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Rapid Techniques (rapid + techniques)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Rapid techniques for the extraction of vitamin E isomers from Amaranthus caudatus seeds: ultrasonic and supercritical fluid extraction

PHYTOCHEMICAL ANALYSIS, Issue 5 2002
Renato Bruni
Abstract Supercritical fluid extraction (SFE) of seeds of Amaranthus caudatus (Amaranthaceae) and the use of ultrasound as a co-adjuvant in the extraction process were compared with methods traditionally used in the extraction of tocopherols and fatty acids. The use of readily available ultrasound equipment as an adjunct to the classical methods employed for the extraction of tocols provided qualitatively acceptable results more rapidly and more economically. SFE gave quantitatively better yields in shorter times, with solvent-free extracts obtained under conditions that minimised the degradation of thermolabile components. No significant variations were observed in the profile of the fatty acids extracted from amaranth oil by SFE or other methods, thus confirming the qualitative comparability of the faster supercritical extraction with the more time-consuming classical techniques even when processed with the aid of ultrasound. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Rapid techniques for assessing fibre quality of flax breeding lines and cultivars using visible and near infrared spectroscopy, and thermal analysis

ANNALS OF APPLIED BIOLOGY, Issue 2 2006
Z. Jankauskien
Abstract Fifteen different flax cultivars and breeding lines (E-68, Baltu,iai, Belinka, Vega 2, Ilona, Elise, Kasty,iai, Evelin, 1963-3, Ariane, Hermes, 01057-12, 1698-13a, 2017-3, 1864-24) were cultivated, harvested, water-retted, scutched and resulting fibres passed through pin frames to produce representative samples for each variety. The aim of this investigation was to develop rapid techniques for assessing quality of fibre obtained from a comparative agronomical trial. The fibres produced were then assessed using visible and near infrared spectroscopy (Vis,NIRS), thermal analysis, scanning electron microscopy and airflow method for measuring fibre fineness. The relationships between agronomical characteristics, fibre fineness, thermal and spectral results were assessed using principal component analysis and partial least squares regression methods. The micrographs of the samples revealed the presence of residual pectic and cuticular tissues on all fibres, and significant differences between the 15 fibre samples were not observed. A significant relationship of the differences in fibre fineness of the test samples as measured by airflow method and Vis,NIR spectra was observed with an R2 of 0.97 and standard error of calibration (SEC) of 1.69 dtex, and the former parameter also correlated with the measured thermal combustion parameters showing an R2 of 0.91 and SEC of 2.86 dtex, indicating that the two rapid techniques could be used for the assessment of fibre quality of selected plants from the breeding programme. The advantages of using the two instrumental techniques compared with the existing airflow method are briefly discussed. [source]

Fast miniaturised sample preparation for the screening and comprehensive two-dimensional gas chromatographic determination of polychlorinated biphenyls in sludge

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 11 2005
E. Maria Kristenson
Abstract Polychlorinated biphenyls (PCBs) in sludge are usually extracted by a technique such as Soxhlet with subsequent fractionation prior to long GC runs using GC,ECD or GC,HRMS. In this study, the extraction of selected chlorinated biphenyls (CBs) from a spiked sludge sample by three rapid techniques, i.e. ultrasonic (USE), pressurised-liquid (PLE), and microwave-assisted (MAE) extraction using a domestic microwave, was studied, with subsequent direct GC,ECD, GC,MS, or GC×GC,,ECD analysis of the extracts. The main goal was to select an appropriate, and miniaturised, extraction method after only a brief optimisation and demonstrate the power of GC×GC analysis of dirty extracts. For PLE similar CB recoveries were found when extracting with either n -hexane or n -hexane/acetone (1/1). For USE and MAE, n- hexane/acetone (1/1) was the preferred extraction solvent. USE gave the best recoveries (80,95%; except 130% for CB 105). The only clean-up needed prior to GC,MS or GC×GC,,ECD analysis was the removal of sulphur-containing compounds. GC,ECD was not suitable for these dirty extracts. The lowest LODs for the CBs (20 fg or 0.1 ng/g sludge) were found when combining USE and GC×GC,,ECD, because of the powerful extraction, high separation power and excellent detectability provided by this technique. [source]