Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) for the analyses of oligonucleotides has generally been carried out using negative ionisation conditions, usually following ammonium ion-exchange chromatography and the addition of ammonium buffers to the MALDI matrix. The molecular ion region is complex, due to the varying degrees of ammoniation of the phosphate backbone of the oligonucleotide. This gives rise to an overall decrease in sensitivity compared with similar size peptides and can cause ambiguity of assignment of the relative molecular mass of the sample. This study describes the use of H(+) ion exchange resin in situ as the means of removing alkali metal ions from the phosphate backbone of the oligonucleotide. An increase in resolution, sensitivity and identification of the molecular species is reported, with little or no difference in sensitivity observed between positive or negative ionisation spectra. This method is now used for routine screening of synthetic oligonucleotides with a gain in sensitivity of 1-2 orders of magnitude compared with previous methods, and mass assignment errors of +/-0.1% are routinely recorded for externally calibrated data.

Original publication

DOI

10.1002/(SICI)1097-0231(19990915)13:17<1717::AID-RCM704>3.0.CO;2-R

Type

Journal article

Journal

Rapid Commun Mass Spectrom

Publication Date

1999

Volume

13

Pages

1717 - 1723

Keywords

Ion Exchange Resins, Oligonucleotides, Sensitivity and Specificity, Sequence Analysis, DNA, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization