Quantitative Analysis of Artificial Sweeteners by Capillary Electrophoresis with a Dual‐Capillary Design of Molecularly Imprinted Solid‐Phase Extractor

Abstract

A novel coupling system of capillary electrophoresis (CE) and monolithic molecularly imprinted polymer (MIP) was developed for selective and sensitive determination of sweeteners; sucrose, sucralose, and aspartame, based on an in‐column and open‐tube molecularly imprinted solid‐phase extraction (MISPE) concentrator. The MISPE was fabricated by coating a short layer of MIP material (about 3 mm long) directly at the inlet end of the inner wall of capillaries under the irradiation of light emitting diode (LED). Compared with the conventional methods using hydrodynamic injection by MISPE fiber, the MISPE concentrator provides increase in sensitivity without significant loss of separation efficiency. In this work, LED‐induced in‐multiple capillary MISPE was used for extraction and determination of artificial sweeteners, sucrose, sucralose, and aspartame, from beverage samples. The results of MISPE showed good extraction ability with the enrichment ratios of >150 for sucrose and sucralose, and of >200 for aspartame with acceptable analytical performance. The reproducibility of on‐line MISPE concentrator was 1.6% for sucralose and 2.7% for aspartame under the same fixed set of experimental conditions. The developed multiple MISPE system has been successfully adapted for practical application for commercial soda drink samples.