示差折光和光散射双检测体积排除色谱的绝对定量化  

ABSOLUTE QUANTIFICATION FOR SIZE EXCLUSION CHROMATOGRAPHY WITH DIFFERENTIAL REFRACTOMETRY AND LIGHT SCATTERING DUAL DETECTORS

作　　者：刘承果[1] 谢鸿峰[1] 郑云[1] 程镕时[1,2] 

机构地区：[1]南京大学化学化工学院介观化学实验室高分子科学与工程系,南京210093 [2]华南理工大学材料学院高分子研究所,广州510640

出　　处：《高分子学报》2008年第11期1031-1036,共6页Acta Polymerica Sinica

基　　金：国家自然科学基金重点基金(基金号50633030)资助项目

摘　　要：讨论了示差折光和光散射联用双检测体积排除色谱的绝对定量化的原理,强调指出了试样注入量在数据处理中的重要作用.测量注入试样的这两种检测器的检测常数,可以同时得到试样的折光指数增量和重均分子量的绝对值.这一方法除了适用于各种均聚物外,还可以应用于高分子混合物的分析.此时,如将混合物看作为单一溶质,从所得折光指数增量和重均分子量,可对它们的组成作出定量分析,还可以判断共混物两个组分之间有无分子缔合等现象的产生.这一方法应用于聚甲基丙烯酸甲酯/聚苯乙烯(PMMA/PS)混合物的溶液,指明在四氢呋喃中两者产生缔合而形成了复合物.The principle of absolute quantification for size exclusion chromatography（SEC） with refractive index-light scattering（RI-LS） dual detectors was discussed with emphasis on the importance of the injected mass of the sample.By the measurement of the response constant of dual detectors for the injected whole sample,the specific refractive index increment （dn/dc）and the absolute weight average molecular weight（Mw） could be simultaneously determined.The proposed data treatment procedures are first applied to a series of narrow-MWD polystyrene（PS） samples for determining the values of （dn/dc） and Mw.The experimental relationship between dn/dc and Mw for PS is in coincidence with the theoretical formula derived from the end group effect.The correction of dn/dc when Mw〈10^4 must be considered.The proposed method is not only useful for homo-polymers,but is also applicable to polymer mixture and blends.Regarding an unlike polymer mixture with a given composition as a single solute,the specific refractive index increment and the absolute weight average molecular weight of the polymer mixture can be measured to decide whether molecular association between the two components happens or not.The method is illustrated by the system of poly（methyl methacrylate） and polystyrene（PMMA/PS） in THF solution.PMMA chains will partially associate with PS chains to form complexes.The Mw values of PMMA/PS mixtures in THF show a great positive deviation from the linear composition addition rule.The deviation is attributed to the formation of PMMA/PS complex.The complex formation could be described by a simple reaction scheme of nA＋mB=AnBm.Analyzing and fitting the experimental data yields：n=3,m=1/3 and an association constant of Ka=4.6×10^5.

关 键 词：体积排除色谱 RI-LS双检测器 检测常数 高分子混合物间的缔合 

分 类 号：O657.7[理学—分析化学]