ANALYSIS OF CATIONIC STARCHES - DETERMINATION OF THE SUBSTITUTION PATTERN OF O-(2-HYDROXY-3-TRIMETHYLAMMONIUM)PROPYL ETHERS

A method was developed to determine the substitution pattern of O-(2-h ydroxy-3-trimethylammonium)propyl ethers of starch. As model compounds cationic cyclomaltoheptaose and cyclomaltooctaose were prepared. Afte r cleavage of the glucosidic linkages by methanolysis und subsequent p ermethylation, the positively charged substituents were transformed to the neutral O-(2-methoxy)-2-propenyl ethers. These compounds could di rectly be separated by capillary GLC or after mild hydrolysis as the m ore stable O-(2-oxo)propyl derivatives. To halve the number of degrada tion products, the methyl glucosides could be reduced to the correspon ding 1,5-anhydroglucitols. Results for two model compounds [degree of substitution (ds) 0.33 and 0.46] and three cationic starches (ds 0.02- 0.05) are given.