Enantiomeric determination and evaluation of the racemization process of atropine in Solanaceae seeds and contaminated samples by high performance liquid chromatography-tandem mass spectrometry

Abstract

A new method has been developed for the enantioselective separation of (−) and (+) hyoscyamine in Solanaceaes seeds and contaminated buckwheat. Chromatographic separation was optimized, evaluating two chiral columns, Chirobiotic V and Chiralpal-AY3. Better resolution was obtained using a ChiralpakAY3 column, utilizing as mobile phase ethanol (0.1% diethanolamine). An extraction procedure based on a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) was applied, using water and acetonitrile containing 1% of acetic acid, and a clean-up step utilizing primary secondary amine (PSA) and graphitized carbon black (GCB) as sorbents. The extract was diluted with ethanol (50/:50, v/v) prior to chromatographic analysis, and the separation was carried out avoiding the racemization during this stage. Enantiomerization process of atropine was studied in samples at different conditions such as temperature (30, 50 and 80 ◦C) and pH (3, 5, 7 and 9), observing that racemization occurs at high pH (9) and temperature (80 ◦C). Stramonium and Brugmansia seeds were analyzed and the concentration of (−)-hyoscyamine was 1500 mg/kg and 320 mg/kg respectively. Contaminated buckwheat was also determined and (−)- hyoscyamine was detected at 170 !g/kg.