Analytical Sciences

MALDI Mass Spectrometry Using 2,4,6-Trihydroxyacetophenone and 2,4-Dihydroxyacetophenone with Cyclodextrins: Suppression of Matrix-related Ions in Low-molecular-weight Region

Takashi FUJITA, Tatsuya FUJINO, Kazunori HIRABAYASHI, and Takashi KORENAGA

Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry of a model peptide, Substance P (SubP), was carried out using 2,4,6-trihydroxyacetophenone (THAP) and 2,4-dihydroxyacetophenone (DHAP) with cyclodextrins (cyclodextrin-supported matrix). It was found that the use of a cyclodextrin-supported matrix simplified the mass spectrum in the low-molecular-weight region. The interaction between THAP/DHAP and cyclodextrin (CD) was studied by UV-vis absorption spectroscopy and the incorporation of matrix molecules into the cyclodextrin cavity was confirmed by ¹H-NMR spectroscopy. DHAP showed tight incorporation with βCD (βCD(DHAP)) rather than THAP and it was found that the matrix-related peaks could be weakened by less than one third of the peak intensity of a protonated analyte. The βCD(DHAP) matrix was applied to the measurements of two low-molecular-weight compounds; adenosine and adrenaline. It became clear that the cyclic structure of the CD and the host-guest interaction between βCD and the matrix molecule were important to reduce the matrix-related peaks of THAP and DHAP.

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