CHARACTERIZATION OF (METHOXYMETHYL)MELAMINE RESIN BY COMBINED CHROMATOGRAPHIC MASS-SPECTROMETRIC TECHNIQUES

Three complementary techniques were applied to the characterization of a complex (methoxymethyl)melamine mixture: gradient reversed-phase li quid chromatography/mass spectrometry (LC/MS), size-exclusion chromato graphy/mass spectrometry (SEC/MS) and capillary zone electrophoresis/m ass spectrometry (CZE/MS). The LC/MS system was used with an atmospher ic-pressure chemical ionization interface and the spectra obtained sho wed characteristic fragmentation patterns and detailed structural info rmation of the monomeric components: up to 18 individual monomeric and 7 dimeric components could be identified. The SEC/MS system was used with a (pneumatically-assisted) electrospray interface, thus providing sort ionization and molecular information about the trimers, the dine rs, and the monomers, indicating that the total number of components e xceeds one hundred. In addition, the applicability of CZE/MS and H/D-e xchange CZE/MS was demonstrated using a tricoaxial sheath-flow electro spray interface. The CZE separation turned out to be governed by the n umber of unreacted melamine positions only. Detailed structural inform ation could be deduced simply by combining the CZE migration behavior, the mass spectrometry data and the total number of exchangeable hydro gen atoms as calculated from the H/D exchange experiments.