Method development guidelines: SPE using ISOLUTE® SCX 2 sorbents for the extraction of aqueous samples

The ISOLUTE® family of cation exchange sorbents are used to extract organic cations (basic compounds capable of exhibiting a positive charge) from both aqueous and non-aqueous matrixes. Although extraction is by the same mechanism, each sorbent has properties that influence the way they are used.

Cation exchange SPE can be accomplished by strong (low pKa) and weak (higher pKa) ion exchangers. ISOLUTE® SCX-2, ISOLUTE® SCX and ISOLUTE® SCX-3 are strong cation exchangers. They maintain a permanent negative charge over the whole pH range (pH 1–14). ISOLUTE® SCX-2 has little non-polar character, so secondary non-polar interactions with analytes are very weak. This allows elution of analytes with a totally aqueous solvent if necessary. 

Literature number: TN107.V.1