many modern analytical methods deal with the trace-level determination of compounds of interest in highly complex environmental samples by means of chromatographic techniques. the introduction of a “clean” sample into an analytical instrument can make analyses easier and prolongs the equipment life. the use of solid-phase extraction (spe) has grown and is a fertile technique of sample preparati...

It is a common practice to extract steroids from plasma, serum, or tissue samples prior to steroid measurement by radioimmunoassay (RIA) or enzyme immunoassay (EIA). Steroid extraction is critical because it can remove substances that interfere with the RIA or EIA. Steroid extraction is commonly achieved using organic solvents, such as diethyl ether or dichloromethane. However, organic solvent ...

BACKGROUND Quantification of 5-hydroxyindole-3-acetic acid (5-HIAA) in urine is useful in diagnosing and monitoring of patients with carcinoid tumors and in the study of serotonin (5-hydroxytryptamine) metabolism in various disorders. We describe an automated method that incorporates on-line solid-phase extraction (SPE) and HPLC to measure urinary 5-HIAA. METHODS Automated prepurification of ...

A faster and more efficient way of isolating and subsequently cleaning up the sterol fraction obtained from seed oils was developed based on an existing established method that used thin-layer chromatography (TLC) to isolate the sterol fraction (3). The newly developed method used solidphase extraction (SPE) to separate the sterol fraction from other compounds found in the unsaponifiable portio...

An UHPLC-MS/MS multiresidue method based on an on-line solid phase extraction (SPE) procedure was developed for the simultaneous determination of 9 perfluorinated carboxylates (from 4 to 12 carbon atoms) and 3 perfluorinated sulphonates (from 4 to 8 carbon atoms). This work proposes using an on-line solid phase extraction before chromatographic separation and analysis to replace traditional met...

To examine the effects of weak intermolecular interactions on solid-phase extraction (SPE) and chromatographic separation, we synthesized some novel stationary phases with a heavy atom effect layer by immobilizing halogenated aromatic rings and hydroxyl groups onto the surface of a hydrophilic base polymer. Using SPE cartridges packed with the functionalized materials, we found that the heavy a...

An automated extraction method for extracting the major urinary metabolite of cannabis, 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) was developed on the four-probe Gilson ASPEC XL4trade mark solid-phase extraction (SPE) system. The method works on liquid-liquid extraction principles but does not require the use of SPE cartridges. The limits of detection and quantitation an...

A gas chromatographic technique with flame ionization detection, which is based on a solid-phase extraction (SPE) procedure using mixed-mode SPE columns, for the simultaneous quantitation of dextropropoxyphene and norpropoxyphene in urine is presented. Urine is treated with sodium hydroxide in order to rearrange, by base catalysis, norpropoxyphene to norpropoxyphene amide, which is then extract...

We report the formation of a highly stable amino stationary phase on diamond and demonstrate its use in solid-phase extraction (SPE). This process consists of spontaneous and self-limiting adsorption of polyallylamine (PAAm) from aqueous solution onto oxidized diamond. Thermal curing under reduced pressure or chemical cross-linking with a diepoxide was shown to fix the polymer to the particles....

For sample preparation solid-phase extraction (SPE) became very popular during the 1980s and 1990s. Because method development and its optimization is very time consuming, in most cases C18 is used as standard carrier material without knowing if it possesses the highest efficiency. Therefore detailed studies with different stationary phases are necessary for optimal recovery rates. Due to the r...