National Institute for Occupational Safety and Health

“ The concentration of Paraquat in the generation system was verified by an independent method [7] . Recovery was 101% in the range 23.7 to 94.6 μg per sample; another study found 79% recovery of 25 μg per sample and 98% recovery in the range 77 to 463 μg per sample [3] . Collection efficiency of the filter was determined by collecting six filter samples at about 1.8 mg/m 3 for a 90-L sample. The sampler consisted of two filters per cassette arranged so that the back filter was supported by the backup pad and the front filter was separated from the back filter. ”

“ SPECIAL PRECAUTIONS: Paraquat is listed as a severe poison. Use care in handling [4,5] . SAMPLING: 1. 2.
Calibrate each personal sampling pump with a representative sampler in line. Sample at an accurately known flow rate between 1 and 4 L/min for a total sample size of 40 to 1000 L. Do not exceed 2 mg total dust on filter.
SAMPLE PREPARATION: 3. 4.
Carefully transfer the filter from the cassette to a vial using tweezers. Add 5 mL deionized, distilled water to each vial. Cap the vial and gently swirl it to dissolve the sample completely. ”

“ The working range is 0.1 to 10 mg/m 3 for a 200-L air sample. The paraquat cation is the analyte for this method; therefore, either salt, the dichloride or bismethyl sulfate, can be quantitated. The standards are prepared from a solution of the dichloride salt with appropriate stoichiometric factor applied. ”