THE PROTONATION SITE OF 2-METHOXYETHANOL UNDER CHEMICAL-IONIZATION - AN EXPERIMENTAL AND THEORETICAL-STUDY

The mess spectral behavior of 2-methoxyethanol was studied under chemi cal ionization conditions with methane, isobutane, acetone and 3-penta none as reagent gases. The protonated ion, [M+H](+), was of high abund ance in the case of methane, isobutane and acetone chemical ionization . The ion decomposed readily by loss of water. However, using acetone or 3-pentanone chemical ionization, a number of adduct ions were produ ced, including the ions [M+43](+) and [M+59](+), or [M+57](+) and [M+8 7](+), respectively. The most probable protonation site of 2-methoxyet hanol and different conformations of the structures were studied by th eoretical ab initio calculations. Together, six different low-energy c onformers, where the proton is situated either on the ether oxygen or on the hydroxyl oxygen, were located.