Absorption spectroscopy spectrometry, spectrophotometry

GFAAS = graphite furnace (flameless) atomic absorption spectroscopy TLC = thin layer chromatography HFP-AES = high frequency plasma-atomic emission spectroscopy NAA = neutron atomic analysis ICP-AES = inductively coupled plasma-atomic emission spectroscopy AAS = atomic absorption spectrometry GSE = graphite spectroscopic electrode UV = ultraviolet spectrophotometry PD = photodensitometer and (3,5-diBr-PADAP) = 2(-3,-5-dibromo-2-pyridylazo)-5- diethyl-ami nophenol. 

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. 

The chemical methods for detecting total strontium include spectrophotometry, fluorometry, kinetic phosphorescence, atomic absorption spectroscopy (e.g., flame and graphite furnaces), inductively coupled plasma spectroscopy atomic emission and mass spectrometry applications (i.e., ICP-AES and ICP-MS). 

This article provides some general remarks on detection requirements for FIA and related techniques and outlines the basic features of the most commonly used detection principles, including optical methods (namely, ultraviolet (UV)-visible spectrophotometry, spectrofluorimetry, chemiluminescence (CL), infrared (IR) spectroscopy, and atomic absorption/emission spectrometry) and electrochemical techniques such as potentiometry, amperometry, voltammetry, and stripping analysis methods. Very few flowing stream applications involve other detection techniques. In this respect, measurement of physical properties such as the refractive index, surface tension, and optical rotation, as well as the a-, //-, or y-emission of radionuclides, should be underlined. Piezoelectric quartz crystal detectors, thermal lens spectroscopy, photoacoustic spectroscopy, surface-enhanced Raman spectroscopy, and conductometric detection have also been coupled to flow systems, with notable advantages in terms of automation, precision, and sampling rate in comparison with the manual counterparts. 

Numerous methods have been pubUshed for the determination of trace amounts of tellurium (33—42). Instmmental analytical methods (qv) used to determine trace amounts of tellurium include atomic absorption spectrometry, flame, graphite furnace, and hydride generation inductively coupled argon plasma optical emission spectrometry inductively coupled plasma mass spectrometry neutron activation analysis and spectrophotometry (see Mass spectrometry Spectroscopy, optical). Other instmmental methods include polarography, potentiometry, emission spectroscopy, x-ray diffraction, and x-ray fluorescence. 

Infrared Spectrophotometry. The isotope effect on the vibrational spectmm of D2O makes infrared spectrophotometry the method of choice for deuterium analysis. It is as rapid as mass spectrometry, does not suffer from memory effects, and requites less expensive laboratory equipment. Measurement at either the O—H fundamental vibration at 2.94 p.m (O—H) or 3.82 p.m (O—D) can be used. This method is equally appticable to low concentrations of D2O in H2O, or the reverse (86,87). Absorption in the near infrared can also be used (88,89) and this procedure is particularly useful (see Infrared and raman spectroscopy Spectroscopy). The D/H ratio in the nonexchangeable positions in organic compounds can be determined by a combination of exchange and spectrophotometric methods (90). 

In 1C, the election-detection mode is the one based on conductivity measurements of solutions in which the ionic load of the eluent is low, either due to the use of eluents of low specific conductivity, or due to the chemical suppression of the eluent conductivity achieved by proper devices (see further). Nevertheless, there are applications in which this kind of detection is not applicable, e.g., for species with low specific conductivity or for species (metals) that can precipitate during the classical detection with suppression. Among the techniques that can be used as an alternative to conductometric detection, spectrophotometry, amperometry, and spectroscopy (atomic absorption, AA, atomic emission, AE) or spectrometry (inductively coupled plasma-mass spectrometry, ICP-MS, and MS) are those most widely used. Hence, the wide number of techniques available, together with the improvement of stationary phase technology, makes it possible to widen the spectrum of substances analyzable by 1C and to achieve extremely low detection limits. 

UV/Vis spectrophotometry, see Absorption spectrophotometry Reflectance spectrophotometry Spectrometry Spectroscopy... 

Inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry have been applied to the determination of zinc, as discussed under Multi-Metal Analysis of Soils in Sects. 2.55 (inductively coupled plasma atomic emission spectrometry) and 2.55 (inductively coupled plasma mass spectrometry). Other techniques include atomic absorption spectrometry (Sect. 2.55), X-ray fluorescence spectroscopy (Sect. 2.55), electron probe microanalysis (Sect. 2.55), photon activation analysis (Sect. 2.55), emission spectrometry (Sect. 2.55), neutron activation analysis (Sect. 2.55), spectrophotometry (Sect. 2.55) and ion chromatography (Sect. 2.55). 

Both molecular and atomic detectors have been used in combination with SCF extractors for monitoring purposes. Thus, the techniques used in combination with SFE are infrared spectroscopy, spectrophotometry, fluorescence spectrometry, thermal lens spectrometry, atomic absorption and atomic emission spectroscopies, mass spectrometry, nuclear magnetic resonance spectroscopy, voltammetry, and piezoelectric measurements. 

Absorption spectrophotometry Fluorescence methods Atomic-absorption methods Flame photometry Neutron activation analysis Emission spectroscopy Spark source mass spectrometry Reaction gas chromatography of chelates using electron-capture detection... 

Chemical analysis of hazardous substances in air, water, soil, sediment, or solid waste can best be performed by instrumental techniques involving gas chromatography (GC), high-performance liquid chromatography (HPLC), GC/mass spectrometry (MS), Fourier transform infrared spectroscopy (FTIR), and atomic absorption spectrophotometry (AA) (for the metals). GC techniques using a flame ionization detector (FID) or electron-capture detector (BCD) are widely used. Other detectors can be used for specific analyses. However, for unknown substances, identification by GC is extremely difficult. The number of pollutants listed by the U.S. Environmental Protection Agency (EPA) are only in the hundreds — in comparison with the thousands of harmful... 

The quality control analyses of these chemicals are performed using almost the whole range of trace analysis techniques available. Among the most important are atomic absorption spectrophotometry in all its forms, ICP emission spectrometry, and ICP mass spectroscopy, ion chromatography, gas and liquid chromatography, ultraviolet and visible absorption spectrophotometry, voltammetry, and spectro-fluorimetry. 

See also Atomic Absorption Spectrometry Principles and Instrumentation. Chiroptical Analysis. Chromatography Overview Principles. Clinical Analysis Glucose. Enzymes Enzyme-Based Electrodes. Food and Nutritional Analysis Overview. Infrared Spectroscopy Overview. Mass Spectrometry Overview. Nuclear Magnetic Resonance Spectroscopy Overview. Nuclear Magnetic Resonance Spectroscopy Applications Food. Optical Spectroscopy Detection Devices. Sampling Theory. Spectrophotometry Overview. Sweeteners. X-Ray Absorption and Diffraction Overview. 

See also Asbestos. Color Measurement. Forensic Sciences Thin-Layer Chromatography. Gas Chromatography Pyrolysis Mass Spectrometry Fourier Transform Infrared Spectroscopy. Microscopy Applications Forensic. Spectrophotometry Diode Array. Textiles Natural Synthetic. X-Ray Absorption and Diffraction X-Ray Diffraction - Powder. X-Ray Fluorescence and Emission X-Ray Fluorescence Theory Energy Dispersive X-Ray Fluorescence Total Reflection X-Ray Fluorescence. 

Acid digestion or extraction, atomic absorption spectrometry (flame, cold vapor, hydride generation, and electrothermal), emission spectroscopy (plasma and flame), spectrophotometry, anodic stripping voltametry... 

Several different methods have been utilized for measuring iron in these biological samples. However, spectrophotometry is the most widely used because it does not require unusual equipment and is readily amenable to automation. Atomic absorption spectrometry is effectively used for tissue and urine analyses [33-35], but unreliable results are obtained with serum due to sensitivity limitations as well as matrix and hemoglobin interferences [35]. Other methods utilizing inductively coupled plasma emission spectroscopy [36], coulometry [37], proton induced X-ray emission [38], neutron activation analysis [39], radiative energy attenuation [40], and radiometry with Fe [41] have been described but, with the exception of coulometry, have not become standard procedures in the clinical chemistry laboratory, inasmuch as sophisticated and expensive instrumentation is required in some instances. However, some of them, e.g., neutron activation, may be the method of choice for definitive accurate analysis. 

Determination of the rare-element content in rock samples is a more difficult analytical problem than determination of the main components. The development of optical spectroscopy, X-ray fluorescence analysis, atomic absorption spectrophotometry (AAS), mass spectrometry and other analytical methods from the middle of the 20 century made careful mapping of the composition of the crust possible, even for the rarer elements. The content of each element is given in the corresponding element chapter. 

This chapter focuses on the extraction and handling of retinoids and carotenoids, their separation by various chromatographic techniques, and their detection and quantitation, primarily by absorption spectrophotometry, fluorescence, and mass spectrometry. A variety of other methods exist for their identification and characterization, including circular dichroism (333), infrared spectroscopy (334), resonance Raman spectroscopy (335), NMR spectroscopy (336), and x-ray crystallography (337). Although some of these procedures require substantial amounts of a retinoid or a carotenoid in an essentially pure form for study, others, such as resonance Raman spectroscopy, are extremely sensitive and can be used to detect the localization of carotenoids in single cells (338,339). 

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