Fast separation and determination of carnosic acid and rosmarinic acid in different rosemary (Rosmarinus officinalis) extracts by capillary zone electrophoresis with ultra violet-diode array detection

Carnosol, carnosic acid, rosmarinic acid and other not identified phenolic compounds were separated by capillary zone electrophoresis (CZE) using a 40-cm long capillary and a 20 mM tetraborate buffer (pH 9.0), within 3 min. A UV-diode array detector was employed to collect spectra of phenolic compounds. The effect of some separation parameters on peak resolution and migration time of phenolic species present in a refined rosemary extract was studied. The repeatability of the method was also investigated: the intraday relative standard deviation on total peak area was less than 4%, while the intraday relative standard deviation on migration time was less than 0.6%. Moreover the CZE method showed good sensitivity (0.0007 g mL(-1) for carnosic acid and rosmarinic acid). Carnosic acid and rosmarinic acid have been quantified in different commercial extracts of rosemary Finally, the optimized method was also applied to evaluate the recovery of these two compounds when different organic solvents were employed during the extraction procedure.