Direct secondary-ion mass spectrometric analysis of mixtures separated by thin-layer chromatography and electrophoresis

Secondary-ion mass spectrometry (SIMS) is used to sputter ions directly from thin-layr chromatograms in which components in a mixture have been separated. Mixtures of phenothiazine drugs and small peptides have been separated an detected by the chromatography/SIMS method. Phosphonium salts have been separated by thin-layer chromatography and imaged in situ by mass spectrometer. Organometallic compounds such as the transition metral acetylacetonates have been simialry determined. Mixtures that have been separated by gel electrophoresis are transferred by using a standard blotting procedure to a nitrocellulose support, which is then examined by secondary-ion mass spectrometry. A mixture of organic dyes was separated by gel electrophoresis, and characterized by secondary-ion mass spectrometry. The use of the mass spectral information to deconvolute overlapping components on the chromatogram is discussed, and the ultimate spatial resolution for molecular mapping is estimated as about 1 μm.