Download or read book The Influence of PAH Concentration and Distribution on Real Time In Situ Measurements of Petroleum Products in Soils Using Laser Induced Fluorescence written by and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Real-time laser induced fluorescence (LIF) in situ measurements of soil samples provide a reliable and cost-effective screening tool for hydrocarbon site assessments. The site characterization and analysis penetrometer system (SCAPS), is a truck-mounted cone penetrometer probe modified with a sapphire window and connected to a laser by fiber optics. The pulsed nitrogen laser 337-nm excitation source induced fluorescence in polynuclear aromatic hydrocarbons (PAHs), which are present in petroleum products. The fluorescence response of these compounds is measured with a fluorometer. The SCAPS can provide continuous hydrocarbon screening measurements to soil depths greater than 100 feet. Discrete soil samples collected from SCAPS boreholes were extracted and analyzed for total petroleum hydrocarbons (TPH), by gas chromatography with flame ionization detection (GC/FID), and 16 parent and over 100 alkyl substituted PAH compounds by gas chromatography with mass spectrometry detection (GC/MS). This method provides a basis for evaluating the relationship between TFH and PAH concentrations in the soil samples and laser induced fluorescence measurements from the soil borings.
Download or read book Tri Service Characterization and Analysis Penetrometer System SCAPS Accelerated Sensor Development Project written by and published by . This book was released on 1999 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Induced Fluorescence Over Optical Fibers for Real Time in Situ Measurement of Petroleum Hydrocarbons in Seawater written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fiber optic-based fluorometer system is described that uses a pulsed laser to induce fluorescence and a time-gated linear photodiode array coupled to a spectrograph for rapid measurement of fluorescence emission spectra and fluorescence decay times. Data is presented from studies conducted in San Diego Bay where the system has been used for real-time in situ measurements of temporal and spatial variability of petroleum hydrocarbons in seawater. Results show that the optical fiber fluorometer system is capable of direct quantification of low level (parts-per-billion diesel fuel marine equivalent) concentrations of petroleum hydrocarbons. Analysis times for measurement of complete fluorescence emission spectra are fast (tens of milli-seconds) and compare with the temporal response characteristics for temperature and conductivity sensors that are used for measuring standard physical hydrographic parameters. Results obtained with the fiber optic fluorometer system during a mapping study in San Diego Bay show good correlation with GC-MS analysis of total polycyclic aromatic hydrocarbons (PAHs) measured on discrete samples collected during the study ... CIVAPP: Environmental programs, CIVAPP: Marine biology, CIVAPP: Analytical chemistry.
Download or read book Comparison of In Situ Laser Induced Fluorescence LIF Measurements of Petroleum Hydrocarbons in Soils with Conventional Laboratory Measurements written by and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This presentation reports the results of a comprehensive field validation effort in which measurements from the cone penetrometer deployed LIF sensor are compared directly with results from conventional laboratory-based chemical analyses of samples collected using traditional methods. To minimize spatial and temporal variability associated with sampling, discrete samples were collected immediately after push measurements by overboring the push hole with an auger and collecting soil samples with a split spoon sampler. Secondary fluorescence measurements were made on splits of the laboratory samples to provide direct comparison with laboratory results. All discrete samples were analyzed by EPA Methods 418.1, Total Recoverable Petroleum Hydrocarbons (TRPH) and DHS Method 8015-Modified, TPH. At some sites samples were also analyzed for SVOC, EPA Method 8270, and/or an enhanced 8270 that quantifies 40 individual polynuclear aromatic hydrocarbons (PAHs).
Download or read book Laser Induced Fluorescence Spectroscopy for In situ Detection of Petroleum Contamination written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fiber-optic chemical sensor has been developed using laser induced fluorescence (LIF) to provide high resolution, real-time, in-situ field detection of underground petroleum contamination. Recent experiments using a 308 nm XeCl laser source have shown improved performance, particularly at detecting light molecular weight (i.e. aviation) fuels.
Download or read book Applications of Laser Induced Fluorescence Excitation Emission Matrix Spectroscopy for the Analysis of PAHs written by Sean J. Hart and published by . This book was released on 1998 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt: For HPLC and FIA, the data are analyzed by examining the summed fluorescence plots and qualitatively comparing the EEMs with standard measurements made with the same system. Species are qualitatively identified and quantitated by RAFA using pure component EEMs as standards and the EEMs measured during an analysis as the unknowns. RAFA calculated PAH concentrations in HPLC and FIA were in the near-quantitative regime, typically within a factor of 2 of the known concentration for laboratory-prepared mixtures. Several real world samples were analyzed and the results were generally acceptable: for HPLC all components were identified and all except two were quantitated to within a factor of 2. Analysis of lab mixtures by FIA yielded good agreement with known concentrations. The analysis of complex real world samples with many components provided reasonable qualitative identification of species and estimates of concentration.
Download or read book Toxicological Profile for Polycyclic Aromatic Hydrocarbons written by and published by . This book was released on 1995 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book PAHs written by Peter E. T. Douben and published by John Wiley & Sons. This book was released on 2003-07-25 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polycyclic aromatic hydrocarbons (PAHs), or polyarenes, are one of the largest and most structurally diverse class of organic molecules known. High percentages of polyarenes, representing a wide range of molecular sizes and structural types, are present in coal tars and petroleum residues. The major sources of PAHs are crude oil, coal and oil shale. The fuels produced from these fossil sources constitute the primary source of energy for the industrial nations of the world, and the petrochemicals from these raw materials are the basis of the synthetic fibre and plastics industries. PAHs are however, widespread pollutants and their impact on the environment and human health must be monitored and controlled. This book will review and assess our scientific understanding of the ecological exposure and effects PAHs have in different environments and habitats. It will accomplish this by taking the recipients of the pollution in the environment as starting points and working its way back through pathways to access what is required for our understanding of effects and rationale for control. Although this book will concentrate on ecological exposure of PAHs, the general impacts of PAHs on human populations will be touched upon. It is thought to be the first book to focus on the ecological aspects of PAHs.
Download or read book Biochemical Sensors In 2 Volumes written by Huangxian Ju and published by World Scientific. This book was released on 2021-06-08 with total page 997 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the full scope of biochemical sensors and offers a survey of the principles, design and applications of the most popular types of biosensing devices. It is presented in 19 chapters, written by 20 distinguished scientists as well as their co-workers. The topics include the design of signal transducers, signal tags and signal amplification strategies, the structure of biosensing interfaces with new biorecognition elements such as aptamers and DNAzymes, and different newly emerging nanomaterials such as Au nanoclusters, carbon nitride, silicon, upconversion nanoparticles and two-dimensional materials, and the applications in wearable detections, biofuel cells, biomarker analyses, bioimaging, single cell analysis and in vivo sensing.By discussing recent advances, it is hoped this book will bridge the common gap between research literature and standard textbooks. Research into biochemical sensors and their biomedical applications is proceeding in a number of exciting directions, as reflected by the content. This book is published in honor of the 90th birthday of Professor Shaojun Dong, who performed many pioneering studies on modified electrodes and biochemical sensors.
Download or read book Laser Induced Fluorescence Study of the Heterogeneous Interaction of Polycyclic Aromatic Hydrocarbons with Aqueous Surfaces microform Adsorption and Reaction with Gas phase Ozone written by Baagi Thema Mmereki and published by Library and Archives Canada = Bibliothèque et Archives Canada. This book was released on 2005 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have also measured the kinetics and products of a reaction between gas-phase ozone and anthracene adsorbed at the air-aqueous interface. The reactions at the "uncoated" air-water interface and at an interface consisting of a monolayer of various organic compounds were studied. In all the cases, the reaction follows a Langmuir-Hinshelwood mechanism, in which ozone first adsorbs to the air-aqueous interface, and then reacts with adsorbed anthracene. For typical atmospheric ozone concentrations, the estimated reactive uptake coefficient ranges from 2 x 10-8 to 3 x 10-7 depending on the nature of the air-aqueous interface. Smaller (C4, C6) carboxylic acids at the interface inhibit the reaction (compared to the "clean" water surface); 1-octanol enhances it. Under some circumstances, oxidation by ozone on aqueous surfaces may be more important in the atmosphere than gas phase oxidation by OH radicals. The fate of atmospheric semi-volatile organic compounds (SOCs) such as polycyclic aromatic hydrocarbons (PAHs) depends, in part, on their distribution between the gas phase and particulate phases, and oxidation reactions. In the daytime troposphere, photochemically produced OH radicals dominate these reactions, whereas chlorine atoms may contribute to the oxidation of certain PAHs in coastal areas. In the dark, oxidation by nitrate radicals (NO3) may also be important, whereas ozone can contribute to the oxidation both during the day and at night. We have developed a laser-induced fluorescence (LIF) method to study adsorption and oxidation of PAHs at the air-aqueous interface. This method allows to directly probe the mechanisms and extent of PAH uptake on aqueous surfaces. The kinetics of the adsorption of anthracene and pyrene onto "pure" water and water coated with an organic film were measured. The surface uptake coefficients of both PAHs are estimated to be on the order of 10-5, and increase by a factor of 2--3 for uptake to the 1-octanol coated water surface. However, the surface uptake of pyrene to a hexanoic-acid-coated aqueous surface does not display this enhancement. Resolved fluorescence spectra of pyrene adsorbed onto 1-octanol-coated surfaces indicate that pyrene is in a less polar environment than when adsorbed at the hexanoic-acid-coated surfaces.
Download or read book Investigation of Premixed Sooting Flames by Combined Laser Induced Incandescence and Laser Induced Fluorescence written by Jaclyn Dunn and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study applies the techniques of laser induced incandescence (LII) and laser induced fluorescence (LIF) to investigate laminar sooting flames of premixed ethylene air. The approach involves using three different excitation wavelengths, together with temporally and spectrally resolved detection, generating a rich dataset concerning the formation of soot and polycyclic aromatic hydrocarbons (PAHs). Both prompt and delayed detection are used to perform LII when exciting with short wavelengths, both with issues involved. Delayed detection gives an underestimation of soot volume fraction at low heights in the flame, as a result of particle size effects. Prompt detection gives overestimation of soot volume fraction due to fluorescence in the measurement volume. It is shown that care must be taken with either method and through evaluation of the associated errors this study shows delayed detection provides a more accurate measure of soot volume fraction. The ability to obtain the fluorescence signals over a range of heights above burner and stoichiometries is demonstrated. The approach relies on heating the soot particles equivalently with three excitation wavelengths so the LII contribution to the signals can be subtracted, leaving only fluorescence. Fluorescence profiles obtained show similar features to those seen in the literature for invasive measurements, including a reduction in the fluorescence signal generated by 283 nm excitation at intermediate heights above the burner surface followed by a re-increase. Although the data do not allow species-selective measurements of PAHs, these in-situ measurements allow inferences to be drawn about changing concentration of different size classes of these precursors to soot formation. Finally the method of obtaining subtracting the LII contribution to signals was used to obtain fluorescence spectra both for 283 nm and 532 nm excitation. This showed the possibility that fluorescence can yield useful information that it is otherwise impossible to obtain in-situ under sooting conditions.
Download or read book Field Validation of a Penetrometer based Fiber optic Petroleum Oil and Lubricant POL Sensor written by William C. McGinnis and published by . This book was released on 1997 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive comparisons of in situ measurements from a cone penetrometer-deployed laser induced fluorescence (LIF) petroleum, oil, and lubricant (POL) sensor with traditional field screening methods were performed. Operational procedures were developed to facilitate comparison between methods and across multiple sites. Using a field screening detect/non-detect criterion, agreement between sensor measurements corresponding to the sampled interval and the laboratory analytical measurements on those samples was better than 85 percent. Comparison between measurements from the two accepted analytical techniques, on splits of the same sample, was only slightly better. We conclude that the LIF-POL sensor, deployed from a cone penetrometer, provides significant advantages for subsurface field screening of POL-contaminated sites. The LIF technique offers the advantages of rapid, in situ, real-time measurements, coupled with increased data density, not possible with traditional screening methods.
Download or read book Forensic Analysis of Commercial Petroleum Products Using Selective Fluorescence Quenching written by SB. Howerton and published by . This book was released on 2001 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel method for the forensic analysis of commercial petroleum products is presented. In this approach, the petroleum sample is extracted with nitromethane and then separated by capillary liquid chromatography with laser-induced fluorescence detection. The addition of selective fluorescence quenching agents allows the sample to be profiled by the distribution of alternant and nonalternant polycyclic aromatic hydrocarbons (PAHs) In preliminary studies, the quenching behavior of nitromethane and diisopropylamine was established by using a standard mixture of sixteen PAHs ranging in size from two to six aromatic rings. Subsequent examination of new and used motor oil demonstrated that characteristic differences arise in the PAH content, which may allow for the unique identification of oil from a particular engine or vehicle. In addition, three brands of petrolatum jelly were successfully distinguished. Although a number of alternant alkylated and heterocyclic PAHs were found in all petrolatum samples, there were significant differences in the relative concentrations of alternant as well as nonalternant PAHs. This allowed for clear differentiation of the samples through qualitative inspection of their chromatograms as well as quantitative statistical correlation techniques.
Download or read book Radical Concentration and Temperature Measurements in Sooting Flames by Cavity Ring down Spectroscopy and Laser induced Fluorescence written by Yuxuan Hu and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sooting laminar flames at atmospheric pressure present a very complex chemical environment with numerous sources of interference for optical measurement techniques. Absolute concentration profiles of 1CH2 and HCO have been measured under a range of flame conditions in a sooting laminar premixed C2H4-air flat-flame by Cavity-Ring Down Spectroscopy performed at wavelengths in the range 615 to 625 nm. Also, concentration profiles of the OH radical have been detected via the band of A2 ∑(v' = 0) ← X2 ∏(v'' = 0) system by Laser-Induced Fluorescence and quantitatively calibrated by Cavity-Ring Down Spectroscopy. In situ measurements of these radicals in sooting flames have hitherto been lacking and are essential for validation of chemical kinetic models of aromatic hydrocarbon and soot formation in flames. The experimental results are compared to simulated concentration profiles generated using the Appel-Bockhorn-Frenklach mechanism. Temperature profiles obtained using OH LIF thermometry are used in interpreting the CRDS data and as input for flame simulation. Additionally, weak broadband absorption is observed by CRDS in the region between the reaction zone and the onset of soot formation; this may be attributable to low concentrations of large aromatic species.
Download or read book Polycyclic Aromatic Hydrocarbons in Work Atmospheres written by Alf Bjorseth and published by CRC Press. This book was released on 2018-05-04 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with the sources, distribution, analytical methods, and monitoring of Polycyclic aromatic hydrocarbons (PAH) in the occupational environment. It is hoped that this book will make a contribution to understanding the formation and determination of PAH in work atmosphere and that it will make a particular contribution to occupational health projects. Much of the information given in this book has been generating in studies carried out in cooperation with the Norwegian aluminium industry.
Download or read book Laser induced Fluorescence Measurements of Vapor phase Polycyclic Aromatic Hydrocarbons I Evaluation of One and Two photon Excitation Processes for Mixture Analysis II Flame Temperature Measurements Using the Anomalous Fluorescence of Pyrene written by Diane LeAnna Peterson and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bioavailability of Contaminants in Soils and Sediments written by National Research Council and published by National Academies Press. This book was released on 2003-05-03 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.
