HPLC Enantioseparation of the Alkaloid Canadine and Determination of Enantiomeric Purity With Chiral/Photometric and Achiral/Polarimetric Detection

Abstract

& This work reports two methods developed for the determination of enantiomeric purity of canadine, the major alkaloid present in goldenseal extracts, by HPLC: 1) with physical separation of enantiomers using a chiral column with a stationary phase consisting of (S)-tert-leucine and (S)-1-(a-naphthyl)ethylamine, UV detection at 235 nm; and 2) without physical separation of enantiomers, using reverse-phase (C-18 column) and polarimetric detection at 830 nm (Diode-Laser).Pyrkle-type chiral column and photometric detection was used to obtain base-line separation of canadine enantiomers (Rs ¼ 1.78). A RP-18 achiral column and polarimetric detection provided a new nonchiral method to calculate enantiomeric purity.Enantiomeric purity of 41.6 % S-(À)-canadine and 58.4 % R-(þ)-canadine was obtained using Chirex-3019 column and photometric detection. Detection limit was 0.3 lg and linear range was 0.4 to 2 lg. RP-18 column and polarimetric detection provided a 1.5 lg detection limit and a dynamic range of 25.200 lg. Fluorimetric detection showed that R-(þ)-canadine contained 7.4 % S-(À)-canadine.Assays using chiral column and photometric detection indicated that results obtained by both methods are concordant. The methods established are appropriate for the analysis of canadine enantiomers.

Enantioseparation of the fungicide imazalil in orange juice by chiral HPLC. Study on degradation rates and extractive/enrichment techniques

“…The percentages (%) of each enantiomer in the mixture from peak areas (Sánchez, Diaz, & de Vicente, 2008;Sánchez, Diaz, Lama, Aguilar, & Algarra, 2014;Sánchez et al, 2012) were obtained using the equations:…”