混合溶剂作淋洗剂的体积排除色谱谱图中溶剂化高分子峰和溶剂峰之间内在关系的理论分析  

THEORETICAL ANALYSIS OF THE RELATIONSHIP BETWEEN SOLVATED POLYMER PEAK AND SOLVENT PEAK IN CHROMATOGRAMS FROM SIZE-EXCLUSION CHROMATOGRAPHY WITH MIXED ELUENTS

作　　者：王庆国[1] 李小文[1] 程时 

机构地区：[1]深圳大学化学与化工学院,深圳518060 [2]南京大学化学与化工学院

出　　处：《高分子学报》2008年第4期318-324,共7页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20474040)资助项目

摘　　要：根据体积排除色谱(SEC)研究高分子溶质优先溶剂化的基本原理,证明在SEC色谱图中被束缚溶剂产生的面积与自由溶剂产生的面积大小相等方向相反,在研究优先溶剂化时从高分子峰入手和从自由溶剂峰入手在理论上具有等价性.分析表明,通过对溶剂化高分子峰的研究,还可以得到另一个重要物理参数——恒化学位时高分子溶液的折光指数增量.Each size-exclusion chromatography （SEC） curve generally exhibits two peaks when a solvent mixture isemployed as the eluent. The first peak is the solvated-polymer peak and the second is the free-solvent peak. The area of the solvated-polymer peak A3^eff can be regarded as the sum of contributions from the naked-polymer A3 and from the extra polymer-bound solvent A1^＊ , The free-solvent peak, however, is caused by deficiency of the same solvent that enriches itself around polymer chains. Theoretical analysis shows that the size of free-solvent peak A2^＊ and that of the extra polymer-bound solvent A1^＊ are equal in magnitude but opposite in sign. This relationship suggests that the preferential adsorption coefficient λv can also be determined from the analysis of the polymer peak. Polystyrene （3）-benzene（1）-methanol （2） is the system taken to test the correctness of the theoretical analysis. The polystyrene （PS） sample was purchased from Krauer Company,with Mw = 9.26 × 10^4 ,and Mw/Mn = 1.1. Solvents （analytical grade purity） were purified before use. Benzene was purified by repeatedly shaking with concentrated sulphuric acid （15 vol% benzene） in a separating funnel until the acid phase remained colorless. The benzene phase was then washed with water, aqueous sodium hydroxide （10 wt% ）, again with water, dried withanhydrous calcium chloride, and finally distilled. Methanol was fractionally distilled, and the middle cut was used. The eluents were benzene-methanol mixtures of different compositions at a flow rate of 0.4 cm^3/min. The mixtures were made by volume and equilibrated in the reservoir of the GPC system. The injected sample solutions wereprepared using solvent mixtures from the solvent reservoir. The range of volume fraction of benzene in the eluent U10 was from 1.00 to 0.80. All measurements were conducted at room temperature with a Waters Associates model 244DS liquid chromatograph, equipped with a model R401 differential refractometer and a model 730 microcomp

关 键 词：体积排除色谱 优先吸附 混合溶剂 

分 类 号：O631[理学—高分子化学]