Qualitative Video Evaluation

Many of the illustrations in this book were produced by a video system. Not only can quahtative results be obtained using such systems, but semiquantitative evaluations are also possible from a good video shot of the chromatogram (see Fig. 72 in Section 5.1.2). Practical tips for the preparation of video shots are closely linked to the documentation and given described in detail in Section 8.4. 

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Modern TLC is thus an effective tool for separation of complex solutions into their components. Analysis can be qualitative or quantitative. When the composition or the analysed solution is known approximately, identification of the substance contained in a particular spot by its positional coordinates is frequently adequate. HPTLC provides the means not only for flexible screening procedures but also for demanding quantitative determinations. HPTLC features highly sensitive scanning densitometry and video technology for rapid chromatogram evaluation and documentation. 

In today s industry, digital cameras have replaced most video systems. All information about the illumination system, data processing equipment and image output system given in Section 7.3 also apply here. Only the current software determines how to achieve a qualitative and/or quantitative evaluation of chromatograms. For the topic Digital Camera see Documentation , Section 8.5. 

The high reproducibility of the positions of the spots, which is very important for interpretation of protein 2-DE maps, has been particularly improved with IPGs used in the first, lEF, dimension. For qualitative and quantitative analysis and for intergel comparison the 2-DE maps are converted into digital data using densitometers, scanners, or video cameras and evaluated by computer image analysis. 

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