Experimental aspects of the high-speed membrane osmometer

Because several different workers in our laboratory have found the Mechrolab model 503 high-speed membrane osmometer 3 3 Hewlett Packard Company, Avondale, Pennsylvania. to be an instrument which is extremely sensitive to some seemingly unimportant steps in the experimental procedure used, we wish to communicate the experience obtained while working with aqueous solvents in this machine. We feel that this may help other workers who are, or will be, working with the osmometer. In our opinion, the steps outlined below represent the most efficient procedure for obtaining meaningful and reproducible data with the instrument.