Nicolet 360 ftir spectrometer

The M_w of TSP was measured by HPLC with a TSK gel G5000PWxl column (Tosoh, Tokyo, Japan) using 0.05 mol/L Na₂SO₄ as the mobile phase on an Agilent 1260 HPLC system (Santa Clara, CA, USA) equipped with a refractive index detector (Santa Clara, CA, USA). The column temperature was 35 °C, and the flow rate of the mobile phase was 0.5 mL/min. Dextran standards (1 kDa, 5 kDa, 12 kDa, 50 kDa, 80 kDa, 270 kDa, and 670 kDa; Sigma, Mendota Heights, MN, USA) were used to calibrate the column.
The total sugar content of TSP was analyzed by the phenol-sulfuric acid method [40 (link)] using galactose as the standard. Sulfate content was determined by the barium chloride gelatin method [7 (link)]. The molar ratios of the monosaccharide composition were determined according to the method of Sun et al. [41 (link)]. 1-Phenyl-3-methyl-5-pyrazolone (PMP) precolumn derivation HPLC was used to determine the molar ratio of the monosaccharide composition. Mannose, rhamnose, fucose, galactose, xylose, glucose, and glucuronic acid from Sigma-Aldrich (St. Louis, MO, USA) were used as standards. FTIR spectra of TSP were determined on a Nicolet-360 FTIR spectrometer (Thermo, Waltham, MA, USA) between 400 cm⁻¹ and 4000 cm⁻¹.

FTIR was used to analyze the functional groups present in inorganic hydroxyapatite and organic mineralized collagen fibrils (MCFs). The samples were vacuum freeze‐dried and recorded using a Nicolet™ 360 FTIR spectrometer (Thermo Fisher Scientific, Waltham, MA). A spectral range from 500 to 4000 cm^‐1 with a resolution of 2 cm⁻¹ was analyzed.