MASS-SPECTROMETRY OF NUCLEIC-ACIDS - THE PROMISE OF MATRIX-ASSISTED LASER DESORPTION-IONIZATION (MALDI) MASS-SPECTROMETRY

In the past several years, significant progress has been made in the a pplication of matrix-assisted laser desorption-ionization (MALDI) mass spectrometry to the analysis of large biopolymers, including nucleic acids. By isolating analyte molecules in an appropriate matrix and irr adiating the sample with a high-intensity, pulsed laser beam, MALDI ca n generate intact, gas-phase ions of these analytes. Primarily used wi th time-of-flight mass spectrometers, this relatively new, soft ioniza tion technique has allowed for the routine analysis of oligonucleotide s up to 60 or so nucleotides in length. Recent results have also shown that base specific, matrix-dependent fragmentation is an important fa ctor in the MALDI analysis of oligonucleotides. Further extension of t he technique to longer oligonucleotides will rely on both the continue d search for new matrix materials and an increased understanding of th e desorption and ionization process in MALDI.