Determination of cyclodextrins in serum 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) in serum. The method involves solid-phase extraction of CDs, separation on a C18 reversed-phase column using a mixture of water, tetrahydrofuran and methanol as an eluent, eluent pH modification with a cation-exchange membrane reactor surrounded by 1.5 M sodium hydroxide solutions, and pulsed amperometric detection (PAD) with a gold working electrode. The solid-phase extraction on a C18 bonded-silica column was effective for removing the PAD sensitive components in serum. The calibration graphs constructed by internal standard method were linear over the range 6.25-200 pmol of CDs in serum. The detection limits for CDs were about 5 pmol at a signal-to-noise ratio of 3.