Whatman Puradisc Aqua 30 from Cytiva's business is specifically designed for environmental sample filtration prior to dissolved organic carbon (DOC) and chemical oxygen demand (COD) analysis. From the Puradisc FP 30 range Low protein binding, hydrophilic cellulose acetate syringe filter media Prewashed cellulose acetate (CA) syringe filter for reduced organic carbon extractables Designed for sample preparation in support of dissolved organic carbon and chemical oxygen demand analysis Standard inlet and outlet luer connectors Recyclable after use. Learn how you can recycle it. Prewashed, hydrophilic CA syringe filter DOC (dissolved organic carbon) and COD (chemical oxygen demand) analysis are common methods to determine organic pollutant levels. Precisely filtering a sample is a crucial step in DOC and COD, and the quality of the syringe filter should preserve sample integrity. Aqua 30 Puradisc syringe filters come prewashed, designed to minimize carbon leaching from the cellulose acetate membrane that could otherwise lead to sample contamination. Cytiva's Whatman quality – lab testimonial Water and Waste GmbH, a premier Austrian water-testing laboratory has high praise for Cytiva's Whatman syringes and membrane filters.