National Institute for Occupational Safety and Health

“ Allow to stand 30 min with occasional agitation.
CALIBRATION AND QUALITY CONTROL: 8.
9.
Calibrate daily with at least six working standards over the range 0.05 to 13 mg THF per sample. a. Add known amounts of THF to CS 2 in 10-mL volumetric flasks and dilute to the mark with CS 2 to produce concentrations in the range 0.1 to 26 mg THF/mL. b. Analyze together with samples and blanks (steps 11 and 12) . c. Prepare calibration graph (peak area vs. mg THF) . Determine desorption efficiency (DE) at least once for each lot of charcoal used for sampling in the calibration range (step 8) . ”

“ Tetrahydrofuran and carbon disulfide are toxic and extremely flammable (flash points -17 °C and -30 °C, respectively) [4] . All work should be performed in a well-ventilated hood.
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. Sample at an accurately known flow rate between 0.01 and 0.2 L/min for a total sample size of 1 to 9 L. Cap the samplers. Pack securely for shipment.
SAMPLE PREPARATION: 5. 6. 7. ”