The simultaneous determination of selected flavonol glycosides and aglycones in Ginkgo biloba oral dosage forms by high-performance liquid chromatography-electrospray ionisation-mass spectrometry

An accurate, precise and sensitive liquid chromatography-tandem mass spectrometric (LC-MS-MS) method was developed for the determination of two flavonol glycosides, rutin and quercitrin, together with the algycone markers, quercetin, kaempferol and isorhamnetin in several Ginkgo biloba solid oral dosage forms. In addition, a novel quercetin glycoside, not yet reported in Ginkgo extracts, was identified. Liquid chromatography was performed using a minibore high-performance liquid chromatography (HPLC) column (150 mm × 2.0 mm i.d.) and a one step gradient of acetonitrile-formic acid (0.3%) at a flow rate of 0.5 ml/min. Baseline separation of the five selected flavonol marker compounds was achieved within 20 min at 45 °C. Tandem mass spectrometry was performed using electrospray ionisation (ESI) in the negative ion mode. The marker compounds exhibited linearity over the range of 3-26 μg/ml and intra- and inter-day standard deviations were better than 7% and 16%, respectively. All Ginkgo products investigated were found to contain varying amounts of target analytes.