Comparison of Video Technology with Classical Densitometry

Classical densitometry uses the spectral range from 190 to 800 nm with high spectral selectivity. Absorption spectra for substance identification can be recorded within this whole span. In contrast, video technology functions only in the visible range. The UV region - exceptionally productive for planar chromatography - is only indirectly accessible through the use of an UV indicator embedded in the layer and in cases where samples fluoresce. In this respect video technology parallels the human eye.

Spectral selectivity, a strong point of the classical densitometer, is not accessible with a video system. The greater the absorbance of the analyte at or near the excitation maximum of the UV indicator (254 nm), the higher are the sensitivity and accuracy of video quantification. In certain cases they may even become comparable to those of classical den-sitometry.

In fluorescence mode video and classical den-sitometry are comparable in respect to detection of emissions in the visible region, caused by long-wave UV light (366 nm). However, video technology lacks the variable-excitation-based selectivity of classical densitometry.

The limitation of image processing to visible light is not caused by the video camera, but by the fact that no solution has yet been found for uniformly illuminating a plate with monochromatic light of a selected

Figure 4 (See Colour Plate 30) Camag automated multiple development chamber AMD 2.

wavelength. In situ spectroscopy is only possible with the classical densitometer.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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