An extractor has been developed for microporous membrane liquid-liquid extraction (MMLLE) of lipophilic xenobiotics at trace levels in biological fluids. This new construction allows the sample phase to be stirred, while the organic phase is pumped. The extractor was evaluated using human blood plasma with added organophosphate esters. The size exclusion properties of the membrane reduced lipid...

Introduction Capillary gas chromatography (GC) is a mature technique commonly used in routine analysis laboratories. Despite the performance of modern chromatographs, sample preparation is still a vital step of the analytical process as it ensures samples are suitable for chromatographic determination (1). Figure 1 summarizes some of the pretreatment steps employed prior to gas chromatographic ...

Applying a simple and selective sample preparation procedure prior to instrumental analysis is the most important and crucial step in an analytical process. Up to now, various sample preparation techniques based on solid phase extraction (SPE) systems have been developed to isolate various types of analytes from different matrices. In the method presented for preconcentration and measurement of...

Applying a simple and selective sample preparation procedure prior to instrumental analysis is the most important and crucial step in an analytical process. Up to now, various sample preparation techniques based on solid phase extraction (SPE) systems have been developed to isolate various types of analytes from different matrices. In the method presented for preconcentration and measurement of...

A reversed-phase solid-phase extraction-gas chromatography (SPE-GC)-electron capture detection method is developed to quantitate individual rethrin residues in pyrethrum-exposed brown tree snakes. Aliquots (6 g) of homogenized snake tissue are extracted with 10 mL acetonitrile. The rethrins are recovered from the acetonitrile extract and concentrated using C8 SPE. The rethrins are eluted from t...

We have developed a novel solid-phase extraction (SPE) system utilizing a temperature-responsive polymer hydrogel-modified stationary phase. Aminopropyl silica beads (average diameter, 40 - 64 μm) were coated with poly(N-isopropylacrylamide) (PNIPAAm)-based thermo-responsive hydrogels. Butyl methacrylate (BMA) and N,N-dimethylaminopropyl acrylamide (DMAPAAm) were used as the hydrophobic and cat...

The HPLC-SPE-NMR technique was used for the analysis of a root-bark extract of Croton membranaceus. The components of the extract were separated on an analytical-size reversed-phase HPLC column, the chromatographic peaks were trapped on SPE (solid-phase extraction) cartridges after post-column dilution of the eluate with water and the compounds were eluted from the cartridges with acetonitrile-...

Seven liquid solvent systems--dichloromethane, dichloromethane-pentane (1:1), freon 113, diethyl ether-pentane (1:1 and 1:9), ethyl acetate-pentane (with and without an additional salting-out effect) (1:3 and 1:20), and seven solid-phase extraction (SPE) systems (Amberlite XAD-2, 4, 7, and 16; Porapak Q; C8; and C18)--are comparatively studied. The distribution coefficients between the extracti...

Two modifications of the HPLC-ED method with respect to extraction procedure used have been developed for psilocin, the active metabolite of psilocybin, in human plasma using either liquid-liquid extraction (LLE) or automated on-line solid-phase extraction (on-line SPE). Each type of the sample preparation required a different HPLC system followed by electrochemical detection at 650 to 675 mV. ...

Clean up is one of the most important steps to remove co-extractives and undesired interfering substances from the sample before analysis in pesticide residue analysis. Some advanced, sophisticated and efficient methods of clean up have emerged out which is able to save time as well as amount of solvents. These are Solid Phase Extraction (SPE), Gel Permeation Chromatography (GPC) and Supercriti...