Polycyclic aromatic hydrocarbons (PAHs) are frequently measured in the atmosphere for air quality assessment, in biological tissues for health-effects monitoring, in sediments and mollusks for environmental monitoring, and in foodstuffs for safety reasons. In contemporary analysis of these complex matrices, gas chromatography (GC), rather than liquid chromatography (LC), is often the preferred approach for separation, identification, and quantification of PAHs, largely because GC generally affords greater selectivity, resolution, and sensitivity than LC. This article reviews modern-day GC and state-of-the-art GC techniques used for the determination of PAHs in environmental samples. Standard test methods are discussed. GC separations of PAHs on a variety of capillary columns are examined, and the properties and uses of selected mass spectrometric (MS) techniques are presented. PAH literature on GC with MS techniques, including chemical ionization, ion-trap MS, time-of-flight MS (TOF-MS), and isotope-ratio mass spectrometry (IRMS), is reviewed. Enhancements to GC, for example large-volume injection, thermal desorption, fast GC, and coupling of GC to LC, are also discussed with regard to the determination of PAHs in an effort to demonstrate the vigor and robustness GC continues to achieve in the analytical sciences.

The Henry's law constants for 26 polychlorinated biphenyl (PCB) congeners were measured using a gas-stripping apparatus at five environmentally relevant temperatures between (4 and 31) °C. The Henry's law constants ranged between (0.079 ± 0.003) Pa·m3·mol-1 for 2,2‘,3,3‘,4,4‘,5,6-octachlorobiphenyl (IUPAC congener #195) at 4 °C and (308 ± 29) Pa·m3·mol-1 for 2,2‘,3,3‘,4,5‘,6,6‘-octachlorobiphenyl (IUPAC congener #201) at 31 °C. The temperature dependence of each PCB congener's Henry's law constant was modeled to calculate the enthalpy and entropy of the phase change between the gaseous and dissolved phases. For many PCB congeners, this study reports the first experimentally measured temperature variations of their Henry's law constants. The enthalpies of phase change (ΔH H) ranged between (14.5 ± 3.4) kJ·mol-1 for 2,2‘,4,6,6‘-pentachlorobiphenyl (IUPAC congener #104) and (167 ± 13) kJ·mol-1 for 2,2‘,3,3‘,4,4‘,5,6-octachlorobiphenyl (IUPAC congener #195). These data can be used to predict PCB congener Henry's law values within the experimental temperature range within a relative standard error of less than 10%.

Sorption isotherms for five aromatic hydrocarbons were obtained with a natural wood char (NC1) and its residue after solvent extraction (ENC1). Substantial isotherm nonlinearity was observed in all cases. ENC1 showed higher BET surface area, higher nitrogen-accessible micropore volume, and lower mass of extractable organic chemicals, including quantifiable polycyclic aromatic hydrocarbons (PAHs),while the two chars showed identical surface oxygen/ carbon (O/C) ratio. For two chlorinated benzenes that normally condense as liquids at the temperatures used, sorption isotherms with NC1 and ENC1 were found to be statistically identical. For the solid-phase compounds (1,4-dichlorobenzene (1,4-DCB) and two PAHs), sorption was statistically higher with ENC1, thus demonstrating sorption effects due to both (1) authigenic organic content in the sorbentand (2)the sorbate's condensed state. Polanyi-based isotherm modeling, pore size measurements, and comparisons with activated carbon showthe relative importance of adsorptive pore filling and help explain results. With both chars, maximum sorption increased in the order of decreasing molecular diameter: phenanthrene < naphthalene < 1,2-dichlorobenzene/1,2,4-trichlorobenzene < 1,4-DCB. Comparison of 1,4- and 1,2-DCB shows that the critical molecular diameter was apparently more important than the condensed state, suggesting that 1,4-DCB sorbed in the liquid state for ENC1.