National Institute for Occupational Safety and Health

“ Aniline calibration stock solution, 102.2 mg/mL.* Dissolve 1 mL aniline in 2 mL benzene; dilute to 10 mL with hexane. NOTE: Benzene possibly could be replaced with toluene, alcohol, or acetone to minimize the analyst's exposure to suspect carcinogens. Effects of this substitution are not known and should be tested. 6. o-Toluidine calibration stock solution, 100.6 mg/mL.* Dilute 1 mL o-toluidine to 10 mL with n-hexane. 7. 2,4-Xylidine calibration stock solution, 97.8 mg/mL.* Dilute 1 mL 2,4-xylidine to 10 mL with n-hexane. ”

“ Calibrate daily with at least six working standards over the range 0.01 to 3 mg analyte per sample. a. Add known amounts of calibration stock solution, or a dilution thereof, in n-hexane to 95% ethanol in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samples and blanks (steps 11 and 12) . c. Prepare calibration graph (peak area or height vs. mg analyte) . Determine desorption efficiency (DE) at least once for each lot of silica gel used for sampling in the calibration range. ”

“ Flasks, volumetric, 10-mL.
See SPECIAL PRECAUTIONS.
SPECIAL PRECAUTIONS: n-Hexane and ethanol are flammable. Aniline, o-toluidine, 2,4-xylidine, and benzene are suspect carcinogens [7,8] . Absorption through skin is a potential hazard. All work with these chemicals should be performed in a hood. Use proper protective clothing including gloves. Analytes (1) , (2) , (3) , and (5) are severe poisons.
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. ”