Curcumin: a multipurpose matrix for MALDI mass spectrometry imaging applications.

Curcumin, 1,7-bis-(4-hydroxy-3-methoxy-phenyl)-hepta-1,6-diene-3,5-dione, is a polyphenolic compound naturally present in the Curcuma longa plant, also known as tumeric. Used primarily as a coloring agent and additive in food, curcumin has also long been used for its therapeutic properties in a number of medical scenarios. Here, we report on an entirely novel use of curcumin; its extended structure of conjugated double bonds suggested the potential of this compound to be a good matrix assisted laser desorption ionization mass spectrometry (MALDI MS) matrix candidate. In the quest for novel and more efficient MALDI MS matrices, curcumin is revealed to be a versatile and multipurpose matrix. It has been applied successfully for the analysis of pharmaceuticals and drugs, for imaging lipids in skin and lung tissues, and for the analysis of a number of compound classes in fingermarks. In each case, the use of curcumin is shown to promote analyte ionization very efficiently as well as provide excellent mass spectral image quality.