CDS Empore 2241 and 2341 Environmental SDB-RPS Disks are solid phase extraction (SPE) tools made from polystyrenedivinylbenzene-reversed phase sulfonate with a 12 µm particle size. These reversed-phase disks provide π-π and cation exchange interactions, ideal for the extraction of aromatic and positively charged compounds. Effective across a pH range of 1–14, they are suitable for applications involving drugs, pesticides, and metabolites under EPA 515.2 or related methods.