Liquid-nitrogen -cooled ZnSe

A modified out-of-compartment IRE holder (SPECAC) that could be configured as a 125 pi flow cell was used for this study. The IREs used here measure 72x10x6 mm they have a 45° angle of incidence, and 7 internal reflections. Interferograms were collected on a Nicolet 800 FTIR spectrometer equipped with a liquid nitrogen cooled MCT detector. For each spectmm, 1000 interferograms were co-added at 4 cm resolution (total collection time 6 minutes). Duplicate data sets were collected on Ge and ZnSe IREs. For each spectmm, 500-1000 pi of a 3 or 30mg/ml protein solution (20 mM phosphate, pH 7.0) were used. The protocol developed for the collection of solution spectra is summarized in Table I. 

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