National Institute for Occupational Safety and Health

“ As an alternative to the glass fiber filters, air samples ofp-toluenesulfonic acid canbe collected in midget impingers containing isopropanol at 1 L/min. After sampling, the impinger solution is transferred to a 20-mL glass vial and transported to the laboratory. The vial is placed onto a heating plate maintained at 80C, and the isopropanol is evaporated to dryness with a gentle stream of nitrogen (total evaporation time is about 1.5 hours) . A 2-mL aliquot of 2% isopropanol in water is added to the vial, and the vial is placed into an ultrasonic bath for 30 seconds. ”

“ CALIBRATION AND QUALITY CONTROL: 9. Calibrate daily with at least six working standards over the range of interest: 0.04 to 60 μg/mL. a. Prepare working standards over the range of interest. Add a known amount of the calibration stock solution to an aliquot of the extraction solution. b. Analyze together with samples and blanks (steps 12 and 13) . c. Prepare calibration graph (peak area or height vs. μg of analyte) . 10. Determine recovery (R) at least once for each lot of glass fiber filters in the calibration range (step 9) . ”

“ Add 20 mL of isopropanol to distilled water to make 1 L of solution. 7. p-Toluenesulfonic acid calibration stock solution, 4.0 mg/mL. Dissolve 200 mg ptoluenesulfonic acid in extraction solution to make 50 mL of solution.
See SPECIAL PRECAUTIONS SPECIAL PRECAUTIONS: p-Toluenesulfonicacid is highly irritating to the skin and mucous membranes; also, it can cause a potentially explosive reaction of acetic anhydride with water. Acetonitrile is toxic and is a fire hazard (flash point = 12.8 C) . Wear protective clothing and work in a well ventilated hood. ”