o-TERPHENYL: METHOD 5021, Issue 2, dated 15 August 1994 - Page 3 of 3 8.
9.
Determine recovery (R) at least once for each lot of filters used for sampling in the calibration range (step 7). Prepare three filters at each of five levels plus three media blanks. a. Spike a known amount of calibration stock solution directly onto the filter with a microliter pipet or syringe. b. Allow to stand overnight in the dark. c. Extract (steps 4 through 6) and analyze together with working standards (steps 10 and 11). d. Prepare graph of recovery vs. mg o-terphenyl recovered. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and recovery graph are in control.
MEASUREMENT: 10.
11.
Set gas chromatograph according to manufacturer's recommendations and to conditions given on page 5021-1. Inject 5-µL sample aliquot manually using solvent flush technique or with autosampler. NOTE: If peak area is above the linear range of the working standards, dilute with CS 2, reanalyze, and apply the appropriate dilution factor in calculations. Measure peak area.
CALCULATIONS: 12. 13.
Determine the mass, mg (corrected for recovery) of o-terphenyl found in the sample (W) and in the average media blank (B) from the calibration graph. Calculate concentration, C, of o-terphenyl in the air volume sampled, V (L):
EVALUATION OF METHOD: Method S27 was issued on November 8, 1974, and was validated for o-terphenyl with both spiked filters and an aerosol generated from a 0.25% (w/v) solution of o-terphenyl in toluene by an aspiration/spray dry technique [1]. The collection efficiency for o-terphenyl of a mixed cellulose ester membrane filter was 1.00 ± 0.01 when sampling an atmosphere containing 18.8 mg/m 3 at 1 L/min for 15 min. No o-terphenyl was detected on charcoal tubes preceded by glass fiber filters when sampling an atmosphere containing 17 mg/m 3 o-terphenyl. Storage stability of the samples was not determined.
REFERENCES: [1] Documentation of the NIOSH Validation Tests, S27, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-185 (1977), available as GPO Stock #017-033-00231-2 from Superintendent of Documents, Washington, DC 20402. [2] NIOSH Manual of Analytical Methods, 2nd ed., Vol. 2, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-157-A (1977). [3] 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: B. R. Belinky, NIOSH/DPSE; S27 originally validated under NIOSH Contract CDC-99-74-45. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
