Graphene Oxide/Polyethylene Glycol-Stick for Thin Film Microextraction of β-Blockers from Human Oral Fluid by Liquid Chromatography-Tandem Mass Spectrometry.

A wooden stick coated with a novel graphene-based nanocomposite (Graphene oxide/polyethylene glycol (GO/PEG)) is introduced and investigated for its efficacy in solid phase microextraction techniques. The GO/PEG-stick was prepared and subsequently applied for the extraction of β-blockers, acebutolol, and metoprolol in human oral fluid samples, which were subsequently detected by liquid chromatography tandem mass spectrometry (LC-MS/MS). Experimental parameters affecting the extraction protocol including sample pH, extraction time, desorption time, appropriate desorption solvent, and salt addition were optimized.

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.

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.

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.