New suitable deprotonating matrices for the analysis of carboxylic acids and some acidic compounds by matrix-assisted laser desorption/ionization mass spectrometry in negative ion mode.

摘要: Rationale Direct non-derivatization analysis of organic acids and acidic compounds by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) in positive ion mode is not always possible due to the low ionization efficiency analytes. Some new efficient deprotonating matrices were suggested that allowed production negative ions from during MALDI-MS experiments. Methods Various tested carboxyl-containing as well with properties mixed [4-dimethylaminobenzaldehyde (DMABA), N,N-dimethylamino-p-phenylenediamine or 3-aminoquinoline] applied on a standard MALDI target followed recording spectra mode. Results All produced abundant [M - H]- under conditions. DMABA strongest signals reflecting greater sensitivity analysis. Conclusions The are commercially available good alternatives well-known this kind and, particular, often used 9-aminoacridine. best potential suitable for detection molecular weight compounds, substituted phenols, mixtures naphthenic (-)MALDI-MS.