BACKGROUND Khat (Catha edulis Forsk) is an evergreen shrub of the Celastraceae family. It is widely cultivated in Yemen and East Africa, where its fresh leaves are habitually chewed for their momentary pleasures and stimulation as amphetamine-like effects. The main psychostimulant constituents of khat are the phenylpropylamino alkaloids: cathinone, cathine and norephedrine. RESULTS In this st...

A simple and solvent-minimized sample preparation technique based on hollow fibre-protected liquid-phase micro-extraction has been developed for extraction of fifteen organic sulphur compounds from aqueous samples. The analysis of the extracted them was performed by gas chromatography equipped with mass spectrometry and/or flame photometric detectors. 3.3 µL of organic solvent located in the lu...

Increasing emissions of chemical compounds to the environment, especially of pesticides, is one of factors that may explain present honeybee colony losses. In this work, an analytical method employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) was optimized for the simultaneous screening of 19 pesticides which have not been yet determined in honeybee samples from northern Poland ...

A selective and simple method for separation and preconcentration of zinc ions was developed by using dispersive liquid-liquid microextraction. Parameters that have an effect on the microextraction efficiency such as volume of extraction and disperser solvent, extraction time, and adding salt were investigated. Under optimum conditions, a preconcentration factor of 250 was obtained. The limit o...

a rapid, simple and sensitive high-performance liquid chromatography method was developed for determination of ciprofloxacin in plasma by means of ultraviolet detection. ofloxacin was used as an internal standard and separation carried on a novapak c18 column using a mobile phase of 0.01 m phosphate buffer (ph =2.6): methanol (82: 18 v/v). extraction of drug was performed from plasma by liquid-...

This paper describes a dispersive liquid–liquid microextraction (DLLME) procedure using room temperature ionic liquids (RTILs) coupled with flame atomic absorption spectrometry detection with microsample introduction system capable of quantifying trace amounts of lead. In the proposed approach, ammonium pyrrolidine dithiocarbamate (APDC) was used as a chelating agent and 1-hexyl-3-methylimmidaz...

An efficient, sensitive and fast method was developed based on an ultrasound-assisted extraction followed by an ion-pair dispersive liquid-liquid microextraction (USAE-IP-DLLME) for the simultaneous determination of five commonly used synthetic sulfonate dyes (tartarazine, quinoline yellow, sunset yellow, azorubine, and brilliant blue) in ice cream samples using high performance liquid chromato...

In this paper, we describe a new combination method based on polytetrafluorethylene (PTFE) film-based liquid three-phase micro extraction coupled with differential pulse voltammetry (DPV) for the micro extraction and quantification of atorvastatin calcium (ATC) at the ultra-trace level. Different factors affecting the liquid-three phases micro extraction of atorvastatin calcium, including organ...

the kinetics of the potassium thiocyanate transport mediated by dicyclohexyl-18-crown-6 (l) through a bulk liquid membrane is studied experimentally and theoretically. the proposed model is based on the assumption of a pure diffusion of the complex salt [k·l]+scn¯ through the liquid membrane stagnant films at the interfaces. it illustrates the connection between liquid-liquid extraction equilib...

Abstract In this study, microfunnel-supported liquid-phase microextraction method (MF-LPME) was optimized and applied for the determination of some chlorophenoxyacetic acids (CPAAs) from natural water samples. The extraction was performed with 540 μL toluene which was retained at the surface of the sample solution using an upside down microfunnel. After the extraction, toluene was moved in...