用荧光光谱跟踪钙-海藻酸水溶液的Sol-gel转变

Fluorescence Spectrum Study of Sol-gel Transition in Alginate Aqueous Solutions Induced by Calcium Cations

为了克服传统方法在测定凝胶化点的同时,作用力对物理交联点的破坏和对大分子链运动的干扰,探索和建立不施加应力的凝胶化点测定方法,采用荧光光谱跟踪了异硫氰酸荧光黄(FITC)标记海藻酸与钙离子在水溶液中螯合的物理凝胶化.随着凝胶化的进行,荧光相对强度和各向异性比在凝胶化时间曲线的80 min时出现了明显的转折点,与Winter方法得到的凝胶化点(80 min)完全一致.因此可以利用FITC标记的荧光发射相对强度及各向异性比来决定钙-海藻酸体系凝胶化点.

In order to establish an experiment method to determine the gelation point for the physical gelation without disturbing the system mechanically, the fluorescence spectrum was used to monitor the sol-gel transition in the aqueous solutions of FITC labeled alginate induced by Ca^2＋. The slope change was found from the curves of the emission strength and fluorescence anisotropy against gelation time, indicating the gelation time of 80 min, which just equaled that determined by rheology measurement. The label fluorescence strength and anisotropy can be used to determine the gel point for the physical gelation.