Processed stigmas of Crocus sativus L. imaged by MALDI-based MS

The processed, i.e. dried under certain conditions, stigmas of Crocus sativus L. are one of the most expensive plant parts used commercially. For the color, aroma and biological activity a very complex mixture of glycolipids termed crocins are responsible. Therefore studying structural composition and distribution in the commercial plant material is of great interest. We showed successfully the application of a MALDI-based mass spectrometric imaging (MSI) approach for stigmas towards different crocin species. MSI opens up the investigation of processed plant materials in various fields allowing studying the processing in detail as well as adulteration attempts (which are quite frequent due to the price of the material). Furthermore, we could demonstrate that a similar number of crocins present in stigmas could be detected by MALDI MSI compared to the classical approach of analyzing the solvent-extract of stigmas by MALDI-MS.