Miscellaneous Spectroscopies and Methods

Miscellaneous Spectroscopy and Physical Chemistry. The photochemistry of retinal and analogues and visual pigments has been reviewed.Another review discusses flash photolysis and pulse radiolysis of some carotenoids and visual pigments.Theoretical and experimental studies of carotenoids by various spectroscopic methods have been reported. Similar studies on retinal and derivatives have also been published. ... 

Degraded Carotenoids Physical Methods Separation and Assay N.M.R. Spectroscopy Mass Spectrometry Chiroptical Methods Electronic Absorption Spectroscopy Infrared and Resonance Raman Spectroscopy Other Spectroscopic Techniques Miscellaneous Physical Chemistry Photoreceptor Pigments Biosynthesis and Metabolism Stereochemistry Enzyme Systems Inhibition and Regulation... 

Modified fiber-optic-based sensors can be used for sensing pollutants, explosives, drugs, pharmaceuticals, and miscellaneous organics (Yeh et al. 2006). Optical fibers coated with porous silica can be used to detect the presence of chlorinated hydrocarbons. Alternatively, these compounds can also be detected using fiber-optic-coupled surface plasmon resonance methods. Aromatic compounds were detected by evanescent wave absorption spectroscopy. Suitably modified fiber-optic array tips can be used to detect presence of explosive materials (Wolfbeis 2000). 

Finally, a few miscellaneous methods for the syntheses of 1,3,2-dioxathiane 2-oxides and 2,2-dioxides have been reported. For example, germacrene-D 199 dropped into an ice-cooled mixture of ether and concentrated sulfuric acid causes the precipitation of sulfate 200 as colorless crystals <1988CPB3161>. The formation of the intramolecular cyclic sulfate was proven by IR and H and NMR spectroscopy (Scheme 57). The treatment of 2,5-norborna-diene with Phl/oleum provided a mixture of cyclic sulfates in 72% yield with the six-membered stmcture 202 being preferred (Scheme 57) <1986ZOR450>. Finally, a few 1,3,2-benzodioxathiins 204 were synthesized from the enaminones 203 by reaction with oleum or chlorosulfuric acid <1991AP949>. 

Ultraviolet and Visible Microwave Spectroscopy Miscellaneous Spectroscopic Methods Summary... 

This chapter is devoted to describing the basic aspects of the measurement, instmmentation, measurement techniques, and practical applications of potential-modulated UV-visible spectroscopy as a representative spectroelectrochemi-cal tool to characterize thin organic films on electrode surfaces and to track the kinetics of the electrode surface processes. At the same time, miscellaneous features of the measurement, which may be important for those who intend to apply for the first time the potential-modulated UV-visible spectroscopic method in their experiments, will also be included. However, because of the Hmit to the chapter length as well as the existence of superior review articles on UV-visible reflectance spectroscopy at electrode/solution interfaces [2,6-9], detailed comprehensive description is minimized. With the intention of overviewing the UV-visible spectroscopic method for the benefit of experimental electrochemists, optical issues, especially optical reflection theory, are not detailed. 

Miscellaneous other uses of emission spectroscopy should be mentioned. The cement and glass industries use spectroscopic methods for quality control. The food and beverage industries monitor trace element concentrations during processing. Spectroscopy is used for forensic purposes, usually to help identify samples as to source or origin. Meteorite composition also has been studied by spectroscopic methods, as have lunar samples returned to earth by astronauts. Emission spectroscopy also has served as a research tool in chemistry and physics by providing composition information on research samples. 

Miscellaneous methods. Some other techniques, such as dielectric constant measurements , conductimetry , mass spectrometry , and electronic spectroscopy are used less frequently but can also be useful. Change in vapor pressure determined with a manometric device can be used when the reaction mixture contains a volatile compound such as ethylene oxide... 

Henrich developed a comprehensive TLC method for identification of surfactants in formulations (4). She specified two reversed-phase and four normal phase systems, with detection by fluorescence quenching, pinacryptol yellow and rhodamine B, and iodine. Prior to visualization, one plate was scanned with a densitometer at 254 nm, and UV reflectance spectra were recorded for each spot detected. Tables were prepared showing the Rf values of 150 standard surfactants in each of the six systems, along with the reflectance spectra and response to the visualizers. This system allows for systematic identification of compounds of a number of surfactant types (LAS, alcohol sulfates and ether sulfates, alkane sulfonates, sufosuccinate esters, phosphate compounds, AE, APE, ethoxylated sorbi-tan esters, mono- and dialkanolamides, EO/PO copolymers, amine oxides, quaternary amines, amphoterics and miscellaneous compounds). Supplementary analysis by normal phase HPLC aided in exactly characterizing ethoxylated compounds. For confirmation, the separated spots may be scraped from one of the silica gel plates and the surfactant extracted from the silica with methanol and identified by IR spectroscopy. 

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