Differentiation between isomeric phenylglycidyl ether adducts of 2′-deoxyguanosine and 2′-deoxyguanosine-5′-monophosphate using liquid chromatography/electrospray tandem mass spectrometry

Abstract

The reaction between phenylglycidyl ether and 2′‐deoxyguanosine or 2′‐deoxyguanosine‐5′‐monophosphate yields a variety of different nucleoside and nucleotide adducts. The corresponding mixtures were analyzed by liquid chromatography/electrospray tandem mass spectrometry and the product ion spectra of the different isomers are discussed using the correct cone voltage and collision energy. The latter were selected by looking at the energy‐resolved spectra. From these data the formation of N7 and N2 isomers was proposed. However, detailed NMR analysis of the latter proved this isomer to be the N1‐alkylated adduct. The reaction between phenylglycidyl ether and 2′‐deoxyguanosine or 2′‐deoxyguanosine‐5′‐monophosphate yields a variety of different nucleoside and nucleotide adducts. The corresponding mixtures were analyzed by liquid chromatography/electrospray tandem mass spectrometry and the product ion spectra of the different isomers are discussed using the correct cone voltage and collision energy. The latter were selected by looking at the energy‐resolved spectra. From these data the formation of N7 and N2 isomers was proposed. However, detailed NMR analysis of the latter proved this isomer to be the N1‐alkylated adduct. 2′‐Deoxyguanosine‐5′‐monophosphate was alkylated by phenylglycidyl ether at the 5′‐phosphate position. If the nucleotide base moiety was alkylated, the corresponding tandem mass spectrometric data strongly suggested alkylation of N7. In the case of bis‐PGE–dGMP adduct, evidence was found for simultaneous 5′‐phosphate and N7‐alkylation.2′‐Deoxyguanosine‐5′‐monophosphate was alkylated by phenylglycidyl ether at the 5′‐phosphate position. If the nucleotide base moiety was alkylated, the corresponding tandem mass spectrometric data strongly suggested alkylation of N7. In the case of bis‐PGE–dGMP adduct, evidence was found for simultaneous 5′‐phosphate and N7‐alkylation. Copyright © 1999 John Wiley & Sons, Ltd.

In-source CID of guanosine: Gas phase ion-molecule reactions

“…Product ions lower in the genealogical ladder are also accessible by applying relatively high collision energies in the collision cell. Yet disentanglement of different dissociation pathways originating from a communal progenitor is -in general-still confined to QIT set ups, although the interpretation of energy resolved spectra also has proven its usefulness [3].Recently we and others showed [4 -6] that by making optimal use of in-source CID, combined with the inherent tandem MS capabilities of the QqTOF, what is in effect up to MS 5 data can be acquired. Compared to QIT data the QqTOF data obtained is superior in respect of higher mass accuracy.…”

“…Product ions lower in the genealogical ladder are also accessible by applying relatively high collision energies in the collision cell. Yet disentanglement of different dissociation pathways originating from a communal progenitor is -in general-still confined to QIT set ups, although the interpretation of energy resolved spectra also has proven its usefulness [3].…”

“…By in-source CID of the protonated guanosine the second generation product ion (Figure 1), was produced [5,9]. Its in-source formed adducts with H 2 18 O and CH 3 OH were subsequently submitted to tandem MS analysis by QqTOF MS and accurate mass data of the according product ions was acquired. Different neutral gain/ neutral loss sequences involving H 2 O and CH 3 OH were distinguished.…”

Analysis of urinary nucleosides. II. Comparison of mass spectrometric methods for the analysis of urinary nucleosides

“…In order to increase the sample concentration we tried to use a column switch technique, a technique that we, and others,15–17 apply frequently for low‐concentration samples. Using column switching would allow us to desalt the samples at the same time and it would make the use of the divert valve unnecessary.…”