Polycyclic aromatic hydrocarbons from asphalt binder: extraction and characterization (original) (raw)
Related papers
International Journal of Environmental Research, 2011
Development and optimisation of fast, efficient, quantitative, economic and environmentally friendly analytical extraction techniques for the extraction clean up, and pre-concentration in the quantification of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in contaminated soils have been carried out. Three different extraction methods (Soxhlet, ultra sonication and mechanical shaking) were investigated on a low-level PAH soil certified reference material (CRM131-100) and the results were compared to determine the technique with the highest extraction efficiency. The clean up and pre-concentration procedures were optimized using both the conventional method (i.e. column packing with silica gel) as well as the solid phase extraction (SPE). Chromatographic conditions for the separation of PAHs using High Performance Liquid Chromatography (HPLC) using UV-DAD and fluorimetric detection with programmed excitation and emission wavelengths were also optimized. Six different extraction solvents: acetone, cyclohexane, 2-propanol, methanol, acetonitrile and dichloromethane, were tested to select the most suitable solvent for the extraction of the 16 PAHs from the certified soil reference material. Acetonitrile, dichloromethane and tetrahydrofuran were also tested as eluants for the optimisation of SPE clean up. The optimized ultrasonic extraction procedure utilizing four 15 minutes extraction cycles at 50 ºC and SPE clean up with tetrahydrofuran: acetonitrile (1:1) and subsequent separation by gradient reversed phase HPLC with fluorimetric detection extracted the PAHs from the certified reference material with recoveries ranging from 63.6 % to over 100 % .
Solid-phase extraction of polycyclic aromatic hydrocarbons from soil samples
Journal of Chromatography A, 1995
ABSTRACT A new solid-phase extraction (SPE) method was developed for the analysis of 16 polyaromatic hydrocarbons (PAHs) on the US Environmental Protection Agency priority list, in soil samples. Different types of SPE columns were tested and conditioning and elution steps were optimised. In the final procedure, soil samples are extracted with acetone and, after dilution with HPLC-grade water, loaded on a C8 SPE column. After washing, all PAHs are eluted with tetrahydrofuran (THF). The final THF extract is analysed on an HPLC system for PAHs.Recoveries of the volatile PAHs, naphthalene, acephthylene and acenaphthalene were 80–90%. All other recoveries are comparable with standard liquid-liquid extraction (LLE) and range from 75 to 90%.The method is compared with the conventional LLE method for different types of real soil samples of a Dutch monitoring programme. Results indicate that SPE is a good method for the sample preparation for the analysis of PAHs in soil samples. Compared with LLE, correlation coefficients are better than 0.9 with relative standard deviations for SPE between 0.8 and 9.1%. LLE standard deviations ranged from 1.1 to 15.1%.
African Journal of Environmental Science and Technology, 2014
In this study, polycyclic aromatic hydrocarbons (PAHs) associated with airborne particulate pollutants of aerodynamic size 10 μm (PM10) were studied for three months, from October to December 2010 in the Vanderbijlpark area. Some PAHs are highly carcinogenic and could be more harmful when combined with inhalable PM10. A dual E-Sampler which combines the light scatter and the gravimetric filter methods was used. A 10 mg/L standard stock solution that contained naphthalene (Naph), 2-methyl naphthalene (2-MNaph), phenanthrene (Phe), anthracene (Anth), benzo(b)fluoranthene (BbFl), benzo(k)fluoranthene (BkFl), benzo(a)pyrene (BaPy) and dibenzo(a,h)anthracene (DiBahAn) was prepared, compounds were indentified and quantified with an Agilent high performance liquid chromatography (HPLC). A dichloromethane (DCM) and n-hexane (1:1) extraction mixture was used to extract the pollutants from both exposed and unexposed (blank) filters. Detection limits obtained ranged from 0.001 to 0.0305 mg/L and R-values ranged from 0.996 -0.999. Very good percentage recoveries were obtained with the lowest 97.63% and highest 101.57% associated with DiBahFl and 2-MNaph, respectively. Total concentration of 2-MNaph obtained per month were 325.2 ng/L (October 2010), 162.4 ng/L (November 2010) and 381.2 ng/L (December 2010). Relatively high levels of 2-MNaph were detected consistently when compared with other pollutants in the three months. Concentration ranges of other PAH compounds were Anth (7.2 -14.76 ng/L), BbFl (6.7 -13.6 ng/L), BaPy (6.8 -13.0 ng/L) and BkFl (6.7 -10.8 ng/L). Daily and monthly mass concentration levels obtained were lower than the strict regional daily limit of 0.075 µg/m 3 , as well as national and international daily limits of 0.150 µg/m 3 . These results could be used as the basis for undertaking a comprehensive study on the status of these organic compounds from the heavily industrialized Vaal Triangle region.
A method using ultrasonication extraction and solid phase extraction (SPE) clean-up for determination of US EPA 16 priority pollutant polycyclic aromatic hydrocarbons (PAHs) in soils by reversed-phase liquid chromatography (RP-LC) with ultraviolet (UV) absorption detection was studied. Separation and detection of the 16 PAHs were completed in 31 min by RP-LC with a C 18 column (Bakerbond PAH 6 PLUS 125Â3.0 i.d. mm or Phenomenex ENVIROSEP-PP 125Â3.2 i.d. mm), acetonitrile± water gradient elution and UV absorption detection. The detection limits, for a 10 ml of solution injection, determined at 254 nm were less than 1 mg/ml, except for acenaphthene, which was 1.05 mg/ml. Because individual PAHs are present in soils at the ng/g level or below and few sample matrices can be analyzed directly without serious interference, ef®cient extraction, preconcentration and clean-up of PAHs from the samples are indispensable prior to the determination of the PAHs. Several organic solvents were tested for extraction of the PAHs from soils, and ultrasonication extraction was used for the extraction in acetone of the 16 PAHs in soils. Several SPE procedures were tested and compared, and Supelco 6 ml LC-18 SPE cartridge and acetone:tetrahydrofuran (THF)1:1 eluant were used for the preconcentration and clean-up of the 16 PAHs in the soil. The method was successfully applied to determine the 16 PAHs in the soil sampled from an industrial land in the UK. # 1998 Elsevier Science B.V.
African Journal of Environmental Science and Technology, 2011
The development of a fast, efficient and quantitative technique for the extraction, clean-up, and preconcentration of the 16 United States Environmental Protection Agency (USEPA) priority polycyclic aromatic hydrocarbons (PAHs) was carried out on contaminated soils. The effect of Soxhlet, ultrasonication and mechanical shaking used in the extraction of a low-level PAH soil certified reference material (CRM131-100) was investigated. Six different extraction solvents: acetone, cyclohexane, 2-propanol, methanol, acetonitrile and dichloromethane, were tested to select the most suitable solvent for the extraction of the 16 PAHs from the certified soil reference material. The results were compared to determine the method with the highest extraction efficiency. The clean up and preconcentration procedures for the PAHs were optimised using the solid phase extraction (SPE). Acetonitrile, dichloromethane and tetrahydrofuran were tested as eluants for the optimisation of SPE clean up. Chromatographic conditions for the separation of PAHs using High Performance Liquid Chromatography (HPLC) using UV-DAD and fluorimetric detection with programmed excitation and emission wavelengths were also optimised. The optimised ultrasonic extraction procedure and SPE clean-up extracted the PAHs from the certified reference material with recoveries ranging from 63.6 % to over 100%.
Journal of The Chilean Chemical Society, 2019
Background: Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals which have 2 to 7 fused aromatic rings. It is demonstrated that even trace amounts of PAHs are carcinogens, mutagens, and teratogens which can lead to serious risk to the health of humans. According to these facts, determination of PAHs in environmental samples is essential. Methods: In this study, ultrasonic in combination with salt-assisted liquid-liquid extraction was used efficiently for the extraction of PAHs from soil and water samples. In order to evaluate the performance of the proposed method three PAHs, naphthalene, anthracene and pyrene were selected as model analytes. Influential parameters on the extraction efficiency of analytes such as extraction solvent and its volume, salting-out agent and its concentration, ultrasonic time, ultrasonic amplitude and pulse were investigated and optimized. Results: The optimum conditions were as follow; extracting solvent; tetrahydofuran, extracting solvent volume; 3 mL, salting-out agent; sodium acetate, salting-out agent concentration; 20 %w/v, ultrasonic time; 10 s, ultrasonic amplitude; 60% and ultrasonic pulse; 0.5 s. The limits of quantitation for pyrene, naphthalene and anthracene were 1.0, 1.0 and 0.7 ng g-1 , respectively. Under the optimum conditions, obtained recoveries in different matrices were in the range of 80.0 to 100.0% with a relative standard deviation better than 7.5%. Conclusions: In the proposed method, after the UAE, sample was exposed to SALLE without need of solid residue removal from the sample. Therefore, extraction steps such as filtration and centrifuge were removed which lead to time saving.
Analytica Chimica Acta, 2007
An accurate and reliable method for determining polycyclic aromatic hydrocarbons (PAHs) in atmospheric aerosols is described. This optimised gas chromatography-mass spectrometry (GC-MS) method permits a wide range of concentrations to be analysed without the influence of interferences. Pre-treatment comparison of four kinds of aerosol collector filters determined that quartz and glass fibre filters were the most suitable. Solvents like cyclohexane, toluene, acetonitrile and dichloromethane were evaluated for their PAH-extraction capacity. Ultrasonic extraction using CH 2 Cl 2 was selected because it is rapid and easy; moreover, this solvent increases the sample-throughput capacity. PAH compounds were quantitatively collected and ultrasonically extracted twice using 15 mL of CH 2 Cl 2 for 15 min for each replicate. Rotavapor concentration, fractionation and dissolution were also optimised. A certified standard mixture (16 EPA PAHs), a deuterated compound and precision recovery assays were used for validating the proposed methodology. Adequate analytical parameters were obtained. Detection limits were (1.6-26.3) × 10 −5 ng and quantification limits were (5.2-87.6) × 10 −5 ng. Analysis of the environmental samples detected 4-10 EPA list PAH compounds. In addition, 2-11 tentative compounds were found, and their molecular structures were described for the first time. Our study of both Youden method and the standard addition method has shown that the proposed determination of PAHs in environmental samples is free of systematic errors. In conclusion, this unbiased methodology improves the identification and quantification of PAH compounds. High sensitivity as well as acceptable detection and quantification limits were obtained for the environmental applications.
2015
Polycyclic Aromatic Hydrocarbons (PAHs), which arise from incomplete combustion during engine operation, escape the combustion chamber, leading to lubricant contamination. PAHs have been declared highly detrimental to living organisms, and thus, PAH regulation in the environment is crucial because used engine oil accumulates PAHs in high levels. Engine oil samples were collected at different car maintenance workshops around Johannesburg, where the analysis of 5 target PAHs was carried out in both fresh and used engine oil samples (different oil bands), and then subjected to Gas Chromatography-Mass Spectrometry (GC/MS) and High Performance Liquid Chromatography (HPLC). In contrast to preliminary studies reporting higher PAH values of 300+ in used engine oil, the PAH value has decreased significantly, with PAH content being 70 and 7 times more in used engine oil by HPLC and GCMS respectively due to the different capabilities of the two instruments. Fourier Transform Infrared (FTIR) revealed evidence showing the formation of PAHs, which was corroborated by the presence of a band at 1600 cm-1 , which is associated with a CC stretch in a ring. In comparison to fresh oil, used oil quantitative proton Nuclear Magnetic Resonance (NMR) revealed a new intense peak at the aromatic region between 7-7.5 ppm, which may have arisen due to PAH formation. It was also observed that the PAH content was considerably lower compared to other constituents found in the oil sample. This drastic reduction in PAH concentration, may be due to the significant improvements made in lubricating (engine) oil formulations, refining processes, and engine designs. iii DEDICATION In memory of the fallen soldiers belonging to squad: Shakoane, Khumalo, Monareng and Mashego I would also like to extend my gratitude to the Chemical Industries Education and Training Authority (CHIETA) for funding both my research and coursework, the School of Chemistry and School of Chemical and Metallurgical engineering for their support and permission to use their facilities for analysis. I would also like to thank the personnel that took part to see through this study namely
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants generated primarily during the incomplete combustion of organic materials (e.g. coal, oil, petrol, and wood). Emissions from anthropogenic activities predominate; nevertheless, some PAHs in the environment originate from natural sources such as open burning, natural losses or seepage of petroleum or coal deposits, and volcanic activities. Major anthropogenic sources of PAHs include residential heating, coal gasification and liquefying plants, carbon black, coal-tar pitch and asphalt production, coke and aluminum production, catalytic cracking towers and related activities in petroleum refineries as well as and motor vehicle exhaust. PAHs are found in the ambient air in gas-phase and as sorbet to aerosols. Atmospheric partitioning of PAH compounds between the particulate and the gaseous phases strongly influences their fate and transport in the atmosphere and the way they enter into the human body. The removal of PAHs from the atmosphere by dry and wet deposition processes are strongly influenced by their gas/particle partitioning. Atmospheric deposition is a major source for PAHs in soil. Many PAHs have toxic, mutagenic and/or carcinogenic properties. PAHs are highly lipid soluble and thus readily absorbed from the gastrointestinal tract of mammals. They are rapidly distributed in a wide variety of tissues with a marked tendency for localization in body fat. Metabolism of PAHs occurs via the cytochrome P450-mediated mixed function oxidase system with oxidation or hydroxylation as the first step. Several different remediation technologies have been tested in efforts to remove these environmental contaminants. Among them, bioremediation is showing particular promise as a safe and cost-effective option. In spite of their xenobiotic properties, a variety of genera of gram-positive and-negative bacteria, fungi and algae have been isolated and characterized for their ability to utilize PAHs.
Recent Advances in the Extraction of Polycyclic Aromatic Hydrocarbons from Environmental Samples
Molecules
Polycyclic aromatic hydrocarbons (PAHs) comprise a group of chemical compounds consisting of two or more fused benzene rings. PAHs exhibit hydrophobicity and low water solubility, while some of their members are toxic substances resistant to degradation. Due to their low levels in environmental matrices, a preconcentration step is usually required for their determination. Nowadays, there is a wide variety of sample preparation techniques, including micro-extraction techniques (e.g., solid-phase microextraction and liquid phase microextraction) and miniaturized extraction techniques (e.g., dispersive solid-phase extraction, magnetic solid-phase extraction, stir bar sorptive extraction, fabric phase sorptive extraction etc.). Compared to the conventional sample preparation techniques, these novel techniques show some benefits, including reduced organic solvent consumption, while they are time and cost efficient. A plethora of adsorbents, such as metal-organic frameworks, carbon-based ...