Dynamic ultrasound-assisted extraction of polyphenols in tobacco

A novel extraction method, namely dynamic ultrasound-assisted extraction, is investigated. This technique is efficient with respect to both time and solvent consumption because it utilizes ultrasonic energy in dynamic mode during extraction. Polyphenols (chlorogenic acid, esculetin, rutin, scopoletin, and quercitrin) are extracted from a tobacco (Nicotina tobaccum L.) sample for 10 min with 6 mL of solvent. Fresh solvent is continuously pumped through the sample, with which the analytes can be rapidly extracted, and the possibility of degradation efficiently avoided. Methanol involving 0.5% w/v ascorbic acid was used as extraction solvent; optimal flow rate and extraction time were investigated. The extract was cleaned up by C18 disposable cartridge. The spiked and nonspiked tobacco samples were used for the evaluation of the proposed method. Recoveries obtained were varied from 96 to 108% and RSDs from 2.0 to 4.6%. This extraction technique was revealed to recover larger amounts of polyphenols from tobacco, compared to the static ultrasound-assisted extraction method.     

Comparison of Liquid–Liquid Extraction,Simultaneous Distillation Extraction,Ultrasound-Assisted Solvent Extraction,and Headspace Solid-Phase Microextraction for the Determination of Volatile Compounds in Jujube Extract by Gas Chromatography/Mass Spectrometry

Jujube extract has a unique flavor that has been used as a common fragrance due to the volatile compounds. In this study, the volatiles of jujube extract were isolated by liquid–liquid extraction, simultaneous distillation extraction, ultrasound-assisted solvent extraction, and headspace solid-phase microextraction, and analyzed by gas chromatography–mass spectrometry. Altogether 92 compounds were identified by the four methods, of which 53 components were identified for the first time; however, only 21 compounds were identified by all these methods. The performance characteristics of the four pretreatment techniques were compared by principal component analysis which showed that the volatile compounds obtained by liquid–liquid extraction and ultrasound-assisted solvent extraction were similar both in categories and in content; whereas, the volatiles extracted by simultaneous distillation extraction, ultrasound-assisted solvent extraction, and headspace solid-phase microextraction greatly varied. The results indicated that a multi-pretreatment technique should be adopted in order to obtain the most complete information about the volatile compounds in jujube extract. The ultrasound-assisted solvent extraction method exhibited excellent repeatability and recoveries, and was very suitable for quantitative analysis. Although the recoveries and reproducibility of headspace solid-phase microextraction were inferior to the other methods, it was more sensitive than other methods.     

Determination of eight fluoroquinolones in groundwater samples with ultrasound-assisted ionic liquid dispersive liquid–liquid microextraction prior to high-performance liquid chromatography and fluorescence detection

An ultrasound-assisted ionic liquid dispersive liquid–liquid microextraction (US-IL-DLLME) procedure was developed for the extraction of eight fluoroquinolones (marbofloxacin, norfloxacin, ciprofloxacin, lomefloxacin, danofloxacin, enrofloxacin, oxolinic acid and nalidixic acid) in groundwater, using high-performance liquid chromatography with fluorescence detection (HPLC-FD). The ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution using a small volume of disperser solvent (0.4 mL of methanol), which increased the extraction efficiency and reduced the equilibrium time.     

Ultrasound-assisted extraction of phenolic antioxidants from Acacia confusa flowers and buds

Acacia confusa Merr. (Leguminosae), a species native to Taiwan, is widely distributed on the hills and lowlands of Taiwan, and has been used in traditional medicines. In this study, the application of ultrasound-assisted extraction was used to extract the phenolic compounds from A. confusa flowers and buds for the first time. Among the extraction methods, it can significantly enhance the contents of phenolic compounds and antioxidant activities in A. confusa flower and bud extracts using ultrasound-assisted extraction (10 min×12 times). Considering both the solvent consumption and the time needed for extraction, ultrasound-assisted extraction was found to be the most practical approach for the rapid and efficient extraction of bioactive phenolic constituents. In addition, gallic acid, myricitrin-3-rhamnoside, quercitrin-3-rhamnoside, europetin-3-rhamnoside, kaempferol-3-rhamnoside, rhamnetin-3-glucoside, and rhamnetin-3-rhamnoside were also quantified in different extracts by RP-HPLC. It is clear that ultrasound-assisted extraction is an efficient method for extracting phenolic compounds from A. confusa flowers and buds.     

Comparison of supercritical fluid and ultrasound-assisted extraction of carotenoids and chlorophyll a from Dunaliella salina

In the work described here the extraction processes of carotenoids and chlorophylls were analysed using two extraction techniques, namely ultrasound-assisted extraction and supercritical fluid extraction, and the results are compared. The solvents used for the ultrasound-assisted extraction were N,N′-dimethylformamide and methanol and for the supercritical fluid extraction, carbon dioxide. The raw material studied was Dunaliella salina, a microalgae characterized by the high levels of carotenoids present in its cellular structure. The results indicate that the supercritical fluid extraction process is comparable to the ultrasound-assisted extraction when methanol is used as solvent. In addition, the supercritical extraction process is more selective for the recovery of carotenoids than the conventional technique since it leads to higher values for the ratio carotenoids/chlorophylls. Finally, the effects of pressure and temperature on the extraction yields of the supercritical fluid extraction process were studied.     

Development of liquid phase microextraction based on manual shaking and ultrasound-assisted emulsification method for analysis of organochlorine pesticides in aqueous samples

A novel method using sample preparation method, "ultrasound-assisted emulsification microextraction" (USAEME) with manual shaking, coupled with gas chromatography using and an electron capture detector (GC-ECD) was developed for the analysis of organochlorine pesticides (OCPs) in aqueous samples. The apparatus is simple and easy to operate. After manual shaking for 10s, ultrasound was used to accelerate emulsification of the organic solvent (1-decanol) in aqueous solution. Only 10 μL of the low-toxicity extraction solvent is used in this method; no dispersive solvent is required and the total extraction time is ～4 min. Manual shaking before ultrasound-assisted emulsification enhances the extraction efficiency by >100%. The effects of horizontal and vertical orientation as well as the location of the sample within the ultrasonic bath were studied. After centrifugation, we used an improved solvent collection system (ISCS) to reduce the amount of extraction solvent required. A 1 μL sample of the extract was injected into the GC column. Under optimum conditions, the linear range of the method is 5-2500 ngL(-1) for most of the OCPs, and the limit of detection of the method ranged from 0.6 to 2.9 ngL(-1).The relative recoveries ranged from 75 to 107% for sea water and from 70 to 99% for field fresh water. The method, which provides good enrichment factors, low LODs and minimization of the consumption of organic solvent, provides a rapid, simple and environment-friendly procedure for determining OCPs in aqueous samples.     

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.     

Isolation and determination of ginsenosides in American ginseng leaves and root extracts by LC-MS

Ginseng saponins (ginsenosides) were extracted from the root and leaves of locally cultivated American ginseng (Panax quinquefolium L.). For the isolation of compounds from plant samples three different extraction methods were utilized: accelerated solvent extraction, the ultrasound-assisted solvent extraction and mechanical shaking assisted solvent extraction. The separation of compounds was achieved with a water–acetonitrile gradient system using a C18 reversed-phase column. Target compounds were identified in MS² and MS³ experiments. The relative distribution of these ginsenosides in each root and leaf extract was established. The limit of detection of the method was less than 30 ng/ml. Recovery of ginseng saponins in spiked samples exceeded 80%, while the relative standard deviation ranged from 7.1 to 9.1%. The total concentrations of ginsenosides were 41 and 13 mg/g in root and leaves.     

Pressurized liquid extraction as a sample preparation method for the analysis of isoflavones in pulses

In this work, we describe a rapid and simple analytical method that exploits pressurized liquid extraction (PLE) and liquid chromatography with diode array detection for the determination of isoflavones in samples of Spanish pulses. Confirmation of the analytes present was performed using ion-trap mass spectrometry. To optimize the PLE extraction, variables such as the dispersing agent, type of solvent and sample amount, and the experimental parameters, such as temperature and the number of extraction cycles, were studied. Separation was carried out using a reverse-phase C18 with polar endcapping as the stationary phase and acetonitrile/water with 0.2?% of formic acid, under a gradient regime, as the mobile phase. Optimal extraction of formononetin and biochanin-A from chickpeas with PLE was achieved using Hydromatrix as a dispersant agent, methanol/water (50:50), a temperature of 90?°C, and three cycles. The same optimal conditions-except methanol/water (75:25)-for solvent extraction were obtained for the extraction of daidzin, genistin, and formononetin from lentils. Recoveries ranged from 97 to 110?%, and standard deviations lower than 20?% were obtained. The contents obtained for daidzin in lentils using the proposed method were not significantly different from those obtained using another official method of analysis.     

Ultrasound-assisted pressurized solvent extraction for aliphatic and polycyclic aromatic hydrocarbons from soils

In the present work the efficiency of extraction of aliphatic diesel range organics (DROs) and polycyclic aromatic hydrocarbons (PAHs) from soil was assessed by using dynamic modes of pressurized solvent extraction (PSE), and ultrasound-assisted pressurized solvent extraction (US-PSE). Optimization studies were carried out using a blank soil (Non-Polluted Soil#1, CLN-1, RTC) and a real soil which was previously spiked with the analyte mixture and aged for 90 days. A laboratory-made manifold with controlled temperature and pressure was used to carry out the leaching processes. The extraction cell was inserted into an oven for PSE and into an ultrasound bath for US-PSE. The following variables were studied in each case, keeping the pressure at about 1800 psi: extraction temperature, time of static and dynamic extraction and solvent flow rate. In addition, the time of ultrasound application was also studied in US-PSE. For PSE with dichloromethane (DCM) the recoveries were about 90-95% for both the families of analytes, using extraction times of 20 min. Analyte extraction was quantitative by using US-PSE with DCM for 10 min. In all cases, after the extraction process, the analytes were determined by GC-MS. Application of the method to a natural contaminated sample suggests that either the extraction time used in US-PSE should be increased to 20 min or the solvent (DCM) should be replaced by a mixture of DCM:acetone (1:1), to reach comparability with Soxhlet extraction.     

Microwave-assisted extraction of phenolics from Canarium album L. and identification of the main phenolic compound

Microwave-assisted extraction (MAE) was applied in the extraction of phenolics from Canarium album L. Effects of various conditions including the solvent, solvent to material ratio, microwave power and irradiation time on extraction yield of phenolics were investigated. In terms of the optimal conditions of MAE, it was concluded that 70% (v/v) of ethanol was the proper extraction solvent, the solvent to material ratio was 10 : 1 (mL : g), and the microwave power and irradiation time were 600 W and 15 s, respectively. Compared with normal stirring extraction and ultrasound-assisted extraction, the MAE of phenolics from C. album L. was more time efficient and gave a high extraction rate. More than 1.2% extraction yield was achieved with MAE, and the purity of the phenolics in the extract product was up to 25%. In addition, by ultraviolet-visible (UV) spectrometry and electrospray ionised mass spectrometry (ESI/MS), the main phenolic compound in the extract product was identified as gallic acid.     

Rapid and sensitive determination of pyrethroids indoors using active sampling followed by ultrasound-assisted solvent extraction and gas chromatography

A fast and simple method to analyze pyrethroids as well as other components of frequently used domestic insecticide preparations in indoor air is presented. The proposed method, based on sampling with an adsorbent followed by ultrasound-assisted solvent extraction, was developed with the aim to simplify the traditional extraction methodologies applied up to date to determine pesticides in air. The analytes were retained on a very small amount of adsorbent, which allowed using solely 1 mL of solvent for desorption. The quantification was performed by gas chromatography with microelectron-capture detection (GC-muECD) and gas chromatography coupled to mass spectrometry (GC-MS). The influence of main factors involved in the ultrasound-assisted solvent extraction step (type of adsorbent and type of solvent, solvent volume and extraction time) was studied using an experimental design approach to account for possible factor interactions. The sampling step was studied for two adsorbents (Tenax TA and Florisil), finding that 1 m(3) air could be sampled without losses of analytes. In this way, the analysis of pyrethroids in air by the proposed method could be carried out within a total time shorter than an hour, including sampling. Linearity was demonstrated in a wide concentration range. Efficiency of the total sampling-extraction process was studied at several concentration levels (2, 10, 100 and 1000 ng/m(3)), obtaining quantitative recoveries for all compounds, with good precision (RSD < 10%). Method detection limits were below 1 ng/m(3) in air when GC-muECD was employed, and about one order of magnitude higher for GC-MS. In addition, the proposed method was applied to real samples collected in contaminated closed rooms, in which some of the target compounds were determined.     

Simultaneous derivatization and extraction of chlorophenols in water samples with up-and-down shaker-assisted dispersive liquid–liquid microextraction coupled with gas chromatography/mass spectrometric detection

A new up-and-down shaker-assisted dispersive liquid–liquid microextraction (UDSA-DLLME) for extraction and derivatization of five chlorophenols (4-chlorophenol, 4-chloro-2-methylphenol, 2,4-dichlorophenol, 2,4,6-trichloro-phenol, and pentachlorophenol) has been developed. The method requires minimal solvent usage. The relatively polar, water-soluble, and low-toxicity solvent 1-heptanol (12 μL) was selected as the extraction solvent and acetic anhydride (50 μL) as the derivatization reagent. With the use of an up-and-down shaker, the emulsification of aqueous samples was formed homogeneously and quickly. The derivatization and extraction of chlorophenols were completed simultaneously in 1 min. The common requirement of disperser solvent in DLLME could be avoided. After optimization, the linear range covered over two orders of magnitude, and the coefficient of determination (r ²) was greater than 0.9981. The detection limit was from 0.05 to 0.2 μg L^?1, and the relative standard deviation was from 4.6 to 10.8 %. Real samples of river water and lake water had relative recoveries from 90.3 to 117.3 %. Other emulsification methods such as vortex-assisted, ultrasound-assisted, and manual shaking-enhanced ultrasound-assisted methods were also compared with the proposed UDSA-DLLME. The results revealed that UDSA-DLLME performed with higher extraction efficiency and precision compared with the other methods.     

A simple and fast micromethod for the analysis of polychlorinated biphenyls in air by sorbent enrichment and ultrasound-assisted solvent extraction

A combination of sorbent enrichment and ultrasound-assisted solvent extraction has been used to determine polychlorinated biphenyls in air. Analytes were sampled by pumping a known volume of air through a porous polymer (Tenax TA). The enriched adsorbent was transferred into a glass vial, and ultrasound-assisted extraction of the analytes was then performed in n-hexane. Quantification was carried out by using gas chromatography coupled to tandem mass spectrometry. Breakthrough volume of the sampling step was studied, indicating that 10 m³ of air could be processed without losses of the most volatile compounds. Good recoveries (75–96%) were obtained, and limits of detection at the sub ng m^–3 were achieved for all the analytes. The proposed method is very simple and fast, avoiding the use of large solvent volumes and time-consuming preconcentration steps.     

Investigation on Ultrasound-Assisted Extraction and Separation of Enduracidin from <Emphasis Type="Italic">Streptomyces</Emphasis> sp. NJWGY3665

Ultrasound-assisted extraction of enduracidin from Streptomyces sp. NJWGY3665 was studied. The effects of various factors on the yield of target components were investigated. The results showed that the extraction by ultrasound-assisted extraction is four times faster than those by conventional solvent extraction. The results also indicated that fast extraction rate was obtained in the first 30 min, and the maximum yield was obtained at the power of 150 W. The effects of other factors such as different solvents, solvent concentration, solvent to solid ratio, and extraction batches on the field were also discussed. The optimum conditions were found at solvent of methanol, time of 30 min, power of 150 W, pH of 7.0, solvent to solid ratio of 50 ml/g, solvent concentration of 70% and extraction batches of four times.     

唐古特大黄中大黄酚苷超声提取工艺的响应面优化及HPLC测定

采用响应曲面法优化了唐古特大黄中大黄酚1-O-β-D-葡萄糖苷和大黄酚8-O-β-D-葡萄糖苷的超声提取工艺及提取时间、液料比、提取温度等工艺参数,依据回归分析确定最佳工艺条件为:提取时间41 min,液料比23 mL/g,提取温度40℃;建立了这两种大黄酚苷的HPLC分析方法。色谱条件:AgilentEslipse-XDB C18(250*4.6 mm,5μm)色谱柱,以水和甲醇为流动相梯度洗脱,流速1.0 mL/min,检测波长280 nm,两种大黄酚苷的高效液相色谱峰面积与浓度呈良好的线性关系(R2=0.9999)。     

Comparison of soxhlet, ultrasound-assisted and pressurized liquid extraction of terpenes, fatty acids and Vitamin E from Piper gaudichaudianum Kunth

This paper describes a comparative study of extraction methods of terpenes (terpenic alcohols and phytosterols), fatty acids and Vitamin E from leaves of Piper gaudichaudianum Kunth. The analysis of extracts was done by gas chromatography with mass spectrometric detection. The identification and quantification was made by co-injections of the extract with certified standards. The use of pressurized liquid extraction (PLE; Dionex trade name: ASE, for accelerated solvent extraction) decrease significantly the total time of extraction, the amount of solvent and the manipulation of sample and solvents in comparison with soxhlet (SE) and ultrasound-assisted (USE). In addition, PLE was more effective for the extractions of terpenes (terpenic alcohols and phytosterols), fatty acids and Vitamin E.     

Pressurized liquid extraction versus other extraction techniques in micropreparative isolation of pharmacologically active isoflavones from Trifolium L. species

As a new sample preparation technique, pressurized liquid extraction (PLE), in combination with reversed-phase liquid chromatography (RP-LC) and photodiode-array (PDA) detection were used for the isolation and determination of phytoestrogenic isoflavones in hydrolyzed extracts obtained from aerial parts of five Trifolium L. (clover) species. To optimize the effectiveness of PLE procedure, variable extraction parameters: methanol and acetone (or their 75% aqueous solutions), as extraction solvents, temperatures (75, 100 and 125 °C) and the changeable number of static extraction cycles were tested. Additionally, two other micropreparative techniques: ultrasound-assisted extraction (UAE), and conventional solvent extraction (CSE), under optimized conditions, were also used and compared. Optimum extraction efficiency, expressed in the highest yield of biochanin A, formononetin, daidzein and genistein from plant material, with PLE, using methanol-water (75:25, v/v) as an extraction solvent, an oven temperature of 125 °C and three 5-min static extraction cycles, was obtained.     

Effect of extraction method on phenolic content and antioxidant activity of mistletoe extracts from Viscum album subsp. abietis

The total content of polyphenols and flavonoids determined in the same plant and their corresponding antioxidant activities may vary widely, depending on the extraction conditions applied. This study was conducted to optimise the extraction conditions of phenolics and flavonoids from the mistletoe plant. Various extraction methods, i.e. ultrasound-assisted extraction technology, maceration, maceration with stirring, accelerated solvent extraction (ASE), and extraction under reflux were evaluated for their percentage extraction of polyphenols (TPC) and flavonoids (TFC) from Viscum album subsp. abietis. In addition, the anti-radical activity of extracts was analysed using the 2,2-diphenyl-1-picrylhydrazyl method. The effects of temperature, solvent type, and concentration on the phenolic extraction efficiency and antioxidant activity were studied using chemometric and statistical methods. The results showed that the extracts of V. album subsp. abietis contained large amounts of polyphenols and flavonoids (up to 57.673 mg g^?1 and 9.955 mg g^?1 of dry extract, respectively) and exhibited potent antioxidant activity, hence representing promising sources of powerful antioxidants. Due to its high extraction efficiency and considerable saving of time and solvent, ASE was more effective than the other extraction techniques. Extracts prepared with water-polar solvent mixtures displayed the highest TPC, TFC, and antioxidant activity, while organic polar solvents were the least efficient extractants.