ACETALDEHYDE: METHOD 2538, Issue 2, dated 15 August 1994 - Page 3 of 4
9.
µg acetaldehyde. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph is in control. NOTE: A desorption efficiency study is not usually necessary since standards are prepared on the coated sorbent.
MEASUREMENT: 10.
11.
Set gas chromatograph to conditions given on page 2538-1. Set air and hydrogen flows on the flame ionization detector to manufacturer's specifications. Inject 1-µL sample aliquot via the splitless injection technique. Retention time = 6.8 min for acetaldehyde under these conditions. Measure peak area. Divide the peak area of analyte by the peak area of the internal standard on the same chromatogram.
CALCULATIONS: 12.
13.
Determine the mass, µg, of acetaldehyde found in the sample front (W f) and back (W b) sorbent sections, and in the average media blank front (B f) and back (B b) sorbent sections. NOTE 1: If W b > W f/10, report breakthrough and possible sample loss. NOTE 2: Under these conditions, there is typically no detectable acetaldehyde blank level. Calculate concentration, C, of acetaldehyde in the air volume sampled, V (L):
EVALUATION OF METHOD: This method was originally developed and fully validated by OSHA [2} over the range 180 to 720 mg/m per sample. A storage study was done by spiking commercially-available tubes with standard solutions of acetaldehyde [1]. Recovery (26.8 and 107 µg/sample) was 100% after 21 days of refrigerated storage. A migration study was also performed at the above concentrations. After 21 days refrigerated storage, no acetaldehyde was detected on the back sections of the samples. Additional evaluation information is available [2]. Field samples of acetaldehyde were also successfully analyzed by utilizing this method [1]. This method has not been evaluated by NIOSH, except for the storage and migration studies. REFERENCES: [1] [2] [3]
[4]
Williams, Karen J. Analytical Report for Acetaldehyde Samples, NIOSH (MRSB) Sequence
- 6384, Unpubl. NIOSH (1988).
"OSHA Analytical Methods Manual, " U.S. Dept. of Labor, Occupational Safety and Health Administration, OSHA Analytical Laboratory, Salt Lake City, UT, Method #68 (1988). NIOSH/OSHA Occupational Health Guidelines for Occupational Hazards, U.S. Department of Health and Human Services, Publ. (NIOSH) 81-123 (1981), available as GPO Stock #017-03300337-8 from Superintendent of Documents, Washington, DC 20402. IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans: Allyl Compounds, Aldehyde, Epoxides and Peroxides, International Agency for Research on Cancer Vol 36:101-132 Lyon, France (1984).
METHOD REVISED BY: Karen J. Williams.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
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