Influence of the extraction methodology on the analysis of polycyclic aromatic hydrocarbons in pasture vegetation (original) (raw)
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Validation of Procedures to Quantify Nonextractable Polycyclic Aromatic Hydrocarbon Residues in Soil
Journal of Environment Quality, 2003
plished by solvent extraction methods. These include batch solvent shaking extraction, continuous soxhlet ex-This study was conducted to optimize butanol solvent shake extractraction, and improved versions such as the soxtec extion, dichloromethane soxtec extraction, and methanolic saponification extraction for the selective extraction of aged polycyclic aromatic tractor and accelerated solvent extraction (Northcott hydrocarbons from soil. Extraction kinetics for these methods was and Jones, 2000c). Differences in the ability of specific established to determine the optimal time necessary to achieve exhausaqueous and organic solvents to extract compounds tive compound extraction. This resulted in times of 12, 6, and 5 h, from environmental solids can provide information rerespectively, for butanol, dichloromethane, and saponification, to exgarding compound retention mechanisms (Cheng, 1990; tract polycyclic aromatic hydrocarbons from previously spiked, then Kubiak et al., 1990). It aged soil. Increasing the soil mass to butanol volume ratio reduced the is generally accepted that solvents extract the available proportion of polycyclic aromatic hydrocarbon extracted by butanol, compound fraction of contaminant and not the bound highlighting the importance of determining and maintaining a constant or sequestered residues. Various studies have used soil to solvent ratio for comparative purposes. Drying soil samples before dichloromethane soxtec extraction reduced by 30 to 76% the n-butanol (BuOH) as a "mild" solvent for extracting amount of polycyclic aromatic hydrocarbons extracted. The effect of the bioavailable, or labile, fraction of polycyclic arosample drying is discussed with relevance to enhancing the formation matic hydrocarbons (PAHs) in soil, and dichloromethof nonextractable compounds in soil and compound losses previously ane (DCM) as a "vigorous" solvent for the quantitative assumed by volatilization. The optimized extraction procedures proextraction of total extractable PAHs (Hatzinger and vided low variability with relative standard deviations Յ 5.2% for Alexander, 1995; Kelsey and Alexander, 1997; White et analysis of multiple replicates. The results obtained by the optimized al., 1997). procedures provided equivalent or improved reproducibility to those Conventional and enhanced solvent extraction techobtained by other methods reported in the literature.
Extraction techniques for polycyclic aromatic hydrocarbons in soils
2010
This paper aims to provide a review of the analytical extraction techniques for polycyclic aromatic hydrocarbons (PAHs) in soils. The extraction technologies described here include Soxhlet extraction, ultrasonic and mechanical agitation, accelerated solvent extraction, supercritical and subcritical fluid extraction, microwave-assisted extraction, solid phase extraction and microextraction, thermal desorption and flash pyrolysis, as well as fluidised-bed extraction. The influencing factors in the extraction of PAHs from soil such as temperature, type of solvent, soil moisture, and other soil characteristics are also discussed. The paper concludes with a review of the models used to describe the kinetics of PAH desorption from soils during solvent extraction.
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%.
Determination of trace amounts of polycylic aromatic hydrocarbons in soil
Fresenius' Zeitschrift f�r Analytische Chemie, 1987
Summary. A method is described for the determination of polycyclic aromatic hydrocarbons in natural soil. The soil is dried and extracted by ultrasonic agitation with dichloromethane. The extract is purified by liquid-liquid partitioning with dimethylformamide, water and hexane followed by high performance liquid chromatography on a silica column. Quantitative analysis of the purifred extract is carried out by combined gas chromatography/mass spectrometry. The method yields reliable results at the ng/g level. naphthalene, biphenyl, acenaphthene, fluorene, phenanthrene, fl uoranthene, pyrene, chrysene/triphenylene and benzo-a-pyrene. Three additional PAHs were used as internal standards; d1s-biphenyl, 3,6-dimethylphenanthrene and 1,1-binaphthyl.
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%.
Polycyclic Aromatic Hydrocarbon Accumulation in Urban, Suburban, and Rural Vegetation
Environmental Science & Technology, 1997
This study aims to evaluate levels and effects of Polycyclic Aromatic Hydrocarbons (PAHs) in cockles (Acanthocardia tuberculatae) collected from two differently influenced areas in the Mediterranean Western Moroccan coasts. PAHs accumulation was studied in soft tissues using Soxhlet extraction and separation on silica column methods. The measure of those organic compounds was realized by Gas chromatography coupled to Mass spectrometer technics (GC/MS). The impact evaluation was carried out by the study of biochemical responses in gills and digestive gland using two enzymes activities: Glutathione S-Transferase (GST) and Acetylcholinesterase (AchE). The PAHs displayed significant rates of accumulation ranging from 10.12µg/g Dried Weight (DW) to 11.65µg/g (DW) respectively in Oued Laou and Martil sites. Pyrolytic and petrogenic origins were observed in both sites. Pyrolytic origin of PAHs was strongly detected in Oued Laou site while petrogenic origin was mostly detected in Martil site. Biochemical study revealed significant enzymatic response of GST and AchE in gills and digestive gland. The study showed significant biochemical response more important in Martil site than Oued Laou site traduced by GST induction and AchE inhibition. Those results seemed to be related to accumulation rates of PAHs, which was also suggested by the statistical analysis PCA.
Chemosphere, 1997
Extraction with N-methyl-2-pyrrolidinone (NMP) in a microwave oven at 130°C for one hour was significantly the most efficient method for the extraction of PAHs from extraction sludge and wet harbour sediment. It was also one of the most efficient methods for extraction from air-dried industrial soil. During the first step of a two-step extraction, at least 99.8% of the PAHs were extracted with NMP. Extraction with NMP in a microwave oven was compared to extraction with acetone, methanol, ethanol, a methanol/toluene mixture, hydrolysis with KOH and tetra methyl ammonium hydroxide combined with ultrasonic treatment, rotary tumbling, Soxhlet extraction and extraction in a microwave oven. The second best method was extraction with a 4:1 (v/v) mixture of acetone and water in a microwave oven at 100°C for one hour.
Journal of Chromatographic Science, 2009
Two simple methods using headspace solid-phase microextraction (HS-SPME) coupled to a gas chromatograph with a flame ionization detector were compared for the determination of polycyclic aromatic hydrocarbons (PAH) in soils. These compounds were included in the US Environmental Protection Agency's Priority Pollutants list. Direct hot water HS-SPME extraction and sonication organic extraction followed by HS-SPME were optimized using experimental designs. The first method was chosen for PAH determination. The validation of the proposed method was carried out by analyzing PAHs in the certified soil reference material RTC-CRM 123. The accuracy obtained for the PAHs was shown to be inside the prediction interval with the certified material. The optimized method was applied to the analysis of several superficial soils from Gipuzkoa (Basque Country, North Spain).
Miniaturisated method for the analysis of polycyclic aromatic hydrocarbons in leaf samples
Journal of Chromatography A, 2010
A new methodology is proposed for monitoring 16 priority polycyclic aromatic hydrocarbons, using tree leaves as passive samplers, by means of a mini-ultrasonic probe coupled with reversed-phase liquid chromatography (RP-LC) and fluorescence (FL) detection. Separation and detection of the 16 PAHs were completed in 19 min, using a 3 m (particle size) C 18 column RP-LC with acetonitrile-water gradient elution. The ultrasonic probe device used was equipped with a 2 mm titanium tip, and sample and solvent amounts used were just 50 mg and 1 mL, respectively. Multivariate optimisation of the variables affecting extraction was conducted by means of full factorial analysis to determine which of the variables were significant. A central composite design was applied to define surface responses and to calculate optimal values for the variables. The accuracy of the method was determined by both analysis of a Certified Reference Material with a similar matrix (IAEA-140 OC, seaweed) and by comparison of the results obtained with those from a previously developed method. The proposed analytical method avoids some of the main problems encountered in the determination of PAH in complex matrices; no clean-up step is necessary, consequently sample preparation time and costs can be significantly reduced. The developed method was applied to determine PAH in leaf samples from medlar and red and white mangrove trees, situated near PAH pollution sources.