Study of factors influencing pressurised solvent extraction of polar steroids from plant material. Application to the recovery of withanolides

2001 ◽  
Vol 54 (5-6) ◽  
pp. 394-398 ◽  
Author(s):  
B. Kaufmann ◽  
P. Christen ◽  
J. -L. Veuthey
Weed Science ◽  
1985 ◽  
Vol 33 (S2) ◽  
pp. 11-17 ◽  
Author(s):  
Fritz Führ

Most herbicides are applied preemergence onto bare soil or during the early stage of plant development. Therefore, the major part of the active ingredient either reaches the soil surface immediately or later with decaying plant material. The further fate of the herbicide depends largely on the physicochemical behavior of the respective compound, the amount and method of application, and a number of soil, plant, and climatic factors influencing the persistence and bio availability of organic compounds in a given soil (5, 7). Especially in the upper 2-cm soil layer, drastic changes in temperature and moisture content during a growing season have a great influence on the degradation and adsorption of herbicides in soil (10, 31).


1983 ◽  
Vol 66 (4) ◽  
pp. 825-849 ◽  
Author(s):  
Douglas I Mcgregor ◽  
William J Mullin ◽  
Gruffydd R Fenwick

Abstract New analytical techniques and instrumentation and increased knowledge of the diversity and distribution of glucosinolates, the diversity of their enzymatically released products, and factors influencing their release, have led to significant advances in methodology for analysis of glucosinolates over the past three decades. However, many of the methods have been developed for specific agricultural crops or commodities and their particular glucosinolate compositions. They can only be applied to certain types of plant material or can detect and quantitate only certain glucosinolates or their products. Other methods have been designed to meet specific research, regulatory, or quality control requirements. This had necessitated sacrifice of either speed, simplicity, accuracy, precision, or the ability to distinguish different glucosinolates or their products. This review examines the methods available for sample preparation, identification, and quantitation of glucosinolates in light of current knowledge of their diversity, distribution, and chemistry. Consideration is given to the suitability of methods for rapid screening or precise, discriminating measurement, and to the standardization of methodology and reporting of results.


2013 ◽  
Vol 746 ◽  
pp. 31-34
Author(s):  
Xing Yao Wang ◽  
Ma Cong ◽  
Juan Liu

Solvent extraction technique was performed to optimize the conditions for maximum removal of iron (III) from the simulated bauxite hydrochloric acid leaching liquor of FeCl3+AlCl3+CaCl2+HCl. Some factors influencing the extraction, such as the extractant and concentration of Fe, Al, and Ca were investigated. The results indicated that the N235 is an effective extractant for selective extraction of iron (III) from chloride liquor. The concentration of Fe in raffinate is under 0.0165 gL-1 and the losing of Al is 0.50 % by N235.


1941 ◽  
Vol 24 (4) ◽  
pp. 916-926
Author(s):  
W M Broadfoot ◽  
G M Browning

1998 ◽  
Vol 81 (3) ◽  
pp. 638-644 ◽  
Author(s):  
James M Desmarchelier ◽  
Sylvia E Allen ◽  
Yong-Lin Ren

abstract Phosphine (PH3) and methyl bromide (ChhBr) are the main fumigants used on stored grains. Published multiresidue methods, including those based on solvent extraction and on purge-and-trap techniques, give poor recoveries of CH3Br and, in our hands, close to zero recovery of PH3 and carbonyl sulfide (COS), a potential fumigant. We examined factors influencing fumigant analysis, including stability of chemicals in leachates and partitioning of fumigant between leachate and air. The partition ratio, defined as the ratio of fumigant concentration in leachate to that in the headspace, varied between 1.1 for PH3 and >100 for ethylene dibromide (EDB). An official procedure involving solvent extraction followed by partitioning was modified by being performed in sealed flasks. This change raised the recovery of ChfoBr from 28 to 85%. Volatile fumigants, including PH3 and COS, were determined from concentrations in the headspace over the leachate (aqueous acidified acetone). Recoveries were nearly quantitative at levels down to 3 ng PH3/g and 16 ng COS/g, provided that fortified samples were used as analytical standards. Thus an existing multifumigant procedure was adapted to enable determination of the main fumigants used on staple foodstuffs.


Author(s):  
Samuel C. Iwuji ◽  
Chidimma V. Ogbonna ◽  
Chinonye I. Iwu ◽  
Wilson C. Okafor ◽  
Emmanuel C. Chibuike

Aims: The study determined and compared the herbal extraction yields using water, ethanol and hydromethanol solvent and the solvent extracting the highest antidiabetic constituents. Place: The study took place in the Department of Chemistry (Organic Laboratory), Federal University of Technology Owerri, Nigeria. Methodology: The antidiabetic contents of Moringa oleifera (Moringa) and Vernonia amygdalina (bitter leaf) were extracted by soaking using water, ethanol and hydromethanol (1:1) as solvents. The phytochemicals analysis was done both qualitatively and quantitatively (using Spectrophotometer (UV-V15)). Data collected were statistically analysed using SPSS version 10 tools. Results: The crude ethanolic extraction was found to give the highest extract yield of 46.06% and 38.91% from Moringa and bitter leaf, respectively. There were more phytochemicals obtained from Moringa (28+) than from Vernonia crude extracts (21+). The antidiabetic phytochemicals identified in both plants included Steroids, Phenols, Cardiac glycosides and Terpenoids. Ethanol extracted the Glycosides, Terpenoids and Phenols in relative abundance.. Hydromethanol solvent extraction yielded the highest concentrations of Steroids from Moringa (59.87mg/100g) and bitter leaves (75.43mg/100g) as well as highest extraction of Cardiac glycosides from both plants. Water extracted the highest concentrations of Phenols from both Moringa (0.32mg/g); bitter leaf (0.25mg/g) and Terpenoids from Moringa. Conclusion: This study suggests that the choice of solvent (s) for phytochemical extraction (s) should consider factors such as the plant material (s) and the phytochemical (s) involved. So, Water > Hydromethanol > ethanol could be used for extracting phytochemicals for diabetes therapy.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1180c-1180
Author(s):  
T. R. Hamilton-Kemp ◽  
J. H. Loughrin ◽  
R. A. Andersen

Two methods for collecting headspace vapors produced by plant samples are presented. The first involves entraining volatiles in a stream of air and trapping the entrained compounds on a porous polymer such as Tenax. The volatiles are recovered from the trap by solvent extraction or heat desorption and analysed by gas chromatography. A second method entails removing headspace vapor above plant material with a gas-tight syringe and injecting the sample directly into the gas chromatograph. An evaluation of the usefulness of these techniques will be presented.


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