Journal articles: 'Laser-induced fluorescence (LIF)'

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Bras, N. "Laser Induced Fluorescence." Laser Chemistry 10, no. 5-6 (1990): 405–12. http://dx.doi.org/10.1155/1990/82962.

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Laser induced fluorescence (LIF) has become a common detector of atoms and molecules allowing to determine their internal state distributions. In this paper we mention the advantages of both kinds of lasers, cw or pulsed. We review some aspects of the LIF process, such as saturation or polarization effects, which could alter the results if they were not taken into account. We also indicate how LIF can be used to measure relaxation times and thus rate constants of the relaxation processes: some experimental results obtained in our laboratory illustrate these points.

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Chappelle, Emmett, and Darrel Williams. "Laser-Induced Fluorescence (LIF) from Plant Foliage." IEEE Transactions on Geoscience and Remote Sensing GE-25, no. 6 (1987): 726–36. http://dx.doi.org/10.1109/tgrs.1987.289742.

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Terzic, M., B. P. Marinkovic, D. Sevic, J. Jureta, and A. R. Milosavljevic. "Development of time-resolved laser-induced fluorescence spectroscopic technique for the analysis of biomolecules." Facta universitatis - series: Physics, Chemistry and Technology 6, no. 1 (2008): 105–17. http://dx.doi.org/10.2298/fupct0801105t.

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Our developments of the time-resolved laser-induced fluorescence (TR-LIF) detection system for biomolecules are presented. This system is based on the tunable (320 nm to 475 nm) Nd:YAG laser pulses used to excite various biomolecules. The detection part is the Streak System for Fluorescence Lifetime Spectroscopy (Hamamatsu, Japan). The system consists of a C4334-01 streakscope, as a detector, DG 535 digital pulse/delay generator, C5094-S Spectrograph and HPD-TA System, as a temporal analyzer. The TR-LIF spectrometer is designed primarily to study the temperature and pressure effects on fluorescence behavior of biomolecules upon excitation with a single nanosecond pulse. The design of this system has capability to combine laser-induced breakdown (LIB) with fluorescence, as well to study optodynamic behavior of fluorescence biomolecules.

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Le, X. Chris, Victor Pavski, and Hailin Wang. "2002 W.A.E. McBryde Award Lecture Affinity recognition, capillary electrophoresis, and laser-induced fluorescence polarization for ultrasensitive bioanalysis." Canadian Journal of Chemistry 83, no. 3 (2005): 185–94. http://dx.doi.org/10.1139/v04-175.

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The combination of affinity recognition, capillary electrophoresis (CE), laser-induced fluorescence (LIF), and fluorescence polarization for the ultrasensitive determination of compounds of biological interest is described. Competitive immunoassays using CELIF eliminate the need for fluorescently labeling trace analytes of interest and are particularly useful for determination of small molecules, such as cyclosporine, gentamicin, vancomycin, and digoxin. Fluorescence polarization allows for differentiation of the antibody-bound from the unbound small molecules. Noncompetitive affinity CELIF assays are shown to be highly effective in the determination of biomarkers for DNA damage and HIV-1 infection. An antibody (or aptamer) is used as a fluorescent probe to bind with a target DNA adduct (or the reverse transcriptase of the HIV-1 virus), with the fluorescent reaction products being separated by CE and detected by LIF. Aptamers are attractive affinity probes for protein analysis because of high affinity, high specificity, and the potential for a wide range of target proteins. Fluorescence polarization provides unique information for studying molecular interactions. Innovative integrations of these technologies will have broad applications ranging from cancer research, to biomedical diagnosis, to pharmaceutical and environmental analyses.Key words: capillary electrophoresis, laser-induced fluorescence, fluorescence polarization, immunoassay, affinity probes, antibodies, aptamers, DNA damage, toxins, therapeutic drugs.

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Vazquez, Benjamín, Naser Qureshi, Laura Oropeza-Ramos, and Luis F. Olguin. "Effect of velocity on microdroplet fluorescence quantified by laser-induced fluorescence." Lab Chip 14, no. 18 (2014): 3550–55. http://dx.doi.org/10.1039/c4lc00654b.

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Ko, E. J., C. K. Lee, Y. J. Kim, and K. W. Kim. "Monitoring pah‐contaminated soil using laser‐induced fluorescence (LIF)." Environmental Technology 24, no. 9 (2003): 1157–64. http://dx.doi.org/10.1080/09593330309385656.

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Johansson, O., J. Bood, M. Aldén, and U. Lindblad. "Detection of Hydrogen Peroxide Using Photofragmentation Laser-Induced Fluorescence." Applied Spectroscopy 62, no. 1 (2008): 66–72. http://dx.doi.org/10.1366/000370208783412618.

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Photofragmentation laser-induced fluorescence (PF-LIF) is for the first time demonstrated to be a practical diagnostic tool for detection of hydrogen peroxide. Point measurements as well as two-dimensional (2D) measurements in free-flows, with nitrogen as bath gas, are reported. The present application of the PF-LIF technique involves one laser, emitting radiation of 266 nm wavelength, to dissociate hydrogen peroxide molecules into OH radicals, and another laser, emitting at 282.25 nm, to electronically excite OH, whose laser-induced fluorescence is detected. The measurement procedure is explained in detail and a suitable time separation between photolysis and excitation pulse is proposed to be on the order of a few hundred nanoseconds. With a separation time in that regime, recorded OH excitation scans were found to be thermal and the signal was close to maximum. The PF-LIF signal strength was shown to follow the same trend as the vapor pressure corresponding to the hydrogen peroxide liquid concentration. Thus, the PF-LIF signal appeared to increase linearly with hydrogen peroxide vapor-phase concentration. For 2D single shot measurements, a conservatively estimated value of the detection limit is 30 ppm. Experiments verified that for averaged point measurements the detection limit was well below 30 ppm.

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Wang, Xue Fei, Wei Ping Yan, Hai Ming Bai, and Wei Li. "Auto Focusing Confocal Laser Induced Fluorescence Detection System." Key Engineering Materials 437 (May 2010): 364–68. http://dx.doi.org/10.4028/www.scientific.net/kem.437.364.

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Laser induced fluorescence (LIF) detection is one of the main means of Capillary Electrophoresis (CE) chip detection, in which the confocal detecting device is commonly used for its higher sensitivity and signal-to-noise ratio (SNR). Based on confocal LIF detection principle, the confocal laser induced fluorescence detecting system, which could realize the auto focusing, and auto tracking was presented, and it contained the confocal optical system, the microprocessor control system and the computer process system. This device can acquire the fluorescence data by PMT or the chip images by CCD, and 3-dimensional electric moving stage could be controlled to accomplish the auto focusing and auto tracking by image process. The device could detect or observe the CE chip data in real time.

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Ballard, M. K., R. J. Hoobler, Chun He, L. P. Gold, R. A. Bernheim, and P. Bicchi. "Multiphoton LIF in atomic 6Li." Canadian Journal of Physics 72, no. 11-12 (1994): 808–11. http://dx.doi.org/10.1139/p94-106.

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The multiphoton laser-induced fluorescence excitation spectrum of 6Li vapor has been measured with a tunable, pulsed, nanosecond laser scanned between 13 600 and 14 500 cm−1. Two- and three-photon allowed excitation transitions originating from the 22S and 22P levels were observed, the latter likely originating from photodissociation products of Li2. Laser polarization and power dependencies are consistent with the multiphoton transition probabilities. Evidence for a parity "forbidden" multiphoton transition is also present.

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Li, Qingzhou, Wen Zhang, Zhiyang Tang, et al. "Determination of uranium in ores using laser-induced breakdown spectroscopy combined with laser-induced fluorescence." Journal of Analytical Atomic Spectrometry 35, no. 3 (2020): 626–31. http://dx.doi.org/10.1039/c9ja00433e.

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Bukin, Oleg, Dmitry Proschenko, Chekhlenok Alexey, et al. "New Solutions of Laser-Induced Fluorescence for Oil Pollution Monitoring at Sea." Photonics 7, no. 2 (2020): 36. http://dx.doi.org/10.3390/photonics7020036.

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Laser-induced fluorescence (LIF) spectral features for oil products of different states (solutions in the seawater and thin slicks) are discussed in this article. This research was done to evaluate LIF application for the identification of oil products and the measurement of the volume of ocean pollution by bilge water disposal. It was found out that the form of LIF spectral distribution was changed depending on the oil product state (pure fuel, slick or solution). The LIF method was calibrated for the most common types of heavy and light marine fuels at the standard measurement method of solution concentrations and limit of detection (LoD) values were established for each type. The time dynamics of the solution spectra were researched, and the time change features were determined. The smallsized LIF sensor for the unmanned aerial vehicle (UAV) is described and aims to investigate the LIF for oil pollution at sea.

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Cheng, Yong Qiang, Cui Lian Guo, Bin Zhao, and Li Yang. "Research of Laser Induced Fluorescence Detection Techniques Based on Microfluidic Devices." Advanced Materials Research 989-994 (July 2014): 2761–63. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.2761.

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Laser induced fluorescence (LIF) detection technique is one of the most sensitive detection method in micro total analytical systems (μTAS) as its good monochromaticity, strong collimation and high optical density. It is widely used in biochemical analysis systems and the detection limit could reach 10-9-10-12mol/L. Due to the important role in μTAS, different optical structure arrangements of LIF detection techniques were continuously developed. We reviewed the recent progress of the optical structure arrangement and the applications of the LIF detection techniques.

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Razvi, M. A. N., Ahmed Bakry, A. Saeed, et al. "Diagnosis of Oral Squamous Cell Carcinoma (OSCC) Using Laser Induced Fluorescence." Science of Advanced Materials 12, no. 6 (2020): 853–60. http://dx.doi.org/10.1166/sam.2020.3759.

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Cancer is a dreaded disease; a large number of deaths occur every year due to this disease. Oral squamous cell carcinoma (OSCC) is the most common cancer of the head and neck, which is approximately 16% to 40% of all malignancies. In this study, Laser induced fluorescence (LIF) spectroscopy has been utilized to discriminate OSCC against healthy (normal) tissues and to investigate whether the LIF could provide information from formalin-fixed paraffin-embedded (FFPE) tissue samples similar to that reported using fresh tissues. Samples were prepared after biopsy from ten patients using standard FFPE tissues methods. LIF system consists of a continuous wave (CW) He–Cd laser at 325 nm, a seven-core optical fiber cable coupled to the laser, a spectrometer with cooled charge coupled device (CCD) detector, and a computer for acquisition of the LIF spectra. Spectra were decomposed using second derivative and curve fitting analysis to reveal the changes in molecular composition of the samples. Moreover, samples spectra were discriminated by hierarchical cluster analysis (HCA) and principal components analysis (PCA). Spectral results showed differences in peak areas and positions between normal and OSCC tissues. LIF spectroscopy revealed significant decrease in the peak area of collagen and decrease in peak area of coenzymes of OSCC tissues. In addition, significant shift in the peak position of coenzymes was recorded. HCA and PCA of LIF indicated a very clear discrimination of the normal and FFPE-OSCC tissues. The achieved discrimination between elliptic polygons of normal and OSCC tissues was 96.3% by PCA. This study confirms that the LIF spectroscopy is a good diagnostic tool for OSCC and it could be used with samples that are prepared using FFPE tissues methods.

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Fiorani, Luca, Luisa Caneve, Francesco Colao, et al. "Real-Time Diagnosis of Historical Artworks by Laser-Induced Fluorescence." Advanced Materials Research 133-134 (October 2010): 253–58. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.253.

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Laser-induced fluorescence (LIF) is a powerful remote analysis tool that has been successfully applied to the real-time diagnosis of historical artworks, allowing the observation of features invisible to the naked eye, as pigment composition, biological attack and restoration technique. This paper presents a LIF-based optical radar and reports on the results of its deployment during a field campaign conducted in February 2010 in Seville, Spain.

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Marques da Silva, Jorge, and Andrei Borissovitch Utkin. "Application of Laser-Induced Fluorescence in Functional Studies of Photosynthetic Biofilms." Processes 6, no. 11 (2018): 227. http://dx.doi.org/10.3390/pr6110227.

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Biofilms are a ubiquitous form of life for microorganisms. Photosynthetic biofilms such as microphytobenthos (MPB) and biological soil crusts (BSC) play a relevant ecological role in aquatic and terrestrial ecosystems, respectively. On the other hand, photosynthetic epilithic biofilms (PEB) are major players in the microbial-induced decay of stone structures of cultural heritage. The use of fluorescence techniques, namely, pulse-amplitude-modulated fluorometry, was crucial to understanding the photophysiology of these microbial communities, since they made it possible to measure biofilms’ photosynthetic activity without disturbing their delicate spatial organization within sediments or soils. The use of laser-induced fluorescence (LIF) added further technical advantages, enabling measurements to be made at a considerable distance from the samples, and under daylight. In this Perspective, we present state-of-the-art LIF techniques, show examples of the application of LIF to MPB and present exploratory results of LIF application to BSC, as well as to PEB colonizing stone structures of cultural heritage. Thereafter, we discuss the perspectives of LIF utilization in environmental research and monitoring, in cultural heritage conservation and assessment, and in biotechnological applications of photosynthetic biofilms.

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Anglos, Demetrios, Maria Solomidou, Ioanna Zergioti, Vassilis Zafiropulos, Theodore G. Papazoglou, and Costas Fotakis. "Laser-Induced Fluorescence in Artwork Diagnostics: An Application in Pigment Analysis." Applied Spectroscopy 50, no. 10 (1996): 1331–34. http://dx.doi.org/10.1366/0003702963904863.

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The applicability of laser-induced fluorescence (LIF) spectroscopy as a nondestructive analytical technique for artwork diagnostics is investigated. In this work, LIF is employed in the examination of a set of cadmium sulfide- and cadmium selenide sulfide-based pigments in a series of oil painting test samples. Fluorescence spectra of the oil colors are recorded upon pulsed laser excitation at 532, 355 (Nd:YAG), and 248 nm (KrF excimer). The technique is shown to be suitable for differentiating among the various cadmium pigments used in this study and, furthermore, to be capable of identifying individual components in mixtures of these pigments on the basis of their characteristic fluorescence emission. Future prospects and the potential for the extension of LIF from a research laboratory technique into a conservator's tool for artwork diagnostics are discussed.

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Kiefer, Johannes, Bo Zhou, Johan Zetterberg, Zhongshan Li, and Marcus Alden. "Laser-Induced Fluorescence Detection of Hot Molecular Oxygen in Flames Using an Alexandrite Laser." Applied Spectroscopy 68, no. 11 (2014): 1266–73. http://dx.doi.org/10.1366/14-07512.

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The use of an alexandrite laser for laser-induced fluorescence (LIF) spectroscopy and imaging of molecular oxygen in thermally excited vibrational states is demonstrated. The laser radiation after the third harmonic generation was used to excite the B–X (0-7) band at 257 nm in the Schumann–Runge system of oxygen. LIF emission was detected between 270 and 380 nm, revealing distinct bands of the transitions from B(0) to highly excited vibrational states in the electronic ground state, X ( v > 7). At higher spectral resolution, these bands reveal the common P- and R-branch line splitting. Eventually, the proposed LIF approach was used for single-shot imaging of the two-dimensional distribution of hot oxygen molecules in flames.

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Gavelli, Filippo, and Kenneth Kiger. "High-resolution boron dilution measurements using laser induced fluorescence (LIF)." Nuclear Engineering and Design 195, no. 1 (2000): 13–25. http://dx.doi.org/10.1016/s0029-5493(99)00201-0.

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Wang, K., A. Nourbakhsh, N. Nishioka, P. Kelsey, and O. Cass. "Optical biopsy of colonic polyps using laser-induced fluorescence (LIF)." Gastroenterology 114 (April 1998): A699. http://dx.doi.org/10.1016/s0016-5085(98)82870-9.

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Takayanagi, Masao, and Ichiro Hanazaki. "Stimulated-Emission-Pumping Laser-Induced-Fluorescence Spectroscopy of Phenol and Anisole." Laser Chemistry 14, no. 1-3 (1994): 103–17. http://dx.doi.org/10.1155/1994/21635.

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The SEP–LIF (stimulated emission pumping-laser induced fluorescence) technique was applied to the investigation of dynamical behavior of vibrationally excited phenol and anisole produced in the supersonic expansion. In the SEP–LIF scheme, a molecule excited to a specific vibrational state by SEP is detected by measuring the LIF excitation spectrum with an appropriate delay to probe the vibrational relaxation. Four vibrational states, 6a1, 16a2, 121 and 11, of phenol, and six vibrational states, 18b1, 18b2, 6a1, 121, 16a2 and 11, of anisole were investigated. For both of phenol and anisole, it is found that the relaxation of the vibrational states below 1,000 cm-1 in the ground electronic state is so slow under the collisionless condition that only the transitions from the vibrational states initially prepared by SEP are observed as the SEP-induced bands in the SEP–LIF spectra. The low frequency torsional motion of methyl group in anisole does not accelerate IVR (intramolecular vibrational redistribution) much in this energy region.

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Yuan, Ju Long, Fei Yan Lou, Zhao Zhong Zhou, Zhi Wei Wang, and Bing Hai Lv. "Visualized Characterization of Slurry during CMP Based on LIF." Key Engineering Materials 315-316 (July 2006): 279–83. http://dx.doi.org/10.4028/www.scientific.net/kem.315-316.279.

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Chemical mechanical polishing has emerged recently as an indispensable processing technique in large scale integration. In chemical and mechanical polishing process, chemical and mechanical principle is the vital factor in the removal process. Little is known about what is occurring beneath a wafer during Chemical Mechanical Polishing (CMP) processes. The paper provides a LIF technology to visualize the fluid flow between the wafer and pad. In this paper, the experiment setup is built. And then, the images of fluorescence intensity excited by LIF have been obtained from CCD. Finally, the relationships between pH, temperature, laser power, film thickness and fluorescence intensity excited by LIF (Laser induced Fluorescence) are studied.

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Nevin, Austin, and Demetrios Anglos. "Assisted Interpretation of Laser-Induced Fluorescence Spectra of Egg-Based Binding Media Using Total Emission Fluorescence Spectroscopy." Laser Chemistry 2006 (December 28, 2006): 1–5. http://dx.doi.org/10.1155/2006/82823.

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Laser-induced fluorescence (LIF) spectroscopy can provide nondestructive, qualitative analysis of protein-based binding media found in artworks. Fluorescence emissions from proteins in egg yolk and egg white are due to autofluorescent aromatic amino acids as well as other native and age-related fluorophores, but the potential of fluorescence spectroscopy for the differentiation between binding media is dependent on the choice of a suitable excitation wavelength and limited by problems in interpretation. However, a better understanding of emission spectra associated with LIF can be achieved following comparisons with total emission fluorescence spectra where a series of consecutive emission spectra are recorded over a specific range. Results using nanosecond UV laser sources for LIF of egg-based binding media are presented which are rationalised following comparisons with total emission spectra. Specifically, fluorescence is assigned to tryptophan and oxidation products of amino acids; in the case of egg yolk, fatty-acid polymerisation and age-related degradation products account for the formation of fluorophores.

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Zhang, Hao, Shun Wang, Keke Chang, et al. "Optical Characterization of Paper Aging Based on Laser-Induced Fluorescence (LIF) Spectroscopy." Applied Spectroscopy 72, no. 6 (2018): 913–20. http://dx.doi.org/10.1177/0003702818761669.

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Paper aging and degradation are growing concerns for those who are responsible for the conservation of documents, archives, and libraries. In this study, the paper aging was investigated using laser-induced fluorescence spectroscopy (LIFS), where the fluorescence properties of 47 paper samples with different ages were explored. The paper exhibits fluorescence in the blue-green spectral region with two peaks at about 448 nm and 480 nm under the excitation of 405 nm laser. Both fluorescence peaks changed in absolute intensities and thus the ratio of peak intensities was also influenced with the increasing ages. By applying principal component analysis (PCA) and k-means clustering algorithm, all 47 paper samples were classified into nine groups based on the differences in paper age. Then the first-derivative fluorescence spectral curves were proposed to figure out the relationship between the spectral characteristic and the paper age, and two quantitative models were established based on the changes of first-derivative spectral peak at 443 nm, where one is an exponential fitting curve with an R-squared value of 0.99 and another is a linear fitting curve with an R-squared value of 0.88. The results demonstrated that the combination of fluorescence spectroscopy and PCA can be used for the classification of paper samples with different ages. Moreover, the first-derivative fluorescence spectral curves can be used to quantitatively evaluate the age-related changes of paper samples.

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Lähdetie, Anni, Paula Nousiainen, Jussi Sipilä, Tarja Tamminen, and Anna-Stiina Jääskeläinen. "Laser-induced fluorescence (LIF) of lignin and lignin model compounds in Raman spectroscopy." Holzforschung 67, no. 5 (2013): 531–38. http://dx.doi.org/10.1515/hf-2012-0177.

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Abstract Raman spectroscopy is a technique that provides structural information on lignin and other components of wood and pulp in situ. However, especially lignin-containing samples may produce laser-induced fluorescence (LIF) that overlaps with Raman bands. In the worst case, this background signal can overwhelm the weaker Raman signal completely. In this study, the LIF of lignin was investigated with the excitation wavelength 532 nm applied in Raman spectroscopy to clarify the correlations between lignin structure and LIF intensity. Raman spectroscopic analyses with lignin model compounds illustrated that the 5-5′ structures induce LIF. It was also shown that the intensity of LIF was significantly less intense when the 5-5′ model compound was structurally rigid (as in dibenzodioxocin) compared with the flexible simple counterpart. The comparison between the free phenolic model compounds with the methylated analogue showed that the presence of the free phenolic structure was not a prerequisite for LIF. It was thus concluded that the conformation of the molecule is the key factor with respect to fluorescence. The role of conformational aspects was further investigated by comparing wood with chemical pulps and isolated lignins.

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Guibert, Philippe, William Perrard, and Ce´line Morin. "Concentration Measurements in a Pressurized and Heated Gas Mixture Flow Using Laser Induced Fluorescence." Journal of Fluids Engineering 124, no. 2 (2002): 512–22. http://dx.doi.org/10.1115/1.1456462.

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The fuel concentration in a pressurized and heated gas mixture flow was measured by LIF (laser induced fluorescence) technique. Diacetyl was used as the fluorescence tracer of fuel and was excited at a wavelength of 355 nm. Influent parameters on the LIF intensity among the equivalence ratio, the environment temperature and pressure, the flow velocity were determined from a parametric study. The technique of plans of experiments with statistical tests and analysis was investigated to determine exactly the preponderant parameters and their influence on the LIF intensity. For the experimental conditions explored in this work, the value of the LIF intensity was calculated by developing a quadratic model. By inversion of the transfer function, the equivalence ratio was deduced with a low mean relative error.

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Stone, Daniel, Lisa K. Whalley, Trevor Ingham, et al. "Measurement of OH reactivity by laser flash photolysis coupled with laser-induced fluorescence spectroscopy." Atmospheric Measurement Techniques 9, no. 7 (2016): 2827–44. http://dx.doi.org/10.5194/amt-9-2827-2016.

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Abstract. OH reactivity (k′OH) is the total pseudo-first-order loss rate coefficient describing the removal of OH radicals to all sinks in the atmosphere, and is the inverse of the chemical lifetime of OH. Measurements of ambient OH reactivity can be used to discover the extent to which measured OH sinks contribute to the total OH loss rate. Thus, OH reactivity measurements enable determination of the comprehensiveness of measurements used in models to predict air quality and ozone production, and, in conjunction with measurements of OH radical concentrations, to assess our understanding of OH production rates. In this work, we describe the design and characterisation of an instrument to measure OH reactivity using laser flash photolysis coupled to laser-induced fluorescence (LFP-LIF) spectroscopy. The LFP-LIF technique produces OH radicals in isolation, and thus minimises potential interferences in OH reactivity measurements owing to the reaction of HO2 with NO which can occur if HO2 is co-produced with OH in the instrument. Capabilities of the instrument for ambient OH reactivity measurements are illustrated by data collected during field campaigns in London, UK, and York, UK. The instrumental limit of detection for k′OH was determined to be 1.0 s−1 for the campaign in London and 0.4 s−1 for the campaign in York. The precision, determined by laboratory experiment, is typically < 1 s−1 for most ambient measurements of OH reactivity. Total uncertainty in ambient measurements of OH reactivity is ∼ 6 %. We also present the coupling and characterisation of the LFP-LIF instrument to an atmospheric chamber for measurements of OH reactivity during simulated experiments, and provide suggestions for future improvements to OH reactivity LFP-LIF instruments.

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Larsson, Kajsa, Dina Hot, Andreas Ehn, et al. "Quantitative Imaging of Ozone Vapor Using Photofragmentation Laser-Induced Fluorescence (LIF)." Applied Spectroscopy 71, no. 7 (2017): 1578–85. http://dx.doi.org/10.1177/0003702817691528.

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Merrigan, Tony L., C. Adam Hunniford, David J. Timson, Martin Catney, and Robert W. McCullough. "Development of a novel mass spectrometric technique for studying DNA damage." Biochemical Society Transactions 37, no. 4 (2009): 905–9. http://dx.doi.org/10.1042/bst0370905.

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An experimental system, based upon UV and IR laser desorption, has been constructed to enable the production and characterization of neutral biomolecular targets. These targets are to be used for interaction experiments investigating radiation-induced damage to DNA. The viability of the laser-desorption techniques of MALDI (matrix-assisted laser-desorption ionization), SALDI (surface-assisted laser-desorption ionization) and DIOS (desorption/ionization on silicon), for production of these gas targets is discussed in the present paper. Fluorescent dye tagging and LIF (laser-induced fluorescence) imaging has been used to characterize the biomolecular plumes, revealing their spatial density profiles and temporal evolution.

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Gómez-Morón, María Auxiliadora, Rocío Ortiz, Francesco Colao, et al. "Monitoring the Restoration of a Seventeenth-Century Wooden Artwork Using Laser-Induced Fluorescence and Digital Image Analysis." Applied Spectroscopy 75, no. 1 (2020): 70–80. http://dx.doi.org/10.1177/0003702820944505.

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The present paper is aimed at demonstrating the capabilities of digital image analysis (DIA) to support conservation of painted artwork. Laser-induced fluorescence (LIF) imaging has been usually used in the diagnosis of wall paintings. In this case, LIF is applied to the case study of a painted wooden canopy, and most successful data processing techniques are presented in the discussion of results. The Jesús del Gran Poder canopy, completed by Francisco Ruiz Gijón in 1692, is an oil panel painting on wood. Eight panels of the canopy have been study by LIF. This technique is capable of remotely acquiring hyperspectral images operating in fluorescence mode following ultraviolet laser excitation. LIF spectra combined with principal component analysis, spectral angle mapper, and DIA provide a chemical mapping of the treated wooden surface of the panels. Besides, LIF spectrum is as a fingerprint of the panels that allows stablishing differences between them. LIF imaging analysis has proven to be a very useful tool for mapping retouching work, tracking previous restorations, and detecting chemicals on the wood in order to monitor restorations.

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Mizutani, Masakazu, Hiromichi Niikura, Atsunari Hiraya, and Koichiro Mitsuke. "Laser-induced fluorescence excitation spectroscopy of N2 + produced by VUV photoionization of N2 and N2O." Journal of Synchrotron Radiation 5, no. 3 (1998): 1069–71. http://dx.doi.org/10.1107/s0909049597015367.

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Synchrotron radiation emitted from the UVSOR storage ring is monochromated by a grazing-incidence monochromator and introduced coaxially with the second harmonic of a mode-locked Ti:sapphire laser. Sample gases, N2 and N2O, are photoionized into vibronically ground N2 + with the fundamental light of the undulator radiation at 18.0 and 18.6 eV, respectively. Laser-induced fluorescence (LIF) excitation spectra of N2 + from N2 and N2O are measured in the laser wavelength region of the (B 2Σ u +, v′ = 0) ← (X 2Σg +, v′′ = 0) transition at 389–392 nm. The LIF excitation spectra of N2 + exhibit two maxima due to the P and R branches in which rotational bands are heavily overlapped. The rotational temperature is determined by simulating an LIF excitation spectrum by using the theoretical intensity distribution of rotation bands convoluted with the spectral width of the laser.

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Pollack, Thomas, Marc Dangers, and Hermann Seitz. "Analysis of the release kinetics of surface-bound proteins via laser-induced fluorescence." Current Directions in Biomedical Engineering 1, no. 1 (2015): 340–44. http://dx.doi.org/10.1515/cdbme-2015-0084.

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AbstractThe drying and resolving processes of surface-bound proteins were analysed with a stereoscopic microscope combined with laser-induced fluorescence (LIF) with the aim to assist the advancement of a semiautomated point-of-care allergy diagnostic device. The results shown in this paper present the use of the LIF-method for concentration calibration and the analysis of drying and resolving dyed proteins. The method is established successfully and delivers precise results.

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Kang, W., O. Fujita, and K. Ito. "Visualization of Formaldehyde Distribution Above Platinum Plate Catalyst by Using LIF Method." Journal of Energy Resources Technology 118, no. 1 (1996): 82–87. http://dx.doi.org/10.1115/1.2792698.

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Visulization has been attempted to measure formaldehyde formation during catalytic combustion of methanol/air mixtures. The visualization of formaldehyde distribution above a platinum plate in methanol premixed gas flows was carried out by a LIF (laser-induced fluorescence) method. Formaldehyde (CH2O) has fluorescence spectra in the 340.6–493.3-nm range when it is excited by the third harmonic wavelength of Nd:YAG laser (355 nm). In our study, formaldehyde was excited by a pulse laser shot and the fluorescence at wavelength of 412.2 nm was selected for investigation. By this laser technique, the time resolved instantaneous distribution of formaldehyde on the platinum plate was successfully observed. The results show that the distribution of formaldehyde fluorescence is affected by gas velocity, catalyst temperature, and especially excess air ratio. The results correspond well with the results of a mathematical modeling for formaldehyde formation over Pt, and it confirms that this method is useful for analyzing the mechanism of catalytic combustion.

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Nguyen, Binh Thanh, and Min-Jung Kang. "Application of Capillary Electrophoresis with Laser-Induced Fluorescence to Immunoassays and Enzyme Assays." Molecules 24, no. 10 (2019): 1977. http://dx.doi.org/10.3390/molecules24101977.

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Capillary electrophoresis using laser-induced fluorescence detection (CE-LIF) is one of the most sensitive separation tools among electrical separation methods. The use of CE-LIF in immunoassays and enzyme assays has gained a reputation in recent years for its high detection sensitivity, short analysis time, and accurate quantification. Immunoassays are bioassay platforms that rely on binding reactions between an antigen (analyte) and a specific antibody. Enzyme assays measure enzymatic activity through quantitative analysis of substrates and products by the reaction of enzymes in purified enzyme or cell systems. These two category analyses play an important role in the context of biopharmaceutical analysis, clinical therapy, drug discovery, and diagnosis analysis. This review discusses the expanding portfolio of immune and enzyme assays using CE-LIF and focuses on the advantages and disadvantages of these methods over the ten years of existing technology since 2008.

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González Pérez, Martha, Débora Marcondes Bastos Pereira Milori, Ladislau Martin-Neto, et al. "Laser-induced fluorescence of organic matter from a Brazilian Oxisol under sewage-sludge applications." Scientia Agricola 63, no. 3 (2006): 269–75. http://dx.doi.org/10.1590/s0103-90162006000300009.

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Sludge applications have been used to maintain fertility of agricultural soils without damaging the natural ecosystem. The aim of this study was evaluating the influence of sewage-sludge addition on the quality of organic matter (OM) of a Brazilian Oxisol by Laser Induced Fluorescence (LIF). LIF was used to analyze OM of whole soil and different soil fractions separated by chemical and physical methods. The high fluorescence contribution of humin fraction to the fluorescence of whole soils was shown, stressing the importance of studying OM associated to mineral matrix of soil. Spectra with different shapes were obtained for every particle size fraction, indicating differences in organic compounds bounded to them. The fraction with the higher carbon content was the 2-20 µm, that contains ~5% C and represents only 10% in soil, but stores 34-39 % of total C and shows the highest fluorescence intensity. The spectrum of this fraction shows its heterogeneity and a higher concentration of compounds which fluorescence is centered at 510 nm. This indicates a higher concentration of unsaturated bond systems capable of high degree of resonance, increased conjugation of the electron pi system, and higher aromaticity comparing with other fractions. No differences were detected for treatments of sewage-sludge applications. LIF spectroscopy is a promising technique for OM studies in whole soils, allowing to study spatial distribution of OM within the soil's mineral matrix, including Oxisols.

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Алгазинов, Э. К., В. А. Шульгин, И. А. Лавриненко та А. А. Сирота. "Анализатор спектра флуоресценции на основе оптоволоконного Y-циркулятора". Письма в журнал технической физики 44, № 14 (2018): 50. http://dx.doi.org/10.21883/pjtf.2018.14.46344.17238.

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AbstractWe consider a method of probe analysis employing fiber-optic a composite Y-circulator design for the implementation of laser-induced fluorescence (LIF) spectroscopy diagnostics. The proposed principle of the LIF analyzer is based on spatially separated directed optical beams of excitation and fluorescence radiations. Conditions of the effective Y-circulator operation as a passive fiber-optic switch are determined. Experimental investigation of the switched radiation losses is performed. An example of using the proposed analyzer for LIF diagnostics of biological media is presented.

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Hernandez-Castillo, A. O., Johannes Bischoff, Ju Hyeon Lee, et al. "High-resolution UV spectroscopy of 1-indanol." Physical Chemistry Chemical Physics 23, no. 12 (2021): 7048–56. http://dx.doi.org/10.1039/d0cp06170k.

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Chen, Qingai, Lijun Deng, Jinxin Chi, Min Liu, Xucong Lin, and Zenghong Xie. "Sensitive profiling of trace neurotoxin domoic acid by pressurized capillary electrochromatography with laser-induced fluorescence detection." RSC Advances 7, no. 85 (2017): 53778–84. http://dx.doi.org/10.1039/c7ra10662a.

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A stable, sensitive and low-reagent consumption method for the quantification of trace neurotoxin domoic acid (DA) was presented by pressurized capillary electrochromatography (pCEC) with laser-induced fluorescence (LIF) detection.

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Zare, Richard N. "My Life with LIF: A Personal Account of Developing Laser-Induced Fluorescence." Annual Review of Analytical Chemistry 5, no. 1 (2012): 1–14. http://dx.doi.org/10.1146/annurev-anchem-062011-143148.

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Scheider, DM, BC Wilson, S. Hassaram, et al. "Laser-induced fluorescence (LIF) for the detection of neoplasia in the esophagus." Gastroenterology 108, no. 4 (1995): A534. http://dx.doi.org/10.1016/0016-5085(95)26451-5.

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Zhang, Yan, Yating Zhang, Luqi Zhu, Pingang He та Qingjiang Wang. "High sensitivity detection of Escherichia coli based on the measurement of β-galactosidase activity by microchip capillary electrophoresis combined with field-amplified sample injection". Analytical Methods 11, № 11 (2019): 1558–65. http://dx.doi.org/10.1039/c9ay00067d.

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Zhang, Yanmei, Feng Li, and Jingwu Kang. "Screening of histone deacetylase 1 inhibitors in natural products by capillary electrophoresis." Analytical Methods 9, no. 37 (2017): 5502–8. http://dx.doi.org/10.1039/c7ay01428g.

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A method for the screening of histone deacetylase 1 (HDAC1) inhibitors in natural products by using capillary electrophoresis (CE) coupled with laser induced fluorescence (LIF) detection was developed.

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Naulin, Christian, Michel Costes, Asmae Benseddik, and Gérard Dorthe. "Kinematic Effects on Laser-induced Fluorescence Measurements Performed in Reactive Crossed Beam Experiments." Laser Chemistry 8, no. 2-4 (1988): 283–302. http://dx.doi.org/10.1155/lc.8.283.

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A simple, realistic model is developed to take into account kinematic effects on laser-induced fluorescence (LIF) measurements in crossed beam reactive scattering experiments. The conversion factor from nascent populations to measured densities (which are proportional to the LIF intensity) is calculated for several cases of practical interest. The density-flux transformation proposed by Zare and coworkers arises from the model as a limiting case. Results concerning the C+NO→CN+O reaction, studied in a pulsed crossed supersonic beam experiment, are also included. Calculations carried out under various conditions emphasize the dramatic importance of beam collimation and pulse duration on detection efficiency.

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Gu, Yanhong, Zhaolu Zuo, Chaoyi Shi, and Xueyou Hu. "Feasibility Study for Spatial Distribution of Diesel Oil in Contaminated Soils by Laser Induced Fluorescence." Applied Sciences 10, no. 3 (2020): 1103. http://dx.doi.org/10.3390/app10031103.

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Laser induced fluorescence (LIF) technique has been demonstrated as a powerful technology for analyzing the contamination of petroleum due to its excellent attributes of rapid analysis speed and slight sample preparation. This study focuses on the monitoring application of LIF in petroleum hydrocarbon-contaminated soils by establishing the three-dimensional diffusion models. In this paper, to improve the analysis accuracy, the effects of soil matrix difference for fluorescence intensities were considered. In order to validate the practicability of LIF, the longitudinal penetration laws and the lateral diffusion laws of diesel oil in different humidity soils were analyzed. These laws indicate that the longitudinal penetration depth decreases and the lateral diffusion range increases with the increase of soil moisture. Then, the three-dimensional diffusion models were established, the relative standard deviation (RSD) of the predictions for diesel oil in different soil moisture are 5.09%, 9.62%, 7.92%, and the contaminated volumes of soils by diesel oil are 233.90 cm3, 332.70 cm3, and 660.05 cm3, respectively. These results express that the soil moisture extends the extent of diesel-contaminated soils. The present work shows the feasibility of LIF technique for the field monitoring of petroleum.

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Hartwig, Jason, Gaurav Mittal, and Chih-Jen Sung. "Acetone Tracer Laser-Induced Fluorescence (LIF) at 282 nm Excitation as a Diagnostic Tool in Elevated Pressure and Temperature Systems." Applied Spectroscopy 73, no. 4 (2019): 395–402. http://dx.doi.org/10.1177/0003702819830447.

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This paper provides new data at constant pressure, variable temperature and constant temperature, variable pressure over the range of temperature (295–750 K) and pressure (0.5–40 atm), in air and nitrogen bath gases at both constant number density and constant mole fraction needed to enable acetone laser-induced fluorescence (LIF) as a diagnostic tool in an elevated temperature and pressure environment. Results clearly indicate that the effect of elevated pressure on the temperature sensitivity of acetone LIF is negligible when the excitation wavelength is chosen near the absorption maximum, making acetone LIF ideal for measuring temperature fields in high-pressure systems. The data also show that the temperature sensitivity of fluorescence is relatively insensitive to changes in pressure at 282 nm excitation. Furthermore, at 282 nm, fluorescence per mole fraction can be used to extract temperature while fluorescence per molecule is relatively insensitive to temperature, making it optimal for concentration or pressure measurements.

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Bottorff, Brandon, Emily Reidy, Levi Mielke, Sebastien Dusanter, and Philip S. Stevens. "Development of a laser-photofragmentation laser-induced fluorescence instrument for the detection of nitrous acid and hydroxyl radicals in the atmosphere." Atmospheric Measurement Techniques 14, no. 9 (2021): 6039–56. http://dx.doi.org/10.5194/amt-14-6039-2021.

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Abstract. A new instrument for the measurement of atmospheric nitrous acid (HONO) and hydroxyl radicals (OH) has been developed using laser photofragmentation (LP) of HONO at 355 nm after expansion into a low-pressure cell, followed by resonant laser-induced fluorescence (LIF) of the resulting OH radical fragment at 308 nm similar to the fluorescence assay by gas expansion technique (FAGE). The LP/LIF instrument is calibrated by determining the photofragmentation efficiency of HONO and calibrating the instrument sensitivity for detection of the OH fragment. In this method, a known concentration of OH from the photo-dissociation of water vapor is titrated with nitric oxide to produce a known concentration of HONO. Measurement of the concentration of the OH radical fragment relative to the concentration of HONO provides a measurement of the photofragmentation efficiency. The LP/LIF instrument has demonstrated a 1σ detection limit for HONO of 9 ppt for a 10 min integration time. Ambient measurements of HONO and OH from a forested environment and an urban setting are presented along with indoor measurements to demonstrate the performance of the instrument.

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Danish, Azeem, Sang-Yong Lee, and Christa E. Müller. "Quantification of green fluorescent protein-(GFP-) tagged membrane proteins by capillary gel electrophoresis." Analyst 142, no. 19 (2017): 3648–55. http://dx.doi.org/10.1039/c7an00981j.

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A fast and robust procedure for the quantification of GFP-tagged membrane proteins in cell homogenates was developed employing capillary gel electrophoresis coupled to laser-induced fluorescence detection (CGE-LIF).

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Kröll, S., C. Löfström, and M. Aldén. "Background-Free Species Detection in Sooty Flames Using Degenerate Four-Wave Mixing." Applied Spectroscopy 47, no. 10 (1993): 1620–22. http://dx.doi.org/10.1366/0003702934334633.

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The background radiation disturbance in luminous environments has been compared for degenerate four-wave mixing (DFWM) and laser-induced fluorescence (LIF) for OH radical detection in a sooty propane/oxygen flame. The LIF signal generally was considerably stronger than the DFWM signal, but in strongly sooty environments the LIF signal was accompanied by a significant background signal, while the DFWM signal was background-free under all soot loads tested.

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de Sercey, G., M. Heikal, M. Gold, et al. "On the use of laser-induced fluorescence for the measurement of in-cylinder air—fuel ratios." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 216, no. 10 (2002): 1017–29. http://dx.doi.org/10.1243/095440602760400986.

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This paper presents the development of a new strategy for the calibration of air-fuel ratio measurements in engines by laser-induced fluorescence (LIF). After a brief introduction to the LIF technique, the paper highlights the structured approach undertaken to ensure that accurate quantitative measurements were produced. In particular, the new approach to coping with the fluorescence dependency on pressure and temperature, the issues related to the choice of a fluorescence tracer, the careful determination of the optimum tracer concentration and the complete calibration methodology are described, together with the resolution of some of the obstacles encountered. The paper concludes with some examples of calibrated measurements accompanied by a comparison of the results with combustion and emission performances. These results show a very good correlation.

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Novelli, A., C. Cho, H. Fuchs, et al. "Experimental and theoretical study on the impact of a nitrate group on the chemistry of alkoxy radicals." Physical Chemistry Chemical Physics 23, no. 9 (2021): 5474–95. http://dx.doi.org/10.1039/d0cp05555g.

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The chemistry of nitrated alkoxy radicals, and its impact on RO<sub>2</sub> measurements using the laser induced fluorescence (LIF) technique, is examined by a combined theoretical and experimental study.

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SHARIKOVA, ANNA V., and DENNIS K. KILLINGER. "LIF DETECTION OF TRACE SPECIES IN WATER USING DIFFERENT UV LASER WAVELENGTHS." International Journal of High Speed Electronics and Systems 17, no. 04 (2007): 689–95. http://dx.doi.org/10.1142/s0129156407004898.

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We have conducted studies of deep UV laser-induced fluorescence (LIF) for the reagentless detection of trace species and Dissolved Organic Compounds (DOC's) in water. Our LIF detection system had two interchangeable UV lasers, 266 nm and 355 nm, illuminating a flow cell containing a water sample. The fluorescence emitted at 90 degrees to the laser beam was collected by focusing optics, passed through cut-off and interference filters with 21 optical bandpass channels (240–680 nm ), and detected by a photomultiplier tube (PMT). The samples analyzed by the system included bottled, tap and river water; we have also worked with biological and chemical species (Bacillus Globigii, malathion). In terms of the excitation wavelength, it was observed that the deep UV excitation resulted in spectra that contained more features, and had better separation of the LIF from the Raman peak, thus enhancing the detection of unique spectral features.

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Journal articles on the topic 'Laser-induced fluorescence (LIF)'

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