Oligonucleotide analysis by MALDI-MS

Matrix-assisted laser desorption (MALDI) time-of-flight (TOF) mass spectrom etry (MS) has been successfully used for oligonucleotide analysis. Delayed extraction is shown to dramatically improve the overall quality of mass spe ctra. Described applications include oligonucleotide sequence conformation, determination of the extent of synthetic DNA failure sequences, characteri zation of the oxidation of phosphorothioate oligonucleotides, and use of MA LDI-TOF for DNA sequencing by the Sanger dideoxy termination reaction.