Quantitative analysis of synthesized CG
Quantitative analysis of synthesized CG was carried out by HPLC (Thermo Fisher Scientific Inc.) equipped with a C18 column (Kinetex 5 mm, 150×4.6 mm) fitted with an ultraviolet-visible detector (UVD) at 25oC, and eluted with a binary solvent system consisting of solvent A (pH 3 water with H3PO4) and solvent B (acetonitrile). The chromatographic separation was carried out using 9.8% B as an isocratic elution at a flow rate of 1 mL/min. The eluate was monitored at 325 nm. The retention time of CG was approximately 7 min. Purified CG was used to construct standard curve, which was used to calculate the yield of CG using the Eq (1). Each analysis was performed in triplicate and reported as mean values.
(1)
Where YCG is the yield of CG;CCG is the concentration of CG measured by HPLC;V is the volume of the sample solution, mL;mCG is the theoretical mass of CG, mg.