Page:NIOSH Manual of Analytical Methods - 5800.pdf/4

 POLYCYCLIC AROMATIC COMPOUNDS, TOTAL: METHOD 5800, Issue 1, dated 15 January 1998 - Page 4 of 5

NOTE: A guard column placed between the solvent delivery system and autosampler provides backpressure that aids the pumps in maintaining their prime. 13. Place two fluorescence detectors in series. Set the wavelengths of first detector at 254 nm ex and 370 nm em. Set the wavelengths of the second detector at 254 ex and 400 nm em. 14. Inject 25 µL of the sample into the solvent stream. 15. Measure peak areas. CALCULATIONS: NOTE: The mass of total PACs measured at each set of wavelengths is considered a separate analysis. Therefore, the establishment of calibration curves and data analysis are independent for each detector. 16. From the calibration graphs, read the mass (µg corrected for R or DE) of total PACs measured at each wavelength setting found on the filter (Wfil), front sorbent section (Wsf), and back sorbent section (Wsb) and on the average media blank filter (B fil) and sorbent tube sections (B sf and Bsb). 17. Calculate concentration of PACs at each wavelength setting (C 254ex/370em or C 254ex/400em) in the air volume sampled V(L) as the sum of the particulate concentration (filter) and the vapor concentration (sorbent tube). A dilution factor of 2 is applied since 2 mL of the original 4 mL of sample is processed through the SPE and liquid/liquid extraction.

2 (Wfil

C (ex/em)

NOTE: µg/mL

Wsf

Wsb

Bfil

Bsf

Bsb)

V

, mg/m 3

mg/m3

EVALUATION OF METHOD: The method gives an indication of exposure to PACs as measured by two separate sets of spectrofluorometric wavelengths. The 254 nm ex/370 nm em response is used as an indication of the lower (2 to 4) ringed PACs that are usually considered irritants.The 254 nm ex/400 nm em response is used as an indication of the higher ringed (4 to 6) PACs that may be mutagenic or carcinogenic. As these measurements are only indications, the data are only applicable to exposures using the same asphalt fume source. No direct correlation of the data to adverse health effects can be made. Recovery studies for the filter and tube were determined using sampling media spiked with known amounts of the Supelco QTM standard. A set of six filters and sorbent tubes were fortified with known amounts of the QTM Test mixture at four different concentrations per set. The efficiency for recovery from the sampling media, fractionation, and flow-injection analysis was shown to be about 90% for the 254 nm ex/370 nm em analysis and about 95% for the 254 nm ex/400 nm em analysis. A 30-day storage study, consisting of sets of six filters and sorbent tubes spiked at four concentration levels with Supelco QTM standard, showed no loss when stored under refrigeration. This is reflected by approximately 90% recovery for the 254 nm ex/370 nm em analysis and about 95% for the 254 nm ex/400 nm em analysis. No collection studies were performed, but the sampling train was adopted from NMAM Method 5506 [4]. REFERENCES: [1] Neumeister CE [1997]. Polycyclic aromatic compounds backup data report (unpublished), NIOSH, DPSE. [2] NIOSH [1998]. Benzothiazole in asphalt fume: Method 2550. In: Eller PM, Cassinelli ME, Eds, NIOSH Manual of Analytical Methods, 4th Ed., 2nd Supplement. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) 98-. [3] NIOSH [1998]. Benzene solubles and total particulate (asphalt fume): Method 5042. In: Eller PM, nd Cassinelli ME, Eds, NIOSHManual of Analytical Methods, 4th Ed., 2 Supplement. Cincinnati, OH: NIOSH Manual of Analytical Methods (NMAM), Fourth Edition