Parallel determination of rosmarinic and caffeic acids by TLC-densitometry

A TLC-densitometric method was introduced for the parallel determination of rosmarinic and caffeic acids. Experiments performed to establish the optimal measurement parameters related to the excitation wave-length, colour stability, linearity of the calibration curves, sensitivity and reproducibility. The application of TLC permits utilization of the fluorescence of both phenols, often without the need for prior purification. This fluorescence measurement makes the detection extremely sensitive. The densitometric quantification allows the routine analysis of many samples in a short time with reasonable accuracy. The practical application of the elaborated method will be demonstrated on 5 Salvia species.