Electro-assisted solid-phase microextraction of Hg(II) in rice and water samples using NiCo-LDH-MXene fiber.

Food and water contamination with heavy metals is still a significant public health issue, necessitating development of simple and rapid analytical methods. Herein, a novel electro-assisted solid-phase microextraction (EA-SPME) method was developed to determine mercury (Hg(II)) in rice and water samples. A novel SPME-fiber coating was prepared through electrosynthesis of NiCo-layered double hydroxide (NiCo-LDH) onto MXene deposited onto the graphenized pencil fiber.

Nickel oxide nanoparticles modified with dimethylglyoxime grafted on a cellulose surface as an efficient adsorbent for thin film microextraction of tramadol in biological fluids followed by its determination using HPLC.

In the current study, nickel oxide nanoparticles (NiO NPs) modified with dimethylglyoxime (DMG) were deposited onto the cellulose surface (Ni(DMG)-NiO-Cell) and used as an efficient adsorbent for thin film microextraction (TFME) of tramadol (TRA). The extracted TRA was determined using a high-performance liquid chromatography-ultraviolet detector (HPLC-UV). NiO NPs were synthesized by co-precipitation method on the surface of the cellulose substrate; afterward, its surface was modified by DMG to increase the extraction capability of the thin film toward TRA.

Fabrication of MXene/chitosan/polyurea nanocomposite decorated on a graphenized substrate for electro-enhanced solid-phase microextraction of diclofenac followed by its determination using differential pulse voltammetry.

A novel solid-phase microextraction fiber based on MXene-chitosan-polyurea (MXene/CS/EPPU) nanocomposite decorated on a graphenized pencil lead fiber (MXene/CS/EPPU/GPLF) was prepared and utilized for electro-enhanced solid-phase microextraction (EE-SPME) of diclofenac (DCF) in biological samples. After extraction and desorption of DCF, it was determined by differential pulse voltammetry (DPV). For this purpose, the working electrode was prepared by deposition of the mentioned MXene/CS/EPPU nanocomposite onto the graphenized pencil lead.

A novel self-supportive thin film based on graphene oxide reinforced chitosan nano-biocomposite for thin film microextraction of fluoxetine in biological and environmental samples.

In this research, for the first time, graphene oxide doped chitosan (GO/CS) nano-biocomposite (NBC) is designed and prepared as a novel self-supportive thin layer for thin film microextraction (TFME) of fluoxetine (FLX) followed by determination applying HPLC-UV-Vis. The properties of the prepared self-supportive thin film were characterized applying ATR-FTIR, FESEM, and XRD techniques. The extraction capability of GO/CS NBC toward FLX has been evaluated, and the obtained results revealed that incorporation of GO into CS has led to higher extraction efficiency in comparison to the CS thin film.

Zr-based metal-organic framework incorporated polystyrene nanocomposite as a novel sorbent for ultrasound assisted-thin film microextraction of organophosphorus pesticides from complex samples.

In this work, a novel ultrasound assisted-thin film microextraction (USA-TFME) method has been developed to determine organophosphorus pesticides (OPPs) in some fruits and vegetables samples followed by gas chromatography. In this regards, a novel nanocomposite (NC) was prepared by incorporation of zirconium-based metal-organic framework (MOF) into polystyrene (UiO-66/PS) and used as an efficient thin film. The effect of MOF doping level into UiO-66/PS NC and also the effective parameters influencing the TFME method has been studied.

Application of nanocomposite-based sorbents in microextraction techniques: a review.

This paper presents a comprehensive review concerning the recent trends for the preparation of nanocomposites (NCs) and their applications in microextraction techniques. NCs are defined as organic-inorganic hybrid materials in which at least one dimension of one component is less than 100 nm. Numerous synthesis routes have been introduced to prepare NCs in recent years.

Conductive polymer-based microextraction methods: a review.

Conductive polymers (CPs) are classified as materials which exhibit highly reversible redox behavior and the unusual combined properties of metal and plastics. CPs, due to their multifunctionality, ease of synthesis and their stability, have attracted more attentions in different fields of research, including sample preparation. CPs along with several commercial hydrophilic sorbents, are alternative to the commercially available hydrophobic sorbents which despite their high specific surface areas, have poor interactions and retentions in the extraction of polar compounds.

Multiresidue determination of pesticides from aquatic media using polyaniline nanowires network as highly efficient sorbent for microextraction in packed syringe.

A simple, rapid and sensitive method based on microextraction in packed syringe (MEPS), in combination with gas chromatography-mass spectrometry (GC-MS) was developed. Polyaniline (PANI) nanowires network was synthesized and used as sorbent of MEPS for the multiresidue determination of selected analytes from triazine, organochlrorine and organophosphorous pesticides in aqueous samples. The PANI nanowires network was prepared using soft template technique and its characterization was studied by scanning electron microscopy (SEM).

Reinforced polydiphenylamine nanocomposite for microextraction in packed syringe of various pesticides.

Reinforced polydiphenylamine (PDPA) nanocomposite was synthesized by oxidation of diphenylamine in 4 molL(-1) sulfuric acid solution containing a fixed amount of carbon nanotubes (CNTs) in the presence of cetyltrimethylammonium bromide (CTAB). The surface characteristic of PDPA and PDPA/CNT nanocomposites was investigated using scanning electron microscopy (SEM). The prepared PDPA/CNT nanocomposite was used as an extraction medium for microextraction in packed syringe (MEPS) of selected pesticides from aquatic environment.

Polypyrrole/polyamide electrospun-based sorbent for microextraction in packed syringe of organophosphorous pesticides from aquatic samples.

A novel method based on microextraction in packed syringe (MEPS) as sample preparation technique coupled off-line with gas chromatography-mass spectrometry was developed using electrospun nanofibers as sorbent. For electrospinning of polypyrrole/polyamide-based nanofiber, a homogeneous solution containing nylon 6, ferric chloride and pyrrole monomer was prepared and then was drawn into a 2.5-mL syringe.

Novel unbreakable solid-phase microextraction fiber by electrodeposition of silica sol-gel on gold.

A new technique for preparation of an unbreakable solid-phase microextraction (SPME) fiber, using sol-gel technology is developed. Primarily, an ultrathin two-dimensional intermediate film was prepared by hydrolysis of 3-(trimethoxysilyl)-1-propanthiol self-assembled monolayer grafted onto gold, then a stationary phase by electrodeposition of 3-(trimethoxysilyl)propylmethacrylate as a precursor, tetramethyl orthosilicate and polyethylene glycol as a coating polymer was produced. The scanning electron microscopy images revealed that the new fiber exhibits a rather porous and homogenous surface.

Electrospun composite of polypyrrole-polyamide as a micro-solid phase extraction sorbent.

A micro-solid phase extraction technique was developed using a novel polypyrrole-polyamide nanofiber sheet, fabricated by electrospinning method. The applicability of the new nanofiber sheet was examined as an extracting medium to isolate malathion as a model pesticide from aqueous samples. Solvent desorption was subsequently performed in a microvial, and an aliquot of extractant was injected into gas chromatography-mass spectrometry.

A novel needle trap sorbent based on carbon nanotube-sol-gel for microextraction of polycyclic aromatic hydrocarbons from aquatic media.

A new type of composite material based on carbon nanotubes (CNTs) and sol-gel chemistry was prepared and used as sorbent for needle trap device (NTD). The synthesized composite was prepared in a way to disperse CNTs molecules in a sol-gel polymeric network. CNT/silica composites with different CNT doping levels were successfully prepared, and the extraction capability of each composite was evaluated.