature values as determined by the standard deviation of the difference between the model predicted and experimental retention factors (log k). The system constants provide a breakdown of solute-stationary phase interactions in terms of the contribution to retention of cavity formation and dispersion interactions, lone-pair electron interactions of a dipole-type, and hydrogen-bonding interactions. Combining literature values for the system constants at lower temperatures (60-140°C) with those obtained here allowed system maps to be constructed for the thirteen columns over the full temperature range of 60-240°C. For a wide temperature range the system maps indicate that the relationship between the system constants and temperature is non-linear and that polar interactions are likely to be important in relative and absolute terms to quite high temperatures. Practical Aspects of High Sensitivity in vivo Detection of Neuropeptides by Microdialysis with Capillary LC Multi-stage MS, Qiang Li and Robert T. Kennedy, University of Michigan, Ann Arbor, MI The study of neuropeptides is important in understanding normal brain function, pathophysiology and pharmacology. A valuable approach to study the function of neuropeptides would be to monitor their concentration dynamics using microdialysis sampling. However, monitoring neuropeptides in vivo has been proven difficult as small volumes and low concentrations provided by sampling methods challenge the detection limit of instruments. In previous work we have demonstrated that microdialysis sampling coupled on-line to capillary liquid chromatography with multi-stage mass spectrometry (MS3) allowed detection of Met- and Leu-enkephalin in vivo. In this work, we substantially improve the method by: 1) developing conditions for off-line analysis, 2) identifying the best combinations of sampling conditions and column dimensions for enhanced sensitivity, 3) developing conditions for measuring larger neuropeptides like ?-endorphin, and 4) improving the temporal resolution possible. Off-line analysis was previously limited by rapid degradation of peptide samples after collection. We demonstrate that acidification of samples followed by freezing allows peptides, even at pM concentration, to be stored for at least 5 days without loss. For improved sensitivity, we find that low microdialysis flow rates, where recovery is close to 50%, and small column diameters (25 µm inner diameter) provides the best route to monitoring neuropeptides. Using this approach and a linear ion trap MS, we achieve LOD of 1 attomole for Leu-enkephalin and RSDs of 6%-11% for different opioid peptides. Larger peptides such as ?-endorphin could not be sensitively detected because of poorer ionization efficiency and dispersion of signal among multiple ionization states. We used quantitative trypsin digestion of the samples and monitoring of characteristic fragment peptides to improve detection limits from 5 nM to 2 pM. Finally, using a novel sample injector we are able to automatically analyze fractions collected at 5 min intervals. These improvements make in vivo neuropeptide monitoring practical and feasible for a wide variety of neuropeptides. Lipidome Profiling with Ion Mobility Spectrometry-Mass Spectrometry, Sarah Trimpin1, Bo Tan2, David E. Clemmer3, J. Michael Walker, 2 1 Department of Chemistry, Wayne State University, Detroit, MI, 48202, 2 Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, 3 Department of Chemistry, Indiana University, Bloomington, IN 47405 The localization of signaling molecules within specific brain circuits is crucial information for determining their functions. A vast literature has been devoted to determining the localization of signaling molecules in small diameter cells (SDC) within the dorsal root ganglion (DRG) that contains the cell bodies of peripheral sensory nerve fibers. SDC bodies are of particular interest because these cells evoke pain sensations when activated by noxious stimuli or under pathological conditions in chronic pain. Identifying signaling cascades unique to small caliber DRG cells offers promise for developing novel pharmacotherapies for chronic pain that lack the serious side-effects of current medicines. Despite the central role of lipids in cell signaling, analyses are extremely difficult because of low-abundance and complexity. Multidimensional ion mobility spectrometry (IMS)-MS was evaluated with respect to its capabilities to determine the structural composition of lipids as a logical separation technique to reduce complexity of ionized molecules for which LC separation is not optional. In these studies, ESI-IMS-MS provided an abundance of information that produced intricate but regular patterns when plotted in a 3-dimensional display of data (drift time vs. m/z vs. ion intensity). Thus, IMS-MS separates lipid ions in the gas phase based on their shapes prior to mass spectrometric analysis. Multiply charged lipid ions were separated into families depending on their charge states. Drift time distributions of selected ions showed multiple conformations that depend on activation energy and respective ionization (H+, Na+). These signatures provide unique fingerprints for each class of lipids previously established in MS/MS and MS3 studies. Additionally, lipids show, in contrast to for example peptides, a much increased tendency for the formation of multimers (gas phase inverted micelles). The results indicate that ESI-IMS3-MS tandem fragment ion analysis allows distinguishing between sn-1 and sn-2 positions of glyceride moieties. We also examined the usefulness of ESI-IMS for the analysis of low-abundant lipids in mixtures. Ionization-retarded PALGly and anandamide were detected in the presence of house-keeping and ionization-advanced (localized charge) lipid phosphocholine without prior sample cleanup in nmol concentration, a detection limit only readily achieved for pure lipid samples. This result is promising as it highlights the usefulness of IMS for decongestion of lipid complexity without prior solvent-based separation approaches indicating applicability for tissue imaging of low abundant lipids (signaling molecules). Overall, ESI-IMS-MS integrates powerful solvent-free gas phase separation to MS resulting in simplicity (no solvents or columns) and time-savings (no trouble shooting, sample loss to e.g. column in case of phospholipids). Chemical Identification of Gunshot Residue in Decomposing Tissue and Blowfly Larvae Samples using ICP-MS. Lisa LaGoo1, Brian Hunter2, David W. Szymanski3, and Ruth Waddell Smith1,4, 1 Forensic Science Program, Michigan State University, East Lansing MI 48824, 2 Hurley Medical Center Laboratory, Flint MI 48503, 3 Department of Geological Sciences, Michigan State University, East Lansing MI 48824, 4 Department of Chemistry, Michigan State University, East Lansing MI 48824 Fresh gunshot wounds in corpses are typically identified by visual and microscopic examination of the wound. However, in decomposed corpses, visual identification of gunshot wounds is complicated by decomposition and larval activity. In this presentation, the development of an inductively coupled plasma-mass spectrometry (ICP-MS) method for the chemical identification of gunshot residue (GSR) in decomposing tissue and larvae samples will be presented. Porcine tissue contaminated with GSR was exposed to the environment, and allowed to decompose. The study was conducted initially during early fall and then repeated in the winter months. Tissue samples were collected throughout the decomposition process resulting in sample collection periods of 37 days for the fall study and 60 days for the winter study. Larvae samples were only present during the fall study and were collected as long as present. Tissue and larvae samples were microwave digested and analyzed by ICP-MS using selected ion monitoring (SIM) for the elements considered to be characteristic of GSR: antimony, barium, and lead. Levels of the three elements were significantly greater than the detection limits of the instrument and at least one order of magnitude greater than corresponding levels in control samples. Due to the cold temperatures experienced in the winter study, decomposition did not progress to the same extent as in the fall study, despite the longer sample collection period. It was concluded that the determination of GSR in the tissue samples was more dependent on the decomposition stage rather than the time since the wound was inflicted. IDLs and MDLs: Principles and Application of Confidence Band Calibration Statistics to Trace Quantitative Analysis, Paul R. Loconto, PhD, Michigan Department of Community Health, Bureau of Laboratories, Lansing, Michigan. The fundamental statistical flaw inherent in continuing to apply blank statistics to estimate detection limits in trace quantitative analysis will first be introduced. The key mathematical equations used in confidence band calibration statistics to estimate instrument (IDL) and method (MDL) detection limits will then be presented. Application to AA, ICP-MS and GC-MS data drawn from our laboratory using confidence band calibration statistics to estimate IDLs and MDLs will be presented. Development of a Bio-analytical Lab: Voltammetric Analysis of Catechols, Katherine L. Logan, Francis Maina, Tiffany A. Mathews*, Department of Chemistry, Wayne State University, Detroit MI 48202 A growing area of electrochemistry is measuring chemical messengers, neurotransmitters like dopamine (DA) and its metabolite 3,4-dihydroxyphenethylacetic acid (DOPAC). To introduce upper-level chemistry students to electrochemistry and neuroscience, a lab is being developed to measure DA and DOPAC using various voltammetric techniques such as cyclic voltammetry (CV), linear sweep voltammetry (LSV), and rotating disk electrode voltammetry (RDE). These important electrochemical methods demonstrate the similarities and differences of voltammetric analysis. Two commercially electrochemical instruments were used the BAS-100 electrochemical analyzer (capable of performing CV and RDE experiments) and CH electrochemical system (capable of performing CV and LSV). Both systems used a three electrode set up which included a Ag/AgCl reference, Pt auxiliary, and working glassy carbon electrode. The potential range to observe the oxidation of DA and DOPAC was 100 – 1000 mV at a scan rate of 600 V/s. Using the BAS-100 electochemical analyzer, the oxidation potential of DA was determined to be 760 ± 6 mV; using CV and 702 ± 4 mV; using RDE. The CH instrument oxidizes DA at 621 ± 5 mV; using CV and 628 ± 2 mV using LSV. The oxidation potential of DA was determined to be 625 ± 7 mV using CV and 694 mV ± 3 using LSV on the CH instrument. The BAS-100 electrochemical analyzer showed DOPAC oxidizing at 706 ± 6 mV (CV) and 693 mV ± 13 (RDE). Future experiments will characterizing the parent compound catechol and apply this system to biological samples. Characterization of Dopamine D2/D3 Receptors in the Mouse Nucleus Accumbens and Caudate-Putamen using Fast Scan Cyclic Voltammetry, Francis K. Maina and Tiffany A. Mathews, Department of Chemistry, Wayne State University, Detroit MI 48202 The actions of dopamine (DA) are mediated by five receptor subtypes that can be grouped into two sub-families, D1-like and D2-like. The D2-like family is known to control DA release and is composed of D2, D3 and D4 receptors. The DA D2 and D3 receptors have a fairly restricted pattern of expression in the mammalian brain; specifically the localization of DA D3 receptors in the nucleus accumbens (NAc). Using fast scan cyclic voltammetry (FSCV), we are investigating the ability to measure activity of release-regulating DA D2 and D3 autoreceptors in the NAc and caudate-putamen (CPu). The carbon fiber microelectrode, with a diameter of 7 microns, allows for high spatial resolution to discriminate between these brain regions. FSCV was used to detect stimulated DA release in 400 µm-thick coronal mouse slice containing the NAc and CPu. Increasing concentrations of DA D2 receptor agonist, quinpirole or the DA D3 receptor agonist (+)-PD128907 were added to slices at 30-minute intervals. Preliminary studies using these agonists show a significant difference in the DA D2/D3 EC50 for the CPu and NAc regions. The D2/D3 antagonist sulpiride or nafadotride was able to reverse the effects of the DA D2/D3 receptor agonists. This is the first study to use voltammetry to characterize D2/D3 receptors in the CPu and NAc of mice. Modeling Metal Cation-Phosphate Interactions in Nucleic Acids in the Gas Phase: Activated Dissociation of Triethyl phosphate by Mg+, Al+, Cu+, and Zn+ Chunhai Ruan, M. T. Rodgers*, Department of Chemistry, Wayne State University, Detroit, MI, 48202 Metal ion-nucleic acid interactions are currently of great interest because metal ions and metal-ligand complexes bind to DNA and regulate gene expression, act as drugs, or can be used as tools for molecular biology studies. In the present work, binding affinities and activation of metal cationized phosphate esters are studied. Experimental cross sections are obtained for the CID of M+(PE) complexes, where M+ = Li+, Na+, K+, Rb+, Cs+, Mg+, Al+, Cu+, and Zn+, and PE = trimethyl phosphate (TMP) and triethyl phosphate (TEP), in a guided ion beam tandem mass spectrometer (GIBMS). Simulated annealing and density functional theory at the B3LYP/6-311+G(2d,2p)//B3LYP/6-31G* level of theory are used to determine the structures and energetics for the neutral TEP, M+(TEP) complexes, transition state, and dissociation products. The primary and lowest energy pathway of alkali metal cationized complexes except Li+(TEP) corresponds to loss of intact PE, thereby producing the bare metal ion. No activated dissociation is observed in these complexes as the result of weaker binding of the alkali metal ion to TEP. For M+(TEP) complexes, where M+ = Mg+, Al+, Cu+, and Zn+, activated dissociation resulting in loss of C2H4 corresponds to the primary and lowest energy pathway for all the systems. Sequential loss of additional C2H4 molecules is also observed at elevated energies. Endothermic loss of the intact TEP ligand is also observed at elevated energies for these complexes. Two pathways were found for elimination of one ethane from the complex: TS4M and TS6M. TS6M is found the low energy pathway for all 4 systems. The agreement between theory and experiment for AEs and M+-TEP BDEs is good for all systems. The influence of orbital occupations on the binding and activation ability of these metal cations to eliminate one ethene from TEP is studied. The binding of metal cations to TEP is compared to that of nucleic acid bases. The Development of a New Approach to Tandem Mass Spectrometry Based Upon the Emerging Technology of Electrostatic Traps, Vasiliy Goncharov, Yu Chen, Mary T. Rodgers,* and A.G.Suits, Department of Chesmitry, Wayne State University, Detroit, MI Tandem mass spectrometry (MS) is an important tool for biological research, particularly given the growth and importance of proteomics studies. Here we present progress toward a new approach to tandem MS based upon the emerging technology of electrostatic ion traps to exploit alternative non-ergodic fragmentation methods. Such electrostatic ion traps in many respects may be viewed as two reflectrons coupled together, in which the ions behave much like photons in an optical resonator. Ions of different mass-to-charge propagate at different frequencies inside the trap, and a ring pick-up electrode is used to monitor the ions on each pass with single ion sensitivity. A Fourier transform of the pickup electrode signal yields the oscillation frequency, which maybe converted to ion mass-to-charge ratio and thus provide a mass spectrum. Alternatively, the ions can be extracted from the trap and detected via time-of-flight MS techniques. The overall efficiency of such an electrostatic ion trap is mass independent, capable of achieving resolution in excess of 104. As with time-of-flight analyses, the turn-around region for the ion trap provides an ideal environment for ion activation. Coupling of the two electrostatic ion traps, one for multiply-charged positive ions derived from electrospray ionization (ESI) and the second for electrons or anions can be used to perform electron capture dissociation (ECD) or electron transfer dissociation (ETD). A second, largely unexplored non-ergodic alternative is vacuum ultraviolet (VUV) laser photo-fragmentation. This instrumentation will afford key advantages in many important biological, and in particular, proteomics applications. Structure and Sequential Binding Energies of Zn+(imidazole)x, x = 1-4, Ravichander Rao Peesara and Dr. M. T. Rodgers*, Department of Chemistry, Wayne state university, Detroit, MI 48202, USA The imidazole moiety of the side chain of histidine serves as a ligand to several metal ions associated with a broad class of proteins and enzymes. Histidine exerts several of its biological actions via interaction with metal ions, and in particular Zinc. The active sites of most zinc containing metalloproteins and metalloenzymes generally involve interaction with multiple imidazolic rings of histidine residues, thereby providing the driving force for the current study. Threshold collision-induced dissociation of Zn+(imidazole)x, where x = 1-4 with xenon is studied using guided ion beam mass spectrometry. Density functional theory calculations were performed in order to obtain model structures, vibrational frequencies, rotational constants and enegetics for the neutral imidazole ligand and Zn+(imidazole)x complexes. Geometry optimizations and frequency analyses of the optimized structures were performed at the B3LYP/6-31G* level. Single point energy calculations were performed at the B3LYP/6-311+G(2d,2p) level using the B3LYP/6-31G* optimized geometries. Zero-point energy (ZPE) and basis set superposition error (BSSE) corrections were included in the calculated BDEs. Comparisons are made to the analogous Cu+(imidazole)x complexes to assess the influence of the electronic structure of the metal ion on the binding (Cu+ d10 vs Zn+ s1d10). IRMPD Action Spectroscopy of Sodiated and Protonated Diethyl and Triethyl Phosphate Esters, B. S. Fales1, Nathaniel O. Fujamade1, Chunhai Ruan1, J. Oomens2, and M. T. Rodgers1, *1Department of Chemistry, Wayne State University, Detroit, MI 48202, USA, 2FOM Institut for Plasma Physics “Rijnhuizen”, Nieuwegein, The Netherlands In an attempt to better understand the structural and energetic effects of cation binding to the phosphate backbone of nucleic acids, interactions between sodium cations and protons with several model phosphate esters were examined both theoretically and experimentally. Both sodiated and protonated complexes of diethyl phosphate (DEP) and triethyl phosphate (TEP) generated via electrospray ionization were examined. The structures of these complexes were probed experimentally by infrared multiphoton dissociation action (IRMPD) spectroscopy, carried out in a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) that was coupled to a free electron laser (FEL). Experimental IRMPD action spectra obtained for each system were compared to theoretical IR spectra determined at the B3LYP/6-31G* level of theory. Excellent correlation between the ground state structures predicted for these systems and the measured IRMPD action spectra was found. In some cases the measured spectra exhibit evidence for multiple structures contributing to the ion populations generated under the experimental conditions employed. In all cases the theoretical calculations predict that the sodium binds to these phosphate esters via a bidentate interaction. In contrast, protons always bind in a monodentate fashion, a result of the small atomic radius of the proton. While the experimental measurements are limited to ionized species, the computations are not. Comparison of the spectra computed for these ionic complexes as well as their neutral counterparts provides additional information which should allow more accurate prediction of the structural consequences of cation binding under a variety of cellular conditions. Noncovalent Interactions of Cu+ with Flavonoids (Catechol, 1,4-Benzoquinone, and Dopamine): Collision-Induced Dissociation and Theoretical Studies, Y. Nei, N. Rannulu, and M.T. Rodgers*, Department of Chemistry, Wayne State University, Detroit, MI 48202 Flavonoids are a group of naturally occurring polyphenolic compounds that exhibit many beneficial effects on human health. Many of the beneficial effects of flavonoids have been studied and reported to be related to their interaction with several enyzymes, ability to scavenge free radicals (antioxidants), and most importantly their ligation with metal ions to prevent them from participating in the Fenton and Harber-Weiss cycles to generate superoxide. In the present study, we investigate the interaction between Cu+ and several flavonoids including: catechol, 1,4-benzoquinone, and dopamine by examining the collision-induced dissociation behavior of complexes of Cu+ bound to one or more flavonoid molecules. The cross section thresholds are analyzed to extract bond dissociation energies of these complexes. The experimental data is enhanced and supported by theoretical electronic structure calculations. High-level theoretical electronic structure calculations are performed to determine the structures of the complexes studied and their dissociation products, as well as to provide the molecular constants (vibrational frequencies and rotational constants) necessary for the thermochemical analysis of the experimental data. Comparison in the binding of these metal-ligand complexes with changes in ligand bound and the extent of ligation are examined. Identification of Chemical Constituents in Salvia Divinorum using Gas Chromatography- Mass Spectrometry, Melissa A. Bodnar1, Ruth Waddell Smith1,2, Victoria L. McGuffin1,1. Department of Chemistry, Michigan State University, East Lansing, MI 48824, 2. Forensic Science Program, School of Criminal Justice, Michigan State University, East Lansing, MI 48824 Salvia divinorum is a perennial herb whose active component, salvinorin A, is considered to be the most potent naturally occurring hallucinogen known. Among the known salvinorins and divinatorins that have been isolated in S. divinorum, only salvinorin A is known to bind to the kappa opioid receptor (KOR). The US Drug Enforcement Administration has listed S. divinorum under Drugs and Chemicals of Concern; however, the herb has not yet been federally regulated. Currently, twelve states have banned S. divinorum and nineteen others have proposed legislation against its possession. In the event S. divinorum is controlled nationwide, a validated method will be necessary not only for the forensic identification of the controlled substance, salvinorin A, but also for discrimination of S. divinorum from other Salvia species. Soxhlet extractions of dried S. divinorum leaves (obtained from Frivolity Kingdom, in Jackson, Michigan) were performed in methanol, acetone, hexane and dichloromethane. The extracts were analyzed in triplicate by gas chromatography-mass spectrometry (GC-MS). The chemical constituents found in the extracts, particularly the known salvinorins and divinatorins, were identified and comparisons of the constituents found in each of the extracts was performed. The results of this preliminary study will be used to investigate additional Salvia samples including S. officinalis, S. splendens, S. nemorosa, S. guarantica and two S. divinorum samples differing in origin for the purpose of developing an optimized method for the forensic identification of S. divinorum. Testing Pre-treatment Methods for Nondestructive Radiocarbon Dating of Textiles, Deidre Hardemon, Christina Phillips, Ruth Ann Armitage, Department of Chemistry, Eastern Michigan University, Ypsilanti, MI 48197 The purpose of this study was to determine which method for removing contamination would be the appropriate for nondestructive radiocarbon dating of protein- and cellulose-based textile samples. We carried out thermally-assisted hydrolysis/methylation GC-MS on samples of wool, silk, cotton and linen, which had been buried in soil to simulate the archaeological environment. To determine the best pre-treatment method, portions of the buried material were treated with the standard acid-base-acid wash, a new pH 8 phosphate buffer, and water as the control. It is important for the samples to be clean and free of organic material from soil, as the soil would contribute to the measured radiocarbon age. Based on the results, we concluded that while the ABA pre-treatment method was best at removing soil organic matter from the textiles, there was extensive damage to the samples after the treatment. In contrast, the phosphate buffer preserved the samples; however, the removal of soil organics was not complete. Detection of DDT in the Environment: Water Analyses Using Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry, Caitlin Van De Car and Ruth Ann Armitage, Department of Chemistry, Eastern Michigan University, Ypsilanti, MI 48197 The purpose of this project was to evaluate the efficiency of environmental analyses in an undergraduate analytical chemistry classroom. In winter 2008, students in the NSF-funded Creative Scientific Inquiry Experience Quantitative Analysis course analyzed local water samples for trace quantities of DDT and its metabolites using solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS). Unfortunately, the results were inconclusive as no DDT or its metabolites were detected in the samples, even using selected ion monitoring. One of the themes of the course was how human activity in the past can still be detected in the modern environment. This project carried on the work from the course, attempting to develop a classroom-appropriate method that would introduce students to using GC-MS to measure residues of this long-banned pesticide. Chiral HPLC/SFC Prep Purification: Robust Collection of Enantiomer Peaks Using the +/- Derivative of an Advanced Laser Polarimeter Signal, Gary W. Yanik, PDR-Chiral Inc., 1331A South Killian Drive, Lake Park, Florida, 33403 Prep peak collection using the +/- derivative of an Advanced Laser Polarimeter (ALP) signal is a very convenient and robust way to purify chiral racemates. It is convenient because only the injection volume, cycle time and number of injections are required as input for a typical chiral prep collection job. It is robust because retention time, elution order and loading can change but collection is always correct – the positive peak always goes to the positive enantiomer collection port and the negative peak always goes to the negative enantiomer collection port. ALPs respond only to optical activity (no chromophore required) with no absorbance effects and no anomalies resulting in a very large linear dynamic range and a very definitive and clean signal for collection control. It helps to eliminate problems with impurity peaks in prep peak collection. This technique makes chiral prep collection fully automated. The Health Necessity for Tertiary Treatment of Water and Wastewater, Pardhiva Gogineni, Detroit River Remedial Action Council, Somerset Blvd, Apt # 106, Troy, MI 48084 The health necessity for tertiary treatment of water and wastewater is to remove organics and toxic substances from incoming and outgoing water. Surface waters contain a myriad of organics, which get halogenated in the disinfection process. Wastewater contains pharmaceutical compounds and their derivatives in addition to other organic compounds. The best treatment is activated carbon filtration. Various other filtration systems have been used. Irradiation Studies of Nickel Ethylenediaminetetraacetic acid Complexes in the presence of Titanium Dioxide, Jonathan Shafer, Cleo Vidican, Emily Rames, Katherine C Lanigan* Department of Chemistry and Biochemistry, University of Detroit Mercy, Detroit, MI 48221 Ethylenediaminetetraacetic acid (EDTA) is the most widely produced chelating ligand in the world, with uses in many types of industrial and consumer products, medical treatments, and metal waste remediation. EDTA is also a recalcitrant chemical and as a result can be found at potentially harmful concentrations in rivers and lakes. The potential problem with EDTA is its ability to mobilize metals from sediments and aquifers, alter speciation of metals, and influence metal bioavailability. The goal of this research is to identify the photo-degrative pathway of EDTA when complexed with nickel and adsorbed to titanium dioxide particles. It is proposed that the general mechanism of degradation is through photocatalytic oxidation (PCO). Ultraviolet/visible absorption spectroscopy is for identification of the nickel-EDTA complex and products of irradiation experiments. Experiments include pH dependence, substitution of titanium dioxide with a similar product called Adsorbsiaä, and use of the Nash reagent for identification of products of irradiation.
Identification of Antidegradants in Rubber using Multi-functional pyrolyzer
with GC/MS, dants incorporated in various rubber formulations have a variable role in improving the physical and/or chemical characteristics of the rubber. When analyzing these additives, solvent extraction and/or column chromatography methods are normally used. These methods are often complicated, consume large volumes of solvent and adversely effect data quality; consequently, there is considerable interest in a more rapid and convenient analytical method. Thermal Desorption-GC/MS (TD-GC/MS) can be used for the rapid and convenient analysis of additives. No sample pretreatment is necessary. However, concern about thermal decomposition of the antidegradants limited the wide spread use of TD-GC/MS. This work reports our findings with regard to thermal decomposition during the thermal desorption process. This work also underscores the value of a using a library specifically designed for the identification of compounds commonly employed as polymer additives. Conventional mass spectra libraries, such as Willy and NIST, are not useful for the qualitative analysis of the additives in rubber, because they do not contain sufficient numbers of those additives commonly used when formulating rubber. The mass spectra of 32 antidegradants commonly used in rubber formulation were obtained using TD-GC/MS. The spectra were incorporated into a “rubber antidegradants” library. In every instance both the main constituents and the degradation products were observed in the total ion chromatograms. The viability of the new “rubber antidegradants” library was used by analyzing several typical rubber formulations via TD-GC/MS. The results of this study clearly show the value of an additive library when analyzing “unknown” polymeric samples.
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