Ultra-violet visible spectroscopy

E. Ultra violet/Visible Spectroscopy, Fluorescence, AND Phosphorescence... 

The oil shale of the Julia Creek deposit has been shown to contain a very complex mixture of vanadium porphyrin compounds. Several groups of compounds were isolated by column chromatography and high pressure liquid chromatography and examined by ultra-violet-visible spectroscopy, insertion probe, fast atom bombardment and field desorption mass spectrometry. These groups of compounds were found to consist of several homologous series, and included some compounds tentatively identified as phylloerythrin and chlorin derivatives. 

The UV (Ultra-Violet)-visible spectroscopy experiments were carried out on a Perkin Elmer spectrometer UV-VIS-PIR Lambda 19. 

The interaction of platinum with DNA has been clearly established both in vitro (8-11) and in vivo (12-14), and most modelling studies indicate that, although platinum can interact with the phosphate group (15), the prime interaction is with the purine and pyrimidine bases. Ultra-violet-visible spectroscopy (16,17) nuclear magnetic resonance (18,19) and x-ray photoelectron spectroscopy ( ) studies have been interpreted to suggest that sites of attack could be... 

There are so many techniques in spectroscopy, that I could spend the whole afternoon telling you about them. I have chosen 5 common ones. Mass spectrometry, Raman Spectroscopy, Ultra Violet/ Visible Spectroscopy, Infrared Spectroscopy, and Nuclear Magnetic Resonance Spectroscopy. The date beside them gives you an idea of when these techniques came into acceptance. Generally the data that you might find prior to the 40s and 50s will be of questionable quality. Because of many advancements in techniques in the 60s and 70s the best data can be found in the last 30 years. 

The use of ultra-violet (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. 

Ultra violet-visible reflectance spectroscopy ellipsometry as a spectroscopic tool 3)... 

In absorption spectroscopy, the sample is illuminated by a light with wavelengths in the ultra-violet/visible range by a source such as a tungsten filament, a deuterium arc lamp or light-emitting diodes. A diffraction... 

The absorption spectroscopy has been widely used for monitoring the rate of chemical reactions. During the reaction, if there is either appearance of colour in a colourless solution or disappearance of colour in a coloured solution or a species which absorbed at a specific wavelength is formed, the spectroscopic technique can be used. Instruments like colorimeters and spectrophotometers are available to cover the visible, near infrared and ultra violet region of the spectrum (200-1000 nm). The absorption spectroscopy is governed by well-known Beer-Lambert s Law according to which ... 

S. O Keeffe, C. Eitzpatrick, E. Lewis, An optical fibre based ultra violet and visible absorption spectroscopy system for ozone concentration monitoring. Sens. Actuators B, 125, 372-378 (2007). 

C.N.R. Rao, Ultra-Violet and Visible Spectroscopy, Butterworths, London, 1961. 

Rao, C. N. R. Ultra-violet and Visible Spectroscopy, Chemical Applications, 3rd ed. Butter-worths, London, 1975. 

With exception of the somewhat controversial satellite structures, photoelectron spectra induced by high-energy photons do not provide information about empty orbitals. This is a major simplification relative to spectroscopy in the visible, ultra-violet and X-ray regions, but at the same time, it contributes to the chemist s feeling that the picture obtained is somewhat incomplete. On the other hand, the evidence for the verifiable character of penultimate MO is overwhelmingly massive, and the valence region is now much better understood. 

Emission and absorption spectroscopy give the same information about enei level separations but practical considerations generally determine which technique is employed. Absorption of ultra violet and visible light is chiefly caused by electronic excitation, the spectrum provides limited information about the structure of the molecule. In order to obtain useful information from UV and visible range spectrum of a compound the wavelength of maximum absorption and the intensity of absorption must be measured accurately. The mechanics... 

The unit of wavelength commonly used in visible or ultra-violet spectroscopy is the angstrom unit, A, or the millimicron, m, equal to 10 A. Sometimes the wave number, v — 1/A, is also used. The unit of wave number is the reciprocal centimetre, cm"1. 

---