The Shimadzu CS 920 densitometer: illumination of thin layer chromatograms with a parallel light beam and its effects...

The Shimadzu CS 920 has shown to be an easy to handle flying-spot densitometer that enables rapid quantification of thin layer chromatograms. Linear calibration curves with a relative standard deviation of 3 to 4% in the slope can be obtained for Sudan Yellow on Merck H60 plates. However, contrary to the statements in the instrument manual, the 'linearizer' performance is not in agreement with the Kubelka and Munk theory. Consequently, the CS 920 can only be used after empirically determined adjustment of the 'linearizer'. Furthermore, errors in analysis can increase up to 30% by using TLC-plates with fluctuating layer thickness.