Laser Applications to Chemical Analysis最新文献_第10页

Four Wave Difference Mixing in Sodium Using CH4/Air Flame 用CH4/空气火焰混合钠的四波差

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1992.tua4

J. Singh, F. Yueh

引用次数: 0

Laser Ionization of Biomolecules in Solution 溶液中生物分子的激光电离

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1994.tha.5

Kermit K. Murray, M. D. Beeson, D. Russell

{"title":"Laser Ionization of Biomolecules in Solution","authors":"Kermit K. Murray, M. D. Beeson, D. Russell","doi":"10.1364/laca.1994.tha.5","DOIUrl":"https://doi.org/10.1364/laca.1994.tha.5","url":null,"abstract":"Many powerful laser based methods are unavailable for the analysis of molecules in solution. Techniques for the analysis of liquids are particularly important for the study of biomolecules, whose natural environment is a water solution. Mass spectrometry is a powerful analytical technique, but liquids and mass spectrometers are fundamentally incompatible. We have developed a technique for laser ionization of biomolecules in solution by applying matrix-assisted laser desorption ionization (MALDI) to liquid aerosols. In the typical MALDI experiment, the analyte biomolecule is deposited from solution onto a metal surface with a 100 to 50,000 molar excess of a suitable matrix, usually a UV absorbing organic acid.1 The solvents are allowed to evaporate and the sample is inserted into the source region of a mass spectrometer. Light from a pulsed laser is absorbed by the matrix causing both ablation of the surface and ionization of the intact biomolecule. In the aerosol MALDI experiment, 2,3 the analyte biomolecule is dissolved in a methanol solution with an ultraviolet absorbing matrix. The aerosol is sprayed into vacuum, desolvated, and ionized by pulsed UV laser radiation. The ions are mass separated in a time-of-flight (TOF) mass spectrometer. Aerosol MALDI mass spectra have been obtained for a variety of peptides and proteins with molecular weights as large as 80,000. We have used aerosol MALDI as a liquid chromatography detection method4 (LC/MS) and as a probe of aerosol and cluster chemistry.5 This paper gives a general description of aerosol MALDI and discusses some recent results for peptide and protein ionization.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"69 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133155975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An Ultrasensitive Laser Microprobe for Detection of Surface Contamination 一种用于表面污染检测的超灵敏激光微探针

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1992.thb5

M. Duignan, C. Christensen

引用次数: 0

Wavelength Modulation Atomic Absorption Spectrometry With Semiconductor Diode Lasers 波长调制原子吸收光谱与半导体二极管激光器

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1994.wb.4

K. Niemax, C. Schnürer-Patschan, A. Zybin, H. Groll, Y. Kuritsyn

{"title":"Wavelength Modulation Atomic Absorption Spectrometry With Semiconductor Diode Lasers","authors":"K. Niemax, C. Schnürer-Patschan, A. Zybin, H. Groll, Y. Kuritsyn","doi":"10.1364/laca.1994.wb.4","DOIUrl":"https://doi.org/10.1364/laca.1994.wb.4","url":null,"abstract":"Commercial semiconductor laser diodes of the AlGaAs and AlGaInP types are small, long-lived devices with excellent spectroscopic properties [1]. They are easy to operate and have low power consumption. These are the requirements for the arrangement of many independently operating laser diodes in compact instruments for simultaneous multielement analysis [2]. The main drawback of atomic diode laser spectroscopy is the limited wavelength range of commercially available laser diodes (625-950 nm). It will be extended to shorter wavelengths in the short and medium run. However, if low radiation powers can be used in experiment, it can be overcome by second harmonic generation (SHG) in non-linear crystals. Depending on the fundamental power of the laser diodes and on the efficiency of the crystal used, extracavity SHG-powers in the nW and μW can be generated easily in the range 315-500 nm. Such powers are sufficiently high for laser atomic absorption spectroscopy (LA AS). A list including more than 50 elements which can be measured by LA AS with fundamental and SHG radiation is given in a recent review paper [3].","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123348410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cellular and Biological Applications of Laser Induced Fluorescence 激光诱导荧光的细胞和生物学应用

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1994.thc.1

L. Sklar, G. M. Jones, T. G. Houghton

引用次数: 0

Laser Desorption Jet-Cooling Spectroscopy of Organic Molecules 有机分子的激光解吸射流冷却光谱

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1990.pd5

G. Meijer, M. de Vries, H. Wendt, H. Hunziker

引用次数: 0

Fluorescence Analysis of Microdroplets: An Approach to Single Molecule Detection 微滴荧光分析:一种单分子检测方法

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1990.tha4

J. Ramsey, W. Whitten

{"title":"Fluorescence Analysis of Microdroplets: An Approach to Single Molecule Detection","authors":"J. Ramsey, W. Whitten","doi":"10.1364/laca.1990.tha4","DOIUrl":"https://doi.org/10.1364/laca.1990.tha4","url":null,"abstract":"The extreme sensitivity of fluorescence spectrophotometry results from the fact that a molecule can undergo many excitation-emission cycles before destruction by photochemical degradation. For example, Rhodamine 6G (R6G) can emit in excess of 105 photons before photolysis takes place (1). The fraction of emitted photons collected and converted to countable pulses can be as high as 10-3, although 10-4 is more readily attainable. Therefore, sufficient signal exists for single molecules to be detectable. Detection limits for molecules in solution have been limited by background signal from solvent Raman scattering and fluorescence. This background signal adds noise to the measurement and has effectively restricted the detectable concentration to about 10-13 molar. Over the past decade, advances in detection of fewer molecules have all been made by reducing the measurement volume and/or increasing the measuring time. Given the above concentration detection limit a reduction of the measurement volume to 1 pL leads to a minimum observable quantity of ≈ 1 molecule. The ability to detect a single molecule in condensed phase could have many important applications in addition to being an interesting problem. The obvious application of this approach is to situations where small quantities of material are available for analysis. The capability to reliably detect a single fluorophore might also allow the screening and/or sorting of a collection of molecules. Such abilities would have application to many biological problems such as DNA sequencing and detection of DNA adducts.","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128318686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Fluorescence Spectroscopy on a Single Molecule Basis with a Near-field Spectrometer 利用近场光谱仪进行单分子荧光光谱分析

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1994.thd.4

X. S. Xie, R. Dunn

引用次数: 0

Degenerate Four Wave Mixing techniques for Combustion Diagnostics 燃烧诊断中的简并四波混频技术

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1992.tua1

P. Ewart

{"title":"Degenerate Four Wave Mixing techniques for Combustion Diagnostics","authors":"P. Ewart","doi":"10.1364/laca.1992.tua1","DOIUrl":"https://doi.org/10.1364/laca.1992.tua1","url":null,"abstract":"Degenerate Four Wave Mixing, DFWM, is a third order nonlinear optical process which has been used for high resolution spectroscopy and, by virtue of its phase conjugating property, for adaptive optics(1). The process is closely related to Coherent Anti-Stokes Raman Scattering, CARS, which is widely used for temperature and concentration measurements of majority species in combustion studies(2). Minority species, on the other hand are usually detected using the more sensitive technique of Laser Induced Fluorescence, LIF. DFWM shares the coherence property of CARS and the sensitivity of LIF and thus provides a coherent technique for the detection of minority species such as radicals and combustion intermediates. This new technique has the added advantageous property of phase conjugation. DFWM signals have been generated from atomic Na in seeded flames(3,4) and the potential of the technique for combustion diagnostics was demonstrated by the detection of the OH radical in a methane/air flame(3). More recent developments have included two-dimensional single-shot imaging of atomic and molecular distributions(5,6), accurate flame temperature measurements based on rotationally resolved DWFM spectra(7), broadband or multiplex DFWM in flames(8) and two-dimensional mapping of temperature fields(9).","PeriodicalId":252738,"journal":{"name":"Laser Applications to Chemical Analysis","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126367138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

CARS from Lift-Off to Re-Entry 从发射到重返大气层

Laser Applications to Chemical Analysis Pub Date : 1900-01-01 DOI: 10.1364/laca.1990.mb1

J. Taran

引用次数: 0