MATRIX-ASSISTED LASER-DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY - A POWERFUL TOOL FOR THE MASS AND SEQUENCE-ANALYSIS OF NATURAL AND MODIFIED OLIGONUCLEOTIDES

We report the analysis and characterization of natural and modified ol igonucleotides by matrix-assisted laser desorption ionization time-of- flight mass spectrometry (MALDI-TOF MS). The present technology was hi ghly improved for this class of compounds by using a new matrix, 2,4,6 -trihydroxy acetophenone, together with di- and triammonium salts of o rganic or inorganic acids to suppress peak broadening due to multiple ion adducts. This methodology can be used in combination with time dep endent degradation of oligonucleotides by exonucleases as powerful too l to determine sequence compositions.