表面活性剂与叶酸的相互作用及其对光氧化降解的影响  

Interactions between Surfactants and Folic Acid and the Effects of Surfactants on the Photodegradation of Folic Acid

作　　者：罗思琪 王美娜 赵微微 王毅琳[1,2] LUO Siqi;WANG Meina;ZHAO Weiwei;WANG Yilin(Key Laboratory of Colloid,Interface and Chemical Thermodynamics,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,P.R.China;University of Chinese Academy of Sciences,Beijing 100049,P.R.China)

机构地区：[1]中国科学院化学研究所,胶体界面与化学热力学实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《物理化学学报》2019年第7期766-774,共9页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21633002)资助项目~~

摘　　要：表面活性剂与有机小分子作用不仅能提高表面活性剂的聚集能力,还能提高小分子的溶解度、稳定性等应用性能,因此研究二者之间的相互作用机理对于促进表面活性剂的发展和实际应用具有重要意义。本工作提出了一种利用功能有机小分子调控表面活性剂聚集行为,进而提高不稳定小分子自身稳定性的新策略。利用表面张力、紫外可见吸收光谱、荧光光谱、动态光散射、等温滴定量热和核磁共振技术研究了在pH为7.0时,叶酸分别与十二烷基硫酸钠(SDS)、十二烷基三甲基溴化铵(DTAB)、季铵盐Gemini 12-6-12和季铵盐线性三聚12-3-12-3-12四种表面活性剂之间的相互作用及其导致的叶酸光氧化降解性能的变化,结果表明,阴离子表面活性剂SDS抑制叶酸光氧化降解的效率较低,而阳离子表面活性剂都能够显著抑制叶酸的光氧化降解,且随着表面活性剂寡聚度的增加,抑制效果增强,所需表面活性剂的浓度显著降低,寡聚表面活性剂12-3-12-3-12的抑制效率高达96%。Interactions between surfactants and small organic molecules not only enhance the surface activity of the surfactants and induce aggregate transitions in them, but also improve the solubility and stability of the organic molecules. Understanding the interaction between surfactants and small molecules will help in widening the scope of application of surfactants. Folic acid, a member of the vitamin B family, has a pteridine ring, paraaminobenzoic acid, and glutamic acid, and is crucial for many reactions inside the human body. The unique structure of folic acid also facilitates the preparation of functional materials such as liquid crystals and gels. However, the poor solubility and precipitation of folic acid limit its applications. Therefore, it is essential to improve the solubility and stability of folic acid. Surfactants are efficient in solubilizing and stabilizing small molecules. The interactions of folic acid with four types of surfactants, namely, an anionic surfactant, sodium dodecyl sulfate (SDS);a cationic surfactant, dodecyl trimethylammonium bromide (DTAB);a cationic ammonium gemini surfactant, 12-6-12;and a cationic ammonium trimeric surfactant, 12-3-12-3-12;have been investigated at pH 7.0 by surface tension measurements, ultraviolet-visible (UV) absorption spectroscopy, dynamic light scattering, isothermal titration calorimetry, and nuclear magnetic resonance spectroscopy. At pH 7.0, the carboxylic acid groups of folic acid are deprotonated, so each folic acid molecule carries two negative charges. The addition of a small amount of folic acid sharply reduces the critical micelle concentration (CMC) of cationic surfactants and their surface tension at the CMC. However, the surface activity and aggregation of SDS show only minimal changes with the introduction of folic acid. In addition, the photodegradation of folic acid in the presence of different surfactants is studied by fluorescence and UV absorption spectroscopy. When irradiated with UV light, folic acid undergoes rapid degradation in aqueou

关 键 词：叶酸 表面活性剂 寡聚度 相互作用 光氧化降解 

分 类 号：O648[理学—物理化学]