DETERMINATION OF LUTEOLIN AND APIGENIN IN HERBS BY CAPILLARY ELECTROPHORESIS WITH DIODE ARRAY DETECTION

Capillary electrophoresis with a diode array detector was employed for the determination of luteolin and apigenin in plant extracts. The experimental factors affecting the elution of the analytes were carefully optimized. The final analysis was achieved utilizing a fused silica capillary (58cm effective length, 75m ID) and a background electrolyte solution consisting of borax buffer (20mM, pH 10.0) and methanol (90: 10, v/v) with a 23kV driving voltage and detection at 210nm. The method was fully validated as per the guidelines of the International Conference on Harmonization for Analytical Procedures. The relationship between peak area and concentration was linear between 3 and 800g/mL for both compounds with detection limits of 1.05 for luteolin and 0.53g/mL for apigenin. The method was employed for the determination of the analytes in extracts of thyme and parsley. Both compounds were resolved from interfering peaks that were present in the extracts. Recovery studies were performed by fortifying the extracts with standards and demonstrated good accuracy with recovery values between 97.29 and 104.88% for luteolin and 96.89 and 105.18% for apigenin. Thyme and parsley were shown to contain high concentrations of luteolin and apigenin.