NEW PROCEDURE FOR THE USE OF HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY FOR THE ANALYSIS OF NUCLEOTIDES AND OLIGONUCLEOTIDES

A method is described which allows the combination of high-performance liquid chromatography (HPLC) and electrospray ionization mass spectro metry for the analysis of nucleotides and oligonucleotides without com promising the performance of either technique. The essential feature o f the method uses 1,1,1,3,3,3-hexafluoro-2-isopropanol as an additive to the HPLC mobile phase. This novel additive results in both good HPL C separation and efficient negative ion mode electrospray ionization. The method is demonstrated for oligonucleotides samples such as synthe tic homopolymers of thymidine (PolyT), of fragments based on the pBR32 2 plasmid sequence and analysis of phosphorothioate ester antisense ol igonucleotides. The differentiation of phosphorylation states of natur al nucleotides as well as nucleotide analogues, such as ziduvodine (AZ T), is also demonstrated. (C) 1997 Elsevier Science B.V.