5002

WARFARIN
C H O MW: 308.33 CAS: 81-81-2 RTECS: GN4550000 METHOD: 5002, Issue 2
EVALUATION: PARTIAL
Issue 1: 15 February 1984
Issue 2: 15 August 1994
PROPERTIES: solid, MP 161 °C; VP not available
SYNONYMS: 3-(α-acetonylbenzyl)-4-hydroxycoumarin.
SAMPLING
MEASUREMENT
SAMPLER:
TECHNIQUE:
ANALYTE:
FLOW RATE:
EXTRACTION:
VOL-MIN:
INJECTION
VOLUME:
SHIPMENT:
MOBILE PHASE:
STABILITY:
BULK
SAMPLE:
DETECTOR:
CALIBRATION:
ACCURACY
RANGE STUDIED:
ESTIMATED LOD:
OVERALL PRECISION (S
): 0.056 [1]
PRECISION (S
ACCURACY:
APPLICABILITY: The working range is 0.05 to 0.5 mg/m 3 for a 400-L air sample.
INTERFERENCES: No interferences have been studied.
OTHER METHODS: This is P&CAM 313 [2] in a new format. Analytical methods for Warfarin in some rodenticides [3] and in
drugs [4] are available; these are spectrophotometric methods for bulk materials.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 WARFARIN: METHOD 5002, Issue 2, dated 15 August 1994 - Page 2 of 3 REAGENTS:
EQUIPMENT:
1. Sampler: 37-mm diameter PTFE membrane filter, 1-µm pore size, and cellulose backup pad in two-piece filter holder held together Calibration stock solution, 2 mg/mL.* Dissolve 2. Personal sampling pump, 1 to 4 L/min, with 3. High pressure liquid chromatograph with 20 to 50-µL injection loop; 25 to 30 cm, 10-µm C 18 column; UV absorption detector at 280 nm;and integrator.
4. Jars, squat form, 60-mL, ointment, with PTFE 5. Tweezers.
6. Pipet, 5-mL, and pipet bulb.
7. Syringes, microliter.
8. Volumetric flasks, 10-mL and 1-L.
SPECIAL PRECAUTIONS: Methanol is flammable and toxic. Use in fume hood and away from ignition
sources.
Warfarin is toxic and can be absorbed through the skin.
Phosphoric acid is corrosive. Use gloves, goggles and other appropriate equipment to prevent eyecontact and repeated or prolonged skin contact. Wash skin with water and change clothes if contactoccurs.
SAMPLING:
Calibrate each personal sampling pump with a representative sampler in line.
Sample at an accurately know flow rate between 1 and 4 L/min for a sample size of 200 to1000 L. Do not exceed a total loading of 2 mg on the filter.
SAMPLE PREPARATION:
Transfer filter with tweezers to jar.
Add 5.0 mL methanol. Cap the jar. Swirl to wet filter thoroughly.
CALIBRATION AND QUALITY CONTROL:
Calibrate daily with at least six working standards covering the range 4 to 120 µg Warfarin persample.
a.
Add aliquots (2 to 60 µL) of calibration stock solution to 5 mL methanol in ointment jars.
Analyze the working standards together with the samples and blanks (steps 7 and 8).
NOTE: Duplicate injections should differ by no more than 3% in peak area.
Prepare a calibration graph (peak area vs. µg Warfarin).
Determine recovery at least once in the calibration range for each lot of filters. Prepare threefilters at each of five levels plus three media blanks.
a.
Inject known volumes of calibration stock solution onto blank filters with a microliter syringe. Include media blanks.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 WARFARIN: METHOD 5002, Issue 2, dated 15 August 1994 - Page 3 of 3 Allow the filters to air dry overnight.
Analyze the filters (steps 3, 4, 6 and 7).
Prepare a graph of recovery vs. µg of Warfarin recovered.
MEASUREMENT:
Set liquid chromatograph according to manufacturer's recommendations and to conditions givenon page 5002-1.
Make duplicate injections of each sample and working standard. Measure peak area.
CALCULATIONS:
Read the mass, µg (corrected for recovery) corresponding to the sample peak area of thesample (W) and average media blank (B) from the calibration graph.
Calculate the concentration, C (mg/m 3), of Warfarin in the volume of air sampled, V (L): EVALUATION OF METHOD:
Method P&CAM 313 was issued on April 13, 1979 [2]. Lab testing was done with spiked samples andatmospheres dynamically generated by Wright dust feeder from commercial formulation; no adequateindependent method was used for verification [1,5]. Storage stability was 93.5% for 60-µg samplesstored seven days at ambient conditions. Collection efficiency = 100% for 408-L samples at0.24 mg/m 3; no evidence of vapor in Tenax backup. Precision was as given on page 5002-1.
REFERENCES:
Backup Data Report, P&CAM 313, prepared under NIOSH Contract 210-76-0123 (unpublished,April, 1979).
NIOSH Manual of Analytical Methods, 2nd. ed., V. 6, P&CAM 313, U.S. Department of Healthand Human Services, Publ. (NIOSH) 80-125 (1980).
Horwitz, W., Ed. Official Methods for Analysis of the AOAC, 13th ed., p. 85 (1980).
NIOSH Research Report-Development and Validation of Methods for Sampling and Analysis ofWorkplace 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

Source: http://www.siafa.com.ar/recursos/metodos/warfarina.pdf