Opus program version 7

FTIR measurements were performed by using the ATR accessory of the equipment. Samples were kept in amber vials until analysis at 4 °C. The spectral parameters of resolution and accumulation were selected as 4 cm⁻¹ and 16 scans, respectively. Data were acquired and processed by using the OPUS program Version 7.2 (Bruker Gmbh, Bremen-Germany). A quantity of 100 mL of each sample was dripped on the crystal, after which the diamond crystal of the ATR accessory was cleaned with pure ethyl alcohol. An air spectrum was used as a background spectrum prior to each acquisition.

All samples were kept at room temperature (25 °C) for 30 min prior to the FTIR analyses. An ATR accessory (single bounce) was used in all spectral acquisition. Spectral measurement parameters of resolution and accumulation were selected as 4 cm⁻¹ and 16 scans, respectively. OPUS program Version 7.2 (Bruker Gmbh) was used for instrument control and data acquisition. Each sample was placed on a diamond ATR crystal with the help of a Pasteur pipette. The ATR crystal was cleaned with ethanol (80% v/v) prior to each spectral acquisition. The background air spectrum was scanned before each acquisition.