Abstract

Circular dichroism (CD) is the differential absorption of a sample with respect to the right and left circularly polarized light components. Widely employed in Proteomics, Pharmaceutics, Food control, Biotechnology and Material Science, CD spectroscopy is an important experimental technique for the investigation of chiral molecules and supramolecular structures (i.e., amino acids, proteins, DNA/RNA). CD spectroscopy provides information about the isomeric purity of a sample, but is mainly used for peptides and proteins conformation studies, both in solutions and in thin films. Conventional CD spectrometers rely on the modulation of the polarization of a monochromatic light between the left and right circular states. Beside an intense broad-spectrum light source, they basically comprise a monochromator, a polarizer, a phase-modulator and a phase-sensitive detector. The acquisition of a CD spectrum occurs in a sequential way, one wavelength at a time, therefore limiting their spectral rate in kinetic processes investigations. Moreover, because of the working principle, conventional CD spectrometers are prone to show artefacts in cases of non-random distribution in the orientation of molecules (i.e. thin film).

© 2009 IEEE