Comparison of different extraction techniques for the determination of polychlorinated organic compounds in sediment

The performance of various enhanced extraction techniques, such as accelerated solvent extraction, microwave-assisted extraction, Soxhlet extraction, ultrasonic extraction and fluidized-bed extraction for the determination of polychlorinated organic compounds in dry sediment was investigated in two laboratories. The results of the two laboratories were in good agreement. The extraction yields from the batch extraction methods were lower than those from the dynamic techniques. Accelerated solvent extraction, especially, exhibited higher extraction efficiency than the standard procedure, Soxhlet extraction, whereas the results of fluidized-bed extraction were comparable.     

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%).     

微波场协同提取野菊花黄色素的研究

研究了微波提取野菊花 (Chrysanthemumindicum)黄色素的新工艺并确定了最佳工艺条件 :原料为 2 0 0 0 0g野菊干花 ,提取剂为无水乙醇 ,提取剂比例为 1 /70 ,微波功率为 80 0W ,提取时间为 45 0s,提取次数为 3次 ,最佳工艺条件下色素的提取率为 91 1 % ,产率为 1 4 6% ,色价E ( 1 % ,3 2 1nm)为 42 2 ,产品pH值为 6 5。与溶剂浸提法相比 ,微波提取野菊花黄色素的每次提取时间由 1 2h减小为 45 0s,提取率从 88 6%增加到 91 1 %。     

Comparison of techniques for the extraction of the hypotensive drugs geniposidic acid and geniposide from Eucommia ulmoides

The extraction of geniposidic acid and geniposide from Eucommia ulmoides was carried out by Soxhlet extraction, enzyme-assisted aqueous extraction, semi-bionic extraction and supercritical fluid extraction techniques and the extracts were analyzed by high performance liquid chromatography. The results showed that the best methods for extraction of geniposidic acid and geniposide are enzyme-assisted aqueous extraction and semi-bionic extraction. Compared with various extraction methods, the semi-bionic extraction was more efficient, yielding the highest amount of geniposidic acid and geniposide. In semi-bionic extraction, no organic solvent was used. Semi-bionic extraction was performed at the same pH as that of the human body. The results indicated that semi-bionic extraction was the best method for large-scale efficient extraction of geniposidic acid and geniposide from plant materials. The supercritical fluid extraction process required more time than the other methods, and gave the lowest yields of geniposidic acid and geniposide.     

木蹄多糖提取工艺研究

通过对木蹄多糖提取得率有影响的子实体粉末颗粒大小、料水比、提取温度和提取时间进行的单因素研究,其中对料水比、提取温度和提取时间3个因素采用应用响应面法进行了优化,确定了木蹄子实体多糖的最佳提取工艺条件：子实体粉末颗粒60目,料水比1：42．92,提取温度88．92℃,提取时间3．92h,多糖得率达到5．68％。     

正交实验法在小麦粉中甲醛振荡提取条件的应用研究

小麦粉中甲醛的提取问题是一个比较复杂的多因素问题。采用正交实验法,选用L9(34)正交实验表,在提取试剂、提取温度、提取时间等多个因素和水平中优选小麦粉中甲醛振荡提取的最佳条件。实验中甲醛提取量采用Nash试剂柱前衍生高效液相色谱法测定。结果表明,提取温度是小麦粉中甲醛提取的最主要因素,最佳的提取条件为提取温度30℃、提取液为硫酸钠、提取时间为40min。     

Pressurized liquid extraction as a green approach in food and herbal plants extraction: A review

Pressurized liquid extraction is a “green” technology for the extraction of nutraceuticals from foods and herbal plants. This review discusses the extraction principles and the optimization of the extraction parameters that improves the extraction efficiency. The use of different solvent mixtures and other extraction additives to enhance the efficiency of the extraction are discussed. Dynamic mode of extraction in Pressurized liquid extraction, and the use of combined and hyphenated sample preparation and analytical techniques are presented. This work discusses how different studies used Pressurized liquid extraction to enrich phenolic compounds, lignans, carotenoids, oils and lipids, essential oils and other nutraceuticals from foods and herbal plants.     

Comparison of different extraction techniques for the determination of chlorinated pesticides in animal feed

The performances of Soxhlet extraction, dive-in Soxhlet extraction, microwave-assisted extraction (MAE), accelerated solvent extraction (ASE), fluidized-bed extraction (FBE), and ultrasonic extraction (UE) for the analysis of organochlorine pesticides in animal feed have been investigated. ASE and MAE provided significantly better extraction efficiency than Soxhlet extraction. The concentrations were 126.7 and 114.8%, respectively, of the values obtained by classical Soxhlet extraction, whereas the results from FBE and dive-in Soxhlet were comparable with those from the standard Soxhlet procedure. The reproducibility of FBE was the best, with RSDs ranging from 0.3 to 3.9%. Under the investigated operation conditions UE was not efficient, with the recoveries of target compounds being about 50% less than Soxhlet. Additionally, the performances of Soxhlet, dive-in Soxhlet, MAE, ASE and FBE were validated by determination of the certified reference material BCR-115. The results from the extraction techniques were in good agreement with the certified values.     

The extraction of iridium and platinum from organic solvents by polyurethane foam

The feasibility of extracting iridium and platinum from organic solvents onto polyurethane foam was studied. Distribution ratios obtained were 1.1 x 10(4) for the extraction of iridium from ethyl acetate, 225 for the extraction of iridium from acetone and 4.8 x 1O(3) for the extraction of platinum from ethyl acetate. Capacities of about 16% w/w were obtained for extraction of iridium from ethyl acetate, and about 2.4% for extraction from acetone.     

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.     

超声微波酶解协同提取油茶壳中原花青素

建立了超声微波酶解协同提取油茶壳中原花青素的方法。通过单因素试验,探讨了超声微波协同提取油茶壳中原花青素过程中各主要因素对原花青素提取率的影响规律。实验中发现,往提取液中加入适量纤维素酶,可显著提高原花青素的提取率。在此基础上,通过正交试验,优化并获得了超声微波酶解协同提取原花青素的最适宜条件。最适宜提取条件为:超声波频率40 KHz、微波功率200 W、提取时间60 s、料液比1∶6、提取温度50℃、0.1%纤维素酶0.5 mL、提取次数2次。在最适宜条件下,原花青素的提取率为4.46%,分别是超声提取、微波提取和超声-微波协同提取的4.0、3.3和1.8倍。本文所建立的超声微波酶解协同提取油茶壳中原花青素的方法具有简便、快速、高效和节能等优势,有利于应用推广。     

Study of polyethylene glycol as a green solvent in the microwave-assisted extraction of flavone and coumarin compounds from medicinal plants

In this paper, the application of polyethylene glycol (PEG) aqueous solution as a green solvent in microwave-assisted extraction (MAE) was firstly developed for the extraction of flavone and coumarin compounds from medicinal plants. The PEG solutions were optimized by a mono-factor test, and the other conditions of MAE including the size of sample, liquid/solid ratio, extraction temperature and extraction time were optimized by means of an orthogonal design L(9) (3(4)). Subsequently, PEG-MAE, organic solvent-MAE, and conventional heating reflux extraction (HRE) were evaluated with nevadensin extraction from Lysionotus pauciflorus, aesculin and aesculetin extraction from Cortex fraxini. Furthermore, the mechanism of PEG-MAE was investigated, including microwave-absorptive property and viscosity of PEG solutions, the kinetic mechanism of PEG-MAE and different microstructures of those samples before and after extraction. Under optimized conditions, the extraction yields of nevadensin from L. pauciflorus, aesculin and aesculetin from C. fraxini were 98.7%, 97.7% and 95.9% in a one-step extraction, respectively. The recoveries of nevadensin, aesculin and aesculetin were in the range of 92.0-103% with relative standard derivation lower than 3.6% by the proposed procedure. Compared with organic solvent-MAE and conventional extraction procedures, the proposed methods were effective and alternative for the extraction of flavone and coumarin compounds from medicinal plants. On the basis of the results, PEG solution as a green solvent in the MAE of active compounds from medicinal plants showed a great promising prospect.     

Comparison of extraction techniques for isolation of steroid oestrogens in environmentally relevant concentrations from sediment

The comparison of four extraction techniques for isolation of five native and one labelled steroid oestrogens from sediment was described. The three conventional extraction techniques Soxhlet warm extraction (SWE), accelerated solvent extraction (ASE), microwave-assisted extraction (MAE) and a promising technique QuEChERS were tested for isolation of low environmentally relevant oestrogen concentrations using different extraction conditions. The least expensive and time-consuming method QuEChERS provided the best extraction recoveries (53–84%) from all techniques. MAE achieved the highest recovery from conventional techniques for less polar oestrogens using dichloromethane: acetone 3:1 mixture as an extraction solvent (50–71%), but for extraction of the whole group of oestrogens including more polar estriol acetone or methanol must be used. ASE provided higher extraction recoveries using dichloromethane at 60°C (53–74%) for less polar oestrogens. However, the repeatability of results was unsatisfactory and recoveries using other extraction conditions were lower than for MAE. The most time-consuming SWE achieved the worst extraction recoveries and for isolation of low oestrogen concentrations from sediments, it is completely unsuitable.     

Multiple solid-phase microextraction of drugs from human urine

Summary The applicability of multiple solid-phase microextraction to the analysis of biological samples has been shown by extraction of a variety of compounds from human urine. Multiple solid-phase microextraction, in which extraction and desorption are repeated and analytes are collected at the head of the separation system before starting the analysis, has been combined with gas chromatography. Amphetamine, lidocaine, procaine, and mepivacaine were extracted from buffered urine by direct immersion of a 100-μm polydimethylsiloxane-coated fiber, to demonstrate that multiple SPME can be used for analytes with different extraction behavior. Multiple solid-phase microextraction was optimized for high extraction yield or short extraction time. For example, the total sample-handling time (extraction plus desorption) for the extraction of mepivacaine from urine can be reduced from approximately 60 min (one extraction) to 33 min (three extractions) without reducing extraction yield. In addition, the extraction yield for mepivacaine can be increased from 14.6% (one extraction) to 27.0% (five extractions) within the same total sample handling time of approximately 60 min. A good match between theoretical and experimental values was obtained. Chromatograms are shown to illustrate the usefulness of the procedure.     

Negative-Pressure Cavitation Extraction of Four Main Vinca Alkaloids from <em>Catharanthus </em><em>r</em><em>oseus</em> Leaves

In the present study, an improved method termed negative-pressure cavitation extraction (NPCE) followed by reverse phase high-performance liquid chromatography (RP-HPLC) was developed for the extraction and quantification of vindoline (VDL), catharanthine (CTR), vincristine (VCR) and vinblastine (VLB) from Catharanthus roseus leaves. The optimized method employed 60-mesh particles, 80% ethanol, a negative pressure of -0.075 MPa, a solid to liquid ratio of 1:20, 30 min of extraction and three extraction cycles. Under these optimized conditions, the extraction yields of VDL, CTR, VCR and VLB are 0.5783, 0.2843, 0.018 and 0.126 mg/g DW, respectively. These extraction yields are equivalent to those from the well-known ultrasonic extraction method and higher than the yields from maceration extraction and heating reflux extraction. Our results suggest that NPCE-RP-HPLC represents an excellent alternative for the extraction and quantification of vinca alkaloids for pilot- and industrial-scale applications.     

Comparison of techniques for the extraction of the anti-cancer drug camptothecin from Nothapodytes foetida

Extraction methods using stirring extraction, Soxhlet extraction, ultrasonic extraction and microwave-assisted extraction (MAE) were evaluated for the percentage extraction of camptothecin (CPT) and 9-methoxycamptothecin (9-Me-CPT) from Nothapodytes foetida. The extracts were analyzed by high performance liquid chromatography (HPLC). Methanol (90%, v/v) extracted high percentage extraction of CPT and 9-Me-CPT compared to ethanol (90%, v/v). The results shows that the percentage extraction of CPT and 9-Me-CPT from N. foetida by MAE was more efficient in short time followed by Soxhlet extraction, ultrasonic and stirring extraction methods. Maximum percentage extraction of CPT (2.67%, w/w) was obtained by MAE technique. MAE has need of 3 min, whereas ultrasonic extraction, Soxhlet extraction and stirring extraction techniques require 30, 120 and 30 min, respectively to leach higher percentage extraction of CPT and 9-Me-CPT. The times taken by the microwave extraction process was 40 times less than the Soxhlet extraction for percentage extraction of alkaloids. The present results show that the extraction efficiency and considerable saving of time by MAE was more competent than the other extraction techniques.     

Dynamic Microwave-assisted Extraction of Flavonoids from Radix Scutellariae

IntroductionRadix Scutellariaeis the root ofScutellaria bai-calensis Georgi(Labiatae), which is widely cultivatedand used as traditional Chinese medicine. It has beendemonstrated to be anti-inflammatory, anti-metamor-phic, antiviral, anti-hot, and live pr…     

Extraction of Palladium(II), Platinum(II), and Platinum(IV) by Bisacylated Diethylenetriamine from Hydrochloric Acid Solutions

The extraction properties of bisacylated diethylenetriamine are studied in the extraction of palladium(II), platinum(II), and platinum(IV) from hydrochloric acid solutions. Optimum extraction parameters are determined. The extraction of metal ions at these parameters follows an ion-associative mechanism. The concentration constants and thermodynamic parameters of extraction reactions are calculated. The feasibility of the extraction separation of palladium and platinum from base metals is verified.     

Extraction of polycyclic aromatic nitrogen heterocycles from spiked soil samples

Extraction recovery of 10 selected polycyclic aromatic nitrogen heterocycles (PANHs), quinoline, 2-methylquinoline, 6-methylquinoline, 8-methylquinoline, acridine, benzo[h]quinoline, phenantridine, indole, 2-methylindole, and carbazole from spiked soil samples was tested. Four different extraction techniques, pressurized solvent extraction (PSE), supercritical fluid extraction (SFE), Soxhlet warm extraction (SOXW) and standard Soxhlet extraction (SOX), were applied and compared. The RP-HPLC technique with a silica-based octadecyl stationary phase was used for recovery determination of individual PANHs. Supercritical fluid extraction has been found to be the most effective method for the extraction of selected PANHs from soil. PSE and SOXW methods offered similar results with slightly lower extraction recoveries compared with SFE. On the contrary, SOX is a time-consuming method with a low recovery of target analytes and is not suitable for the extraction of PANHs from soils.     

野菊花中蒙花苷的提取及其含量的测定

以乙醇为溶剂,采用溶剂回流提取方法结合微波、超声波辅助提取野菊花中的蒙花苷,用HPLC法测定。采用正交试验法研究了野菊花中蒙花苷提取和HPLC实验条件,并比较了采用不同的微波和超声波辅助提取方式对蒙花苷提取结果的影响。结果表明,溶剂回流提取最佳条件为:提取温度80℃,回流时间2.0 h,溶剂用量40 mL。应用于安徽等产地野菊花中蒙花苷的提取分析,结果显示,广东和广西产地药材含量明显更高;在相同的实验条件下采用微波辅助提取可使蒙花苷达到较高的提取率,特别是采用微波辐射药材后再进行溶剂回流提取,提取时间可缩短一半。