1.1 This test method covers the evaluation of the molecular weight cutoff of flat sheet ultrafiltration membranes with cutoffs between 4500 and 1000000 daltons. The nonadsorbing characteristics of the test penetrant utilized by this test method permit the test to be performed on a wide variety of membrane substrates, excluding those which strongly adsorb dextran, from highly hydrophilic to highly hydrophobic. This test method is not applicable for microfiltration membranes with pore sizes of 0.01 µm or larger, nor for reverse osmosis or dialysis membranes with less than 4500 molecular weight cutoff. (It is possible that this test method could be modified to expand the range from 100 to 2 000 000 daltons.) This test method is not applicable to membrane materials that strongly adsorb dextrans since these materials will potentially change the value of the measured molecular weight cutoff and hence will invalidate the test results.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.