Light-cabinet densitometer

Simple design, fast learning curve, moderate price and good accuracy make it a fit for labs of any level. The densitometer requires no change to existing TLC methods and can process any chromatogram visible in daylight or under 254 nm / 365 nm UV.

Kit composition (for UV imaging):

• light cabinet with three modes (daylight, UV 254 nm, UV 365 nm);
• colour video camera;
• video-capture unit;
• Sorbfil TLC View software for evaluation and quantitative calculation.

With the software the densitometer supports two quantitative calculations: percentage composition of a mixture and concentration of an analyte in a sample.

Principle. Modern video technology only sees visible light. The UV region is accessed indirectly, exactly as the human eye does: fluorescent compounds are excited by UV and emit visible light; UV-absorbing compounds appear as dark spots where they quench the fluorescence of the indicator in the plate layer.

A plate of up to 150×150 mm is clamped on the stage and slid into the light cabinet. The chromatogram image — daylight or UV — is captured by the camera, fed via the capture unit to the computer, stored, and processed in the software.

The light cabinet is an opaque metal enclosure. The sample stage slides in and out through a hinged door on the front panel. UV lamps at 254 and 365 nm are mounted on top. Light from the 254 nm lamps passes through filters that isolate that wavelength; the 365 nm lamps carry their own integrated filter.

Distinguishing features of Sorbfil densitometry:

• fast calculation;
• low-cost consumables;
• electronic chromatograms remain available for re-calculation at any time.