Non-aqueous capillary electrophoresis with diode array and electrospray mass spectrometric detection for the analysis of selected steroidal alkaloidsin plant extracts

Nonaqueous capillary electrophoresis coupled to UV detection is described f or the separation and determination of steroidal alkaloids. After optimizat ion of electrophoretic parameters, including the electrolyte nature and the organic solvent composition, a reliable separation of solasodine and solan idine was achieved in a methanol-acetonitrile (20:80, v/v) mixture containi ng 25 mM ammonium acetate and 1 M acetic acid. For quantitative purposes, a fused-silica capillary with a bubble cell was used and detection was perfo rmed at low wavelength (195 nm). Method performances, including migration t ime and peak area reproducibility, Linearity, sensitivity and accuracy, wer e also evaluated. The method was applied to determine solasodine in Solanum elaeagnifolium berries and Solanum sodomaeum leaves and seeds. To further improve sensitivity in the analysis of solasodine-related compounds, solani dine, demissidine and tomatidine, the developed method was interfaced with electrospray ionization mass spectrometry. In the case of solasodine, the d etection limit was estimated at 3 mug/ml for NACE-UV and at 0.05 mug/ml for NACE-MS, in the selected ion-monitoring mode. (C) 2001 Elsevier Science B. V. All rights reserved.