Ultraviolet-visible spectroscopy applications

T.J. Thurston, R.G. Brererton, D.J. Foord, R.E.A. Escott, Principal components plots for exploratory investigation of reactions using ultraviolet-visible spectroscopy application to the formation of benzophenone phenylhydrazone, Talanta, 63, 757-769 (2004). 

Chapter 5 covers ultraviolet-visible spectroscopy and Chapter 6, on immunoassay techniques, emphasizes the wide array of new methodologies that do not use radioisotopes. Chapter 7 discusses one of the most novel techniques for chromatographic separation of molecules—capillary electrophoresis—and its widespread applications to pharmaceuticals. Chapter 8, Atomic Spectroscopy, and Chapter 9, Luminescence Spectroscopy, contain current information on these important technologies. 

Quantitative infrared spectroscopy suffers certain disadvantages when compared with other analytical techniques and thus it tends to be confined to specialist applications. However, there are certain applications where it is used because it is cheaper or faster. The technique is often used for the analysis of one component of a mixture, particularly when the compounds in the mixture are alike chemically or haye very similar physical properties, e.g. structural isomers. In these cases, analysis by using ultraviolet/visible spectroscopy is difficult because the spectra of the components will be almost identical Chromatographic analysis may be of limited use because the separation of isomers, for example, is difficult to achieve. The infrared spectra of isomers are usually quite different in the fingerprint region. Another advantage of the infrared technique is that it is non-destructive and requires only a relatively small amount of sample. 

Applications of wavelet transform in ultraviolet visible spectroscopy... 

Many metal complexes and clusters are colored and have distinctive ultraviolet-visible spectra. [80] The method offers the advantage of ease of application, but it has been used only seldom in the characterization of zeolite entrapped oigano-metallics. The spectra may provide evidence of metal-metal bonds, as has been shown for carbonyl clusters of Fe, Ru, and Os, [81, 82] but there are hardly any data for zeolite entrapped clusters. The absorption bands of dusters are shifted to lower energy as the cluster nudearity increases. [83] Ultraviolet-visible spectroscopy has been used to detect the formation of [HFe3(CO)n] in NaY zeolite [50] and of clusters suggested to be [Pt,(CO),g] in NaY zeolite. [40-42] Since the spectra do not provide highly spedfic structural information, the method is of secondary importance. 

Horn, K., Applications of Ultraviolet/Visible Spectroscopy, Laboratory Report UV 31, Bodenseewerk Perkin-Elmer, Uberlingen, 5 Aug. 1986 25 p. 

The concentration of dye on a fabric after a given dyeing time can be determined by three methods (1) measurement of the decrease in dye concentration in solution with time by ultraviolet-visible spectroscopy, (2) determination of the dye concentration on the fabric dyed for a given time by dye extraction and ultraviolet-visible spectroscopy, or (3) by measurement of the reflectance spectra of the dyed fabric followed by application of the Kubelka-Munk relationship in which K/S. (K/S is the scat-... 

With the exception of single-crystal transmission work, most solids are too opaque to permit the conventional use of ultraviolet/visible (UV/VIS) electronic spectroscopy. As a result, such work must be performed through the use of diffuse reflection techniques [8-10]. Important work has been conducted in which UV/VIS spectroscopy has been used to study the reaction pathways of various solid state reactions. Other applications have been made in the fields of color measurement and color matching, areas which can be of considerable importance when applied to the coloring agents used in formulations. 

The fundamental principles of spectroscopy which are applied for visible spectroscopy are also applicable to ultraviolet region. 

The use of ultraviolet (UV) spectroscopy for on-line analysis is a relatively recent development. Previously, on-line analysis in the UV-visible (UV-vis) region of the electromagnetic spectrum was limited to visible light applications such as color measurement, or chemical concentration measurements made with filter photometers. Three advances of the past two decades have propelled UV spectroscopy into the realm of on-line measurement and opened up a variety of new applications for both on-line UV and visible spectroscopy. These advances are high-quality UV-grade optical fiber, sensitive and affordable array detectors, and chemometrics. 

F.C. Jentoft, Ultraviolet-Visible-Near Infrared Spectroscopy in Catalysis Theory, Experiment, Analysis, and Application Under Reaction Conditions, Adv. CataL, 52, 129-211 (2009). 

B-75MIU20I C. N. R. Rao Ultraviolet and Visible Spectroscopy Chemical Applications ,... 

Identification of the intermediates in a multi-step reaction is the major objective of studies of reaction mechanisms. It is most useful to study intermediates present in low concentrations without chemical interference with the reacting system, i.e. by rapid spectroscopic methods. The most common methods in organic chemistry include ultraviolet-visible (UV-VIS), IR, and EPR spectroscopy. In principle, all other spectroscopic methods for the detection of reaction intermediates are also applicable provided that they are fast enough to monitor the intermediate and able to provide sufficient structural information to assist in the identification of the transient species. 

To describe the principles, methodology, instmmentation and applications of ultraviolet (UV)/visible spectroscopy. 

The simultaneous application of EPR/ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS)/online gas chromatography (GC) to characterize working catalysts was realized a few years ago 14), and laser-Raman spectroscopy has recently been coupled with these to provide the first such simultaneous application of three techniques 15). 

The application of ultraviolet and visible spectroscopy to the identification and measurement of carbenium ions derived from aromatic and dienic monomer has already been discussed (see Sect. II-G-2). The use of this technique to monitor stable carbenium salts is also well known. We have finally stressed in a preceding section that the fate of certain anions could be followed spectrophotometrically during a cationic polymerisation. The limits of detection allowed by the values of the extinction coefficients of all these species and by the sensitivity of present-day instruments is 10 to 10 M. 

Analysis is an integral part of research, clinical, and industrial laboratory methodology. The determination of the components of a substance or the sample in question can be qualitative, quantitative, or both. Techniques that are available to the analyst for such determinations are abundant. In absorption spectroscopy, the molecular absorption properties of the analyte are measured with laboratory instruments that function as detectors. Those that provide absorbance readings over the ultraviolet-visible (UV-vis) light spectrum are commonly used in high-performance liquid chromatography (HPLC). The above method is sufficiently sensitive for quantitative analysis and it has a broader application than other modes of detection. 

Coupled spectroscopic methods such as TLC-UV (ultraviolet) and visible spectroscopy, TLC-mass spectrometry, and TLC-FTIR (Fourier transform infrared) have been developed to overcome this difficulty [7]. Their future application in the TLC analysis of natural pigments will markedly increase the information content of this simple and interesting separation technique. The automation of the various steps of TLC analysis (sample application, automated developing chambers, TLC scanners, etc.) greatly increased the reliability of the method, making it suitable for official control and legislative purposes [8]. 

Rao, CNR. Ultraviolet and Visible Spectroscopy. Chemical Applications. Butterworths, London, 1961, p. 65. 

F.T. Chau, T.M. Shih, J.B. Gao and C.K. Chan. Application of the Fast Wavelet Transform Method to Compress Ultraviolet-Visible Spectra. Applied Spectroscopy. 50(1996), 339-349. 

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