APCI polycyclic aromatic hydrocarbons

The recently introduced atmospheric-pressure laser ionization system (APLI) can be considered as a modification of APPI (Ch. 5.7.3). In APLI, the one-step photoionization of APPI is replaced by a two-photon process in resonantly-enhanced multi-photon ionization [148]. Enhanced response for polycyclic aromatic hydrocarbons (relative to APCI) was demonstrated. Molecular ions rather than protonated molecules are generated in APLI (cf. Ch. 6.5). 

Polycyclic aromatic hydrocarbons have been encountered in different environmental matrices (e.g., soil, atmosphere, water, biota, etc.). Because PAHs have natural fluorescent properties, LC-FLD is advantageous over GC-MS because of its ability to measure the different PAH isomers and comparable detection limits are obtained. LC-DAD and LC-APCI-MS can also be applied and have the advantage... 

Gimeno, R. A., Altelaar, A. F. M., Marce, R. M., and Borrull, F., Determination of polycyclic aromatic hydrocarbons and polycychc aromatic sulfur heterocycles by high-performance liquid chromatography with fluorescence and APCI mass spectrometry detection in seawater and sediment samples, J. Chromatogr. A, 958, 141-148, 2002. 

The results of PAH analysis with different types of interfaces (e.g. ESI, APCI, PBI and TSP - were reported by Clench et al. reviewing the state of the art of various mass spectral techniques [28]. For more polar PAHs pneumatically assisted ESI-LC-MS was used to determine mixtures of hydroxy polycyclic aromatic hydrocarbons. The abundance of ions dependent on flow rates was shown. ESI inonization was found to be less sensitive compared to APCI ionisation [304]. PAH analysis with ESI-LC-MS combined with RP-LC with post-column addition of silver nitrate was applied for the determination of 10 PAHs in river water. PAHs resulted in [Mj and [M-i-Ag]. The detection limits of different PAHs in spiked samples ranged from 0.001 to 0.03 pg L [442]. 

APCI, atmospheric pressure chemical ionization Cl, chemical ionization El, electron impact ESI, electrospray ionization FAB, fast atom bombardment GC, gas chromatography LC, liquid chromatography MALDI, matrix-assisted laser desorption ionization MS, mass spectrometry MS/MS, tandem mass spectrometry PAHs, polycyclic aromatic hydrocarbons PEG, polyethylene glycol PPG, polypropylene glycol. 

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