Abstract
Photoacoustic spectroscopy (PAS) was used to study the vertical concentration distribution of compounds on TLC plates. The results suggest that under the given experimental conditions compounds exhibit irregular concentration profiles in vertical direction and tend to concentrate in the uppermost 61μm thick layer. This irregularity was accounted for by photoacoustic probing of thicker sorbent layers what lead to an improved linearity of calibration curves compared to those obtained by reflectance densitometry.