Inosine Octamer Stabilized by Alkali Earth Metal Cations—As Studied by Electrospray Ionization Mass Spectrometry

Abstract

By using electrospray ionization mass spectrometry, inosine was found to be able to form an octamer stabilized by alkali earth metal cation, namely Ca2+, Sr2+ and Ba2+, of which the most stable is that stabilized by Ca2+ (ion [I8 + Ca]2+). It was established that 9-methylhypoxanthine (M) did not form an analogical octamer, since ion [M8 + Ca]2+ was not detected. On the other hand, 9-methylhypoxanthine can form “mixed” octamers together with inosine (ions [I nM m + Ca]2+, n + m = 8, were detected).