The Use of a Co-matrix for Improved Analysis of Oligonucleotides by Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

✍ Scribed by Tracey A. Simmons; Patrick A. Limbach

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 115 KB
• Volume: 11
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(199704)11:6<567::aid-rcm917>3.0.co;2-o

✦ Synopsis

Cation adduction to oligonucleotides and nucleic acids during mass spectrometric analysis is a recurrent problem. We have found that the use of organic base solutions of high gas-phase proton affinity, as used previously in electrospray ionization mass spectrometry, can significantly reduce the cation adduction problem during matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. A comparison of the utility of adding imidazole or triethylamine as a co-matrix versus the standard addition of cation exchange resin beads was made. The co-matrices studied were found to be more effective than the cation exchange resin beads at reducing cation adducts from samples containing a high level of salt. The use of co-matrices also appears to improve the gas-phase stability of larger oligonucleotides. MALDI-time-of-flight analysis of a binary mixture of oligoribonucleotide 27-mers with a co-matrix exhibited less metastable decomposition than the same analysis using cation exchange resin beads. The use of co-matrices may be a viable strategy for the mass spectrometric characterization of larger oligonucleotides obtained from media containing a high salt content such as polymerase chain reaction products.