Determination of active components in rosemary by capillary electrophoresis with electrochemical detection

Rosemary (Rosmarinus officinalis L.) is a spice and medicinal herb widely used around the world. Among natural antioxidants, rosemary has been widely accepted as one of the spices with the highest antioxidant activity. A capillary electrophoresis method for the determination of its active components using electrochemical detection was developed. Effects of several important factors were investigated to acquire the optimum conditions. The detection electrode was a 300 μm carbon disc electrode at a working potential of +0.90 V (versus SCE). The analytes can be well separated with 25 min in a 75 cm length fused-silica capillary at a separation voltage of 16 kV in an 80 mmol/l borate buffer (pH 9.0). The current response was linear over about three orders of magnitude with detection limits (S/N = 3) ranging from 2 × 10−7 to 1 × 10−6 g/ml for all the analytes. The method was successfully used in the analysis of rosemary with relatively simple extraction procedures, and the assay results were satisfactory.