1068
Anal. Chern. 1980, 52, 1068-1071
Interference of Contaminants from Membrane Filters in Ultraviolet Spectrophotometry David 0. Cooney Department of Chemical Engineering, Clarkson College of Technology, Potsdarn, New York 13676
One polycarbonate and six cellulosic filter membranes were studied for their release of UV-absorbing contaminants into aqueous solutions of various pH values. Contaminant release was signlficant and the apparent level was strongly dependent on the UV wavelength used for analysis. Studies were performed to determine the rate and amount of contaminant release into an adjacent stationary fluid as a function of time. Also, the amount of contamination in a fluid during continuous filtration was determined as a function of filtration rate and volume. The effect of prewashing membranes for an extended duration with various volumes of prewash fluid was studied. With sufficient volumes, the prewash was very effective in minimizing contaminant release during subsequent use of the membranes.
Table I. Membrane Filter Characteristics
material
I I1 I11
polycarbonate mixed cellulose esters mixed cellulose acetate and nitrate mixed cellulose acetate and nitrate cellulose triacetate mixed cellulose esters cellulose triacetate
IV V VI VI1
none 2.5
2.5 none
