Extraction of polar and hydrophobic pollutants using accelerated solvent extraction (ASE)

Accelerated solvent extraction (ASE) shows higher recoveries for PAHs in comparison with traditional Soxhlet extraction, but in a fraction of time and with less solvent consumption. Better recoveries are especially achieved with PAHs of high reactivity, the latter being expressed by the structure-to-count ratio (SCR). To estimate polar pollutants including phenols/benzenediols, the sample was subjected to a combined in-situ derivatization/extraction approach using 2% v/v acetic anhydride in toluene. The main reason for the better recovery obtained in this way, in comparison with the classical ASE approach, is to overcome strong matrix-analyte interactions. Analogously, fatty acids were analyzed as methyl esters obtained by in-situ derivatization/extraction using boron trifluoride.     

Determination of alkylphenols and linear alkylbenzene sulfonates in sediments applying accelerated solvent extraction (ASE)

A time and solvent saving method (accelerated solvent extraction, ASE) for the extraction of anionic surfactants as linear alkylbenzene sulfonates (LAS) and alkylphenols from sediments is presented. The analytes are extracted by methanol at 100 degrees C and 150 atm within 10 min of static and 5 min of dynamic extraction. The presence of methanol and a maximum pressure of 150 atm are essential for the complete extraction of anionic surfactants, whereas the extraction of alkylphenols is independent of both parameters. The extraction of alkylphenolethoxylates yielded only unsatisfactor results. It was demonstrated that the ASE extraction is selective for LAS surfactants, while matrix substances, which are extracted by the methanol extraction and interfere with the target analytes during the HPLC-run, remain in the sample. Thus, a further clean-up procedure of the ASE extract is not necessary.     

Determination of alkylphenols and linear alkylbenzene sulfonates in sediments applying accelerated solvent extraction (ASE)

A time and solvent saving method (accelerated solvent extraction, ASE) for the extraction of anionic surfactants as linear alkylbenzene sulfonates (LAS) and alkylphenols from sediments is presented. The analytes are extracted by methanol at 100° C and 150 atm within 10 min of static and 5 min of dynamic extraction. The presence of methanol and a maximum pressure of 150 atm are essential for the complete extraction of anionic surfactants, whereas the extraction of alkylphenols is independent of both parameters. The extraction of alkylphenolethoxylates yielded only unsatisfactor results. It was demonstrated that the ASE extraction is selective for LAS surfactants, while matrix substances, which are extracted by the methanol extraction and interfere with the target analytes during the HPLC-run, remain in the sample. Thus, a further clean-up procedure of the ASE extract is not necessary.     

Extraction of hydrocarbon contamination from soils using accelerated solvent extraction

Accelerated solvent extraction was studied as a method for the extraction of hydrocarbon contamination from wet and dry soils. Temperatures from 125 to 200 degrees C and six different solvents were investigated. Nonpolar solvents could not achieve complete recovery from wet soils at the temperatures studied. Optimum conditions were found to be 175 degrees C with dichloromethane-acetone (1:1, v/v) with 8 min heat-up time and 5 min static time. Quantitative recoveries for diesel range organics (DROs) and waste oil organics (WOOs) were obtained using the optimized conditions. The recovery of DROs and WOOs from three matrices at two concentrations (5 and 2000 mg/kg) averaged 115%. These results show that accelerated solvent extraction can generate results comparable to those obtained using Soxhlet or sonication.     

Determination of synthetic musks in the sediment of the Taihu lake by using accelerated solvent extraction (ASE) and GC/MS

Synthetic musks, substitutes for natural musks, are widely distributed in environment. They have been detected in water, sludge, fish, shrimp, mussels and other aquatic animals, and even in human's adipose tissue, blood and breast milk. In this study, a new extraction procedure, based on the accelerated solvent extraction (ASE) and in cell clean-up technique was developed and successfully coupled with gas chromatography-mass spectrometry (GC/MS) for the analysis of musks in sediment samples. With this method, the limits of detection as low as 0.03–0.05?ng?g^?1 and the recovery rate of 86.0%–104% are achieved. When compared with soxhlet extraction (SE) and ultrasonic extraction (USE), ASE not only has the best extraction efficiency but also has advantage in extraction time and solvent consumption. Eight synthetic musks, including six polycyclic musks (Tonalide (AHTN), Galaxolide (HHCB), Phantolide (AHDI), Traseolide (ATII), Cashmeran (DPMI) and Celestolide (ADBI)) and two nitro musks (musk xylene (MX) and musk ketone (MK)), were evaluated in sediment samples collected from 15 selected locations of the Taihu lake, one of the largest freshwater lakes in China. The contents of synthetic musks in sediment samples range from 0.336 to 3.10?ng?g^?1 for HHCB, 0.184 to 1.21?ng?g^?1 for AHTN, below detection limit (BDL) to 0.349?ng?g^?1 for MX, and BDL to 0.0786?ng?g^?1 for MK. The contents of DPMI, ADBI, AHMI and ATII are below detection limit in all samples. The results reflect current status of fragrance compound pollution in this area, and provide basic data for environmental policy making.     

Arsenic extraction and speciation in carrots using accelerated solvent extraction, liquid chromatography and plasma mass spectrometry

Arsenic present in freeze-dried carrots was extracted using accelerated solvent extraction (ASE). Several parameters, including selection of the dispersing agent, extraction time, number of extraction cycles, particle size and extraction temperature, were evaluated to optimize the ASE method. Filtering and treatment with C-18 SPE cartridges were also evaluated as part of the sample preparation procedure before speciation analysis. The method was validated by spiking single arsenical and mixed arsenical standards on the dispersing agent and on portions of freeze-dried carrot prior to extraction. LC-ICP-MS was used to determine individual arsenic species in the carrot extracts. A weak anion-exchange column was used for the separation of As(III), As(v), monomethylarsonic acid (MMA), dimethylarsinic acid and arsenobetaine. Optimized sample preparation conditions were applied to the extraction of arsenic in nine freeze-dried carrot samples. Total arsenic concentration in the carrot samples ranged from less than 20 ng g(-1) to 18.7 microg g(-1), dry mass. Extraction efficiency, defined as the ratio of the sum of individual arsenic species concentrations to total arsenic, ranged from 80 to 102% for freeze-dried carrots with arsenic concentrations greater than the limit of quantitation. Inorganic As(III) and As(v) were the only species found in samples that contained less than 400 ng g(-1) total arsenic. MMA and an unidentified arsenic compound were present in some of the samples with higher total arsenic content.     

Optimised accelerated solvent extraction of PCBs and PAHs from compost

This study is the first thorough method optimisation for accelerated solvent extraction (ASE) of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from chemically dried compost. For PCBs, optimised solvent composition, temperature, pressure, number of static cycles, duration, and flush volume were as follows: toluene/acetone 1?:?3 (v/v), 120°C, 2000?psi, 3?×?5?min, and 50%, respectively. Limits of quantification and method precision were between 0.16 and 2.46?µg?kg^?1 dw and 6–17% respectively for individual PCBs. Absolute recoveries of isotope-labelled extraction standards used for each of the analytes ranged from 65 to 105% and relative recoveries were between 85 and 99%. The method proofed to be robust and was successfully applied to different compost samples.

The optimisation of PAHs extraction was performed and resulted in the following conditions: solvent: hexane/acetone 1/3 (v:v), temperature: 140°C, pressure: 1500?psi, extraction time: 3?×?5?min, and 50% flush volume. Limits of detection and method precision for individual PAHs were between 1.1 and 37.2?µg?kg^?1?dw and 12–34% respectively. Absolute and relative recoveries ranged from 24 to 68% and from 85 to 99%, respectively. Optimal extraction conditions for PAHs were more difficult to determine due to the inhomogeneous distribution of PAHs in samples. However, the method appeared to be feasible and suggestions for further improvements are presented.     

Selective solvent extraction of chromium(VI) using 2-hexylpyridine

The extraction behaviour of trace and macroamounts of chromium(VI) from different mineral acid solutions by 2-hexylpyridine in chloroform has been investigated. In the chloride system, the extracted species is apparently (HPyH⁺)₂ (Cr₂O₇)²⁻ or HPy⁺(HCrO ₄ ⁻ ) for macro and trace amounts of chromium(VI), respectively. Among the common anions chloride and sulphate have little effect on extraction up to 1M concentration, while in the case of nitrate there is a continuous decrease in the extraction with the increase of salt concentration in the aqueous phase. The effect of ascorbate, acetate, citrate, oxalate, thiosulphate, thiocyanate ions on the extraction from 1M HCl was also examined. Separation factors of several elements relative to chromium(VI) have been described and the separation of chromium(IV) from a large number of elements has been achieved.     

Extraction of polycyclic aromatic hydrocarbons and organochlorine pesticides from soils: a comparison between Soxhlet extraction, microwave-assisted extraction and accelerated solvent extraction techniques

The methods of simultaneous extraction of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) from soils using Soxhlet extraction, microwave-assisted extraction (MAE) and accelerated solvent extraction (ASE) were established, and the extraction efficiencies using the three methods were systemically compared from procedural blank, limits of detection and quantification, method recovery and reproducibility, method chromatogram and other factors. In addition, soils with different total organic carbon contents were used to test the extraction efficiencies of the three methods. The results showed that the values obtained in this study were comparable with the values reported by other studies. In some respects such as method recovery and reproducibility, there were no significant differences among the three methods for the extraction of PAHs and OCPs. In some respects such as procedural blank and limits of detection and quantification, there were significant differences among the three methods. Overall, ASE had the best extraction efficiency compared to MAE and Soxhlet extraction, and the extraction efficiencies of MAE and Soxhlet extraction were comparable to each other depending on the property such as TOC content of the studied soil. Considering other factors such as solvent consumption and extraction time, ASE and MAE are preferable to Soxhlet extraction.     

Extraction and detection of arsenicals in seaweed via accelerated solvent extraction with ion chromatographic separation and ICP-MS detection

An accelerated solvent extraction (ASE) device was evaluated as a semi-automated means of extracting arsenicals from ribbon kelp. The effect of the experimentally controllable ASE parameters (pressure, temperature, static time, and solvent composition) on the extraction efficiencies of arsenicals from seaweed was investigated. The extraction efficiencies for ribbon kelp (approximately 72.6%) using the ASE were fairly independent ¶(< 7%) of pressure, static time and particle size after 3 ASE extraction cycles. The optimum extraction conditions for the ribbon kelp were obtained by using a 3 mL ASE cell, 30/70 (w/w) MeOH/H₂O, 500 psi (1 psi = 7 KPa), ambient temperature, 1 min heat step, 1 min static step, 90% vol. flush, and a 120 s purge. Using these conditions, two other seaweed products produced extraction efficiencies of 25.6% and 50.5%. The inorganic species present in the extract represented 62.5% and 27.8% of the extracted arsenic. The speciation results indicated that both seaweed products contained 4 different arsenosugars, DMA (dimethylarsinic acid), and As(V). One seaweed product also contained As(III). Both of these seaweed products contained an arsenosugar whose molecular weight was determined to be 408 and its structure was tentatively identified using ion chromatography-electrospray ionization-mass spectrometry/mass spectrometry (IC-ESI-MS/MS).     

Extraction and detection of arsenicals in seaweed via accelerated solvent extraction with ion chromatographic separation and ICP-MS detection

An accelerated solvent extraction (ASE) device was evaluated as a semi-automated means of extracting arsenicals from ribbon kelp. The effect of the experimentally controllable ASE parameters (pressure, temperature, static time, and solvent composition) on the extraction efficiencies of arsenicals from seaweed was investigated. The extraction efficiencies for ribbon kelp (approximately 72.6%) using the ASE were fairly independent (< 7%) of pressure, static time and particle size after 3 ASE extraction cycles. The optimum extraction conditions for the ribbon kelp were obtained by using a 3 mL ASE cell, 30/70 (w/w) MeOH/H2O, 500 psi (1 psi = 7 KPa), ambient temperature, 1 min heat step, 1 min static step, 90% vol. flush, and a 120 s purge. Using these conditions, two other seaweed products produced extraction efficiencies of 25.6% and 50.5%. The inorganic species present in the extract represented 62.5% and 27.8% of the extracted arsenic. The speciation results indicated that both seaweed products contained 4 different arsenosugars, DMA (dimethylarsinic acid), and As(V). One seaweed product also contained As(III). Both of these seaweed products contained an arsenosugar whose molecular weight was determined to be 408 and its structure was tentatively identified using ion chromatography-electrospray ionization-mass spectrometry/mass spectrometry (IC-ESI-MS/MS).     

加速溶剂萃取法快速提取黄连中的生物碱

探讨了快速溶剂萃取法（ASE）提取黄连中生物碱的可行性,并比较了该方法与回流提取法和超声提取法的优越性。以黄连中盐酸小檗碱的提取率为指标,以高效液相色谱法（HPLC）为检测方法,用正交实验对快速溶剂萃取法从黄连中提取盐酸小檗碱的工作条件进行优化。最佳仪器参数：提取溶剂为80%乙醇＋0.5%HCl,提取温度为130℃,静态提取时间为10 min,提取次数为1次。快速溶剂萃取法可作为黄连中生物碱分析测定的前处理方法。     

Fast and accurate determination of arsenobetaine in fish tissues using accelerated solvent extraction and HPLC-ICP-MS determination

A high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) method has been developed for the fast and accurate analysis of arsenobetaine (AsB) in fish samples extracted by accelerated solvent extraction. The combined extraction and analysis approach is validated using certified reference materials for AsB in fish and during a European intercomparison exercise with a blind sample. Up to six species of arsenic (As) can be separated and quantitated in the extracts within a 10-min isocratic elution. The method is optimized so as to minimize time-consuming sample preparation steps and allow for automated extraction and analysis of large sample batches. A comparison of standard addition and external calibration show no significant difference in the results obtained, which indicates that the LC-ICP-MS method is not influenced by severe matrix effects. The extraction procedure can process up to 24 samples in an automated manner, yet the robustness of the developed HPLC-ICP-MS approach is highlighted by the capability to run more than 50 injections per sequence, which equates to a total run-time of more than 12 h. The method can therefore be used to rapidly and accurately assess the proportion of nontoxic AsB in fish samples with high total As content during toxicological screening studies.     

Interfacial phenomena in solvent extraction of metals: Extraction of palladium(II)

4-Octylphenylamine, decyl isonicotiniate, decyl nicotiniate, decyl 2-hydroxyethyl sulphide and its analg with partly fluorinated alkyl group were used for palladium(II) extraction from 3M HCl. The adsorption of these compounds at toluene/HCl solution was also studied and interpreted. 4-Octylphen adsorbs at the hydrocarbon/HCl solution at much lower concentration range than other extractants and can be used as a phase transfer catalyst. The addition of 4-octylphenylamine increases the extraction rate with esters of pyridine carboxylic acids and decreases the time needed to obtain the equilibrium of extraction.     

Determination of acetanilide herbicides in cereal crops using accelerated solvent extraction, solid-phase extraction and gas chromatography-electron capture detector

A method was developed to determine eight acetanilide herbicides from cereal crops based on accelerated solvent extraction (ASE) and solid-phase extraction (SPE) followed by gas chromatography-electron capture detector (GC-ECD) analysis. During the ASE process, the effect of four parameters (temperature, static time, static cycles and solvent) on the extraction efficiency was considered and compared with shake-flask extraction method. After extraction with ASE, four SPE tubes (graphitic carbon black/primary secondary amine (GCB/PSA), GCB, Florisil and alumina-N) were assayed for comparison to obtain the best clean-up efficiency. The results show that GCB/PSA cartridge gave the best recoveries and cleanest chromatograms. The analytical process was validated by the analysis of spiked blank samples. Performance characteristics such as linearity, limit of detection (LOD), limit of quantitation (LOQ), precision and recovery were studied. At 0.05 mg/kg spiked level, recoveries and precision values for rice, wheat and maize were 82.3-115.8 and 1.1-13.6%, respectively. For all the herbicides, LOD and LOQ ranged from 0.8 to 1.7 μg/kg and from 2.4 to 5.3 μg/kg, respectively. The proposed analytical methodology was applied for the analysis of the targets in samples; only three herbicides, propyzamid, metolachlor and diflufenican, were detected in two samples.     

快速溶剂萃取柚皮中的黄酮类化合物

采用快速溶剂萃取法从柚子皮中提取出黄酮类化合物,考察了不同的提取溶剂、提取时间、提取温度、循环次数等提取条件下的提取效果,并与微波法、超声波法及索氏提取法进行了对比.结果表明,快速溶剂萃取法提取柚子皮中的黄酮类化合物,在提取溶剂用量、提取时间和提取效率等方面,均优于传统的提取方法,且自动化程度高,为进一步开发利用柚子皮的药用价值提供了参考.     

Desorption of BTEX from activated charcoal using accelerated solvent extraction: evaluation of occupational exposures

A procedure for the determination of benzene, toluene, ethylbenzene and o-xylene, m-xylene and p-xylene (BTEX) in occupational environments is proposed. These compounds are extracted from activated charcoal using accelerated solvent extraction. Operational parameters are optimized and quantitative recovery is obtained using acetonitrile as the extraction solvent and 1-mL extraction cells, a preheat time of 2 min, a temperature of 160 °C, a pressure of 1,500 psi, a static period of 5 min, a flush volume of 110%, two cycles and a purge time of 90 s. Determination of BTEX compounds is carried out by gas chromatography using a flame ionization detector. The recoveries, obtained for a confidence level of 95%, are 91 ± 4, 100 ± 3, 104 ± 2, 93 ± 4, 99 ± 2 and 99 ± 2% for benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene, respectively. The detection limits are 0.5 μg for benzene, 0.7 μg for toluene and 1.0 μg for the other compounds. The proposed procedure has been applied to real samples collected in several workplaces, like a microbiology laboratory, an analytical chemistry laboratory, a printer’s, a car repair shop and a petrol station. From the results obtained, it can be concluded that the occupational exposures determined are always acceptable because they are lower than the tenth part of the recommended exposure limits (VLA-ED and VLA-EC).     

Determination of pharmaceuticals in biosolids using accelerated solvent extraction and liquid chromatography/tandem mass spectrometry

An analytical method was developed to quantitatively determine pharmaceuticals in biosolid (treated sewage sludge) from wastewater treatment plants (WWTPs). The collected biosolid samples were initially freeze dried, and grounded to obtain relatively homogenized powders. Pharmaceuticals were extracted using accelerated solvent extraction (ASE) under the optimized conditions. The optimal operation parameters, including extraction solvent, temperature, pressure, extraction time and cycles, were identified to be acetonitrile/water mixture (v/v 7:3) as extraction solvent with 3 extraction cycles (15 min for each cycle) at 100 °C and 100 bars. The extracts were cleaned up using solid-phase extraction followed by determination by liquid chromatography coupled with tandem mass spectrometry. For the 15 target pharmaceuticals commonly found in the environment, the overall method recoveries ranged from 49% to 68% for tetracyclines, 64% to 95% for sulfonamides, and 77% to 88% for other pharmaceuticals (i.e. acetaminophen, caffeine, carbamazepine, erythromycin, lincomycin and tylosin). The developed method was successfully validated and applied to the biosolid samples collected from WWTPs located in six cities in Michigan. Among the 15 target pharmaceuticals, 14 pharmaceuticals were detected in the collected biosolid samples. The average concentrations ranged from 2.6 μg/kg for lincomycin to 743.6 μg/kg for oxytetracycline. These results indicated that pharmaceuticals could survive wastewater treatment processes, and accumulate in sewage sludge and biosolids. Subsequent land application of the contaminated biosolids could lead to the dissemination of pharmaceuticals in soil and water environment, which poses potential threats to at-risk populations in the receiving ecosystems.