The Extraction System B-811 and the Syncore Analyst parallel concentrator from Buchi as well as the Pressurized Solvent Extractor from Applied Separations were evaluated for the pretreatment of samples containing PAHs. Recoveries of extraction and subsequent concentration using acetone-n-hexane (1+1) were 70-95% for 2 ring and 90-100% for less volatile 3-5 ring PAHs. A good precision (95% confidence level) of less than 6%, naphthalene excluded (12%), was found. No significant difference was observed between the two extraction methods.
Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants primarily formed by incomplete combustion and incineration. PAHs adsorb strongly to small carbonaceous particles but are also present in the vapor phase. Therefore, they can undergo long range transport. Typical concentrations are in the sub-ppb to ppm range. PAHs also bioaccumulate in food webs and are partially mutagenic and carcinogenic. Therefore, PAH analysis is requested by regulatory bodies. The US Environmental Protection Agency (EPA) introduced a priority pollutant list of 16 PAHs (EPA610) in 1982. For solid and hazardous waste testing, the EPA approved method reference is SW-846.
The analyses of PAHs contamination at the trace level includes sample extraction and extract concentration. Both automated Soxhlet extraction (EPA3541) and pressurized solvent extraction (EPA3545) are approved extraction techniques (EPA3500) for solid samples. The extract volume is reduced to 1 ml for maximum sensitivity (EPA8100).