Determination of Selected Nitropolycyclic Aromatic Hydrocarbons in Water Samples

A new method for the analysis of selected nitropolycyclic aromatic hydrocarbons (NPAHs) at ultra-trace levels in water samples is proposed. Particulate NPAHs were collected on a GC glass fiber filter. Soluble NPAHs were collected on a C18 Empore disk. After simple clean-up and concentration of NPAHs in both phases, the NPAHs were analyzed using HPLC equipped with clean-up, reducer, concentration and chemiluminescence detection units. The proposed method showed good linear calibration curves with correlation coefficients (r(2)) ranging from 0.9954 to 0.9998. The limits of detection ranged from 0.013 to 0.15 nmol/L (soluble NPAHs) and from 0.01 to 0.13 nmol/L (particulate NPAHs) for 5 NPAHs [(9-nitroanthracene, 1-nitropyrene, 6-nitrochrysene (6-NC), 7-nitrobenz[a]anthracene and 6-nitrobenzo[a]pyrene] having 3 to 5 rings analyzed, when 1.5 L of water sample was used. The repeatability for soluble NPAHs ranged between 4.2 and 6.8% (n=5), while for particulate NPAHs, it varied between 2.2 and 2.8% (n=5). The proposed method successfully determined the above NPAHs expect 6-NC in river water samples, suggesting that this method is suitable for the ultra-trace analysis of NPAHs in water samples.