Comparison of mid-infrared Fourier transform vibrational circular dichroism measurements with single and dual polarization modulations.

Fourier transform infrared vibrational circular dichroism (FTIR-VCD) measurements have gone through major advances in the last decade. A major thrust in these advances was to find ways that can minimize the VCD spectral artifacts and obtain the VCD signals at enhanced signal quality. However, all these advances are not incorporated in FTIR-VCD instruments manufactured by some commercial manufacturers. In this article, we compare the measurements obtained with single and dual polarization modulations to seek the attention of the users of single polarization modulation method in minimizing the artifacts in such measurements. We also report that the VCD spectrum of a home-made collagen film can serve as a simple and convenient sample for routine verification of the correct functioning of the VCD spectrometers.