Page:NIOSH Manual of Analytical Methods - 5002.pdf/3

WARFARIN: METHOD 5002, Issue 2, dated 15 August 1994 - Page 3 of 3

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2. Allow the filters to air dry overnight.
3. Analyze the filters (steps 3, 4, 6 and 7).
4. Prepare a graph of recovery vs. µg of Warfarin recovered.

MEASUREMENT:

7. Set liquid chromatograph according to manufacturer's recommendations and to conditions given on page 5002-1.
8. Make duplicate injections of each sample and working standard. Measure peak area.

CALCULATIONS:

9. Read the mass, µg (corrected for recovery) corresponding to the sample peak area of the sample (W) and average media blank (B) from the calibration graph.
10. Calculate the concentration, C (mg/m³), of Warfarin in the volume of air sampled, V (L):

$C={\frac {W-B}{V}}$, mg/m³.

EVALUATION OF METHOD:

Method P&CAM 313 was issued on April 13, 1979 [2]. Lab testing was done with spiked samples and atmospheres dynamically generated by Wright dust feeder from commercial formulation; no adequate independent method was used for verification [1, 5]. Storage stability was 93.5% for 60-µg samples stored seven days at ambient conditions. Collection efficiency = 100% for 408-L samples at 0.24 mg/m 3; no evidence of vapor in Tenax backup. Precision was as given on page 5002-1.

REFERENCES:

1. [1]
   Backup Data Report, P&CAM 313, prepared under NIOSH Contract 210-76-0123 (unpublished, April, 1979).
2. [2]
   NIOSH Manual of Analytical Methods, 2nd. ed., V. 6, P&CAM 313, U.S. Department of Health and Human Services, Publ. (NIOSH) 80-125 (1980).
3. [3]
   Horwitz, W., Ed. Official Methods for Analysis of the AOAC, 13th ed., p. 85 (1980).
4. [4]
   Ibid, 628.
5. [5]
   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).

METHOD REVISED BY:

James E. Arnold, NIOSH/DPSE; P&CAM 313 developed under NIOSH Contract 210-76-0123.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94