Polycyclic Aromatic Hydrocarbons (PAHs) Sample Preparation

Total concentration of PAHs in samples should range from 1 to 2 µg C/µL, for typical samples having 10-20 major peaks and 20+ minor peaks. Lower total concentrations (~0.5 µg C/µL) are acceptable for samples having fewer than 10 major peaks. Large peaks are 50-150 ng C, and the smallest detectable peaks are ~2 ng C, on-column.

Submit samples in standard GC vials (volume: 2 mL OD x length: 12 x 32 mm) with screw caps (9-425 or 10-425). Use inserts for low-concentration samples. With inserts, we can inject up to 4 µL from as little as 30 µL solvent. Use vials with a write-on patch or use clear tape and permanent marker to label vials. Do not wrap vials with opaque marking tape – this makes it difficult to view liquid level. Thick tape causes vials to stick in the autosampler tray. If shipping samples in solvent, please do not overtighten your vial caps. We’ve received samples that leaked from vials because caps were over-tightened, causing the septa to get pinched out of the lids. Turn caps until snug, but not so far that septa start to pucker.

We recommend using an internal standard, if you intend to calculate efficiency of extraction. Please avoid the use of short-chain FAMEs as internal standards (e.g. c11:0, c12:0, c13:0), as we use these compounds as internal standards for our determination of the total amounts of each PAH (total µg as C) and the calibration of isotope-ratio measurements.

Extraction
A wide range of extraction techniques have been employed for the CSIA of PAHs within and between different sample matrices [1]. Currently, the SIF does not offer extraction services for PAHs. If extraction services are required, please contact us.

References

[1] A.J. Buczynska, B.Geypens, R.Van Grieken, K.De Wael 2012. Stable carbon isotopic ratio measurement of polycyclic aromatic hydrocarbons as a tool for source identification and apportionment - a review of analytical methodologies. Talanta 105: 435-450 doi: 10.1016/j.talanta.2012.10.075