PITC-TREATED SILK FIBROIN FIBERS: DIRECT TREATMENT AND PRELIMINARY ATR-FTIR ANALYSIS

This study provides a preliminary assessment of the direct treatment of natural silk fibroin (SF) fibers with phenyl isothiocyanate (PITC) in dimethyl sulfoxide (DMSO), without dissolving and regenerating the fibers. The experimental design included untreated SF and DMSO-treated control samples, as well as samples treated with 0.25–2.00 mL of PITC at 55 °C for 7 h and a sample treated with 1.00 mL of PITC at room temperature for 24 h. The ATR-FTIR spectra of seven samples were examined over an approximate range of 400–4000 cm⁻¹. The characteristic amide I, amide II, and amide III regions of silk fibroin were retained in all spectra. At the same time, certain spectral differences were observed between the PITC-treated samples and the control samples. However, because the point density of the exported spectra and the coverage of the 2000–2200 cm⁻¹ region were not sufficiently uniform, a definitive conclusion based on the characteristic isothiocyanate band could not be drawn. These results provide a preliminary basis for further, more detailed characterization of functionalized natural silk fibers and for subsequent evaluation of their sorption of Au(III) ions.