National Institute for Occupational Safety and Health

“ Immediately before adding dichlorofluoromethane, withdraw from each vial an amount of air equal to that of dichlorofluoromethane to be added. c. Slowly bubble a measured amount of dichlorofluoromethane into the liquid in each vial using a gas-tight syringe. d. Analyze together with samples and blanks (steps 11 and 12) . e. Prepare calibration graph (ratio of peak area of analyte to peak area of internal standard vs. mg dichlorofluoromethane) . Determine desorption efficiency (DE) at least once for each lot of charcoal used for sampling in the calibration range (step 8) . ”

“ Insert a syringe needle vent through the septum to serve as a vent. Add 5.0 mL eluent to each vial with a syringe. Remove the syringe needle vent from the septum. NOTE: To avoid loss of analyte, do not add eluent to the charcoal before sealing the vial. Allow to stand 30 min with occasional agitation.
CALIBRATION AND QUALITY CONTROL: 8.
Calibrate daily with at least six working standards over the range 0.05 to 35 mg (0.01 to 8.2 mL at 20 °C and 101 kPa) dichlorofluoromethane per sample. a. Add 5.0 mL eluent to each of a series of vials. Attach crimp cap to each vial. ”

“ Vials, glass, serum, 10-mL, with PTFE-lined septa and crimp caps. 5. Syringe, 10-μL. 6. Syringes, gas-tight, 10-mL and 100-μL. 7. Syringe needles, 22-gauge.
SPECIAL PRECAUTIONS: Carbon disulfide is toxic and an extreme fire and explosion hazard (flash point = -30 °C) ; work with it only in a hood. Dichlorofluoromethane may cause irregular heartbeat if inhaled [3] .
SAMPLING: 1. 2. 3. 4.
Calibrate each personal sampling pump with a representative sampler in line. Break the ends of the sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. ”