Page:NIOSH Manual of Analytical Methods - 2501.pdf/4

 ACROLEIN: METHOD 2501, Issue 2, dated 15 August 1994 - Page 4 of 4 APPENDIX: SORBENT PREPARATION Add 1 g of the purified 2-(hydroxymethyl)piperidine in 50 mL of toluene for each 9 g of extracted XAD-2 sorbent. Allow this mixture to stand for 1 h with occasional swirling. Remove the solvent by rotary evaporation at 37 °C and dry at 130 Pa (1 mm Hg) at ambient temperature for approximately 1 h. To determine the amount of background for each batch, desorb several 120-mg portions of the coated sorbent with toluene and analyze using steps 6 through 11. No blank peak is expected for acrolein although a blank for formaldehyde and acetaldehyde may be observed. DESORPTION EFFICIENCY The determination of desorption efficiency (DE) is not necessary when using the calibration procedure outlined in this method. The following procedure can be used to determine DE, if necessary: a. Using a 10-µL syringe and the calibration stock solution inject four sampling tubes at each of five levels. Open several blank tubes but add no acrolein to them. Cap all the tubes. b. Using the 10-µL syringe, spike the calibration stock solution into 4-mL vials containing 2 mL of toluene and 10 mg of purified 2-(hydroxymethyl)piperidine. Prepare four replicate vials at each of the five concentrations used in step a. c. Allow the spiked tubes, spiked standard solutions and blank tubes to stand overnight at ambient temperature to assure complete reaction. Desorb and analyze the spiked and blank tubes according to steps 4 through 11. Analyze the spiked solutions according to steps 10 and 11. d. To calculate the recovery, compare the blank-corrected peak areas or heights of the acrolein peak found in the spiked tubes (Q r - B) to the peak area or height of the acrolein peak found in the spiked solutions (Q a).

e.

Prepare a graph of DE vs. mg acrolein recovered.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94