Determination of PAHs in airborne particles by accelerated solvent extraction and large-volume injection-gas chromatography-mass spectrometry.
A sensitive and automated method is presented for the determination of polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matter. The procedure includes extraction of PM10-bound PAHs by accelerated solvent extraction (ASE) followed by gel permeation chromatography (GPC) clean-up, and large-volume programmable temperature vaporizer (PTV-LV) injection coupled to GC-MS. The limit of detection (LOD) of the whole method, based on a signal-to-noise ratio (S/N) of 3:1, ranged from 0.26pgm(-3) to 3pgm(-3) when air volumes of 760m(3) are collected. The hexane-acetone mixture (1:1, v/v) gave the best recoveries when ASE parameters were fixed at 125 degrees C, 1500psi, and a total time of 10min. The recoveries for all PAHs tested ranged from 96% to 103%, rates similar to those obtained by the Soxhlet reference method. To improve the sensitivity, 70muL were injected. The PTV-LV injection settings were optimized using a statistical design of experiments, including a screening 2(4) full factorial design and a further central composite design. A sensitivity increase from 10 to 50 times was achieved as compared with the conventional 2muL splitless injection. The method was validated with the standard reference material SRM 1649a and applied to real PM10 samples from the monitoring network of the Regional Valencia Government (Spain). The analytical performance of the method shows that it is appropriate to monitor PAHs levels in ambient air according to European Union Directives. In addition, the method can be used when a high sensitivity is required.
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Public Health Laboratory of Valencia, Generalitat Valenciana, C/Micer Mascó 31, 46010-Valencia, Spain.
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