PEP, HXN, PS. They are all based on polystyrene/divinylbenzene, which has a larger surface area and a greater capacity compared with silica based sorbents. PS is the alternative of Waters Oasis HLB. The polarity of HXN is between the polarity of PS and PEP. It is designed for the extraction of sulfonylureas from water and soil. It can also be used to extract, enrich and clean up samples from mid polar to high polar compounds. Average particle diameter: 35µm; Average pore size: 80Å; Specific surface area: 600m2/g.