Analytical Chemistry Commons^™

Development Of Fast And Comprehensive Approaches For Gunshot Residue Interpretation Using Ambient Ionization, Mass Spectrometry, And Microparticle Sampling Studies, Thomas Dimmey Ledergerber

Graduate Theses, Dissertations, and Problem Reports (ETD)

The information derived from the forensic examination of gunshot residue (GSR) can be critical during the investigative and trial stages in the criminal justice system. However, the complexity of the GSR deposition, transfer, and persistence mechanisms calls for meticulous handling and identification processes. Novel advances in evidence interpretation and analysis via instrumental methods are current areas of growing interest that must be pushed along the chain from research to practice in a timely manner. Therefore, this research focuses on developing both rapid and comprehensive methods for detecting gunshot residue evidence and effectively communicating its significance to the investigators or trier …

Advancement Of Iterative Optimization Technology Algorithms Toward Calibration-Free Process Analytical Technology Applications, Adam Rish

Electronic Theses and Dissertations

The expansion of spectroscopic process analytical technology (PAT) tools within the pharmaceutical industry has the potential to elevate the current state-of-the-art of pharmaceutical manufacturing by offering opportunities for reduced quality testing times, enhanced process control, and greater production flexibility. Spectroscopic PAT tools are dependent on multivariate models to extract the relevant information from the spectral outputs. However, there is a substantial calibration burden for developing and maintaining these multivariate models that discourages the application of PAT, despite the encouragement from regulators. This has led to an interest in calibration-free methods such as iterative optimization technology (IOT) for spectroscopic PAT that …

Accurate Estimation Of Ethanol Content In Fruit Juices Using Cielab Color Space And Chemometrics Via Smartphone-Based Digital Image Colorimetry, Chairul Ichsan, Yasir Amrulloh, Desti Erviana

Makara Journal of Science

This study aims to investigate the optimal color space and chemometric technique for digital image colorimetry to determine ethanol content (% v/v) in apple, orange, and grape juices, using potassium dichromate (K₂Cr₂O₇) under acidic conditions. The accuracy of colorimetric–chemometric integration across various color spaces (RGB, HSV, CIELab, CMYK, CIELuv, CIEXYZ, and CIELch) was benchmarked against UV–Vis spectrophotometry using metrics such as coefficient of determination (R²), mean absolute percentage error (MAPE), and root–mean–squared error (RMSE). Various chemometric techniques (PLS, PCR, MLR, multivariable–SVR, and multivariable NN regression) were evaluated. Results demonstrate that combining the CIELab color …

Modeling Biliary Polycyclic Aromatic Hydrocarbon Metabolites In Fish Using High Performance Liquid Chromatography With Fluorescence Detection, Principal Component Analysis, And Partial Least-Squares Analysis, Joshua C. Padilla

Honors Projects

Polycyclic aromatic hydrocarbons (PAHs) constitute a diverse class of highly toxic, ubiquitous environmental pollutants, and are thus of high interest in environmental monitoring and regulation. In this study, biliary samples of English soles Parophrys vetulus and smallmouth bass Micropterus dolomieu from Seattle waterways, and chum salmon Onchorynchus keta from the north Pacific Ocean were analyzed by high performance liquid chromatography with fluorescence detection (HPLC-FLD) to gauge PAH exposure. Samples were profiled in three broad molecular weight categories, to capture naphthalene-like (NAPH), phenanthrene-like (PHEN), and benzo[a]pyrene-like (BAP) metabolites. While quantification was not achieved for the chum salmon, the semi-quantitative measurements of …

The Detection And Identification Of Blood On Interfering Substrates Using Raman Spectroscopy And Hamand For Forensic Purposes, Jalissa M. Thomas

Legacy Theses & Dissertations (2009 - 2024)

Body fluids, such as blood and semen, can provide invaluable information to a criminal investigation. As such, it is imperative that body fluid evidence is properly detected and identified. Our laboratory has developed a methodology to universally detect and identify body fluids using Raman spectroscopy and chemometrics. This methodology was developed under ideal conditions, which are rare in the field. Body fluid evidence can be found on substrates that produce a large Raman signal that can hinder detection of body fluid traces, which produce a weak signal. This project proposes the use of a statistical program called HAMAND (Hypothetical Addition …

Mass Spectral And Chemometric Analysis For The Detection And Identification Of Forensically Relevant Materials, Meghan Grace Appley

Legacy Theses & Dissertations (2009 - 2024)

Forensic science is the application of science to the law which in and of itself covers a substantial number of disciplines. Many of these involve the detection and identification of materials using analytical techniques. Traditional analysis methods include microscopy, spectroscopy and mass spectrometry. The materials encountered by forensic practitioners are ever evolving, resulting in the need to develop new methods to complement conventional techniques to enhance the evidentiary value of the samples. The research presented here shows that novel methods including direct analysis in real time–high-resolution mass spectrometry (DART-HRMS), thermal desorption coupled with gas chromatography-mass spectrometry (TD-GC-MS), solid-phase microextraction (SPME) …

Utilizing Raman Spectroscopy And Chemometrics For Novel Medical Diagnostic Purposes, Nicole M. Ralbovsky

Legacy Theses & Dissertations (2009 - 2024)

Many problems exist within the myriad of currently employed diagnostic techniques. Further, an incredibly wide variety of procedures are used to identify an even greater number of diseases which exist in the world. There is a definite unmet clinical need to improve the diagnostic capabilities of these methods, including improving test sensitivity and specificity, objectivity and definitiveness, and reducing cost and how invasive a test is, with an interest in replacing multiple diagnostic methods with one powerful tool. That is, the development of a singular technique which can accurately and objectively diagnose a wide variety of diseases in a cost-effective …

Raman Spectroscopic Examination Of Bloodstains For Forensic Purposes : Background And Race Determination, Ewelina M. Mistek

Legacy Theses & Dissertations (2009 - 2024)

Chapter 1 of this thesis critically overviews recent developments in forensic trace evidence analysis since 2016. It covers improvements to existing techniques as well as new methods for the analysis of fibers, hair, paint, glass, gunshot residue (GSR), and explosives.

Characterizing Body Fluids With Raman Spectroscopy : Towards Real World Application, Marisia Ann Fikiet

Legacy Theses & Dissertations (2009 - 2024)

This project continues the research on a new method of body fluid identification and furthers its field capabilities. This method of identification uses Raman spectroscopy and advanced chemometrics to distinguish between body fluids. It is an improvement on current methods because it is confirmatory, non-destructive, and has simple sample preparation. The first objective of this research is to create a model for differentiating body fluids for a new desktop instrument. It was determined that due to resolution differences from a research grade instrument, a new model needed to be made for this the desktop instrument. This model will be able …

Nmr Metabolomics Protocols For Drug Discovery, Fatema Bhinderwala, Robert Powers

Department of Chemistry: Faculty Publications

Drug discovery is an extremely difficult and challenging endeavor with a very high failure rate. The task of identifying a drug that is safe, selective and effective is a daunting proposition because disease biology is complex and highly variable across patients. Metabolomics enables the discovery of disease biomarkers, which provides insights into the molecular and metabolic basis of disease and may be used to assess treatment prognosis and outcome. In this regard, metabolomics has evolved to become an important component of the drug discovery process to resolve efficacy and toxicity issues, and as a tool for precision medicine. A detailed …

Designing A Calibration Set In Spectral Space For Efficient Development Of An Nir Method For Tablet Analysis, Md Anik Alam

Electronic Theses and Dissertations

Designing a calibration set is the first step in developing a spectroscopic calibration method for quantitative analysis of pharmaceutical tablets. This step is critical because successful model development depends on the suitability of the calibration data. For spectroscopic-based methods, traditional concentration based techniques for designing calibration sets are prone to have redundant information while simultaneously lacking necessary information for a successful calibration model. The traditional method also follows the same design approach for different spectroscopic techniques and different formulations, thereby lacks the optimizing capability to be technique and formulation specific.

A method for designing a calibration set in the Near …

Fast Identification Of Components Commonly Used In Homemade Explosives By Spectroscopic And Chemometric Methods, Deidre Day Vandenbos, Huggins Msimanga, Christopher Dockery

Master of Science in Chemical Sciences Theses

Homemade explosives (HMEs) have become a global pandemic. This forensic research focuses on developing identification methods that can provide quick, cost effective, non-destructive analysis using portable instrumentation. These capabilities would be invaluable to first responders, military, and security officials to establish an evidentiary link between a suspect and a reference in cases of HMEs, IEDs, arson and environmental contamination.

Modern methods for quick identification of the fuels and oxidant sources used in manufacturing HMEs, include Fourier Transform Infrared (FT-IR) and Raman spectroscopy. Visual confirmation alone, however, is not strong enough to discriminate chemicals with nearly identical spectra, which occurs when …

The Therapeutic Potential Of Natural Products From Vaccinium Berries For Viral And Lung Diseases Through An Improved Lc-Ms-Based Chemometric Approach, Vanya I. Petrova

Dissertations, Theses, and Capstone Projects

Smoking is a global epidemic that creates serious health and economic burden. It is the primary, preventative factor for the majority of causes of death worldwide. Analysis of publicly available data revealed that smoking prevalence rates among the youth in developing countries, especially in Bulgaria, are alarmingly high. The Bulgarian population has one of the highest percentages of smokers and the second highest rate among teenage girls. Consequently, chronic diseases affected by smoking, such as chronic obstructive pulmonary disorder (COPD), have been increasing there in the last five years. Poland, on the other hand, is an exemplary outlier for the …

Further Development Of Raman Spectroscopy For Body Fluid Investigation : Forensic Identification, Limit Of Detection, And Donor Characterization, Claire K. Muro

Legacy Theses & Dissertations (2009 - 2024)

The challenges to forensic body fluid analysis have placed limitations on the type of information that investigators can acquire and how that information can be collected. In recent years, Raman spectroscopy has proven itself useful for characterizing body fluids. In 2008, a large-scale investigation was undertaken to explore the use of Raman spectroscopy as a means of identifying body fluids. This work resulted in multidimensional Raman spectroscopic signatures for the five main body fluids: semen, peripheral blood, saliva, vaginal fluid, and sweat. These studies were incredibly successful and created the foundation for years of continued research. Accordingly, the studies included …

Chemometric Curve Resolution For Quantitative Liquid Chromatographic Analysis, Daniel W. Cook

Theses and Dissertations

In chemical analyses, it is crucial to distinguish between chemical species. This is often accomplished via chromatographic separations. These separations are often pushed to their limits in terms of the number of analytes that can be sufficiently resolved from one another, particularly when a quantitative analysis of these compounds is needed. Very often, complicated methods or new technology is required to provide adequate separation of samples arising from a variety of fields such as metabolomics, environmental science, food analysis, etc.

An often overlooked means for improving analysis is the use of chemometric data analysis techniques. Particularly, the use of chemometric …

Chemometric And Bioinformatic Analyses Of Cellular Biochemistry, Bradley Worley

Department of Chemistry: Dissertations, Theses, and Student Research

The amount of information collected and analyzed in biochemical and bioanalytical research has exploded over the last few decades, due in large part to the increasing availability of analytical instrumentation that yields information-rich spectra. Datasets from Nuclear Magnetic Resonance (NMR), Mass Spectrometry (MS), infrared (IR) or Raman spectroscopy may easily carry tens to hundreds of thousands of potentially correlated variables observed from only a few samples, making the application of classical statistical methods inappropriate, if not impossible. Drawing useful biochemical conclusions from these unique sources of data requires the use of specialized multivariate data handling techniques.

Unfortunately, proper implementation of …

Vibrational Spectroscopic Analysis Of Gunshot Residue : A Novel Approach For Detection And Characterization, Justin J. Bueno

Legacy Theses & Dissertations (2009 - 2024)

Due to the increasing prevalence of firearm related crimes, there is a need for an all-encompassing analytical technique which can rapidly detect and analyze trace crime scene firearm evidence. There are several forms of ballistics and trace evidence associated with firearm offenses. Historically, the most neglected piece of evidence has ironically been the most prevalent. Each firearm discharge produces a so called gunshot residue (GSR) sample, expelling dust and particles numbering from hundreds to thousands throughout the shooting environment. The detection of GSR at a crime scene or on a suspect is critical for determining what actually happened during a …

Techniques For Sensor-Integrated Robotic Systems: Raman Spectra Analysis, Image Guidance, And Kinematic Calibration, Luke Anthony Reisner

Wayne State University Dissertations

Robotics and sensor technology have made impressive advancements over the years. There are now robotic systems that help perform surgeries or explore the surface of Mars, and there are sensors that detect trace amounts of explosives or identify diseased human tissue. The most powerful systems integrate robots and sensors, which are natural complements to each other. Sensors can provide information that might otherwise be unavailable due to indirect robotic manipulation (e.g., images of the target environment), and robots can provide suitably precise positioning of an analytical sensor.

To have an effective sensor-integrated robotic system, multiple capabilities are needed in the …

Comparative Analysis Of Peak-Detection Techniques For Comprehensive Two-Dimensional Chromatography, Indu Latha, Stephen E. Reichenbach, Qingping Tao

School of Computing: Faculty Publications

Comprehensive two-dimensional gas chromatography (GC×GC) is a powerful technology for separating complex samples. The typical goal of GC×GC peak detection is to aggregate data points of analyte peaks based on their retention times and intensities. Two techniques commonly used for two-dimensional peak detection are the two-step algorithm and the watershed algorithm. A recent study [4] compared the performance of the two-step and watershed algorithms for GC×GC data with retention-time shifts in the second-column separations.In that analysis,the peak retention-time shifts were corrected while applying the two-step algorithm but the watershed algorithm was applied without shift correction. The results indicated that the …

Advanced Statistical Methods For Biochemical And Forensic Applications Of Raman Spectroscopy, Vitali Sikirzhytski

Legacy Theses & Dissertations (2009 - 2024)

This work is dedicated to the development and application of advanced statistical methods for biochemical and forensic applications of Raman spectroscopy. We developed a new concept of multidimensional Raman signatures for forensic identification of body fluid traces, which was successfully applied to the study of dried blood, semen, saliva, sweat and vaginal fluid stains. Several alternative advanced chemometric techniques were also successfully tested for the problems of pure body fluids discrimination and mixture analysis. Studies of body fluid mixtures with low blood and semen concentrations indicated that the detection limit of a minor contributor was as low as a few …

Development Of Chemometric Models And Calibration Transfer For Rapid Diesel And Jet Fuel Analysis Using Near Infrared Spectroscopy, Christopher Matthew Larkin

Chemistry & Biochemistry Theses & Dissertations

Fuel quality assurance and analysis, as it pertains to the United States armed forces, is crucial for maintaining operability and upholding safety regulations with respect to fuel class. Currently a great amount of effort, money and manpower are dedicated to this task as fuel analysis takes place in off-site laboratories where quality assessment and property determination is performed manually by highly qualified lab technicians. This presents the military with a logistics problem with respect to refueling, transport, and fuel storage as the typical tum-around time is 1-2 weeks. In this thesis it has been demonstrated that near-infrared spectroscopy, in conjunction …