Video densitometry

B. Jaillard, L. Ruiz, and J. C. Arvicu, pH mapping in transparent gel using colour indicator video-densitometry. Plant Soil /83 85 (1996). 

Lenkey, B., Csanyi, J., and Nanasi, P. (1986). A rapid determination of sucrose and fructose in biological samples by video densitometry. J. Liq. Chromatogr. 9 1869-1875. 

TLC coupled with spectrometry and other analytical methods, video documentation, and computer imaging (Chapter 9) quantification by video densitometry (Chapter 10) validation of quantitative results (Chapter 11) and in situ instrumental measurement of radioactive zones (Chapter 13). The fomth edition continues to provide extensive coverage of sample preparation in Chapter 3. We believe that this coverage is unique and differs from that found in other available treatises on TLC. Because of the primary importance of commercial precoated plates, detailed instructions for preparing layers were removed (Chapter 3), and description of documentation by contact printing has been eliminated (Chapter 9). 

Analytical methods based on fluorescence are preferred over absorption for TLC quantiflcation. Fluorescent substances are excited by long-wave UV light (366 nm) the fluorescence emission in the visible region is detected. In this respect classical and video densitometry are comparable. However, video technology lacks the variable-excitation-based selectivity of classical densitometry. For the detection of fluorescent substances the intensity of the emitted fluorescence (/n) is directly proportional to the amount of substance applied. The most serious drawback of fluorescence measurements is the low quantum efficiency of the excitation process. The light intensity available for fluorescence measurements at a given intensity of illumination is, therefore, much smaller than the intensity that, under the... 

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