Amino acid derivatized maltodextrin as a new chiral selector for enantioseparation of four basic drugs using capillary electrophoresis

Today capillary electrophoresis, as one of the most used techniques for enantioseparation is highly regarded due to its prominent advantages of low consumption of samples/buffers, great efficiency, short migration times, versatility and simple instrumentation. Direct addition of a chiral substance known as a chiral selector (CS) to the background electrolyte (BGE) is a common method of chiral separation in CE. Introducing a new class of chiral selectors is an interesting work and this issue is still one of the hot topics in separation science and chirality [1-3].In this work, amino acid derivatized maltodextrin (ADM) was synthesized as a new anionic chiral selector for the first time and the structure of ADM was characterized by 1H-NMR, 13C-NMR, FT-IR spectroscopy, and elemental analysis. Then this new synthetic compound was successfully evaluated as a novel anionic chiral selector for the enantioseparation of basic chiral drugs (citalopram, hydroxyzine, fluoxetine and trihexyphenidyl) as model chiral compounds using capillary zone electrophoresis (CZE). The most important parameters affecting the resolution such as the concentration and pH of the background electrolyte (BGE), the chiral selector concentration, the temperature and applied voltage were optimized. Under the optimized conditions (buffer solution: 50 mM phosphate (pH 4.5-6) and 2-5% (w/v) ADM; applied voltage: 18 kV; temperature: 25°C), baseline enantioseparation was observed for all mentioned chiral drugs. No enantioseparation was observed when instead of ADM, neutral maltodextrin (MD) was used under the same conditions; which means the resolution power of ADM is much higher than MD due to this fact that ADM can offer not only an inclusion complexation interaction, but also strong electrostatic interactions.