Extraction and determination of flavonoids in fruit juices and vegetables using Fe O /SiO magnetic nanoparticles modified with mixed hemi/ad-micelle cetyltrimethylammonium bromide and high performance liquid chromatography.

Extraction and determination of three flavonoids (morin, quercetin, and kaempferol) were performed by dispersive magnetic solid phase extraction based on mixed hemi/ad-micelles and high-performance liquid chromatography with UV detection. The Fe O /SiO nanoparticles were synthesized and characterized by X-ray diffraction, FTIR, scanning electron microscopy, and thermogravimetric analysis. Fe O /SiO nanoparticles coated with mixed hemi/ad-micelles cetyltrimethyl ammonium bromide was applied as a sorbent and used for extraction of flavonoids.

Polyacrylonitrile / graphene oxide nanofibers for packed sorbent microextraction of drugs and their metabolites from human plasma samples.

In the present study, a new graphene based nanofibers material (Polyacrylonitrile/Graphene Oxide (PAN/GO)) was used for microextraction by packed sorbent (MEPS). The PAN/GO nanofiber was synthesized using the electrospinning technique. MEPS online with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was utilized for the extraction and determination of two local anesthetic drugs (lidocaine, prilocaine) and their major metabolites (2,6-xylidine, o-toluidine) in human plasma samples.

Synthesis of magnetic nanoparticle-based molecularly imprinted polymer as a selective sorbent for efficient extraction of ezetimibe from biological samples.

In the present study, a novel and efficient adsorbent constructed of molecularly imprinted polymer on the surface of modified magnetic nanoparticles with oleic acid (MNPs) was applied for the selective extraction of ezetimibe. The magnetic molecularly imprinted polymer (MMIP) was polymerized at the surface of modified MNPs using methacrylic acid as functional monomer, ezetimibe as template and ethylene glycol dimethacrylate as cross-linker. The resulting MMIP showed high adsorption capacity, good selectivity and fast kinetic binding for the template molecule.

Ultrasound-assisted supramolecular-solvent-based microextraction combined with high-performance liquid chromatography for the analysis of chlorophenols in environmental water samples.

An efficient, inexpensive and environmentally benign ultrasound-assisted supramolecular-solvent-based microextraction technique combined with high-performance liquid chromatography was used for the determination of chlorophenols in environmental water samples. Different factors such as amount of decanoic acid, volume of tetrahydrofuran, pH of the sample, ultrasound time and ionic strength were investigated and optimized. The optimized extraction conditions were 60 mg decanoic acid, 1.

Application of Sigmoidal Transformation Functions in Optimization of Micellar Liquid Chromatographic Separation of Six Quinolone Antibiotics.

A chemometrics approach has been used to optimize the separation of six quinolone compounds by micellar liquid chromatography (MLC). A Derringer's desirability function, a multicriteria decision-making (MCDM) method, was tested for evaluation of two different measures of chromatographic performance (resolution and analysis time). The effect of three experimental parameters on a chromatographic response function (CRF) expressed as a product of two sigmoidal desirability functions was investigated.

Human serum albumin-mimetic chromatography based hexadecyltrimethylammonium bromide as a novel direct probe for protein binding of acidic drugs.

Human serum albumin (HSA) is the most important drug carrier in humans mainly binding acidic drugs. Negatively charged compounds bind more strongly to HSA than it would be expected from their lipophilicity alone. With the development of new acidic drugs, there is a high need for rapid and simple protein binding screening technologies.

Hollow fibre-based liquid phase microextraction combined with high-performance liquid chromatography for the analysis of flavonoids in Echinophora platyloba DC. and Mentha piperita.

A simple, inexpensive and efficient three phase hollow fibre liquid phase microextraction (HF-LPME) technique combined with HPLC was used for the simultaneous determination of flavonoids in Echinophora platyloba DC. and Mentha piperita. Different factors affecting the HF-LPME procedure were investigated and optimised.

Biopartitioning micellar chromatography with sodium dodecyl sulfate as a pseudo α(1)-acid glycoprotein to the prediction of protein-drug binding.

A simple and fast method is of urgent need to measure protein-drug binding affinity in order to meet the rapid development of new drugs. Biopartitioning micellar chromatography (BMC), a mode of micellar liquid chromatography (MLC) using micellar mobile phases in adequate experimental conditions, can be useful as an in vitro system in mimicking the drug-protein interactions. In this study, sodium dodecyl sulfate-micellar liquid chromatography (SDS-MLC) was used for the prediction of protein-drug binding based on the similar property of SDS micelles to α(1)-acid glycoprotein (AGP).

Low-density solvent-based dispersive liquid-liquid microextraction followed by high performance liquid chromatography for determination of warfarin in human plasma.

Extraction and determination of warfarin, a widely used anticoagulant drug, in human plasma were performed using a new generation of dispersive liquid-liquid microextraction (DLLME) and high performance liquid chromatography (HPLC). The extraction procedure is based on extraction solvents lighter than water and performing of extraction in a specially designed extraction cell. Some important parameters, including kind and volume of extraction and disperser solvents, pH of the sample solution, salt concentration in the sample solution and extraction time were investigated and optimized.

Simultaneous optimization of the resolution and analysis time of flavonoids in reverse phase liquid chromatography using Derringer's desirability function.

The chemometrics approach was applied for simultaneous optimization of resolution and analysis time of seven flavonoids in reverse phase liquid chromatography. Derringer's desirability function, a multi-criteria decision making method, was used for the evaluation of two different chromatographic performance goals including resolution and analysis time. The selected flavonoids belong to different classes of flavonoids including: flavonols (myricetin, morin, quercetin and kaempferol) flavones (apigenin and luteolin) and flavanones (naringenin).

Three-phase hollow fiber liquid phase microextraction of warfarin from human plasma and its determination by high-performance liquid chromatography.

A simple, inexpensive and efficient sample preparation technique, three-phase hollow fiber liquid phase microextraction (HF-LPME), followed by high-performance liquid chromatography-ultra violet detection (HPLC-UV) was used for the analysis of warfarin in human plasma. Warfarin was extracted from 11.0 ml of aqueous solution with pH=2.

Determination of N-methylcarbamate insecticides in water samples using dispersive liquid-liquid microextraction and HPLC with the aid of experimental design and desirability function.

A rapid and simple method for the extraction and preconcentration of N-methylcarbamates (NMCs) (carbofuran, carbaryl and promecarb) in water samples using dispersive liquid-liquid microextraction (DLLME) using chemometrics was developed. Influence variables such as volume of extracting (CHCl(3)) and dispersing solvents (ACN), pH and ionic strength, extraction time and centrifugation time and speed were screened in a 2(7-4) Plackett-Burman design was investigated. The significant variables were optimized by using a central composite design (CCD) combined with desirability function (DF).