The chemical ionization mass spectra of cyclic glycols and monosaccharides using formaldehyde dimethyl acetal as reagent gas have been studied. In the gas phase, the stereospecific reaction of methylene acetal formation was observed. From the relative abundances of the characteristic ions the stereoisomers of these compounds may be definitely distinguished.

AbstractExtensive networks of metastable ions link the major peaks in the electron impact mass spectra of two crown ethers containing 2,6‐pyrido units. High‐resolution mass measurements and the metastable peaks allow the elucidation of the fragmentation pathways. The spectra are influenced more by the presence of aromatic substituents than by the 2,6‐pyrido units.