PARAQUAT: METHOD 5003, Issue 2, dated 15 August 1994 - Page 3 of 3
CALCULATIONS: 10. 11.
Read the mass, µg, of Paraquat found on the filter, W, and the average media blank, B, from the calibration graph. Calculate concentration of Paraquat cation, C (mg/m 3), in the air volume sampled, V (L):
EVALUATION OF METHOD: Method S294 was issued on March 16, 1979, and validated over the range 0.256 to 1.03 mg/m 3 using a 90-L sample [1,6]. The overall precision, SˆrT, was 0.088 with an average recovery of 98.2%, representing a non-significant bias. 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. The overall collection efficiency was 100%. Samples were stored at room temperature for one week and found to be stable.
REFERENCES: [1] [2] [3] [4]
[5]
[6]
[7]
NIOSH Backup Data Report S294 (unpublished, March, 1979), available as Order No. PB 81-229 684 from NTIS, Springfield, VA 22161. NIOSH Manual of Analytical Methods, 2nd ed., Vol. 5, S294, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 79-141 (1979). User check, Wisconsin Occupational Health Laboratory (NIOSH, unpublished, September 27, 1984). Criteria for a Recommended Standard...Occupational Exposure to Manufacturing and Formulation of Pesticides, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 78-174 (1978). NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards, U.S. Department of Health and Human Services, Publ. (NIOSH) 81-123 (1981), available as GPO Stock #017-033-00337-8 from Superintendent of Documents, Washington, DC 20402. NIOSH Research Report-Development and Validation of Methods for Sampling and Analysis of Workplace Toxic Substances, U.S. Department of Health and Human Services, Publ. (NIOSH) 80-133 (1980). Chevron Chemical Company, Paraquat by Colorimetry, AM-8-1086 (April 7, 1977).
METHOD REVISED BY: Jerome Smith, Ph.D., NIOSH/DPSE; S294 originally validated under NIOSH Contract 210-76-0123.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
