Page:NIOSH Manual of Analytical Methods - 5008.pdf/3

 PYRETHRUM: METHOD 5008, Issue 2, dated 15 August 1994 - Page 3 of 4

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c. Prepare (steps 4 and 5) and analyze together with working standards (steps 9 through 11). d. Prepare a graph of R vs. mg pyrethrum recovered. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and R graph are in control.

MEASUREMENT: 9. 10. 11.

Set HPLC system according to manufacturer's recommendations and to conditions on page 5008-1. Inject sample aliquot using syringe, fixed volume sample loop, or autosampler. Measure peak area. NOTE: Pyrethrum is a mixture of at least six components which elute in two major peaks (tr = 5 to 7 min under these conditions). The minor peaks have been shown by mass spectrometry not to be pyrethrums. The components may be separated by gas chromatography [1,4].

CALCULATIONS: 12. 13.

Determine the mass, mg (corrected for R) of pyrethrum found in the sample (W) and in the average media blank (B) from the calibration graph. Calculate concentration, C, of pyrethrum in the air volume sampled, V (L):

EVALUATION OF METHOD: Method S298 [2] was issued on August 3, 1979, and validated over the range 1.4 to 8.5 mg/m 3 using atmospheres generated from Premium Pyrocide 175 (McLaughlin Gormley King Co.) [1]. Standards and collected filter samples were analyzed by GC/MS. Lab testing was done with spiked filters and atmospheres dynamically generated by atomization of a hydrocarbon solution; verified by PTFE filter/isooctane bubbler analyzed by gas chromatography with electron capture detector (absence of pyrethrum in the bubbler was established by mass spectrometry). Samples containing 0.7 mg pyrethrum collected from a test atmosphere were stable for seven days at ambient conditions (average recovery = 98.2%). Collection efficiency = 99.7% for 120-L samples collected at 1 L/min at 9 mg/m 3. Precision and accuracy are given on page 5008-1.

REFERENCES: [1] Backup Data Report, S298 (NIOSH, unpublished, August 3, 1979). [2] NIOSH Manual of Analytical Methods, 2nd. ed., V. 6, S298, U.S. Department of Health and Human Services, Publ. (NIOSH) 80-125 (1980). [3] Changes in Official Methods of Analysis, J. Assoc. Off. Anal. Chem., 65, 455-456 (1982). [4] UBTL, Inc., NIOSH Sequence Reports 3481-J (unpublished, August 30, 1982) and 4151-J (unpublished, November 3, 1983). [5] 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.

METHOD REVISED BY: James E. Arnold, NIOSH/DPSE. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94