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Analysis of negatively ‘charge tagged’ DNA by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Author(s) -
Berlin Kurt,
Gut Ivo G.
Publication year - 1999
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(19990915)13:17<1739::aid-rcm708>3.0.co;2-7
Subject(s) - chemistry , mass spectrometry , oligonucleotide , dna , ionization , desorption , matrix assisted laser desorption/ionization , derivatization , matrix (chemical analysis) , analytical chemistry (journal) , chromatography , organic chemistry , ion , biochemistry , adsorption
An improvement in detectability and stability of DNA analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) using oligonucleotides modified with a neutralized backbone and a fixed single, positive charge was recently reported. The attachment of the positive charge requires a primary amino group, limiting this approach to accordingly functionalized DNA. The method described here uses backbone neutralized DNA for the same purpose, with a single unmodified phosphate in the DNA backbone carrying the negative charge. Thus, no chemical modification other than neutralizing the remaining charges on the phosphorothioates is required. This is performed in a single methylation step. The enhancement in sensitivity is comparable to that for DNA carrying a single positive charge, interestingly even when using the same non‐protonating matrix. The mechanistic implications of these findings regarding the MALDI process are discussed. The DNA derivatization methods presented help to make MALDI‐MS of DNA applicable and competitive for genome analysis and medical diagnostics. Copyright © 1999 John Wiley & Sons, Ltd.