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J Am Soc Mass Spectrom

Title:		"Unusual analyte-matrix adduct ions and mechanism of their formation in MALDI TOF MS of benzene-1,3,5-tricarboxamide and urea compounds"
Author(s):		Lou X; Fransen M; Stals PJ; Mes T; Bovee R; van Dongen JJ; Meijer EW;
Address:		"Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands. x.w.lou@tue.nl"
Journal Title:		J Am Soc Mass Spectrom
Year:		2013
Volume:		20130629
Issue:		9
Page Number:		1405 - 1412
DOI:		10.1007/s13361-013-0672-3
ISSN/ISBN:		1879-1123 (Electronic) 1044-0305 (Linking)
Abstract:		"Analyte-matrix adducts are normally absent under typical matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) conditions. Interestingly, though, in the analysis of several types of organic compounds synthesized in our laboratory, analyte-matrix adduct ion peaks were always recorded when common MALDI matrices such as 4-hydroxy-alpha-cyanocinnamic acid (CHCA) were used. These compounds are mainly those with a benzene-1,3,5-tricarboxamide (BTA) or urea moiety, which are important building blocks to make new functional supramolecular materials. The possible mechanism of the adduct formation was investigated. A shared feature of the compounds studied is that they can form intermolecular hydrogen bonding with matrices like CHCA. The intermolecular hydrogen bonding will make the association between analyte ions and matrix molecules stronger. As a result, the analyte ions and matrix molecules in MALDI clusters will become more difficult to be separated from each other. Furthermore, it was found that analyte ions were mainly adducted with matrix salts, which is probably due to the much lower volatility of the salts compared with that of their corresponding matrix acids. It seems that the analyte-matrix adduct formation for our compounds are caused by the incomplete evaporation of matrix molecules from the MALDI clusters because of the combined effects of enhanced intermolecular interaction between analyte-matrix and of the low volatility of matrix salts. Based on these findings, strategies to suppress the analyte-matrix adduction are briefly discussed. In return, the positive results of using these strategies support the proposed mechanism of the analyte-matrix adduct formation"
Keywords:
Notes:		"PubMed-not-MEDLINELou, Xianwen Fransen, Michel Stals, Patrick J M Mes, Tristan Bovee, Ralf van Dongen, Joost J L Meijer, E W eng 2013/07/03 J Am Soc Mass Spectrom. 2013 Sep; 24(9):1405-12. doi: 10.1007/s13361-013-0672-3. Epub 2013 Jun 29"