【摘要】 研究了离子排斥色谱中色谱柱温度对有机酸(脂肪酸、芳香酸)保留的影响。采用Shim-pack SCR-102H离子排斥柱,分别以0.2 mmol/L p-甲苯磺酸为淋洗液分离6种脂肪族有机酸(甲酸、乙酸、丙酸、丁酸、戊酸和己酸)以及0.08 mmol/L H2SO4为淋洗液分离6种芳香酸(邻苯二甲酸、水杨酸、苯乙酸、对羟基苯甲酸、苯甲酸、邻甲苯甲酸),流速为1.2 mL/min,柱温控制为25～50℃,直接电导检测。结果表明,有机酸的保留值随温度升高而减小。但每种有机酸的保留受温度的影响程度不同,即当温度改变时,每种有机酸保留值的变化程度不同。一般规律为:有机酸的保留越强,其保留值随温度的变化程度越大。依据范特霍夫曲线的线性回归数据,可知有机酸的范特霍夫曲线具有良好的线性关系,其保留为放热过程。通过改变柱温,可以实现有机酸,特别是强保留有机酸保留值的改变,改善有机酸的色谱峰形和分离状况。更多还原

【Abstract】 The effect of column temperature on the retention behavior of organic acids(aliphatic carboxylic acids and benzenecarboxylic acids) in ion-exclusion chromatography with direct conductivity detection was investigated.Chromatographic separations of organic acids were performed on a Shim-pack SCR-102H ion-exclusion column using p-toluenesulfonic acid or sulfuric acid as mobile phase with a flow rate of 1.2 mL/min at various column temperatures from 25 ℃ to 50 ℃.The separations of six common aliphatic carboxylic acids(formic acid,acetic acid,propionic acid,butyric acid,valeric acid and caproic acid)were performed using 0.2 mmol/L p-toluenesulfonic acid as mobile phase.Six kinds of benzenecarboxylic acids(o-phthalic acid,salicylic acid,benzene acetic acid,p-hydroxybenzoic acid,benzoic acid,o-methylbenzoic acid) were eluted and separated using 0.08 mmol/L sulfuric acid as mobile phase.The results indicated that the retention values of organic acids were decreased with the increase of column temperature.However,for each organic acid,the effect degree of temperature is different.That is to say,the variations of retention values for each organic acid are different with the change of temperature.In general,the variations of retention values for strongly retained organic acids are greater than that for weakly retained species.Through the linear regression data,the conclusion that the linearities of the Vant Hoff plots for organic acids are satisfactory may be derived.By changing the column temperature,the retention value variations of organic acids(especially the strong retain organic acids) can be realized,the peak shapes and separations of organic acids can be improved.更多还原