PENTACHLOROPHENOL: METHOD 5512, Issue 2, dated 15 August 1994 - Page 3 of 4 c. 11.
12.
Prepare a calibration graph of peak area vs. amount (µg) of pentachlorophenol per 25 mL of sample. Determine recovery for each lot of filters used for sampling in the concentration range of interest. Prepare four filters at each of five levels plus three media blanks. a. Spike aliquot of calibration solution onto each filter. b. After air-drying, extract filters in 15 mL ethylene glycol. c. Just before analysis, add 10 mL methanol and analyze (steps 13 through 15). d. Prepare graph of recovery vs. µg pentachlorophenol. Check recovery at two levels for each sample set. Repeat recovery graph determination if checks do not agree to within 5% of recovery graph.
MEASUREMENT: 13. 14.
15.
Set liquid chromatograph according to manufacturer's recommendations and to conditions given on page 5512-1. Inject 20-µL sample aliquot. NOTE: If sample peak area exceeds the linear calibration range, dilute, and apply appropriate dilution factor in calculations. Measure peak area.
CALCULATIONS: 16. 17.
Determine mass, µg (corrected for recovery), of pentachlorophenol (W) found in the sample and the average media blank (B). Calculate concentration of pentachlorophenol in the air volume sampled, V (L):
EVALUATION OF METHOD: This method was validated over the range 0.265 to 1.31 mg/m 3 at 24 C and pressure of 761 mm Hg using 180-L samples [1,2]. Overall sampling and measurement precision, SˆrT, was 0.072, with average recovery of 105%, representing a non-significant bias. The concentration of pentachlorophenol was independently verified by direct UV analysis of sample solutions. Recovery of pentachlorophenol from filters was 101% in the range 45 to 180 µg per sample. Sample stability during storage was evaluated at 100 µg pentachlorophenol per sample. Samples showed 95.3% recovery after eight days of storage at ambient conditions compared to one-day old samples.
REFERENCES: [1] [2] [3]
[4]
Backup Data Report for Pentachlorophenol, prepared under NIOSH Contract 210-76-0123 (1977). NIOSH Manual of Analytical Methods, 2nd. ed., V. 4, S297, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 78-175 (1978). Analysis of NIOSH Samples for Pentachlorophenol and Tetrachlorophenol, NIOSH/MRSB Sequence #4492, Utah Biomedical Research Laboratory, Salt Lake City, UT (unpublished, 1984). Vulcan Materials Co. Analytical Backup Report #1. Determination of Pentachlorophenol in Air, Birmingham, AL 35255 (1982). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
