5-Ethyl-2-mercaptothiazole as matrix for matrix-assisted laser desorption/ionization of a broad spectrum of analytes in positive and negative ion mode

A preliminary investigation of the use of 5-ethyl-2-mercaptothiazole as matrix in matrix-assisted laser desorption/ionization (MALDI) of a broad spectrum of analytes is reported. The analytes studied are substance P, insulin, beta-cyclodextrin, triacylglycerols of coconut oil and polypropylene glycol 2000 (PPG 2000). In the positive ion mass spectra of the matrix/analyte combinations, the formation of M + H]+ and M + cation]+ species were observed and compared with those obtained by using well-established matrices such as alpha-cyano-4-hydroxycinnamic acid, genticic acid, sinapinic acid and dithranol. In addition, the usefulness of this new matrix for MALDI in negative ion mode is also described using substance P and beta-cyclodextrin as examples.