第三章离子排斥色谱法方案.pptVIP

Fall Seminar 2000 Fall Seminar 2000 第三章 离子排斥色谱法（HPIEC） 3.1 离子排斥原理示意图 3.2 离子排斥色谱法分离机理 常见无机酸和有机酸在离子排斥色谱柱上的相对保留值 3.3 固定相 3.4 流动相 淋洗液浓度的影响 淋洗液浓度的影响 淋洗液中有机溶剂的影响 淋洗液流速的影响 色谱柱温度的影响 色谱柱温度的影响 3.5 检测 3.6 应用 有机酸的分离（ICE-AS6） * 9963 Ion Exclusion is widely used in the IC world for the determination of organic acids. The column material is a high capacity cation exchange material, in this example it is sulfonic acid. The mobile phase is typically an acid. At this eluent pH the organic acids (in this example acetic) are protonated and so neutral. The sulfonic acid groups of the column are also protonated and so neutral-this phenomenom creates what is known as the Donnan membrane. The analyte retention is due to interaction with the Donnan membrane. Organic acids are separated by their difference in pKa’s (and to a lesser degree hydrophobicity). Inorganic anions which cannot be protonated are not retained and so are “excluded”. Hence the name, Ion Exclusion. This technique is excellent for organic acid determinations in samples high in inorganic ion concentrations like acids and brines. 9963 Ion Exclusion is widely used in the IC world for the determination of organic acids. The column material is a high capacity cation exchange material, in this example it is sulfonic acid. The mobile phase is typically an acid. At this eluent pH the organic acids (in this example acetic) are protonated and so neutral. The sulfonic acid groups of the column are also protonated and so neutral-this phenomenom creates what is known as the Donnan membrane. The analyte retention is due to interaction with the Donnan membrane. Organic acids are separated by their difference in pKa’s (and to a lesser degree hydrophobicity). Inorganic anions which cannot be protonated are not retained and so are “excluded”. Hence the name, Ion Exclusion. This technique is excellent for organic acid determinations in samples high in inorganic ion concentrations like acids and brines.