DETERMINATION OF THE SUBSTITUTION PATTERNS OF CELLULOSE METHYL ETHERS BY HPLC AND GLC - COMPARISON OF METHODS

The substitution patterns of methyl cellulose as well as of a thexyldimethylsilyl cellulose after permethylation were determined by hydrolysis and separation of the resulting partially methylated glucoses without further derivatization by h.p.l.c.. On an amine-modified silica column the solutes get separated into glucose, 2,3,6-tri-0-methyl glucose and the groups of mono-0-methyl- and di-0-methyl glucoses. A chromatographic run on a reversed-phase column enables the identification of the single mono-0-methyl-and di-0-methyl glucoses. In this way, a determination of both the average degree of substitution and the substitution pattern of cellulose derivatives is possible. Comparison of the results with those obtained by standard methylation analysis including g.l.c.-m.s. proves the correctnes of the method employed.