Capillary electrochromatography of selected phenolic compounds of Chamomilla recutita

This article explores the use of capillary electrochromatography for the analysis of chamomile (Chamomilla recutita L.) extracts. After a thorough study of analytical parameters such as mobile and stationary phase composition, applied voltage, and temperature, a methodology to determine 11 bioactive phenolic compounds (coumarins: herniarin, umbelliferone; phenylpropanoids: chlorogenic acid, caffeic acid; flavones: apigenin, apigenin-7-O-glucoside, luteolin, luteolin-7-O-glucoside; flavonols: quercetin, rutin and flavanone: naringenin) in chamomile extracts was proposed. The method was performed in a Hypersil SCX/C18 column with pH 2.8 phosphate buffer at 50 mmol L−1 containing 50% acetonitrile (pH adjusted before the addition of the organic solvent). All compounds were separated in less than 7.5 min under isocratic conditions. Figures of merit include linearity (peak area versus apigenin concentration) from 50.0–1000 μg/mL (r2 = 0.995), and intra-day precision of retention time and peak area better than 1.3% CV and 15%, respectively. The limits of detection and quantification for apigenin were 35.0 μg/mL and 150.0 μg/mL, respectively. This article also describes an NMR 1H study, carried out to monitor a new clean-up procedure for extracts containing propyleneglycol, whose components are poorly retained in conventional octadecyl silica cartridges.