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Accelerated Solvent Extraction (accelerated + solvent_extraction)
Selected AbstractsImproved automated extraction and separation procedure for soil lipid analysesEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2004G. L. B. Wiesenberg Summary Analysis of soil lipids may contribute to an improved understanding of atmosphere to soil carbon fluxes, soil organic matter source differentiation and pollutant accumulation. Soil lipids, mostly originating from plants and microorganisms, have traditionally been analysed by non-automated extraction and separation methods, which produce several lipid fractions, operationally defined by polarity. Here we present a combination of fast, automated and reproducible techniques, adopted from organic geochemical studies, for preparative separation of individual soil lipid fractions with increasing polarity. These techniques involve commercially available instruments, including accelerated solvent extraction and a two-step automated medium-pressure liquid chromatography procedure. The method yields eight lipid fractions consisting of five fractions fully amenable to gas chromatography/mass spectrometry (GC/MS) (aliphatic hydrocarbons, aromatic hydrocarbons, ketones, alcohols, carboxylic acids), and three fractions of highly polar or high molecular weight compounds (bases, very long-chain wax esters (C40+), high polarity compounds) that were not measurable with GC/MS under standard conditions. We tested the method on five agricultural soils. Results show that (i) mass recoveries for the individual fractions are reproducible, (ii) within individual fractions compound distribution patterns are reproducible, as demonstrated for alkanes and carboxylic acids, and (iii) individual fractions represent distinct and clean compound classes, free of interfering substances detectable by GC/MS. Thus, automated separation can be a fast, effective and reproducible procedure for fractionation of complex mixtures of soil lipids into clean compound classes, directly suitable for a variety of molecular (e.g. GC/MS) and isotopic characterizations (e.g. gas chromatography coupled with isotope ratio monitoring mass spectrometry or accelerator mass spectrometry). [source] Identification and determination of the saikosaponins in Radix bupleuri by accelerated solvent extraction combined with rapid-resolution LC-MSJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2010Yun-Yun Yang Abstract A method based on accelerated solvent extraction combined with rapid-resolution LC,MS for efficient extraction, rapid separation, online identification and accurate determination of the saikosaponins (SSs) in Radix bupleuri (RB) was developed. The RB samples were extracted by accelerated solvent extraction using 70% aqueous ethanol v/v as solvent, at a temperature of 120°C and pressure of 100,bar, with 10,min of static extraction time and three extraction cycles. Rapid-resolution LC separation was performed by using a C18 column at gradient elution of water (containing 0.5% formic acid) and acetonitrile, and the major constituents were well separated within 20,min. A TOF-MS and an IT-MS were used for online identification of the major constituents, and 27 SSs were identified or tentatively identified. Five major bioactive SSs (SSa, SSc, SSd, 6,- O -acetyl-SSa and 6,- O -acetyl-SSd) with obvious peak areas and good resolution were chosen as benchmark substances, and a triple quadrupole MS operating in multiple-reaction monitoring mode was used for their quantitative analysis. A total of 16 RB samples from different regions of China were analyzed. The results indicated that the method was rapid, efficient, accurate and suitable for use in the quality control of RB. [source] RP-HPTLC densitometric determination and validation of vanillin and related phenolic compounds in accelerated solvent extract of Vanilla planifolia,*JOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2007Upendra Kumar Sharma Abstract A simple, fast and sensitive RP-HPTLC method is developed for simultaneous quantitative determination of vanillin and related phenolic compounds in ethanolic extracts of Vanilla planifolia pods. In addition to this, the applicability of accelerated solvent extraction (ASE) as an alternative to microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE) and Soxhlet extraction was also explored for the rapid extraction of phenolic compounds in vanilla pods. Good separation was achieved on aluminium plates precoated with silica gel RP-18 F254S in the mobile phase of methanol/water/isopropanol/acetic acid (30:65:2:3, by volume). The method showed good linearity, high precision and good recovery of compounds of interest. ASE showed good extraction efficiency in less time as compared to other techniques for all the phenolic compounds. The present method would be useful for analytical research and for routine analysis of vanilla extracts for their quality control. [source] Chemical composition of mate tea leaves (Ilex paraguariensis): A study of extraction methodsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2006Rosângela Assis Jacques Abstract The objective of this work was to investigate the extraction of Ilex paraguariensis leaves by means of three extraction techniques: pressurized liquid extraction (PLE, also called accelerated solvent extraction , ASE), maceration, and sonication. Samples of mate tea leaves were collected from an experiment conducted under agronomic control at Indústria e Comércio de Erva-Mate Bar,o LTDA, Brazil. Six solvents with increasing polarities (n -hexane, toluene, dichloromethane, ethyl acetate, acetone, and methanol) were used in this investigation. Chemical analysis of the extracts was performed by GC coupled with a mass spectrometer detector. The identification and quantification were accomplished by coinjections of certified standards. The results showed that no significant differences in the qualities of the extracts were noticed regarding the extraction methods. On the other hand, the PLE technique was found to be more effective for the extractions of caffeine, phytol, palmitic, and stearic acid. The use of PLE led to a significant decrease in the total extraction time, amount of solvent consumption, and manipulation of samples compared to maceration and ultrasound-assisted extraction methods. [source] Comparison of the capabilities of accelerated solvent extraction and sonication as extraction techniques for the quantification of kavalactones in piper methysticum (Kava) roots by high performance liquid chromatography with ultra violet detectionPHYTOCHEMICAL ANALYSIS, Issue 2 2007Emma Warburton Abstract A conventional extraction technique of sonication has been compared, in terms of extraction efficiency, extraction time and amount of solvent, with the more novel technique of accelerated solvent extraction for the extraction of kavain from the powdered roots of Piper methysticum (Kava) with acetone. The extracts were analysed using high-performance liquid chromatography with ultra violet detection. The effects of varying solvent volume and extraction time upon the quantity of kavain extracted with sonication, and the effects of varying temperature upon the kavain extraction efficiency by ASE, were investigated. ASE was found to be more efficient with respect to time and solvent volume required; however, a good agreement was found between the kavain concentration obtained using both extraction techniques. © Crown Copyright 2007. Reproduced with the permission of the Controller of HMSO. Published by John Wiley & Sons, Ltd. [source] Determination of abamectin in soil samples using high-performance liquid chromatography with tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2004Bobby N. Brewer Abamectin, which is comprised of a mixture of avermectins B1a and B1b, is a natural pesticide used as an anti-parasitic agent in livestock, ornamental, and agricultural crops, which can potentially be transported to aquatic systems. These compounds are highly toxic to both aquatic vertebrates and invertebrates at low concentrations in water. This investigation developed high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) techniques to support automated extraction by an accelerated solvent extraction (ASE®) system and chromatographic techniques to measure residues of avermectins in complex soil samples. HPLC along with atmospheric pressure chemical ionization (APCI) MS/MS was used for separation and determination of avermectin isomers in soil samples. Average method recovery for abamectin by UV was 91%, while detection by MS/MS resulted in a 68% recovery for abamectin. Individual method recoveries by MS/MS were 53.6% for avermectin B1a and 36.8% for avermectin B1b. The use of tandem technology eliminated matrix interferences and resulted in an approximately eight-fold increase in sensitivity. Copyright © 2004 John Wiley & Sons, Ltd. [source] Development of a method based on accelerated solvent extraction and liquid chromatography/mass spectrometry for determination of arylphenoxypropionic herbicides in soilRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2001Stefano Marchese A sensitive and specific analytical procedure for determining arylphenoxypropionic herbicides in soil samples, using Ionspray ionization (ISI) liquid chromatography/mass spectrometry (LC/MS), is presented. Arylphenoxypropionic acids are a new class of herbicides used for selective removal of most grass species from any non-grass crop, commercialized as herbicide esters. Previous studies have shown that the esters undergo fast hydrolysis in the presence of vegetable tissues and soil bacteria, yelding the corresponding free acid. The feasibility of rapidly extracting arylphenoxypropionic herbicides from soil by accelerated solvent extraction (ASE) techniques was evaluated. Four different soil samples were fortified with target compounds at levels of 5 and 20,ng/g by following a procedure able to mimic weathered soils. Herbicides were extracted by a methanol/water (80:20 v/v) solution (0.12,M) of NaCl at 90,°C. After clean-up using graphitized carbon black (GCB) as absorbent, the extract was analyzed by HPLC/ISI-MS. The effect of concentration of acid in the mobile phase on the response of ISI-MS was investigated. The effects of varying the orifice plate voltage on the production of diagnostic fragment ions, and on the response of the MS detector, were also investigated. The ISI-MS response was linearly related to the amounts of analytes injected between 1 and 200,ng. The limit of detection (signal-to-noise ratio,=,3) of the method for the pesticides in soil samples was estimated to be less than 1,ng/g. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||