Ontwsep™ C18 is a reverse phase C18 extraction cartridge that uses high purity spherical silica as its matrix. It possesses a high carbon content, excellent hydrophobicity, and chemical stability, as well as efficient non-polar component retention. It is primarily used to extract and purify medicines and their metabolites from blood, plasma, and urine, desalinate macromolecular materials such as proteins and DNA, and enrich organic substances in environmental water samples.