Substitution in cellulose ethers. Part II. Determination of the distribution of alkoxyl substituents on the glucose units using high-performance liquid chromatography

Abstract

A procedure is described for the quantitative characterisation of the distribution of alkoxyl groups in methyl- and ethylcelluloses. The total hydrolysate is derivatised by reaction with benzoyl chloride in sodium hydroxide solution. Several favourable implications of pre-column derivatisation for the subsequent separation by high-performance liquid chromatography are discussed. Isocratic separations are carried out on LiChrosorb Si100, 10 µm, using chloroform with 0.1 and 0.2%V/V ethanol as the eluent. All eight individual glucose ethers present in the hydrolysates, including the positional isomers of alkyl- and dialkylglucoses, can be determined quantitatively from the chromatograms. Thus, the procedure provides data on the distribution of substituents according to their number and position in the anhydroglucose units.