Ion-exchange solid-phase extraction cartridge achieves the purpose of separation through high-energy interactions between ions. Strongly polar solutes can be separated from highly polar water or other solvents. The exchange capacity of strong ion exchange resins is not affected by pH, while weak ion exchange resins depend on changes in pH.
The carrier of the strong cation column is resin or silica gel exchange resin, and the exchange group is sulfuric acid [-SO-3H+];
The weak cation exchange group is a carboxylic acid, which is often used to analyze basic substances (such as catecholamines, purines, and pyrimidines);
The exchange group of the strong anion exchange resin is the fourth amine [-N+(CH3)3];
The exchange groups of weak anion exchange resins are the first and second amines or aminoalkyl groups, and are often used in the analysis of acidic substances (such as bile acids, nucleosides, fatty acids, organic acids, and vitamins).
The separation objects are ionic compounds. For acidic compounds, such as organic acids, inorganic anions, acidic proteins, etc., anion-exchange SPE columns are generally used;
For basic compounds, such as organic amines, metal ions, catecholamines, and basic proteins, a cation-exchange SPE column is used.