Neuropeptidomics

Analysis of modified nucleosides in the urine of patients with malignant cancer by liquid chromatography/electrospray ionization mass spectrometry

“…Detailed evidence for the structures is shown in Scheme , which indicates the suspected fragmentation pathway of 5′‐dehydro‐2′‐deoxyinosine. We first identified this modified inosine using the OASIS® HLB column, as many authors have purified urinary nucleosides via Affi‐Gel 601 affinity columns;1–22 however, such a compound would not be expected to be retained upon the Affi‐Gel 601 affinity column which would only bind nucleosides with a cis‐diol group during purification of the nucleosides.…”

“…Mass spectrometry (MS) has also been successfully applied to analyze nucleosides from various sources including electrospray ionization (ESI),14 matrix‐assisted laser desorption/ionization (MALDI),15 electron ionization (EI),16 chemical ionization (CI) and fast‐atom bombardment (FAB) 17. Electrospray ionization tandem mass spectrometry (ESI‐MS/MS) when coupled with HPLC,18–22 CE23 or capillary liquid chromatography (CapLC)24, 25 has great advantage over previous methods of detection; more structural data can be obtained, thereby allowing improved certainty about the identity of the nucleosides being studied.…”

“…Most researchers have isolated nucleosides from urine by phenylboronate affinity gel chromatography taking advantage of the reaction of phenylboronate with the vicinal OH groups of ribonucleosides 1–12, 22–25. However, this extraction could only retain nucleosides with cis‐diol structure.…”