Infrared spectra were collected using a Thermo Electron Nicolet 4700 Fourier transform IR spectrometer using a DTGS detector and fitted with a grazing angle accessory from the same manufacturer. Spectra were taken using p-polarized infrared radiation produced by fitting an inline KRS-5 linear polarizer. A grazing angle of 86° relative to the normal plane of the sample was used. A resolution of 4 cm -1 was used. Spectra were baseline corrected using manual baseline correction in the manufacturer's OMNIC software package.