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Exhaustive Extraction (exhaustive + extraction)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Analysis of flavor and perfume using an internally cooled coated fiber device

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 7 2007
Yong Chen
Abstract A miniaturized internally cooled coated fiber device was applied for the analysis of flavors and fragrances from various matrices. Its integration with a CTC CombiPAL autosampler enabled high throughput for the analysis of analytes in complex matrices that required simultaneous heating of the matrices and cooling of the fiber coating to achieve high extraction efficiency. It was found that up to ten times increase of extraction efficiencies was observed when the device was used to extract flavor compounds in water, even when limited sample temperatures were used to preserve the integrity of target compounds. The extraction of the flavor compounds in water with the device was reproducible, with RSD not larger than 15%. The lower limits of the linear ranges were in the low ppb range, which was about one order of magnitude smaller than those obtained with the commercialized 100 ,m PDMS fibers. Exhaustive extraction of some perfume ingredients from a complex matrix (shampoo) was realized. All achieved recoveries were not less than 80%. The repeatability of the extraction of the perfume compounds from shampoo was better than 10%. The linear ranges were about 1,3000 ,g/g, and the LOD was about 0.2,1 ,g/g. The automated internally cooled coated fiber device was demonstrated to be a powerful sample preparation tool in flavor and fragrance analysis. [source]

Microwave-assisted extraction of total bioactive saponin fraction from Gymnema sylvestre with reference to gymnemagenin: a potential biomarker

PHYTOCHEMICAL ANALYSIS, Issue 6 2009
Vivekananda Mandal
Abstract Objective , To develop a fast and ecofriendly microwave assisted extraction (MAE) technique for the effective and exhaustive extraction of gymnemagenin as an indicative biomarker for the quality control of Gymnema sylvestre. Methodology , Several extraction parameters such as microwave power, extraction time, solvent composition, pre-leaching time, loading ratio and extraction cycle were studied for the determination of the optimum extraction condition. Scanning electron micrographs were obtained to elucidate the mechanism of extraction Results , The final optimum extraction conditions as obtained from the study were: 40% microwave power, 6,min irradiation time, 85% v/v methanol as the extraction solvent, 15,min pre-leaching time and 25,:,1 (mL/g) as the solvent-to-material loading ratio. The proposed extraction technique produced a maximum yield of 4.3% w/w gymnemagenin in 6,min which was 1.3, 2.5 and 1.95 times more efficient than 6,h of heat reflux, 24,h of maceration and stirring extraction, respectively. A synergistic heat and mass transfer theory was also proposed to support the extraction mechanism Conclusion , Comparison with conventional extraction methods revealed that MAE could save considerable amounts of time and energy, whilst the reduction of volume of organic solvent consumed provides an ecofriendly feature. Copyright © 2009 John Wiley & Sons, Ltd. [source]

High-performance thin layer chromatographic analysis of anti-inflammatory triterpenoids from Boswellia serrata Roxb.

PHYTOCHEMICAL ANALYSIS, Issue 6 2001
K. Krohn
Abstract A rapid and simple high-performance thin layer chromatographic (HPTLC) method was developed for the simultaneous quantitative estimation of the biologically active triterpenoids ,-boswellic acid, 3- O -acetyl-,-boswellic acid, 11-keto-,-boswellic acid and 3- O -acetyl-11-keto-,-boswellic acid from the gum resin of Boswellia serrata. The assay combines the isolation and separation of boswellic acid derivatives on silica gel 60F254 -HPTLC plates with spot visualisation and scanning at 250,nm. Methanol was found to be the most appropriate solvent for the exhaustive extraction of boswellic acid derivatives. Copyright © 2001 John Wiley & Sons, Ltd. [source]

De novo sequencing of peptides by MS/MS

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 4 2010
Joerg Seidler
Abstract The current status of de novo sequencing of peptides by MS/MS is reviewed with focus on collision cell MS/MS spectra. The relation between peptide structure and observed fragment ion series is discussed and the exhaustive extraction of sequence information from CID spectra of protonated peptide ions is described. The partial redundancy of the extracted sequence information and a high mass accuracy are recognized as key parameters for dependable de novo sequencing by MS. In addition, the benefits of special techniques enhancing the generation of long uninterrupted fragment ion series for de novo peptide sequencing are highlighted. Among these are terminal 18O labeling, MSn of sodiated peptide ions, N-terminal derivatization, the use of special proteases, and time-delayed fragmentation. The emerging electron transfer dissociation technique and the recent progress of MALDI techniques for intact protein sequencing are covered. Finally, the integration of bioinformatic tools into peptide de novo sequencing is demonstrated. [source]