Ion chromatography is a type of high performance liquid chromatography. In principle, ion chromatography can be divided into ion exchange chromatography, ion pair chromatography, and ion exclusion chromatography. In principle, ion chromatography can be divided into ion exchange chromatography, ion-pair chromatography, and ion exclusion chromatography.

1. Sub-chromatography Separation by ion chromatography is mainly based on the principle of ion exchange. Ion-exchange resin with low exchange capacity is used to separate ions. It is widely used in ion chromatography. Its main type of packing is organic ion exchange resin.

2. The stationary phase of the sub-pair chromatographic ion-pair chromatography is a hydrophobic neutral packing, and the counter ions used for anion separation are alkyl amines such as tetrabutylammonium hydroxide and hexadecyltrimethylammonium hydroxide. The counter ions used for cation separation are alkyl sulfonic acids such as sodium hexane sulfonate, sodium heptane sulfonate and the like.

3. Substance exclusion chromatography Chromatography ion exclusion chromatography is mainly based on the Donnon membrane repulsion effect: ionized components are not preserved due to repulsion, while weak acids are preserved by a certain principle of preservation. Ion exclusion chromatography is mainly used to separate organic acids and inorganic oxygenates, such as borate, carbonate and sulfate, and organic acids.

4, the application of sub-chromatography inorganic anion detection; inorganic cation detection and organic anion and cation analysis, including bio-amines, organic acids and carbohydrate analysis.

In specific experiments, suitable separation methods should be selected in combination with actual conditions, for example, high hydration energy and weak hydrophobic ions, such as Cl- or K, preferably separated by HPIC. Ions with low hydration energy and high hydrophobicity, such as perchloric acid (ClO4-) or tetrabutylammonium, are preferably separated by a highly hydrophilic ion exchange column or MPIC. An ion with a pKa value between 1 and 7, which has a certain degree of hydrophobicity and significant hydration energy, such as acetate or propionate, is preferably separated by HPICE. Some ions can be separated by anion exchange or cation exchange, such as amino acids, alkaloids and transition metals.