UV Light Fluorescence Measurement

4 Direct Optical Evaluation With 365-nm UV Light (Fluorescence Measurement) 

The chromatograms of greater celandine shown in Section 10.2.3 Effect of Light are examples of fluorescence measurements without previous derivatization. 

Practical Tips for working with traditional TLC scanners  

With older equipment which cannot be used to obtain spectra, the optimal measurement wavelengths are determined as follows If it is known, for example, that the maximum is at a wavelength less than 300 nm, the chromatogram lane containing the substance to be determined is scanned several times using a scheme such as the following  

If two substances on a chromatogram lane are not separated at the base hne, but only one of the two substances is needed for the analytical result, the spectra of both substances are obtained and the measurement wavelength is selected such that there is a minimum for the substance not used. In the ideal case, however, the substance to be determined has a maximmn or at least gives a satisfactory signal. 

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