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NOTICE:  
THIS INFORMATION HAS BEEN EXTRACTED FROM OSHA METHOD #58. IT CONTAINS BASIC INFORMATION NEEDED TO CORRECTLY SAMPLE AND ANALYZE COAL TAR PITCH VOLATILES (CTPV), COKE OVEN EMISSIONS (COE), AND SELECTED POLYNUCLEAR AROMATIC HYDROCARBONS (PAHs). THE NUMBERING IN EACH SECTION CORRESPONDS TO THE SECTIONS IN THE VALIDATED METHOD WHERE THE INFORMATION WAS OBTAINED.



COAL TAR PITCH VOLATILES (CTPV)
COKE OVEN EMISSIONS (COE)
SELECTED POLYNUCLEAR AROMATIC HYDROCARBONS (PAHs)


Method no.:58
 
MatrixAir
 
Procedure:Air samples are collected by drawing known amounts of air through cassettes containing glass fiber filters (GFF). The filters are analyzed by extracting with benzene and gravimetrically determining the benzene-soluble fraction (BSF). If the BSF exceeds the appropriate PEL, then the sample is analyzed by high performance liquid chromatography (HPLC) with a fluorescence (FL) or ultraviolet (UV) detector to determine the presence of selected polynuclear aromatic hydrocarbons (PAHs).
 
Recommended air volume
and sampling rate:
960 L at 2.0 L/min
 
Special requirements:Each GFF must be transferred to a separate scintillation vial after sampling and the vial sealed with a PTFE-lined cap. Samples must be protected from direct sunlight.
 
Status of method: Evaluated method. This method that has been subjected to the established evaluation procedures of the Organic Methods Evaluation Branch.
 
Date: July 1986Chemist: Donald Burright








Organic Methods Evaluation Branch
OSHA Analytical Laboratory
Salt Lake City, Utah



Target concentrations: 0.20 mg/m3 for Coal Tar Pitch Volatiles (PEL)
0.15 mg/m3 for Coke Oven Emissions (PEL)
8.88 µg/m3 (1.22 ppm) for phenanthrene
0.79 µg/m3 (0.11 ppm) for anthracene
9.00 µg/m3 (1.09 ppm) for pyrene
3.27 µg/m3 (0.35 ppm) for chrysene
2.49 µg/m3 (0.24 ppm) for benzo(a)pyrene

Detection limits of the
overall procedure:

0.006 mg/m3 for BSF
0.427 µg/m3 (59 ppb) for phenanthrene (PHEN)
0.028 µg/m3 ( 4 ppb) for anthracene (ANTH)
0.260 µg/m3 (31 ppb) for pyrene (PYR)
0.073 µg/m3 ( 8 ppb) for chrysene (CHRY)
0.045 µg/m3 ( 4 ppb) for benzo(a)pyrene (BaP)

Reliable quantitation limits: 0.034 mg/m3 for BSF
0.740 µg/m3 (100 ppb) for PHEN
0.066 µg/m3 ( 9 ppb) for ANTH
1.13 µg/m3 (140 ppb) for PYR
0.273 µg/m3 ( 29 ppb) for CHRY
0.207 µg/m3 ( 20 ppb) for BaP

Standard errors of estimate
at the target concentration:
(Section 4.6.)

8.3% for BSF
6.0% for PHEN
6.8% for ANTH
6.7% for PYR
6.3% for CHRY
5.8% for BaP




2. Sampling Procedure

2.1. Apparatus

2.1.1. A personal sampling pump calibrated within ±5% of the recommended flow rate with the sampling device in line.

2.1.2. Sampling device is a two-piece cassette containing a glass fiber filter (GFF).

2.1.3. Forceps to transfer the GFF to a scintillation vial.

2.1.4. Scintillation vials with PTFE-lined caps.

2.1.5. Aluminum foil or an opaque container to protect collected samples from light.

2.3. Sampling technique

2.3.1. Attach the cassette to the sampling pump with flexible, plastic tubing so that the GFF in the sampling cassette is exposed directly to the atmosphere. Do not place any tubing in front of the sampler. The sampler should be protected from direct sunlight (Ref. 5.9.) and should be attached vertically in the worker's breathing zone in such a manner that it does not impede work performance.

2.3.2. After sampling for the appropriate time, remove the sampling device and install the two plastic plugs in the open ends of the cassette.

2.3.3. As soon as it is conveniently possible, but before the sample is shipped, fold the filter into quarters (sampling surface inside) and insert it into a scintillation vial (Figure 2.3.3.). Always handle the GFF with clean forceps. To avoid losing any particulate material, the inside of the cassette should be wiped with the folded filter. Install a cap that has a PTFE liner, not a Poly-seal cap. Wrap each vial in aluminum foil or place it in an opaque container to protect the sample from light.

Folding procedure for the glass fiber filter

Figure 2.3.3. Folding procedure for the glass fiber filter.

2.3.5. Submit at least one blank with each set of samples. The blank should be handled the same as the other samples except that no air is drawn through it.

2.4. Extraction efficiencies

The average extraction efficiencies of the analytes are listed below. The target concentrations were used for this determination.

Table 2.4.
Extraction Efficiency form GFF

compoundpercent

BSF  
 PHEN
ANTH
PYR  
CHRY
BaP  
100.3
105.9
112.5
101.4
107.5
108.7

3. Analytical Procedure

3.1. Apparatus

3.1.1. Benzene-soluble fraction

3.1.1.1. A calibrated microbalance capable of determining weight to the nearest microgram. A Mettler M3-03 balance with a data transfer recorder was used in this evaluation.

3.1.1.2. Thirteen-millimeter stainless steel filter holder with a female Luer-Lok fitting.

3.1.1.3. Thirteen-millimeter pure PTFE membrane filters with 5-µm pores.

3.1.1.4. Two-milliliter PTFE cups, Cahn Scientific.

3.1.1.5. Two-milliliter disposable pipets.

3.1.1.6. Ten-milliliter glass syringe barrels with male Luer-Lok fittings.

3.1.1.7. Disposable culture tubes (13 × 100 mm).

3.1.1.8. Vacuum oven.

3.1.1.9. Mechanical shaker.

3.1.1.10.Forceps.

3.1.2. Selected PAHs

3.1.2.1. High performance liquid chromatograph equipped with a fluorescence (FL) or an ultraviolet (UV) detector, manual or automatic injector, gradient flow programmer and chart recorder. A Waters M-6000A pump, Waters WISP 710B autosampler, Waters 660 solvent programmer, Schoeffel 970 FL detector, Waters 440 UV detector, and a Houston dual pen recorder were used in this evaluation.

3.1.2.2. HPLC column capable of separating PAHs from any interferences. A 25-cm × 4.6-mm i.d. DuPont Zorbax ODS (6 µm) column was used for this evaluation.

3.1.2.3. An electronic integrator, or other suitable method for measuring detector response.

3.1.2.4. Vials, 4-mL with PTFE-lined caps.

3.1.2.5. Volumetric flasks, pipets, and syringes.

3.2. Reagents

3.2.1. Acetonitrile (ACN), HPLC grade.

3.2.2. Water, HPLC grade. A Millipore Milli-Q system was used for this evaluation.

3.2.3. Benzene, HPLC grade.

3.2.4. Nitrogen gas.

3.2.5. Phenanthrene (PHEN).

3.2.6. Anthracene (ANTH).

3.2.7. Pyrene (PYR).

3.2.8. Chrysene (CHRY).

3.2.9. Benzo(a)pyrene (BaP).

3.2.10. Tetrahydrofuran (THF), HPLC grade.

3.3. Standard preparation for selected PAHs

Two stock standard solutions are prepared by dissolving the PAHs in benzene. All dilutions of the stock solutions are made with benzene to arrive at the working range.

3.4. Sample preparation

3.4.1. Benzene-soluble fraction (BSF) (CAUTION - All work with benzene must be done in a fume hood.)

3.4.1.1. Clean the PTFE cups by sonicating them in THF for a few minutes, and rinsing them twice with clean THF. Place the cups into a numbered holder. The cups are placed in a preheated oven (40°C under about 20 in. Hg vacuum) for 1 h. The cups are allowed to cool to room temperature and weighed to the nearest microgram. Handle the cups with clean, dry forceps.

3.4.1.2. Pipet 3.0 mL of benzene to each scintillation vial containing the sample filter.

3.4.1.3. Shake the vials for 60 min.

3.4.1.4. Insert a 13-mm pure PTFE membrane filter (5-µm) into the stainless steel holder and attach the holder to a syringe barrel. Add about 3 mL of benzene to the syringe and push the benzene through the filtering unit with nitrogen to check for leaks. A rubber stopper is used on the nitrogen line to pressurize the syringe barrel to 10 psig. Dry the filter by allowing the nitrogen to pass through the filter for 30 s.

3.4.1.5. Transfer the benzene extract from the vial into the syringe barrel, one sample per syringe. If the vial contains a considerable amount of particulate material, decant the extract into the syringe barrel. Push the benzene extract thru the filters into the disposable culture tube (13 × 100 mm) with nitrogen gas.

3.4.1.6. Pipet 1.5 mL of the benzene extract to a tared PTFE cup.

3.4.1.7. Place the PTFE cups in a preheated oven (40°C under about 15 in. Hg vacuum). Provide some air flow in the oven to sweep benzene vapor out of the oven. Heat the cups for about 3 to 4 h. Close the vent valve for the last hour of the drying period.

3.4.1.8. Remove PTFE cups from oven, cool to room temperature and weigh to the nearest microgram.

3.4.2. Selected PAHs

Transfer the remaining benzene solution from the culture tube to a vial and seal with a PTFE-lined cap. This fraction of the sample will be analyzed for PAHs if the concentration of the BSF is equal to or greater than the PEL.

3.5. Analysis

3.5.1. Reverse phase HPLC conditions

column:25-cm × 4.6-mm i.d. stainless steel column packed with 6-µm DuPont Zorbax ODS
mobile phase:85:15 ACN/water (v/v)
flow rate:1.0 mL/min for 5 min, Curve 10 (flow program) for 5 min to 1.5 mL/min, then hold for 10 min
FL detector:254 nm excitation
370 nm emission
UV detector:254 nm
injection size:10 µL
retention time:    7-18 min

3.5.2. An external standard procedure is used to prepare a calibration curve using at least 2 stock solutions from which dilutions are made. The calibration curve is prepared daily. The samples are bracketed with analytical standards.


Reference

5.9. Korfmacher, W.A.; Wehry, E.L.; Mamantov, G.; Natusch, D.F.S., Environ. Sci. Technol., 1980,14(6), 1094.


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