Spectrum 100 system

FTIR was performed as described earlier (36 (link)). Briefly, functional groups of lyophilized samples were monitored using potassium bromide (KBr) pellet method (1:100 w/w). To create translucent 1 mm pellets, potassium bromide was combined with lyophilized samples (0.8–1.0 mg) and pressed with 7500 kg for 30 seconds. Spectra were recorded using the translucent pellet in Perkin Elmer Spectrum 100 system in the spectral region of 4000–400/cm.

The functional groups of the nHAP, Eu-nHAP/CS, Y-nHAP/CS, and Eu,Y-nHAP/CS composites were analyzed through the KBr pellet technique with Fourier transform infrared spectroscopy (FTIR) using a Spectrum 100 system (PerkinElmer Inc., Waltham, MA, USA). To analyze the crystallographic properties of the samples, X-ray diffraction (XRD) measurements were conducted using a X’Pert PRO system (PANalytical, Almelo, the Netherlands) equipped with a CuKα radiation source (operating voltage: 40 kV and current: 30 mA). The surface topographies of the samples were analyzed with field emission scanning electron microscopy (FE-SEM) using a SIGMA VP system (ZEISS, Oberkochen, Germany).