MS/MS Analysis of flavonoids by laser desorption and ionization – ion trap mass spectrometry

A series of flavonoid compounds, traditionally found in easel paintings as organic pigments, are studied using Laser Desorption Mass Spectrometry (LDMS). The LDMS experimental set-up consists of a source chamber coupled by an ion transfer system to an lon Trap Mass Spectrometer (ITMS). Analytes are deposited as thin films onto a probe. Samples for spatially-resolved analysis are embedded in a supportive resin and cross-sectioned. Laser Desorption and lonization (LDI) of material at the surface of the sample is performed by a Q-switched Nd:YAG laser operating in the UV at 355 nm (frequency-tripled output). Alternatively, a solution of DHB is applied over the sample and left to dry to assist in the desorption-ionization process (MALDI). The laser beam is focused to a spot size of cat 40 gm and the sample can be positioned with a micrometric precision by an XYZ manipulator.