Selective and sensitive analysis of 1-nitropyrene in diesel exhaust particulate extract by multidimensional HPLC

Summary A multicolumn (MC) HPLC method for the determination of 1-nitropyrene (1-NP) at trace-levels via on-line reduction to 1-aminopyrene and fluorescence detection is presented. On the first column, packed with a pyrenebutyric acid amide stationary phase, the nitro-derivatives of PAHs are strongly retained and separated from other matrix components. The nitro-PAHs-containing fractions are transferred onto a RP₁₈-column via stepwise gradient elution and finally separated according to their various lipophilicities and sizes. To increase the overall selectivity and sensitivity of the multidimensional method (MD-HPLC system) post-column, on-line reduction of the nitro-PAHs to the respective amino-PAHs via a short catalysis column is performed thus enhancing the sensitivity significantly (to low pg levels). The applicability of this method for the determination of trace amounts of 1-NP in real samples (diesel particulate extracts) is demonstrated.