High Performance Thin Layer Chromatography (HPTLC) is a visual chromatographic technique. What do we mean by the visual approach? The chromatograms, i.e., HPTLC plates, are observed after development. The human eye can see visible spots/bands. If the bands are UV active, we need to observe them under UV. Hence, the HPTLC plate can be visually evaluated, which sets it apart from other chromatographic techniques. The results are monitored and documented.
How are the results observed/ documented?
HPTLC/TLC results are visual and can be observed by the HPTLC Photodocumentation system. For the HPTLC photodoc, CAMAG has modules such as CAMAG TLC visualizer 2. It has a digital CCD camera. The TLC visualizer electronically captures the high-resolution images of chromatograms under white light, UV 254nm, and under fluorescence. It merges three images to give the best image possible, aided by software-controlled visionCATS for documentation. The software has image enhancement tools. The data generated is stored and can be used for further evaluation. “Comparison viewer” is a powerful tool available in software through which bands/tracks from the same /different plates can be compared side by side.
Another TLC photodoc system available with CAMAG is UV Cabinet 4. It has a UV lamp to observe the chromatogram under 254nm and 366nm. A UV filter is provided in viewing windows for eyes protection. This is not a software-controlled module. It can be manually operated, and a person can capture chromatogram images through a mobile phone camera.
CAMAG Smartdigi, one of the TLC photodocumentation modules, is specially designed for the Indian consumer at a low cost. It has a provision for mounting a digital camera to capture images under white light, UV 254nm, and UV 366nm. The visual presentation of the complete chromatogram showing the UV active samples and ideal standards side by side is one of the most convincing arguments for adopting the HPTLC Photodocumentation system. No other technique can directly produce the result as a color image and make it available for visual evaluation.