National Institute for Occupational Safety and Health

“ Determine the desorption efficiency (DE) at least once for each lot of Anasorb CMS used for sampling in the calibration range (step 8) . a. Prepare three tubes at each of five levels plus three media blanks. b. Inject a known amount (5 to 20 μL) of DE stock solution directly onto the front section of each Anasorb CMS tube with a microliter syringe. c. Allow the tubes to air equilibrate for several m inutes, then cap the ends of each tube and allow to stand overnight. ”

“ SPECIAL PRECAUTIONS: Diacetyl is flammable, toxic, and forms explosive mixtures in air. Acetone and methanol are flammable and pose a fire hazard. Work with all chemicals in a well ventilated laboratory safety hood. SAMPLING:
ST OR
and are shipped cold (5 °C) .
IC
1.
Calibrate each personal sampling pump with a representative sampler in line. 2.
Break the ends of the sampling tube immediately before sampling. Attach sampling tube to personal sampling pump with flexible tubing. 3.
Sample at an accurately know flow rate between 0.01 and 0.2 L/min for a total sample size of 10 L. 4. ”

“ Calibrate daily with at least six working standards from below the LOD to 10 times the LOQ. If necessary, additional standards may be added to extend the calibration curve. a. Add known amounts of diacetyl to the solvent in a 10-m L volumetric flask and dilute to the mark. Prepare additional standards by serial dilution in 10-mL volumetric flasks. b. Analyze together with samples and blanks (steps 11 and 12) . c. Prepare calibration graph (peak area vs μg diacetyl) . 9. ”