2.5 ATR-FTIR spectroscopic measurements.
ATR-FTIR spectra were recorded in a 600–4000 cm-1range, at a resolution of 4 cm-1, using a Fourier Transform Infrared spectrometer 670-IR equipped with an ATR device (Varian Inc., now Agilent Technologies Inc., Santa Clara, CA, USA). 32 scans were summed for each acquisition.