Quantification of polycyclic aromatic hydrocarbons (PAHs) found in gas and particle phases from pyrolytic processes using gas chromatography–mass spectrometry (GC–MS)

Abstract

h i g h l i g h t s " A methodology for PAH quantification from thermochemical processes was developed. " Quantification of both PAH adsorbed on soot and at the gas phase was considered. " The method gives reliable results of PAH from complex samples like soot.g r a p h i c a l a b s t r a c t . a b s t r a c tThe outlet stream from combustion processes is a complex mixture of compounds which depends on the specific operating conditions. Thermochemical processes operating under rich fuel conditions enhance the formation of polycyclic aromatic hydrocarbons (PAHs) and soot. PAH play an important role in soot formation, but they can appear adsorbed on soot surface as well as at the gas phase due to their different volatility and molecular weight. Both PAH (the gas phase and adsorbed PAH) fractions are important when considering the total characterization from pyrolytic processes, mainly for determining the emission levels of 16 Environmental Protection Agency (EPA) priority PAH. In this way, an optimized method capable to determine the aromatic compounds in the gas and particle phases in combustion exhaust gases is needed. The method here presented allows the collection and quantification of both the PAH adsorbed on soot and present at the gas phase of the exhaust gases of thermochemical processes. It involves PAH characterization by combining classical Soxhlet extraction of the sample collected, followed by an extract concentration using a rotary evaporator and subsequent micro-concentration under gentle nitrogen stream before the analysis. The EPA-PAH were determined using a gas chromatograph-mass spectrometer (GC-MS). Validation tests using a fully characterized soot, the NIST (National Institute of Standards and Technology) reference material SRM 1650b, and repeatability using diesel surrogate commercial soot named Printex-U, were done. Additionally, experiments of acetylene pyrolysis were carried out and their products analyzed for determining the PAH amount. The results showed good method 0016-2361/$ -see front matter Ó

Polycyclic aromatic hydrocarbons (PAHs) and soot formation in the pyrolysis of the butanol isomers

“…The experiments have been carried out in a tubular flow reactor, under well controlled laboratory conditions, in a facility suitable for soot and PAHs collection, and all the experimental details are described elsewhere [25]. The analytical methodology, developed by our research group [26], has been used with success in previous works addressing the quantification of PAHs [27][28][29], and has demonstrated recoveries higher than 80 % in most cases [e.g. 30,31].…”

Experimental Study on the Flow Field of Particles Deposited on a Gasoline Particulate Filter

“…The components of the particles (soot) were influenced by the types of engines, fuels, and operating conditions, and carbon black (Printex-U, PU), which has been widely used as a commercial diesel and gasoline soot surrogate due to its repeatability [18,[41][42][43][44]. In this study, the focus was on the cone's influence on flow field with particle deposition, the particle size's influence on the flow filed is not involved.…”

Analyzing the solid soot particulates formed in a fuel‐rich flame by solvent‐free matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry

“…Due to the high insolubility of soot particulates, it is difficult to achieve a comprehensive characterization of the entire solid samples by conventional organic analysis techniques, such as gas chromatography/mass spectrometry (GC/MS), high‐performance liquid chromatography (HPLC), and size‐exclusion chromatography (SEC) . The reason is that these systems are mainly designed for those samples which can be converted into liquid or gas phases, but this is unpractical to achieve for the entire soot particulates with poor solubility and volatility.…”