National Institute for Occupational Safety and Health

“ Determine the amount of water present in a bulk sample of the super absorbent polymer. Place an accurately weighed 20-g sample of the super absorbent polymer into an oven at 130 °C for about 16 hours. Determine the weight loss, and calculate the amount of water in the original sample (percent by weight) . Calibrate with at least six working standards. a. Prepare a series of working standards of super absorbent polymer in sucrose by dilution of portions of the calibration stock mixture with sucrose. ”

“ Cap the vial. Place the vial into an ultrasonic bath for 15 min. Collect the copper-polymer precipitate on a 25-mm cellulose ester filter (0.45-μm pore size) by vacuum filtration. NOTE: The copper-polymer precipitate should be collected within about 4 h after the addition of copper acetate solution to samples and blanks. Particles containing copper may appear in copper acetate solution if the solution stands for a few days. These particles would cause a positive interference. Rinse the vial with two 12-mL portions of deionized water, and add the rinses to the filtration apparatus. ”

“ Although PVC filters and interior surfaces of front pieces of cassette filter holders were analyzed in the Cu-SAP method, interior surfaces were not analyzed in the sodium method; thus, the comparisons above are for PVC filters only. Quantities of Sanwet IM-3500 found on interior surfaces of front pieces of cassettes ranged from 12 to 39% of the total quantities found. A bulk sample of Sanwet IM-3500 from the diaper plant contained 7.20% water. See additional information in reference [2] . ”