National Institute for Occupational Safety and Health

“ Add exactly 15 mL Girard T solution to each bubbler using a 15-mL pipet. Mark the initial liquid level in the bubbler with a glass marker. Make impinger-to-trap and trap-to-sampling pump connections with flexible inert tubing. 3.
Sample at an accurately known flow rate between 0.1 and 0.5 L/min for a total sample size of 6 to 60 L. NOTE:
Higher flow rates will cause frothing of the collection medium. If amount of liquid condensed in the trap is greater than 1 mL, collection efficiency of bubbler may be reduced and sample may be invalid. ”

“ Tap bubbler stem lightly against bubbler body to drain contents into the body. If necessary, bring samples up to the 15-mL mark with distilled water. Swirl bubbler to mix contents well. Do not add solution collected in the trap to the sample. 5.
Transfer a 5-mL aliquot to a 100-mL flask and bring to volume with HPLC mobile phase. CALIBRATION AND QUALITY CONTROL: 6.
Calibrate daily with at least six working standards over the range 0.007 to 4 mg acetaldehyde per mL (0.1 to 60 mg acetaldehyde per sample) . a. ”

“ HPLC mobile phase: 0.22 M Na2HPO4•H2O, 0.019 M NaH2PO4•H2O in 20% ethanol. Dissolve and dilute 31.2 g Na2HPO4 and 26.2 g NaH2PO4•H2O to 1 L with DD water. Filter through 5-μm PTFE filter and degas prior to use. ”