Analysis of Duboisia myoporoides R. Br. and Duboisia leichhardtii F. Muell

Duboisia samples were analyzed for scopolamine and hyoscyamine using GLC, by a slope ratio method, and by methods employing homatropine, tetraphenylethylene, and phenylacetyltropine as internal standards. Limits of precision were determined by the inverse prediction method. Phenylacetyltropine was the preferred internal standard. The alkaloids were silanized with either hexamethyldisilazane or N,O-bis(trimethylsily)acetamide to prevent dehydration to the apo forms. Samples from a commercial bale of Duboisia myoporoides were assayed. The alkaloid content varied considerably, depending on the sample position within the bale.