Dec 15, 2010 · Adsorption equilibrium was further studied in the 0.45-μm NYL, PTFE, RC, CA, GMF filters and the 0.2-μm PP filter using a series of 1 ml feed solutions. In each test, a total of 10 ml estrone solution was fed into the filter, where 10 permeate samples, each of a volume of 1 ml, were collected and analysed by HPLC separately.