Analysis of sucrose acetates in a crude 6-O-acetyl sucrose product by on-line hydrolysis-high-performance liquid chromatography with pulsed amperometric detection.

A standard-free and sensitive method was developed for analysis of sucrose acetates in a crude 6-O-acetyl sucrose (S-6-a) product by on-line hydrolysis-high-performance liquid chromatography with pulsed amperometric detection (PAD). Sucrose, three regio-isomers of acetyl sucrose and five regio-isomers of diacetyl sucrose were separated on a C18 column using 3% (v/v) acetonitrile in water as eluent within 25min. After purification with LC followed by semi-preparative HPLC, their chemical structures were identified by 1D, 2D NMR and LC-MS. Moreover, quantification of those regio-isomers was achieved by on-line alkaline hydrolysis to liberate sucrose using a post-column delivery system, and then detected by PAD for indirect estimation of the sucrose acetate content. Under optimal conditions, the linear ranges were from 0.03 to 150μmolL(-1) for sucrose corresponding to sucrose acetates with coefficient of determination as 0.9997 and detection limit as 0.01μmolL(-1) (S/N=3). Good repeatability was obtained (RSD<3%, n=6). Furthermore, this method has been successfully applied to the analysis of sucrose and sucrose acetates in a crude S-6-a product during synthesis, purification and structure elucidation studies. The recoveries were from 94.89% to 102.31% for sucrose and sucrose acetates.