Download or read book Development and Applications of Laser Enhanced Ionization Laser Induced Fluorescence and Photoionization Detection Systems for Trace Detection of Elements and Compounds of Environmental and Biological Significance written by Seth Aaron Elwood and published by . This book was released on 2001 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 2000 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Enhanced Ionization Spectroscopy written by John C. Travis and published by John Wiley & Sons. This book was released on 1996-04-19 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-enhanced ionization (LEI) is a type of optical spectrometrythat employs photoexcitation to ionize atoms selectively. Over thepast two decades, this method--originally known as the optogalvaniceffect--has been the object of extensive worldwide research and thesubject of numerous papers and published articles. Until now,however, no single volume has presented this wealth of theory anddata in a cohesive and accessible form. Laser-Enhanced Ionization Spectrometry fills this gap in theliterature. It synthesizes vast amounts of information previouslyavailable only through scattered research papers and covers everyaspect of the technology, from underlying principles and theory tomethodology and applications. This book examines the state of theart of LEI, compares it with other methods, and demonstrates howlaser-enhanced collisional ionization is especially well suited toanalytical atomic spectrometry. The contributors to this collaborative effort--from Russia,Australia, Europe, and the United States--clarify terminology,explain the inner workings of LEI, and offer derivations for bothidealized forms and realistic approximations. They also analyze thecapabilities and limitations of this technique as an analyticalmethod, including instrumentation, sources of noise, limits ofdetection, interferences, and applications. After concentrating largely on flame LEI as the most commonly usedmethod to derive LEI measurements, the discussion moves to thedevelopment of nonflame technologies for LEI. There is alsoextended coverage of the relationship between LEI and laser-inducedfluorescence, including an examination of the interplay oflaser-induced ionization and fluorescence techniques in differentatomic and molecular reservoirs. Laser-Enhanced Ionization Spectrometry places understanding,usefulness, and practical applications ahead of detailedderivations. For practicing analytical chemists andspectroscopists, it offers a clear and uncluttered approach to acomplex subject, as well as a fresh perspective on a still-emergingtechnology. This book sums up the present understanding and state of the art oflaser-enhanced ionization (LEI)-a unique but underutilized tool foranalytical atomic spectrometry. LEI possesses the special abilityto ionize atoms selectively. The text focuses on the role of thistechnology in analytical chemistry, and covers both theory andapplications in one complete, self-contained volume. Carefully crafted by leading experts from around the globe, withcontributions under six key headings, Laser-Enhanced IonizationSpectrometry * Draws on hundreds of research papers to create a comprehensivereference for LEI * Describes in depth how ions are produced, and how a signal isgenerated and detected * Provides an extensive and up-to-date compilation of published LEIdetection limits * Emphasizes basic understanding and practical applications ratherthan detailed derivations * Discusses terms and definitions and clears up sources ofconfusion in the field * Offers up-to-date coverage of instrumentation and applications * Evaluates the usefulness of LEI as an analytical tool * Deals with questions of limits of detection, interference, andnoise * Devotes an entire segment to nonflame technologies for LEI * Extends the discussion to fluorescence techniques and how theycan be interrelated with LEI in various atomic and molecularreservoirs

Download or read book Laser Photoionization Spectroscopy written by Vladilen Letokhov and published by Elsevier. This book was released on 2012-12-02 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser Photoionization Spectroscopy discusses the features and the development of photoionization technique. This book explores the progress in the application of lasers, which improve the characteristics of spectroscopic methods. Organized into 12 chapters, this book starts with an overview of the fundamentals of the method for atoms and molecules. This text then examines the photoionization spectroscopy, which is based on the laser resonant excitation of particles into high-lying quantum states that are easy to detect by ionization. Other chapters explain the various basic schemes of multistep excitation, which can be used for resonance photoionization of molecules. This book discusses as well the different applications of the resonance photoionization technique in atomic and molecular spectroscopy. The final chapter considers the two well-known types of microscopy, namely, wave and corpuscular. This book is a valuable resource for chemists, physicists, analysts, and geochemists who are interested in laser spectroscopy techniques to solve nontrivial problems.

Download or read book Development of Bio photonic Sensor Based on Laser induced Fluorescence written by Chan Kyu Kim and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced fluorescence (LIF) has been shown to be potentially useful for identifying microorganisms in real time. It is a selective and sensitive technique because the excitation is performed at one wavelength while the emission is monitored at longer wavelengths so that background from the excitation source can be eliminated. This specialized optical property of LIF can be applied to development of an optical sensor capable of quickly, non-invasively, and quantitatively probing complex biochemical transformations in microorganisms. Various bio-photonic optical fiber sensors based on laser-induced fluorescence (LIF) spectroscopy were developed as diagnostic tools for microorganisms. In the first phase, the enhancement of the sensitivity and selectivity of the optical sensor system focused on diagnosis of human breast cancer cell lines and Azotobacter vinelandii (an aerobic soil-dwelling organism). Auto-fluorescence spectra from human breast cancer cell lines and Azotobacter vinelandii corresponding to different growth environments were investigated. Then, the study has expanded to include the use of gold nanoparticles for specific DNA detection. The use of gold nanoparticles opens a door into construction of a compact, highly specific, inexpensive and user-friendly optical fiber senor for specific DNA detection. An optical fiber laser-induced fluorescence (LIF) sensor based has been developed to detect single-strand (ss) DNA hybridization at the femtomolar level. Effects of various experimental parameters and configuration were investigated in order to optimize sensor performance and miniaturize sensor size.

Download or read book UV Laser and LED Induced Fluorescence Spectroscopy for Detection of Trace Amounts of Organics in Drinking Water and Water Sources written by Anna V. Sharikova and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: A UV Laser Induced Fluorescence (LIF) system, previously developed in our laboratory, was modified and used for a series of applications related to the development and optimization of UV LIF spectroscopic measurements of trace contaminants in drinking water and other water sources. Fluorescence spectra of a number of water samples were studied, including those related to the reverse osmosis water treatment and membrane fouling, domestic and international drinking water, industrial toxins, bacterial spores, as well as several fluorescence standards. Of importance was that the long term detection of the trace level of Dissolved Organic Compounds (DOC) was measured, for the first time to our knowledge, over a one week period and with a time resolution of 2.5 minutes. A comparison of LIF emission using both 266 nm and 355 nm excitation was also made for the first time. Such real-time and continuous measurements are important for future water treatment control. The LIF system was modified to accommodate UV Light Emitting Diodes (LED) as alternative excitation sources, and tested for the detection of trace organic species in water. In addition, a compact system using LED excitation and a spectrometer was xviii developed and underwent initial testing. The original LIF system had two laser sources, 266 nm and 355 nm. The additional sources incorporated in the system were UV LEDs emitting at 265 nm, 300 nm, 335 nm and 355 nm. The LED spectral emission was studied in detail, in terms of spectral variability and power output. It was found that all LEDs had some emission in the visible spectrum, and an optical filter was used to remove it. The signal-to-noise ratio for the LED-based systems was determined and compared with that of the LIF system. The fluorescent signal of the LED-based system was smaller by 1 to 2 orders of magnitude, despite the fact that the LED pulse energy was 2 to 3 orders of magnitude less than the laser's. As such, the fluorescent signal from the LED was greater than expected. Therefore, a UV LED may be a compact and much cheaper optical source for future water measurement instruments.

Download or read book Laser Based Optical Detection of Explosives written by Paul M. Pellegrino and published by CRC Press. This book was released on 2018-09-03 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-Based Optical Detection of Explosives offers a comprehensive review of past, present, and emerging laser-based methods for the detection of a variety of explosives. This book: Considers laser propagation safety and explains standard test material preparation for standoff optical-based detection system evaluation Explores explosives detection using deep ultraviolet native fluorescence, Raman spectroscopy, laser-induced breakdown spectroscopy, reflectometry, and hyperspectral imaging Examines photodissociation followed by laser-induced fluorescence, photothermal methods, cavity-enhanced absorption spectrometry, and short-pulse laser-based techniques Describes the detection and recognition of explosives using terahertz-frequency spectroscopic techniques Each chapter is authored by a leading expert on the respective technology, and is structured to supply historical perspective, address current advantages and challenges, and discuss novel research and applications. Readers are left with an in-depth understanding and appreciation of each technology’s capabilities and potential for standoff hazard detection.

Download or read book Development and Evaluation of a Laser induced Fluorescence Experiment for the Detection of Trace Compounds in Water Using a Tuneable UV OPO System written by and published by . This book was released on 1996 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and Application of a Photofragmentation laser induced Fluorescence Detection System for Atmospheric Nitrous Acid written by Michael Owen Rodgers and published by . This book was released on 1987 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Laser Induced Fluorescence Detection in Biomedical Analysis written by John Emerson Kuo and published by . This book was released on 1985 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Laser Spectroscopy written by F. T. Arecchi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Spectroscopic Techniques in Flame and Graphite Furnace for Trace Element Analysis written by Sten Sjöström and published by . This book was released on 1990 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser enhanced Ionization Spectrometry written by John C. Travis and published by . This book was released on 1996 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: The contributors to this collaborative effect - from Russia, Australia, Europe, and the United States - clarify terminology, explain the inner workings of LEI, and offer derivations for both idealized forms and realistic approximations. They also analyze the capabilities and limitations of this technique as an analytical method, including instrumentation, sources of noise, limits of detection, interferences, and applications.

Download or read book Detection of Energetic Materials by Laser Photofragmentation fragment Detection and Pyrolysis laser induced Fluorescence written by Rosario C. Sausa and published by . This book was released on 2001 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Trace concentrations of energetic materials such as 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and hexahydro-l,3,5-tinnitro-s-triazine (RDX) are detected by laser photofragmentationlfragment detection (PF/FD) spectrometry. In this technique, a single laser operating near 227 nm photofragments the parent molecule and facilitates the detection of the characteristic NO fragment by means of its A2lr-X2 II (0,0) transitions near 227 nm. Fragment detection is accomplished by resonance-enhanced multiphoton ionization (REMPI) with miniature electrodes and by laser-induced fluorescence (LIF) with a photodetector. Experiments are also conducted in the visible region using 453.85-nm radiation for photofragmentation and fragment detection. Sand samples contaminated with PETN and RDX are analyzed by a pyrolysis/LIF technique, which involves pyrolysis of the energetic material with subsequent detection of the pyrolysis products NO and NO2 by LIF and PF/LlF, respectively, near 227 nm. Applying these techniques to the trace analysis of TNT, PETN, and RDX at ambient pressure in room air is demonstrated with limits of detection (S/N = 3) in the range of low parts-per-billion to parts-per-million for a 20-s integration time with l0-l20 micronj of laser energy at 226.8 nm and 5 mJ at 453.85 mm An increase in detection sensitivity is projected with an increase in laser energy and an improved system design. The analytical merits of these techniques are discussed and compared to other laser-based techniques.

Download or read book Characteristics of Laser enhanced Ionization LEI and Laser Induced Fluorescence LIF Spectrometry written by Madelen Norberg and published by . This book was released on 1991 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book UV Laser Induced Fluorescence Spectroscopic Studies and Trace Detection of Dissolved Plastics bisphenol a and Organic Compounds in Water written by Vasanthi Sivaprakasam and published by . This book was released on 2002 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tracer based Planar Laser induced Fluorescence Diagnostics written by Brian Ho-yin Cheung and published by Stanford University. This book was released on 2011 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two advances to tracer-based planar laser-induced fluorescence (PLIF) diagnostics are presented in this work. The first improvement is the development of a 3-pentanone fluorescence quantum yield (FQY) database and model for a wide range of conditions in support of quantitative PLIF diagnostics. In addition, this work presents a sensitive, time-resolved tracer-based PLIF diagnostic, accomplished by using a continuous-wave (CW) laser with the high-FQY tracer toluene. Because of its ease of use and desirable photophysical properties, PLIF diagnostics using 3-pentanone as a tracer are common, particularly for internal combustion engine (ICE) diagnostics. Thus, there is a need for 3-pentanone FQY measurements and modeling over a wide range of temperatures, pressures, and excitation wavelengths. For insight into the collisionless process in the FQY model, measurements were made in 3-pentanone vapor at low-pressures across a range of temperatures using a flowing cell. Laser excitation with 248, 266, 277, 308 nm wavelengths were utilized, and Rayleigh scattering of the laser beam was used to calibrate the optical efficiency of the collection optics and detector. This low-pressure data allows calculation of the 3-pentanone fluorescence rate and non-radiative de-excitation rate in the fluorescence model. The vibrational relaxation cascade parameter for 3-pentanone collisions was also determined. Measurements of 3-pentanone FQY were also made over a range of temperatures and pressures relevant to diagnostic applications, and, in particular, combined high-temperature and high-pressure conditions applicable to internal combustion engines (ICE). These data were collected in a custom-built optical cell capable of simultaneous high-pressure and high-temperature conditions. The behavior of the FQY in nitrogen for temperatures up to 745 K and in air up to 570 K was examined for pressures from 1 to 25 bar. These data were used to further optimize the parameters in the FQY model representing collisional processes. The large quantity of data with 308 nm excitation allowed optimization of the nitrogen quenching rate, and data in air were used to optimize the oxygen quenching rate. These data were also used to optimize the vibrational relaxation parameters for nitrogen and oxygen. The model with the updated parameters is consistent with the data collected in the current work, as well as with fluorescence measurements made in optical ICEs up to 1100 K and 28 bar. Another area of tracer-based PLIF diagnostics development is time-resolved imaging. Because PLIF diagnostics are often performed using pulsed lasers, the time resolution of measurements is limited to the pulse rate of laser. Use of a high-powered visible laser with an off-the-shelf cavity frequency doubler is shown to produce a moderate-power CW beam in the ultraviolet wavelength regime. Application of this CW source to excite toluene, a high-FQY tracer, yields a sensitive, time-resolved tracer-based PLIF diagnostic. Fluctuation detection limits for tracer mole fraction were investigated by applying the diagnostic to an atmospheric temperature and pressure nitrogen jet seeded with 4% toluene, and detection limits of better than 1% of the maximum toluene mole fraction were achieved for detection of fluorescence signal at a point, along a line, and over a plane. The diagnostic was also demonstrated on a turbulent jet for line and planar detection and demonstrated the potential for toluene time-resolved PLIF diagnostics with CW lasers.