ABSTRACT
<p><b>OBJECTIVE</b>To discuss mass spectrum characterization of five valepotriates including 'monoene' type (didrovaltrate), 'diene' type (valtrate, acevaltrate) and 'four-olefinic' type (baldrinal and homobaldrinal) by electrospray ionization tandem mass spectrometry (ESI-MS(n)).</p><p><b>METHOD</b>This study was carried out on the basis of electrospray ionization tandem mass spectrometric method and analysis of multistage fragments.</p><p><b>RESULT</b>The fragmentation patterns and structural assignment of 'monoene' type, 'diene' type and 'four-olefinic' type valepotriates in ESI-MSn under positive mode were summarized.</p><p><b>CONCLUSION</b>The compounds have a strong pyrolysis rules and it can provide reference date for valepotriates in rapid structural identification, quantitative analysis and pharmacokinetic study.</p>