Thermal desorption - comprehensive two-dimensional gas chromatography coupled with tandem mass spectrometry for determination of trace polycyclic aromatic hydrocarbons and their derivatives

We developed a highly sensitive method for determination of polycyclic aromatic hydrocarbons (PAHs) and their derivatives (oxygenated, nitrated, and methylated PAHs) in trace particulate samples by using thermal desorption followed by comprehensive two-dimensional gas chromatography coupled with tandem mass spectrometry (TD-GC x GC-MS/MS) with a selected reaction monitoring mode. The sensitivity of TD-GC x GC-MS/MS was greater than that of TD-GC-HRMS and TD-GC x GC-QMS by one or two orders of magnitude. The instrumental detection limits were 0.03-0.3 pg (PAHs), 0.04-0.2 pg (oxygenated PAHs), 0.03-0.1 pg (nitrated PAHs), and 0.01-0.08 pg (methylated PAHs). For small amounts (10-20 mu g) of standard reference materials (SRMs 1649a and 1650b, urban dust and diesel exhaust particles, respectively), the values measured by using TD-GC x GC-MS/MS agreed with the certified or reference values within a factor of two. Major analytes were quantified successfully by TD-GC x GC-MS/MS from diesel exhaust nanoparticles (18-32 nm) and accumulation-mode particles (100-180 nm) from an 8-L diesel engine with no exhaust after-treatment system. The PAH profiles differed among driving conditions but they did not differ markedly among the particle sizes. (C) 2012 Elsevier B.V. All rights reserved.