The on-line separation and structure elucidation of naphthodianthrones, flavonoids, and other constituents of an extract from Hypericum perforatum L. using high performance liquid chromatography (HPLC) coupled on-line with ultraviolet-visible, nuclear magnetic resonance (NMR), and mass spectrometry (MS) is described. A conventional reversed-phase HPLC system using ammonium acetate as the buffer substance in the eluent was used, and proton NMR spectra were obtained on a 500 MHz NMR instrument. The MS and MS/MS analyses were performed using negative electrospray ionization. In the present study, all of the major known constituents in extracts from Hypericum perforatum L. were identified, and two new substances which had not previously been reported as constituents of extracts of Hypericum perforatum L. were identified and their structures elucidated.

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In order to evaluate the composition of active constituents in phytopharmaceutical preparations, valid analytical methods are required. For the determination of the active terpene constituents of Ginkgo biloba (the ginkgolides and bilobalide), a liquid chromatography-mass spectrometry (LC-MS) method has been developed using atmospheric pressure chemical ionisation (APCI) in the negative ion mode. This detection mode was found to be much more sensitive and selective compared to UV; indeed the ginkgo terpene trilactones lack strong UV chromophores and flavonoids interfere with their UV detection. LC-APCI/MS detection allowed a considerable reduction in analysis time when compared to LC-UV, because LC resolution was only needed between the pair of isomers ginkgolide B and ginkgolide J. All compounds were selectively detected by single ion monitoring of their specific deprotonated molecules [M-H]-. The samples were directly injected without pre-purification, and a fast gradient was applied, reducing the total time of analysis to 14 min. With this method, the ginkgo terpene trilactones were detected on-line in the picogram range. Several commercial ginkgo preparations on the Swiss market were analysed, and the ginkgolide and bilobalide contents were evaluated using the method described.

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