Improved extraction of ginkgotoxin (4'-O-methylpyridoxine) from Ginkgo biloba products.

A simple extraction procedure was applied to the analysis of canned/packaged white nuts and Ginkgo biloba extracts. Extraction by shaking with water at room temperature was more convenient to use than a previously published Soxhlet procedure for analysis of packaged Ginkgo biloba seeds (white nuts) for ginkgotoxin; recoveries from spiked dried seeds by the simple extraction procedure averaged 76%. Determination was by liquid chromatography with UV or fluorescence detection. Recoveries of ginkgotoxin from a spiked and unspiked natural health product (powder from Ginkgo biloba capsules) were equivalent by both procedures; recovery from spiked powder by the simple extraction procedure was 81%. Application of this extraction procedure in the analysis of 6 samples of white nuts (vacuum packaged and canned products) showed that free ginkgotoxin was present in 5 samples at concentrations up to 25 microg/g dry weight. Total ginkgotoxin was determined after hydrolysis with beta-glucosidase of sample extracts in which a peak corresponding to the 5'-O-glucoside was detected. Ginkgotoxin was determined in 10 Ginkgo biloba natural health products by the same method at levels up to 181 microg/g.

Analysis of Beer for Fumonisins.

Forty-one samples of beer were analyzed for fumonisins B1 and B2 (FB1 and FB2) using an immunoaffinity column cleanup followed by liquid chromatographic (LC) analysis. These samples included three later brand resamplings. All LC analyses were carried out using o-phthaldialdehyde/2-mercaptoethanol (OPA/MCE) and/or 4-fluoro-7-nitrobenzofurazan (NBD-F) derivatization procedures. Detection limits were 0.4 to 1 ng of FB1 or FB2 per ml of beer with OPA/MCE and 0.7 to 3 ng/ml with NBD-F. Recoveries of FB1 and FB2 spiked into 8 different beer samples at 2 to 10ng/ml ranged from 61 to 114% and 47 to 97%, respectively. Four samples (one of which was a resampled brand) contained >2 ng of FB1 per ml (up to 59 ng/ml).