Remove hydrophobic substances such as aromatic dyes, some aromatic carboxylic acids, hydrocarbons, and surfactants from sample matrices to improve IC performance and facilitate low-level ion analysis. Thermo Scientific™ Dionex™ OnGuard™ II RP Cartridges are an off-line sample preparation technique that uses a macroporous divinylbenzene resin with very high selectivity for hydrophobic substances to eliminate these matrix interferences. Use these cartridges singly or in series, or pretreat up to 12 samples in parallel using the optional Thermo Scientific™ Dionex™ OnGuard™ Sample Prep Station.