Multi-beam circular dichroism detector for HPLC

A novel multi-beam circular dichroism (CD) detector for HPLC is described. A unique feature of this detector is the use of a retardation plate to give many quarter-waves in the wavelength region of interest. When a polarizing prism and a thin quartz plate as the retarder are placed in a conventional photodiode array (PDA) detector, the kinetic spectra of an optically activ e analyte recorded by the instrument contain sinusoidal CD waves in the wav elength axial direction. Extraction of these CD waves superimposed on the a bsorption spectra was performed with MS Excel. Both the instrumental condit ions for the PDA data acquisition and the polynomial data processing were o ptimized by monitoring the chromatographic elution of camphor. The limit of detection for ajimaline, a chiral alkaloid, was 26 ng injected amount.