Isomeric identification and quantification of polycyclic aromatic hydrocarbons in environmental samples by liquid chromatography tandem mass spectrometry using a high pressure quadrupole collision cell

Atmospheric pressure chemical ionization was used to ionize polycyclic aromatic hydrocarbons (PAHs) separated by liquid chromatography using a triple quadrupole mass spectrometer equipped with a high pressure quadrupole collision cell to perform low energy collision induced dissociation (CID) and tandem mass spectrometry. Similarity indices (SI), which were calculated from the relative abundances of dominant fragment ions, were used to quantify the extent of differentiation of isomers. Ratios of intensities of fragments to those of M+· and/or [M+H]+ precursors correlated well with the numbers of hydrogen benzo interactions. Isomeric identification and differentiation was thus possible by CID. Application of this strategy was demonstrated by analyzing standard solutions of perdeuterated PAHs as well as a complex coal tar reference material. Liquid chromatography retention times and intensity ratios were used to identify and differentiate isomers. Quantification of PAHs in the reference material was performed by the method of standard additions, and the results compared with the certified values.