Page:NIOSH Manual of Analytical Methods - 5035.pdf/4

 SUPER ABSORBENT POLYMERS: METHOD 5035, Issue 1, dated 15 August 1994 - Page 4 of 6 in the calibration range (8 to 1000 µg is an approximate calibration range). Shake each dilution in a 20-mL vial by hand for about 5 min, and then grind each mixture in a freezer mill (cooled with liquid nitrogen) for 12 min or with a mortar and pestle. NOTE: Although the super absorbent polymer in the calibration stock mixture and working standards may contain water, it is convenient to express a quantity of super absorbent polymer on the basis of anhydrous super absorbent polymer. b.

17.

Prepare six samples at each level and six blanks. For each sample, accurately weigh 50 to 300 mg of a working standard (polymer-sucrose mixture) in a 20-mL vial with a five-place balance. c. Add 5 mL of deionized water to each vial. Agitate each vial to dissolve the sucrose. d. Add 6 mL of 0.07 M copper acetate solution [filtered (see step 5)]. e. Place each vial into an ultrasonic bath for 10 min. f. Collect the copper-polymer precipitates (steps 8 and 9), prepare samples (step 14), and analyze samples (steps 18 and 19). g. Prepare a calibration graph of instrument response for copper versus µg of anhydrous super absorbent polymer. Estimate recovery (R) of super absorbent polymer from 37-mm PVC membrane filters. a. Prepare six samples at each level. For each sample, accurately weigh 50 to 300 mg of a working standard polymer-sucrose mixture) in a 20-mL vial on a five-place balance. Place a 37-mm PVC filter into each vial. b. Follow steps 9, 11 through 14, and 18 and 19. c. Determine each quantity of super absorbent polymer found from the calibration graph (step 16. g). d. Calculate the recovery for each sample by dividing the quantity of super absorbent polymer found by the original quantity of polymer. NOTE: Each recovery is an estimate because the PVC filters have not been fortified with super absorbent polymer.

MEASUREMENT: 18. 19.

Set instrument for measurement of copper according to conditions specified by the manufacturer. Analyze samples and standards. NOTE: If the concentrations of the samples are above the range of the standards, dilute the samples with dilution acid, reanalyze, and apply the appropriate dilution factor in the calculations.

CALCULATIONS: 20. 21.

Determine the quantity (corrected for recovery) of anhydrous super absorbent polymer in µg, W, in the air sample from the calibration graph (step 16. g). Calculate the concentration, C, of the super absorbent polymer in the air volume sampled, V (L):

EVALUATION OF METHOD: This method was evaluated with Sanwet IM-3500, Water Lock A-100, Water Lock B-204, and Water Lock G-400. Average ratios of quantity of copper found to quantity of anhydrous Sanwet IM-3500 were 0.66, 0.78, 0.69, 0.72, 0.63 and 0.57 for 8-, 16-, 32-, 63-, 515-, and 1466-µg quantities of anhydrous polymer (values of S r for the average ratios were 0.34, 0.12, 0.13, 0.05, 0.05, and 0.03, respectively; NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94