Spectroscopic analysis Fluorescence Spectrometry

Various spectroscopic techniques such as flame photometry, emission spectroscopy, atomic absorption spectrometry, spectrophotometry, flu-orimetry, X-ray fluorescence spectrometry, neutron activation analysis and isotope dilution mass spectrometry have been used for marine analysis of elemental and inorganic components [2]. Polarography, anodic stripping voltammetry and other electrochemical techniques are also useful for the determination of Cd, Cu, Mn, Pb, Zn, etc. in seawater. Electrochemical techniques sometimes provide information on the chemical species in solution. 

Each spectroscopic method has a characteristic application. For example, flame photometry is still applicable to the direct determination of Ca and Sr, and to the determination of Li, Rb, Cs and Ba after preconcentration with ion-exchange resin. Fluorimetry provides better sensitivities for Al, Be, Ga and U, although it suffers from severe interference effects. Emission spectrometry, X-ray fluorescence spectrometry and neutron activation analysis allow multielement analysis of solid samples with pretty good sensitivity and precision, and have commonly been applied to the analysis of marine organisms and sediments. Recently, inductively-coupled plasma (ICP)... 

In both total and sequential dissolutions, the result is a solution containing the components of rocks and soils. This solution is then analyzed by different methods. Mostly, spectroscopic methods are used atomic absorption and emission spectroscopic methods, ultraviolet, atom fluorescence, and x-ray fluorescence spectrometry. Multielement methods (e.g., inductively coupled plasma optical emission spectroscopy) obviously have some advantages. Moreover, elec-troanalytical methods, ion-selective electrodes, and neutron activation analysis can also be applied. Spectroscopic methods can also be combined with mass spectrometry. 

Spectroscopic Methods of Analysis Diffuse Reflectance Spectroscopy / 3375 Spectroscopic Methods of Analysis Fluorescence Spectroscopy / 3387 Spectroscopic Methods of Analysis Infrared Spectroscopy / 3405 Spectroscopic Methods of Analysis Mass Spectrometry / 3419 Spectroscopic Methods of Analysis Near-Infrared Spectrometry / 3434 Spectroscopic Methods of Analysis Nuclear Magnetic Resonance Spectroscopy / 3440... 

Chapter 11 details the relevant methods of analysis for both metals and organic compounds. For elemental (metal) analysis, particular attention is given to atomic spectroscopic methods, including atomic absorption and atomic emission spectroscopy. Details are also provided on X-ray fluorescence spectrometry for the direct analysis of metals in solids, ion chromatography for anions in solution, and anodic stripping voltammetry for metal ions in solution. For organic compounds,... 

There are three main atomic spectroscopic techniques that are used for the analysis of acid digests atomic absorption spectrometry (AAS), inductively coupled plasma-atomic emission spectrometry (ICP-AES) and atomic fluorescence spectrometry (AFS). Of these, AAS and ICP-AES are the most widely used. Our discussion will deal with these techniques and also an affiliated technique, inductively coupled plasma mass spectrometry (ICP-MS). 

A second fluorescent Chl-catabolite, Ca-FCC-2, was isolated from another in vitro system, based on enzymatic activity obtained from ripe (red) sweet pepper (Capsicum annuurri) and its structure was analyzed (67). The new fluorescent catabolite could be shown by mass spectrometry to be an isomer of 10 Further NMR-spectroscopic analysis revealed Ca-FCC-2 to have the same constitution and to differ from pFCC (10) only in the absolute configuration at C(l). Ca-FCC-2 was thus assigned as the epimeric primary I -epz-pFCC (epi-10) (67). 

The application of microtron photon activation analysis with radiochemical separation in environmental and biological samples was described by Randa et al. (2001), and both flame and plasma emission spectroscopic methods are also widely used. A more recently developed technique is that of laser-excited atomic fluorescence spectrometry (LEAFS) (Cheam et al. 1998). 

Owing to their superior fluorescent yield, heavy elements ordinarily yield considerably more intense XRF bands than the light elements. This feature can be exploited to determine the concentration of inorganic species in a sample, or the concentration of a compound that contains a heavy element in some matrix. Many potential XRF applications have never been developed owing to the rise of atomic spectroscopic methods, particularly inductively coupled plasma atomic emission spectrometry [74]. Nevertheless, under the right set of circumstances, XRF analysis can be profitably employed. 

The detection and identification of phenolic compounds, including phenolic acids, have also been simph-fied using mass spectrometry (MS) techniques on-hne, coupled to the HPLC equipment. The electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) interfaces dominate the analysis of phenohcs in herbs, fmits, vegetables, peels, seeds, and other plants. In some cases, HPLC, with different sensitivity detectors (UV, electrochemical, fluorescence), and HPLC-MS are simultaneously used for the identification and determination of phenolic acids in natural plants and related food products.In some papers, other spectroscopic instmmental techniques (IR, H NMR, and C NMR) have also been apphed for the identification of isolated phenolic compounds. 

Vol. 117. Applications of Fluorescence in Immunoassays. By Ilkka Hemmila Vol. 118. Principles and Practice of Spectroscopic Calibration. By Howard Mark Vol. 119. Activation Spectrometry in Chemical Analysis. By S. J. Parry Vol. 120. Remote Sensing by Fourier IVansform Spectrometry. By Reinhard Beer Vol. 121. Detectors for Capillary Chromatography. Edited by Herbert H. Hill and Dennis McMinn... 

Part V covers spectroscopic methods of analysis. Basic material on the nature of light and its interaction with matter is presented in Chapter 24. Spectroscopic instruments and their components are described in Chapter 25. The various applications of molecular absorption spectrometric methods are covered in some detail in Chapter 26, while Chapter 27 is concerned with molecular fluorescence spectroscopy. Chapter 28 discusses various atomic spectrometric methods, including atomic mass spectrometry, plasma emission spectrometry, and atomic absorption spectroscopy. 

Limited periods of illumination or excitation of the sample represent still another cause of photon starvation. Brief periods of illumination are often necessary in a number of spectroscopic applications to avoid deleterious effects. For example, prolonged irradiation of various fluorescing compounds can often result in bleaching. Similarly, microsample analysis by Raman spectrometry can easily cause structural and compositional damage to the sample upon long exposure to the intense excitation radiation. 

Interferences are physical or chemical processes that cause the signal from the analyte in the sample to be higher or lower than the signal from an equivalent standard. Interferences can therefore cause positive or negative errors in quantitative analysis. There are two major classes of interferences in AAS, spectral interferences and nonspectral interferences. Nonspectral interferences are those that affect the formation of analyte free atoms. Nonspectral interferences include chemical interference, ionization interference, and solvent effects (or matrix interference). Spectral interferences cause the amount of light absorbed to be erroneously high due to absorption by a species other than the analyte atom. While all techniques suffer from interferences to some extent, AAS is much less prone to spectral interferences and nonspectral interferences than atomic anission spectrometry and X-ray fluorescence (XRF), the other major optical atomic spectroscopic techniques. 

Commonly used spectroscopic or analytical techniques for characterizing surfaces and coating layers on porous silicon are Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, energy dispersive X-ray spectrometry, fluorescence spectroscopy, UV-Vis absorption/reflectance spectroscopy, thin film optical interference spectroscopy, impedance spectroscopy, optical microscopy, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, ellipsometry, nitrogen adsorption/desorp-tion analysis, and water contact angle. 

The individual separation, identification, and quantification of OL derivatives from natural extracts have been realized basically by chromatographic separation or capillary electrophoresis methods. Both gas and liquid chromatographies have been exploited, combined with several detection methods such as UV, fluorescence, and mass spectrometry (MS) [14], Soft spectroscopic techniques as midium infrared spectroscopy have been recently explored for rapid quantification of OL [61], while high-resolution spectroscopic techniques as nuclear magnetic resonance are considered interesting applicatimi in the analysis of the OL derivative structures [14]. 

There are many techniques [26] for characterization of HPOPs. Spectroscopic methods such as infrared spectroscopy, visible spectroscopy, diffuse reflectance spectroscopy, mass spectrometry (MS), atomic absorption (AA), inductively coupled plasma (ICP), X-ray fluorescence (XRF), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), electron spectroscopy for chemical analysis (ESCA),... 

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