Chromatogram Evaluation

Electronic image acquisition

For electronic image acquisition the camera – like the human eye – captures polychromatic visible light. Under white light illumination it is the light reflected from the layer background. Under long-wavelength UV light (366 nm) it is the light emitted by fluorescent substances. When short-wavelength UV light (254 nm) is used, substances absorbing UV 254 nm appear as dark zones, provided the layer contains a fluorescence indicator (fluorescence quenching). The TLC Visualizer 2 is CAMAG’s imaging and documentation system operated with visionCATS. visionCATS enables an image-based evaluation of chromatograms for quantitative evaluation. The strength of the electronic image acquisition is the overview of the complete chromatogram.

Chromatogram under white light

Chromatogram under UV 254 nm

Chromatogram under UV 366 nm

Scanning densitometry

In classical scanning densitometry the tracks of the chromatogram are scanned with monochromatic light in the form of a slit selectable in length and width. The spectral range of the CAMAG TLC Scanner 4 is 190–900 nm. Reflected light is measured either in the absorbance or in the fluorescence mode. From the acquired data quantitative results are computed with high precision and spectral selectivity.

With the TLC Scanner 4 absorption spectra can be recorded. The strengths of classical densitometry as compared with image evaluation are spectral selectivity and the higher precision of quantitative determinations.

Applying samples in the form of narrow bands allows densitometric evaluation by aliquot scanning, i.e. scanning with a slit about 2/3 of the track width. This improves reproducibility as the center portion of the sample zone is homogeneous and positioning errors, which can occur with samples applied as spots, are avoided.

For quantification sample zones should always be scanned with the wavelength of maximum absorbance which can be determined by spectra recording or by multi-wavelength scanning.


The CAMAG BioLuminizer® 2 is a detection system specifically designed to detect bioluminescence on HPTLC plates.
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TLC-MS Interface 2
The elution-based CAMAG TLC-MS Interface 2 is a highly convenient and versatile instrument allowing for rapid and contamination-free elution of TLC/HPTLC zones with direct transfer to a mass spectrometer.
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TLC Visualizer 2
Professional imaging and documentation system for TLC/HPTLC chromatograms and other planar objects with a state-of-the-art digital CCD camera, connected by USB 3.0
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TLC Scanner 4
The CAMAG TLC Scanner 4 is the most advanced workstation for densitometric evaluation of TLC/HPTLC chromatograms and other planar objects.
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UV Lamp 4
The CAMAG UV Lamp 4 is designed for use in a TLC laboratory.
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UV Cabinet 4
The UV Cabinet 4 is designed for inspecting thin-layer chromatograms or other objects under UV light in absence of ambient light.
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