Determination of polycyclic aromatic hydrocarbons by liquid chromatography–electrospray ionization mass spectrometry using silver nitrate as a post-column reagent

Liquid chromatography–electrospray ionization mass spectrometry (LC–ESI-MS) using silver nitrate as a post-column reagent has been used for the determination of 10 polycyclic aromatic hydrocarbons (PAHs) in river water. In this method, after all the PAHs were separated by reversed-phase liquid chromatography, analytes formed complexes with silver cation by mixing with silver nitrate solution. The complexes then transfer the molecular ion, [M]+, of the PAHs by charge transfer using in source collision-induced dissociation. The positive ion ESI mass spectra of all PAHs tested in this study showed [M]+ as the base peak and abundant [M+Ag]+, [2M+Ag]+ with very weak or no [2M+Ag]+. For the sample extraction, several solid-phase extraction parameters using the blue-chitin column were optimized. The limits of detection (S/N=3) of all PAHs for the spiked river water sample ranged from 0.001 to 0.03 ng/ml, and the detector responses were linear up to 1 ng/ml (correlation coefficients ≥0.0998). Repeatability and reproducibility were in the range from 4.3 to 6.8% and from 6.2 to 9.5%, respectively.