Pigments MALDI analysis

Figure 5-5. A. MALDI mass spectrum of the anthocyanin pigments in the grape variety Marechal Foch. This figure is from the article Matrix-assisted laser desorption ionization mass spectrometry analysis of grape anthocyanins , Am. J. Enol. Vitic. 50 199-203 by Sugui, J. A., Wood, K. V., Yang, Z., Bonham, C. C. and Nicholson, R. L. 1999. Reprinted by permission of the American Society for Enology and Viticulture. B. MALDI mass spectrum of grape anthocyanins acquired on a MALDI mass spectrometer with delayed extraction capabilities. Peak identities are discussed in the text.

Spatially resolved MS techniques that make use of ionic sources based on direct LDI have been employed to study art and archaeological objects since 2002 [43,44]. However, direct LDI is only effective in the study of a limited range of materials. TTie use of matrices that assist the ionization process induced by MALDI has expanded the applicability of LDI-based MS methods to the field of spatially resolved studies of organic components from works of art. Examples of the applicability of MALDI to the analysis of pigments [45], siccative oils [46], proteinaceous binders [47-49], and varnishes [50] are indeed reported in the literature. A proteomic approach based on the use of MALDI-TOF was also used to identify biological samples taken from the more than 5300-year-old Tyrolean mummy, also called iceman or Oetzi [51]. 

The third and the only other online TLC-MS approach in carotenoid analysis was presented in the study of the introduction of TiOj nanoparticles on increase of carotenoid production by the extremophilic haloarchea Haloferax mediterranei [7]. The carotenoids were extracted from bacteria and chromatographed on silica gel TLC plates developed by acetone-n-heptane (1 1, v/v). To prevent the diffusion of bands on the developed silica gel TLC plate, the area surrounding the bands was carefully scraped off prior to the addition of MALDI matrix. Based on the high-resolution mass spectra, the four colored pigments were identified as bisanhydrobac-terioruberin, monoanhydrobacterioruberin, 2-isopentenyl-3,4-dehydrorhodopin, and... 

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