RAMAN OPTICAL-ACTIVITY INSTRUMENT FOR BIOCHEMICAL-STUDIES

A simple and fully computer-controlled backscattering incident circular polarization Raman optical activity (ICP ROA) instrument suitable for chiroptic studies of biologically significant molecules in aqueous solution is described. It consists of a fast single-stage monochromator equipped with a holographic edge filter, a highly efficient holographic diffraction grating and a thinned back illuminated thermoelectrically cooled charge-coupled device detector as the key spectral elements. A longitudinal electro-optic modulator is employed to switch between orthogonal circular polarization states in the incident laser radiation within a backscattering geometry. A thick Lyot depolarizer is used for the depolarization of the backscattered Raman radiation. High-quality backscattering ICP ROA spectra of (1S)-(-)-trans-pinane, (1R)-(+)-trans-pinane, L-alanine, L-alanyl-L-alanine, lysozyme, D-glucose, alpha-D-cyclodextrin and 2'-deoxycytidine are presented as typical examples of the excellent performance characteristics.