Objectives: A liquid/liquid extraction technique on solid support of Δ9-tetradydrocannabinol (THC), 11-hydroxy-Δ9-tetradydrocannabinol (11-OH-THC) and 11-nor-Δ9-tetradydrocannabinol-9-carboxylic acid (THCCOOH) in plasma was developed in order to be assayed by high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS). Methods: The samples were extracted by liquid/liquid ex...

This paper describes the development and validation of analytical methodology for the determination of the use of MDMA, MDEA and MDA in urine. After a simple liquid extraction, the analyses were carried out on a high performance liquid chromatography (HPLC) in an octadecyl column, with fluorescence detection. The mobile phase using a sodium dodecyl sulfate ion-pairing reagent allows good separa...

A general method is described for the detailed qualitative and quantitative analysis of bile acids and related compounds from feces. The technique utilizes a novel combination of liquid-gel and liquid-solid extraction, lipophilic ion exchange chromatography, and capillary column gas-liquid chromatography coupled to mass spectrometry, which permits the detailed composition of bile acids in feces...

RATIONALE Lipoproteins belong to the most commonly measured clinical biochemical parameters. Lipidomics is an orthogonal approach and aims to profile the individual lipid molecules that jointly form the lipoprotein particles. However, in the first step of the extraction of lipid molecules from serum, an organic solvent is used leading to dissociation of the lipoproteins. Thus far it has been im...

A new, sensitive and fast dispersive liquid-liquid microextraction (DLLME) coupled with micro-solid phase extraction (μ-SPE) was developed for determination of zearalenone (ZEN) in wheat samples. The DLLME was performed using acetonitrile/water (80:20 v/v) as the disperser solvent and 1-octanol as the extracting solvent.  The acetonitrile/water (80:20 v/v) solvent was also used to extract ZEN f...

A simple and reproducible HPLC method with spectrophotometric detection was developed for determination of rivastigmine in human plasma. Liquid-liquid extraction of rivastigmine and donepezil (as internal standard) from plasma samples was performed with 1-butanol/n-hexane (2:98 v/v) in alkaline condition followed by back-extraction into diluted acetic acid. Chromatography was carried out using ...

A simplified method for following the urinary excretion of estriol, pregnanediol, and pregnanoloneduring the course of pregnancy is presented. The procedure has been used successfully in a large hospital laboratory. An important advantage is that the estrogen and progesterone metabolites are measured simultaneously, and separate extraction and gas-liquid chromatographyis not required. The urine...

Individual tocopherol profile of five Agaricus mushroom species, widely consumed in Portugal, was obtained by a normal-phase high-performance liquid chromatography (NP-HPLC). It was used a simple solid-liquid extraction procedure without saponification step and the chromatographic separation was achieved using a YMC-Pack Polyamine II column using an isocratic elution with hexane/ethyl acetate (...

A method is developed for the determination of nine organophosphorus pesticide residues in cereals and kidney beans by capillary gas chromatography with flame-photometric detection. In this method, dichloromethane is used for clean-up after liquid-liquid extraction. It is shown that good separations are obtained using a fused-silica capillary column (DB-1701) by the optimized temperature progra...

A liquid chromatographic method was developed and validated for the determination of ginsenosides in Panax ginseng roots by using evaporative light-scattering detection. Eighteen ginsenosides were separated on a reversed-phase C18 column with water-ammonium acetate-acetonitrile as the mobile phase. The method is suitable for the routine determination of ginsenosides in P. ginseng roots and extr...