Direct determination of sinigrin in mustard seed without desulfatation by reversed-phase ion-pair liquid chromatography

Reversed-phase ion-pair liquid chromatography has been investigated for dir ectly analyzing sinigrin in mustard seed without desulfatation. After extra ction by phosphate buffer (pH 7.0) from the grind-pastes of inactivated-myr osinase mustard seeds, sinigrin was first isolated through deproteinization and centrifugation, followed by filtration and injection into the chromato graphic system. A reversed-phase C-18 column was used to separate the sinig rin with an eluent of acetonitrile (ACN)-water (20:80) containing 0.02 M te trabutylammonium (TBA) as the counter ion at pH 7.0. Detection was carried out with an UV detector operated at 227 nm. Factors affecting the chromatog raphic separation and quantitative determination, such as concentrations of TEA and ACN, and pH, were studied. The linear dynamic range is larger than three orders of magnitude and the detection limit is 0.045 mg/L. The RSD i s around 3% and the recovery is 85% (3% RSD, n = 3). (C) 2001 Published by Elsevier Science B.V.