Determination of hexabromocyclododecane diastereoisomers in Sargassum fusiforme and comparison of the extraction efficiency of ultrasonication, microwave-assisted extraction, Soxhlet extraction and pressurised liquid extraction

The concentrations of hexabromocyclododecanes (HBCD) in Sargassum fusiforme, the common Chinese edible seaweed, were investigated by LC‐MS/MS. For the recovery of HBCD, the efficiency levels of ultrasonic‐assisted extraction, microwave‐assisted extraction, Soxhlet extraction and pressurised liquid extraction were compared under different conditions. Pressurised liquid extraction and ultrasonic‐assisted extraction resulted in complete extraction of HBCD (92.7–102.5% recovery). Microwave‐assisted extraction and Soxhlet extraction, on the other hand, offered relatively low extraction recoveries (82.1–90.6%). The instrumental LODs on columns in this study were 1.0, 0.3 and 0.7 ng/g for α‐HBCD, β‐HBCD and γ‐HBCD, respectively. Because of its accuracy, this straightforward method is particularly suitable for routine HBCD analysis.     

Development and optimisation of a novel three‐way extraction technique based on a combination of Soxhlet extraction,membrane assisted solvent extraction and a molecularly imprinted polymer using sludge polycyclic aromatic hydrocarbons as model compounds

A novel technique that integrates extraction and clean‐up into a single step format is reported as part of the search for new sample preparation techniques in the analysis of persistent organic pollutants from complex samples. This was achieved by combining the extraction efficiency of the Soxhlet extractor, the selectivity of a size exclusion membrane and the specificity of a molecularly imprinted polymer for the extraction of polycyclic aromatic hydrocarbons from wastewater sludge followed by quantitation using gas chromatography with time‐of‐flight mass spectrometry. The approach is described as the Soxhlet extraction membrane‐assisted solvent extraction molecularly imprinted polymer technique. This technique was optimised for various parameters such as extraction solvent, reflux time and membrane acceptor phase. The applicability of the developed technique was optimised using a wastewater sludge certified reference material and then tested on real wastewater sludge samples. The method detection limits ranged from 0.14 to 12.86 ng/g with relative standard deviation values for the extraction of the 16 US‐EPA priority polycyclic aromatic hydrocarbons from wastewater sludge samples ranging from 0.78 to 18%. The extraction process was therefore reproducible and showed remarkable selectivity. The developed technique is a promising prospect that can be applied in the analysis of organic pollutants from complex solid samples.     

Fast microwave‐assisted extraction of rotenone for its quantification in seeds of yam bean (Pachyrhizus sp.)

The aim of this study was to find if fast microwave‐assisted extraction could be an alternative to the conventional Soxhlet extraction for the quantification of rotenone in yam bean seeds by SPE and HPLC‐UV. For this purpose, an experimental design was used to determine the optimal conditions of the microwave extraction. Then the values of the quantification on three accessions from two different species of yam bean seeds were compared using the two different kinds of extraction. A microwave extraction of 11 min at 55°C using methanol/dichloromethane (50:50) allowed rotenone extraction either equivalently or more efficiently than the 8‐h‐Soxhlet extraction method and was less sensitive to moisture content. The selectivity, precision, trueness, accuracy, and limit of quantification of the method with microwave extraction were also demonstrated.     

A comparison of accelerated solvent extraction,Soxhlet extraction,and ultrasonic-assisted extraction for analysis of terpenoids and sterols in tobacco

The performance of accelerated solvent extraction in the analysis of terpenoids and sterols in tobacco samples was investigated and compared with those of Soxhlet extraction and ultrasonically assisted extraction with respect to yield, extraction time, reproducibility and solvent consumption. The results indicate that although the highest yield was achieved by Soxhlet extraction, ASE appears to be a promising alternative to classical methods since it is faster and uses less solvent, especially when applied to the investigation of large batch tobacco samples. However, Soxhlet extraction is still the preferred method for analyzing sterols since it gives a higher extraction efficiency than other methods.     

Evaluation of microwave-assisted extraction for aristolochic acid from Aristolochiae Fructus by chromatographic analysis coupled with nephrotoxicity studies

In this paper, a microwave-assisted extraction (MAE) method was established for aristolochic acid-I from Aristolochiae Fructus, and the advantage of MAE was evaluated by chromatographic analysis coupled with nephrotoxicity studies. The experimental parameters of MAE for aristolochic acid-I in Aristolochiae Fructus were investigated and MAE was compared with Soxhlet extraction and ultrasound-assisted extraction in terms of extraction yields and extraction conditions. Under the optimum conditions, MAE could provide higher extraction yields of aristolochic acid-I (1.10 mg/g) than ultrasound-assisted extraction (0.82 mg/g) and Soxhlet extraction (0.95 mg/g), in addition to using less solvent and having a shorter extraction time. Furthermore, the nephrotoxicities of the extracts of Aristolochiae Fructus from different extraction procedures were investigated in Sprague-Dawley rats. The results of nephrotoxicity studies of, for example, general conditions, biochemistry parameters and histopathology examination showed no significantly differences in the nephrotoxicity levels of the extracts from MAE and that from Soxhlet extraction. These results indicated that MAE technique is a simple, rapid and effective extraction method, and the microwave irradiation during MAE procedure did not have any influence on the nephrotoxicity of Aristolochiae Fructus compared with Soxhlet extraction.     

Comparison of extraction techniques for the isolation of explosives and their degradation products from soil

A comparison of four extraction techniques used for the isolation of 14 explosive compounds (Method 8330-Explosives) from spiked soil samples is described. Soxhlet warm extraction (SWE), pressurized solvent extraction (PSE), microwave assisted extraction (MAE) and supercritical fluid extraction (SFE) were included. The effects of basic extraction conditions – i.e. type of extraction solvent, temperature, pressure, and extraction time – were investigated. The best extraction recovery of the monitored compounds from spiked soil was obtained using pressurized solvent extraction. Recoveries of explosives using the PSE technique were in the range from 65 to 112%. Extraction recoveries by Soxhlet warm extraction and supercritical fluid extraction reached 65–99% and 52–75%, respectively. The lowest extraction recoveries (28–65%) were obtained using microwave assisted extraction. A very low extraction recovery for tetryl was observed in all cases but the best results were achieved by pressurized solvent extraction (58%).     

Microalgae amino acid extraction and analysis at nanomolar level using electroporation and capillary electrophoresis with laser‐induced fluorescence detection

Amino acids play a key role in food analysis, clinical diagnostics, and biochemical research. Capillary electrophoresis with laser‐induced fluorescence detection was used for the analysis of several amino acids. Amino acid labeling with fluorescein isothiocyanate was conducted using microwave‐assisted derivatization at 80°C (680 W) during only 150 s. Good electrophoretic resolution was obtained using a background electrolyte composed of sodium tetraborate buffer (100 mM; pH 9.4) and β‐cyclodextrin (10 mM), and the limits of quantification were 3–30 nM. The developed capillary electrophoresis with laser‐induced fluorescence method was used to analyze amino acids in Dunaliella salina green algae grown under different conditions. A simple extraction technique based on electroporation of the cell membrane was introduced. A home‐made apparatus allowed the application of direct and alternating voltages across the electrochemical compartment containing a suspension of microalgae in distilled water at 2.5 g/L. A direct voltage of 12 V applied for 4 min gave the optimum extraction yield. Results were comparable to those obtained with accelerated‐solvent extraction. The efficiency of electroporation in destroying microalgae membranes was shown by examining the algae surface morphology using scanning electron microscopy. Stress conditions were found to induce the production of amino acids in Dunaliella salina cells.     

Comparison of extraction techniques of robenidine from poultry feed samples

In this paper, effectiveness of six different commonly applied extraction techniques for the determination of robenidine in poultry feed has been compared. The sample preparation techniques included shaking, Soxhlet, Soxtec, ultrasonically assisted extraction, microwave – assisted extraction and accelerated solvent extraction. Comparison of these techniques was done with respect to the recovery extraction, temperature and time, reproducibility and solvent consumption. Every single extract was subjected to clean – up using aluminium oxide column (Pasteur pipette filled with 1 g of aluminium oxide), from which robenidine was eluted with 10 ml of methanol. The eluate from the clean-up column was collected in a volumetric flask, and finally it was analysed by HPLC–DAD–MS. In general, all extraction techniques were capable of isolating of robenidine from poultry feed, but the recovery obtained using modern extraction techniques was higher than that obtained using conventional techniques.

In particular, accelerated solvent extraction was more superior to other techniques, which highlights the advantages of this sample preparation technique. However, in routine analysis, shaking and ultrasonically assisted extraction is still the preferred method for the solution of robenidine and other coccidiostatics.     

Determination of three capsaicinoids in Capsicum annuum by pressurized liquid extraction combined with LC‐MS/MS

A new method based on pressurized liquid extraction followed by LC‐MS/MS analysis has been developed for the identification and quantification of three capsaicinoids (capsaicin, dihydrocapsaicin, and nordihydrocapsaicin) in extracts of Capsicum annuum. For the recovery of three capsaicinoids, the efficiency levels of ultrasonic‐assisted extraction, microwave‐assisted extraction, Soxhlet extraction, and pressurized liquid extraction were compared under different conditions. Pressurized liquid extraction resulted in higher yields. Pressurized liquid extractions were performed using methanol; temperature was set at 100°C and pressure at 1500 psi. LC analysis was performed on a Waters XBridge? C₁₈ column (150 × 2.1 mm, id 3.5 μm) eluted by a mobile phase of 0.1% formic acid and ACN. Data acquisition was carried out in multiple reaction monitoring transitions mode, monitoring two‐reaction monitoring transitions to ensure an accurate identification of target compounds in the samples. The proposed method is rapid, simple, and could be utilized for the routine analysis of three capsaicinoids in C. annuum samples.     

Combination of microwave assisted micellar extraction and liquid chromatography for the determination of organophosphorous pesticides in soil samples

A new methodology based on the microwave assisted micellar extraction (MAME) technique has been optimised, using soil samples, to extract and determine a mixture of the eight organophosphorous pesticides mainly used in agriculture. The pesticides under study have been extracted using the non-ionic surfactants polyoxyethylene 10 lauryl ether (POLE) and oligoethylene glycol monoalkyl ether (Genapol X-080). The optimal extraction variables, such as surfactant concentration, pH, radiation time and microwave power were determined for each surfactant. The results show the advantage of using POLE instead of Genapol X-080 for the extraction of the organophosphorus pesticides with recoveries higher than 70% for most of the compounds and relative standard deviations (RSD) below 2.6%. This method was successfully applied to fresh samples as well as to aged samples for the analysis of soils with different characteristics and compared with the traditional Soxhlet technique.     

Comparison of four extraction methods for analysis of volatile hop‐derived aroma compounds in beer

The volatile organic compound profile in beer is derived from hops, malt, yeast, and interactions between the ingredients, making it very diverse and complex. Due to the range and diversity of the volatile organic compounds present, the choice of the extraction method is extremely important for optimal sensitivity and selectivity. This study compared four extraction methods for hop‐derived compounds in beer late hopped with Nelson Sauvin. Extraction capacity and variation were compared for headspace solid‐phase micro extraction, stir bar sorptive extraction, headspace sorptive extraction, and solvent‐assisted flavor evaporation. Generally, stir bar sorptive extraction was better suited for acids, headspace sorptive extraction for esters and aldehydes, while headspace solid‐phase microextraction was less sensitive overall, extracting 40% fewer compounds. Solvent‐assisted flavor evaporation with dichloromethane was not suitable for the extraction of hop‐derived volatile organic compounds in beer, as the profile was strongly skewed towards alcohols and acids. Overall, headspace sorptive extraction is found to be best suited, closely followed by stir bar sorptive extraction.     

New extraction method for the analysis of linear alkylbenzene sulfonates in marine organisms. Pressurized liquid extraction versus Soxhlet extraction

A new method has been developed for the determination of linear alkylbenzene sulfonates (LAS) from various marine organisms, and compared with Soxhlet extraction. The technique applied includes the use of pressurized liquid extraction (PLE) for the extraction stage, preconcentration of the samples, purification by solid-phase extraction (SPE) and analysis by liquid chromatography with fluorescence detection. The spiked concentrations were added to the samples (wet mass of the organisms: Solea senegalensis and Ruditapes semidecussatus), which were homogenized and agitated continuously for 25 h. The samples were extracted by pressurized hot solvent extraction using two different extraction temperatures (100 and 150 degrees C) and by traditional Soxhlet extraction. The best recoveries were obtained employing pressurized hot solvent extraction at 100 degrees C and varied in the range from 66.1 to 101.3% with a standard deviation of between 2 and 13. Detection limit was between 5 and 15 microg kg(-1) wet mass using HPLC-fluorescence detection. The analytical method developed in this paper has been applied for LAS determination in samples from a Flow-through exposure system with the objective of measuring the bioconcentration of this surfactant.     

Evaluation of surfactant‐assisted pressurized hot water extraction for marker compounds in Radix Codonopsis pilosula using liquid chromatography and liquid chromatography/electrospray ionization mass spectrometry

In the move towards the elimination of organic solvents in the extraction process in botanicals, a new method combining surfactant and pressurized hot water extraction (PWHE) with an applied temperature below the boiling point and lower pressure from 10 to 20 bar was developed for the analysis of marker compounds that are reasonably hydrophobic such as tetradeca‐4E,12E‐diene‐8,10‐diyne‐1,6,7‐triol and tetradeca‐4E,12E‐diene‐8,10‐diyne‐1,6,7‐triol‐O‐β‐D‐glucoside in Radix Codonopsis pilosula (DangShen). Because reference substances for the proposed botanicals were not available, a method was developed to isolate the marker compounds in Radix Codonopsis pilosula. Other than surfactant‐assisted PHWE, the marker compounds present in Radix Codonopsis pilosula were extracted using pressurized liquid extraction (PLE) with methanol and PHWE with a mixture of water/ethanol (80:20). The extracts were analyzed using liquid chromatography and liquid chromatography/electrospray ionization mass spectrometry. With surfactant‐assisted PHWE, the effects of different added surfactants such as sodium dodecyl sulfate and Triton X‐100 was studied. Surfactant assisted PHWE with Triton X‐100 proved to be at least equivalent or better compared to Soxhlet extraction in terms of quantitative analysis of marker compounds in Radix Codonopsis pilosula. The method precision was less than 8% (RSD, n = 6). The presence of surfactants in PHWE was found to enhance the solubility of target compounds naturally occurring in medicinal plants.     

Evaluation of an extraction method in the determination of the 2,4,6-trichloroanisole content of tainted cork

A method based on solvent extraction and GC-electron-capture detection analysis for the determination of 2,4,6-trichloroanisole (TCA) from cork has been evaluated and optimised. Our sample treatment consists of an extraction stage with pentane while the sample and solvent are kept in contact in a mechanical shaker (shake-flask extraction). Different extraction conditions have been tested in order to find the best compromise between efficiency and time of analysis. Different columns were evaluated for use in the concentration and purification step. A silica column was found to give the best performance in terms of recovery of TCA and repeatability. Pentane and mixtures of pentane-diethyl ether at different ratios were tested as eluting agents. It was found that 10 ml pentane allowed the recovery of retained TCA. Finally, the eluate was concentrated and injected into the chromatograph for TCA determination. The optimised chromatographic conditions enabled the quantification of TCA and 2,6-dichloroanisole, which was assayed as the internal standard. The shake-flask extraction method was compared with Soxhlet and ultrasound assisted extraction procedures using pentane as a solvent. Similar results were obtained for the shake-flask and Soxhlet extraction methods, while sonication gave significantly lower recoveries. The optimised shake-flask method was applied to determine the distribution of TCA in naturally contaminated cork bark.     

Microwave‐assisted extraction with water for fast extraction and simultaneous RP‐HPLC determination of phenolic acids in Radix Salviae Miltiorrhizae

An optimized microwave‐assisted extraction method using water (MAE‐W) as the extractant and an efficient HPLC analysis method were first developed for the fast extraction and simultaneous determination of D (+)‐(3,4‐dihydroxyphenyl) lactic acid (Dla), salvianolic acid B (SaB), and lithospermic acid (La) in Radix Salviae Miltiorrhizae. The key parameters of MAE‐W were optimized. It was found that the degradation of SaB was inhibited when using the optimized MAE‐W and the stable content of Dla, La, and SaB in danshen was obtained. Furthermore, compared to the conventional extraction methods, the proposed MAE‐W is a more rapid method with higher yield and lower solvent consumption with a reproducibility (RSD <6%). In addition, using water as extractant is safe and helpful for environment protection, which could be referred to as green extraction. The separation and quantitative determination of the three compounds was carried out by a developed reverse‐phase high‐performance liquid chromatographic (RP‐HPLC) method with UV detection. Highly efficient separation was obtained using gradient solvent system. The optimized HPLC analysis method was validated to have specificity, linearity, precision, and accuracy. The results indicated that MAE‐W followed by HPLC–UV determination is an appropriate alternative to previously proposed method for quality control of Radix Salviae Miltiorrhizae.     

油菜蜂花粉中脂肪酸的GC-MS分析

以石油醚和乙醚为溶剂，采用索氏抽提法提取油菜蜂花粉中的粗脂肪，进行甲酯化处理，并用GC－MS技术对脂肪酸甲酯进行分离鉴定，共鉴定出10种脂肪酸；测定其相对含量，其中不饱和脂肪酸相对含量高达76.0%，多不饱和脂肪酸相对含量为53.2%。     

Screening method for linear alkylbenzene sulfonates in sediments based on water Soxhlet extraction assisted by focused microwaves with on-line preconcentration/derivatization/detection

A screening method for linear alkylbenzene sulfonates (LAS) in sediments has been developed. Soxhlet extraction with water assisted by focused microwaves provides recoveries better (>90%) than obtained by conventional Soxhlet extraction (70-80%). Coupling of the extractor with an on-line preconcentration/derivatization/detection manifold through a flow injection (FI) interface allows a fully automated screening approach. A yes/no answer can be obtained in less than 2 h (for the whole analytical process), a short time compared with the at least 24 h of Soxhlet extraction (without final detection). Due to the use of water as leaching agent, the proposed method is environmentally friendly.     

Antioxidant capacity and antibacterial activity from Annona cherimola phytochemicals by ultrasound-assisted extraction and its comparison to conventional methods

In recent years, the food, pharmacy, and cosmetic industries have focused on the search of natural compounds with antimicrobial and antioxidant properties; commonly, these compounds are obtained from Kingdom plantae. The aim of the present work is comparing antibacterial and antioxidant capacity of Annona cherimola Mill leaves, using different extraction methods. The ultrasound assisted extraction technique (UAE) was compared with conventional techniques: Soxhlet and maceration. Water and ethanol were used as solvents for leaves extractions performed with these three methods. The main acetogenins reported in Annona cherimola Mill and Annona muricata L. species were simulated using the functional hybrid B3LYP and to confirm its presence, analysis of the compound composition was performed using FT-IR, UV–Vis and HPLC. Total phenolics (TP) and flavonoids (TF) were determined by spectroscopy techniques and novel Differential Pulse Voltammetry (DPV) electrochemical technique. Total Antioxidant Capacity (TAC) of the extracts was measured, using the DPPH, FRAP and CUPRAC techniques. The highest antioxidant content was found in the Soxhlet water extracts; even so, the UAE technique presented an attractive alternative due to considerable reduction in extraction time, which was greater than 99%, and possible selectivity in compounds extraction. Finally, antibacterial activity of the extracts was evaluated, obtaining the best results against gram-positive bacteria using UAE water extract. In this way, the UAE technique presents an excellent extraction option due to the considerable reduction in time and energy, as well as the increase in antibacterial activity.     

Pressurized liquid extraction of berberine and aristolochic acids in medicinal plants

Berberine and aristolochic acids I and II present naturally in medicinal plants were extracted using a laboratory-made pressurized liquid extraction (PLE) system in the dynamic mode. As the target analytes were present naturally in the medicinal plants, spiking was not done and comparison with ultrasonic extraction and Soxhlet extraction was performed to assess the method accuracy. The effect of temperature, volume of solvent required and particle size were investigated. Method precision (RSD, n=5) between 1.98 and 3.4% was achieved for the extraction of berberine and aristolochic acids I and II in medicinal plants and lower than 8% for lower levels of aristolochic acid II in medicinal plants.     

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.