We offer a complete range of mixed cellulose ester membranes, with a wide choice of pore sizes (from 0.2 to 3 µm) and diameters. The membranes are also available in sterile format and/or with a grid pattern that provides guidance for the quantification of microbial colonies without growth inhibition or enhancement. Whatman mixed cellulose ester membranes are composed of cellulose acetate and cellulose nitrate. The membrane offers a high degree of internal surface area for greater product adsorption. Mixed cellulose ester membranes are biologically inert and are a popular membrane filter choice in analytical and research applications.