Candice Mae Bridge | |
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Alma mater | University of Central Florida Howard University |
Scientific career | |
Institutions | United States Army Howard University University of Central Florida |
Thesis | Discrimination of forensic trace evidence using laser induced breakdown spectroscopy (2007) |
Candice Mae Bridge is an American chemist and Associate Professor of Chemistry and Forensic Science at the University of Central Florida. [1] Her research considers the development of mass spectroscopy for forensic analysis, including the characterization of lubricant from rape victims and residue from gunshots, as well as the identification of drugs in urine samples.
Bridge is from Brooklyn, New York. [2] She was encouraged by her high school guidance counselor to study chemistry at university. [3] Bridge earned her bachelor's degree in chemistry and applied mathematics at Howard University, where she worked in the laboratory of Folahan Ayorinde. She moved to the University of Central Florida for her graduate studies, where she worked alongside Michael Sigman on the development of laser-induced breakdown spectroscopy (LIBS) for forensic analysis. Before the work of Bridge, forensic analysis was conducted using scanning electron microscopy energy-dispersive X-ray spectroscopy (EDX), which is a time consuming analytical tool that is impractical for high throughout analysis. [4] On the other hand, LIBS offers the opportunity for elemental analysis based on the emissions of the ionic, atomic and diatomic molecular components. [4] As part of her doctoral research, Bridge developed statistical methods that allowed analysis of known and unknown samples. She was one of the first people with a doctoral degree in forensic science in the United States. [5] After earning her doctorate, Bridge remained at the University of Central Florida College of Optics and Photonics where she continued to study LIBS and developed sophisticated analytical techniques. In 2008 Bridge joined Howard University as a lecturer of chemistry, and was voted Professor of the Year. [6]
After a year at Howard University, Bridge joined the United States Army Defense Forensic Science Center (DFSC) (formerly known as the U.S. Army Criminal Investigation Laboratory [7] ). She held various positions at the DFSC and was responsible for the examination of trace evidence. She originally worked in Atlanta, Georgia, where she performed forensic investigations into fire debris. [8] She was eventually promoted to the Office of the Chief Scientist, where she oversaw human research projects. [8]
In 2014 Bridge was appointed an Assistant Professor at the University of Central Florida, where she is also part of the National Center for Forensic Science. [9] She was the only Black tenure-track faculty member in the UCF Department of Chemistry. [2] At UCF she developed mass spectrometry, gas chromatography and fourier-transform infrared spectroscopy for use in sexual assault investigations. Bridge proposed that forensic scientists should investigate the lubricant and cosmetic particles left behind at the scene of a crime. [10] In particular, she studies the evidence that is left behind on condoms. [2] In 2016 she was awarded a research grant from the National Institute of Justice to study rape investigation methods in collaboration with the Federal Bureau of Investigation. [5] [11] To assist with rape investigations, Bridge developed the Sexual Lubricant Database, a compilation of data on the identifying characteristics and chemical composition of sexual lubricants. This database allows forensic scientists to analyze the ingredients found in sexual lubricants to identify their molecular signatures specific to certain brands and formulations. These unique elements allow investigators of sexual assaults to potentially identify lubricant evidence left at a crime scene and narrow the suspect pool to individuals who have that product or connect the crimes of a serial offender. For example, a lubricant that contains pulegone will give the product a raspberry scent, allowing investigators to associate trace evidence from a crime scene that smells like raspberries to a specific lubricant. [2] [12]
Analytical chemistry studies and uses instruments and methods to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Separation isolates analytes. Qualitative analysis identifies analytes, while quantitative analysis determines the numerical amount or concentration.
Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum.
Gold fingerprinting is a method of identifying an item made of gold based on the impurities or trace elements it contains.
Forensic toxicology is a multidisciplinary field that combines the principles of toxicology with expertise in disciplines such as analytical chemistry, pharmacology and clinical chemistry to aid medical or legal investigation of death, poisoning, and drug use. The paramount focus for forensic toxicology is not the legal implications of the toxicological investigation or the methodologies employed, but rather the acquisition and accurate interpretation of results. Toxicological analyses can encompass a wide array of samples. In the course of an investigation, a forensic toxicologist must consider the context of an investigation, in particular any physical symptoms recorded, and any evidence collected at a crime scene that may narrow the search, such as pill bottles, powders, trace residue, and any available chemicals. Armed with this contextual information and samples to examine, the forensic toxicologist is tasked with identifying the specific toxic substances present, quantifying their concentrations, and assessing their likely impact on the individual involved.
Laser-induced breakdown spectroscopy (LIBS) is a type of atomic emission spectroscopy which uses a highly energetic laser pulse as the excitation source. The laser is focused to form a plasma, which atomizes and excites samples. The formation of the plasma only begins when the focused laser achieves a certain threshold for optical breakdown, which generally depends on the environment and the target material.
Laser ablation or photoablation is the process of removing material from a solid surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates. At high laser flux, the material is typically converted to a plasma. Usually, laser ablation refers to removing material with a pulsed laser, but it is possible to ablate material with a continuous wave laser beam if the laser intensity is high enough. While relatively long laser pulses can heat and thermally alter or damage the processed material, ultrashort laser pulses cause only minimal material damage during processing due to the ultrashort light-matter interaction and are therefore also suitable for micromaterial processing. Excimer lasers of deep ultra-violet light are mainly used in photoablation; the wavelength of laser used in photoablation is approximately 200 nm.
Forensic chemistry is the application of chemistry and its subfield, forensic toxicology, in a legal setting. A forensic chemist can assist in the identification of unknown materials found at a crime scene. Specialists in this field have a wide array of methods and instruments to help identify unknown substances. These include high-performance liquid chromatography, gas chromatography-mass spectrometry, atomic absorption spectroscopy, Fourier transform infrared spectroscopy, and thin layer chromatography. The range of different methods is important due to the destructive nature of some instruments and the number of possible unknown substances that can be found at a scene. Forensic chemists prefer using nondestructive methods first, to preserve evidence and to determine which destructive methods will produce the best results.
Infrared multiple photon dissociation (IRMPD) is a technique used in mass spectrometry to fragment molecules in the gas phase usually for structural analysis of the original (parent) molecule.
Richard Neil Zare is the Marguerite Blake Wilbur Professor in Natural Science and a Professor of Chemistry at Stanford University. Throughout his career, Zare has made a considerable impact in physical chemistry and analytical chemistry, particularly through the development of laser-induced fluorescence (LIF) and the study of chemical reactions at the molecular and nanoscale level. LIF is an extremely sensitive technique with applications ranging from analytical chemistry and molecular biology to astrophysics. One of its applications was the sequencing of the human genome.
Matrix-assisted laser desorption electrospray ionization (MALDESI) was first introduced in 2006 as a novel ambient ionization technique which combines the benefits of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). An infrared (IR) or ultraviolet (UV) laser can be utilized in MALDESI to resonantly excite an endogenous or exogenous matrix. The term 'matrix' refers to any molecule that is present in large excess and absorbs the energy of the laser, thus facilitating desorption of analyte molecules. The original MALDESI design was implemented using common organic matrices, similar to those used in MALDI, along with a UV laser. The current MALDESI source employs endogenous water or a thin layer of exogenously deposited ice as the energy-absorbing matrix where O-H symmetric and asymmetric stretching bonds are resonantly excited by a mid-IR laser.
Desorption atmospheric pressure photoionization (DAPPI) is an ambient ionization technique for mass spectrometry that uses hot solvent vapor for desorption in conjunction with photoionization. Ambient Ionization techniques allow for direct analysis of samples without pretreatment. The direct analysis technique, such as DAPPI, eliminates the extraction steps seen in most nontraditional samples. DAPPI can be used to analyze bulkier samples, such as, tablets, powders, resins, plants, and tissues. The first step of this technique utilizes a jet of hot solvent vapor. The hot jet thermally desorbs the sample from a surface. The vaporized sample is then ionized by the vacuum ultraviolet light and consequently sampled into a mass spectrometer. DAPPI can detect a range of both polar and non-polar compounds, but is most sensitive when analyzing neutral or non-polar compounds. This technique also offers a selective and soft ionization for highly conjugated compounds.
Instrumental analysis is a field of analytical chemistry that investigates analytes using scientific instruments.
The Federation of Analytical Chemistry and Spectroscopy Societies or FACSS is a scientific society incorporated on June 28, 1972, with the goal of promoting research and education in analytical chemistry. The organization combined the many smaller meetings of the individual societies into an annual meeting that includes all of analytical chemistry. The meetings are intended to provide a forum for scientists to address the development of analytical chemistry, chromatography, and spectroscopy.
Surface-assisted laser desorption/ionization (SALDI) is a soft laser desorption technique used for mass spectrometry analysis of biomolecules, polymers, and small organic molecules. In its first embodiment Koichi Tanaka used a cobalt/glycerol liquid matrix and subsequent applications included a graphite/glycerol liquid matrix as well as a solid surface of porous silicon. The porous silicon represents the first matrix-free SALDI surface analysis allowing for facile detection of intact molecular ions, these porous silicon surfaces also facilitated the analysis of small molecules at the yoctomole level. At present laser desorption/ionization methods using other inorganic matrices such as nanomaterials are often regarded as SALDI variants. As an example, silicon nanowires as well as Titania nanotube arrays (NTA) have been used as substrates to detect small molecules. SALDI is used to detect proteins and protein-protein complexes. A related method named "ambient SALDI" - which is a combination of conventional SALDI with ambient mass spectrometry incorporating the direct analysis real time (DART) ion source has also been demonstrated. SALDI is considered one of the most important techniques in MS and has many applications.
Chemistry and Camera complex (ChemCam) is a suite of remote sensing instruments on Mars for the Curiosity rover. As the name implies, ChemCam is actually two different instruments combined as one: a laser-induced breakdown spectroscopy (LIBS) and a Remote Micro Imager (RMI) telescope. The purpose of the LIBS instrument is to provide elemental compositions of rock and soil, while the RMI will give ChemCam scientists high-resolution images of the sampling areas of the rocks and soil that LIBS targets. The LIBS instrument can target a rock or soil sample from up to 7 m (23 ft) away, vaporizing a small amount of it with about 30 5-nanosecond pulses from a 1067 nm infrared laser and then observing the spectrum of the light emitted by the vaporized rock.
Ron M.A. Heeren is a Dutch scientist in mass spectrometry imaging. He is currently a distinguished professor at Maastricht University and the scientific director of the Multimodal Molecular Imaging Institute (M4I), where he heads the division of Imaging Mass Spectrometry.
Hilkka Inkeri Kenttämaa is a researcher in organic and bioorganic mass spectrometry, and the Frank Brown Endowed Distinguished Professor of Chemistry at Purdue University. She is a pioneer in distonic radical cation research and laser-induced acoustic desorption.
Helen Jill Cooper is a British chemist who is Professor of mass spectrometry at the University of Birmingham. She serves as Deputy Head of the School of Chemistry and holds an Engineering and Physical Sciences Research Council Established Career Fellowship. Her research considers the development of native ambient mass spectrometry to enable direct analysis of intact proteins and protein assemblies from tissue.
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