荧光探针法研究N-月桂酰基-N′-羟乙基乙二胺乙酸盐的微极性

Studies on the Microenvironmental Polarity of N-Lauryl-N′-Hydroxyethylethylenediamine Acetate by Fluorescence Probe

用荧光光谱法测定N-月桂酰基-N′-羟乙基乙二胺乙酸盐(两性乙酸钠)的微极性。芘的荧光强度随着两性乙酸钠浓度的增加而减小,其第一峰(I1)和第三峰(I3)的强度随两性乙酸钠浓度的增加先降低,到达一定浓度后,趋于稳定。由芘的I1/I3与浓度关系可以得出两性乙酸钠的临界胶束浓度(CMC值大约为1.03mmol/L),与表面张力法(1.02mmol/L)测定结果一致。同时研究了无机盐的加入对芘的I1/I3值的影响,无机盐的加入使芘的I1/I3值减小,即无机盐的加入使芘所处的微环境极性减小。

The microenvironmental polarity of N-lauryl-N′-hydroxyethylethhylenediamine acetate（amphoteric sodium acetate） was determined by Fluorescence Probe. When the concentration of amphoteric sodium acetate increased, the fluorescence intensity of the first and third vibronic bands decrease until the concentration reached about 1.0mmol/L and then maintained stable. The critical micelle concentration （CMC） of amphoteric sodium acetate was obtained through analyzing pyrene monomer fluorescence spectrum. The CMC was about 1. 03mmol/L which was consistent with the result （1.02mmol/L） of the surface tension method and the impact of inorganic salt on the value of I1/I3. The addition of inorganic salt made the value of I1/I3 decreased, which meaned microenvironmental polarity decreasied with the adding of inorganic salt.