Circular dichroism of poly-D-glutamic acid adsorbed on air-water interfaces

A quartz cuvette was modified for use to determine the circular dichroism of molecules in thin films at airwater interfaces. By an application of the cuvette, circular dichroism spectra of poly-D-glutamic acid at air-water interfaces have been compared with circular dichroism spectra of the sample in aqueous solution. The results show that poly-D-glutamic acid is a beta structure on the surface of the solution in which the alpha helix or random coil is stable.