Abstract:

Most of TLC analysis are performed in the UV and visible spectral region by measuring reflectance with a slit-scanning densitometer or a CCD camera (1-3). However, such measurements are restricted only to the surface of the TLC plate and do not take into account the vertical sub-surface concentration distribution governed by secondary chromatography (4-7) within the sorbent. It is therefore important to investigate effects connected with secondary chromatography in order to reveal their origin, and to. estimate their impact on the results of TLC measurements and their reproducibility.