Two-Photon Photoionization Limits of Detection of Polycyclic Aromatic Hydrocarbons in Reversed Phase Liquid Chromatography

Two-photon photoionization detection was used to detect 28 polycyclic aromatic hydrocarbons (PAHs) separated by reversed phase liquid chromatography. A windowless flow cell and a nitrogen laser were used to obtain the photoionization signals. The analytical merit of the technique was illustrated by the determination of the limits of detection (LOD) for the 28 PAHs. LODs as low as 50 and 70pg injected were obtained for anthracene and pyrene, respectively. The importance of the chromatographic efficiency is discussed. The dramatic influence of the mobile phase conductivity, which is mainly responsible for the leakage currents, is shown. The lower the leakage current and the solvent polarity, the better the two-photon photoionization detection.