DETERMINATION OF POLYCYCLIC AROMATIC-HYDROCARBONS IN PRECIPITATION USING SOLID-PHASE EXTRACTION AND COLUMN LIQUID-CHROMATOGRAPHY

Solid-phase extraction (SPE) of polycyclic aromatic hydrocarbons (PAHs ) on Sep-Pak C-18 cartridges was studied. Eight 3-6-ring compounds fro m the 16 EPA priority pollutants were selected for investigation. Fact ors affecting the recovery of PAHs such as conditioning of the SPE car tridge, addition of organic modifier to the sample, flow-rate of the s ample loaded on the cartridge, concentration of PAHs in the sample, dr ying after sample loading, elution of the analytes from the SPE cartri dge with different organic solvents and recovery from spiked rainwater were included. Conditioning time was shortened by omitting the applic ation of a 2-propanol-water mixture, The presence of 25% (v/v) 2-propa nol was most appropriate for the enrichment of 3-6-ring aromatic compo unds on Sep-Pak C-18. The flow-rate of the sample influenced the effic iency of sample preparation of compounds with a retention volume close to the sample volume. Recoveries did not change significantly in the 20-2200 ng/l concentration range. Drying of the SPE cartridge after sa mple loading improved recoveries of all PAHs. Elution with dichloromet hane and tetrahydrofuran gave the highest recoveries. The detection li mit was found to be less than 1 ng/l for several PAHs. The concentrati ons of PAHs in rainwater were between 3 and 1000 ng/l.