Determination of carnosic acid and rosmarinic acid in sage by capillary electrophoresis

A simple and rapid capillary electrophoresis method was developed for the identification and quantitative determination of two antioxidative compounds - carnosic acid and rosmarinic acid - in the extracts of commercial Sage (Salvia officinalis) tea-bags. Capillary zone electrophoretic separation of carnosic and rosmarinic acids was performed using 40 mmol/l borate, at pH 9.6 as the running buffer. Weighed sage samples were extracted from tea-bags by sonification and the extracts were directly injected without any purification and pre-separation process. Coumarin was used as internal standard for quantitation and the limits of detection for carnosic acid and rosmarinic acid were obtained as 2.79 and 3.18 μg/ml, respectively using UV detection at 210 nm.