Ion–molecule reactions and dissociation of glycols in a quadrupole ion trap mass spectrometer: Evidence of intramolecular interactions

Polyethylene glycols react with CH 3 OCH 2 + ions from dimethyl ether to form [M + 13] + products. The [M + 13] + ions are stabilized by intramolecular interactions involving the internal ether oxygen atoms and the terminal methylene group. Collisionally activated dissociation (CAD), including MS n and deuterium labeling experiments show that fragmentation reactions involving intramolecular cyclization are predominant. Scrambling of hydrogen and deuterium atoms in the ion‐molecule reaction products is not indicated. The CAD spectra of the [M + 13] + ions provide unambiguous assignment of the glycol size.