MATRIX-ASSISTED LASER DESORPTION IONIZATION USING AN ACTIVE PERFLUOROSULFONATED IONOMER FILM SUBSTRATE/

The use of an active Nafion substrate is shown to enhance the performa nce of MALDI MS. The use of a Nafion substrate with certain matrices c an significantly enhance the signals obtained over those observed with a stainless steel probe substrate. Analytes can often be observed wit h the use of the Nafion substrate that cannot be easily observed with the standard MALDI procedure, and usually a much wider range of peaks can be observed using MALDI from the Nafion substrate than with any si ngle matrix on a stainless steel substrate. This enhancement of signal from the Nafion substrate is observed only with the sequential deposi tion of the sample and the matrix onto the Nafion film. If the analyte and matrix are premixed, then the effect is not observed. The use of the Nafion substrate has been shown to be particularly effective in an alyzing real biological mixtures without prepurification. This has bee n demonstrated for various samples including the analysis of the produ cts of chemical digests of proteins, protein profiling in milk and egg white samples, cell lysate analysis, and oligonucleotide detection.