Determination of cyclodextrins and branched cyclodextrins by reversed-phase chromatography with pulsed amperometric detection and a membrane reactor.

A high-performance liquid chromatographic method has been developed for the determination of cyclodextrins (CDs) and branched CDs. The method involves their separation on a reversed-phase column using a mixture of water and acetonitrile as an eluant, eluant pH modification with a cation-exchange membrane reactor surrounded by 1.5 M sodium hydroxide solutions, and pulsed amperometric detection with a gold working electrode. The calibration graphs constructed by peak height versus injected amount were linear over the ranges 50-1000 pmol. The detection limits for CDs and branched CDs were about 1-5 pmol at a signal-to-noise ratio of 3. The method was successfully applied to the assay of beta-CD in serum samples.