Dual-template imprinted polymer electrochemical sensor for simultaneous determination of malathion and carbendazim using graphene quantum dots.

Malathion (MAL) and carbendazim (CBZ) are organophosphate pesticides and fungicides, respectively. They are often used simultaneously in agriculture, and both have been shown to have harmful effects on humans and animals. Therefore, it is important to be able to measure both of these toxins simultaneously in order to assess their potential risks.

Voltammetric sensing of oxacillin by using a screen-printed electrode modified with molecularly imprinted polyaniline, gold nanourchins and graphene oxide.

An imprinted electrochemical sensor was developed for the determination of the antibiotic oxacillin (OXC). A screen-printed carbon electrode (SPCE) was modified with gold nanourchin and graphene oxide, and then aniline was electro-polymerized in the presence of OXC to obtain a molecular imprint on the SPCE. The morphologies in sequential modification processes and the electrochemical behavior of the modified SCPE were characterized by field emission scanning electron microscopy and cyclic voltammetry.

Temperature-controlled liquid-liquid microextraction combined with high-performance liquid chromatography for the simultaneous determination of diazinon and fenitrothion in water and fruit juice samples.

A simple, environmentally benign, and rapid method based on temperature-controlled liquid-liquid microextraction using a deep eutectic solvent was developed for the simultaneous extraction/preconcentration of diazinon and fenitrothion. The method involved the addition of deep eutectic solvent to the aqueous sample followed by heating the mixture in a 75°C water bath until the solvent was completely dissolved in the aqueous phase. Then, the resultant solution was cooled in an ice bath and a cloudy solution was formed.

Preparation of magnetic mesoporous silica composite for the solid-phase microextraction of diazinon and malathion before their determination by high-performance liquid chromatography.

A novel magnetic mesoporous silica material was synthesized and used as the sorbent for the magnetic solid-phase microextraction of diazinon and malathion before their quantification by high-performance liquid chromatography with UV detection. The sorbent was synthesized by a surfactant-templated one-pot sol-gel procedure using SiO -coated Fe O as the magnetic support, cetyltrimethylammonium bromide as the template and tetraethyl orthosilicate as the silicon source. The characteristics of the prepared sorbent were investigated using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction.

Development of a novel method for determination of mercury based on its inhibitory effect on horseradish peroxidase activity followed by monitoring the surface plasmon resonance peak of gold nanoparticles.

A highly sensitive and simple indirect spectrophotometric method has been developed for the determination of trace amounts of inorganic mercury (Hg(2+)) in aqueous media. The method is based on the inhibitory effect of Hg(2+) on the activity of horseradish peroxidase (HRP) in the oxidation of ascorbic acid by hydrogen peroxide followed by the reduction of Au(3+) to Au-NPs by unreacted ascorbic acid and the measurement of the absorbance of localized surface plasmon resonance (LSPR) peak of gold nanoparticles (at 530 nm) which is directly proportional to the concentration of Hg(2+). Under the optimum conditions, the calibration curve was linear in the concentration range of 1-220 ng mL(-1).

Simultaneous spectrophotometric determination of copper, cobalt, nickel and iron in foodstuffs and vegetables with a new bis thiosemicarbazone ligand using chemometric approaches.

A newly synthesized bis thiosemicarbazone ligand, (2Z,2'Z)-2,2'-((4S,5R)-4,5,6-trihydroxyhexane-1,2-diylidene)bis(N-phenylhydrazinecarbothioamide), was used to make a complex with Cu(2+), Ni(2+), Co(2+) and Fe(3+) for their simultaneous spectrophotometric determination using chemometric methods. By Job's method, the ratio of metal to ligand in Ni(2+) was found to be 1:2, whereas it was 1:4 for the others. The effect of pH on the sensitivity and selectivity of the formed complexes was studied according to the net analyte signal (NAS).

The comparison of sonochemistry, electrochemistry and sonoelectrochemistry techniques on decolorization of C.I Reactive Blue 49.

In this paper, the ability of three decolorization techniques including sonochemistry, electrochemistry and sonoelectrochemistry for decolorization of C.I Reactive Blue 49 in aqueous solutions have been compared. Various parameters affecting decolorization efficiency, such as pH, initial concentration of the dye, the decolorization time, H2O2 concentration and effect of applied potential on electrochemistry and sonoelectrochemistry, were evaluated.

Artificial neural network assisted kinetic spectrophotometric technique for simultaneous determination of paracetamol and p-aminophenol in pharmaceutical samples using localized surface plasmon resonance band of silver nanoparticles.

Spectrophotometric analysis method based on the combination of the principal component analysis (PCA) with the feed-forward neural network (FFNN) and the radial basis function network (RBFN) was proposed for the simultaneous determination of paracetamol (PAC) and p-aminophenol (PAP). This technique relies on the difference between the kinetic rates of the reactions between analytes and silver nitrate as the oxidizing agent in the presence of polyvinylpyrrolidone (PVP) which is the stabilizer. The reactions are monitored at the analytical wavelength of 420nm of the localized surface plasmon resonance (LSPR) band of the formed silver nanoparticles (Ag-NPs).

Simultaneous spectrophotometric determination of Fe(III) and Al(III) using orthogonal signal correction-partial least squares calibration method after solidified floating organic drop microextraction.

A solidified floating organic drop microextraction (SFODME) procedure was developed for the simultaneous extraction and preconcentration of Fe(III) and Al(III) from water samples. The method was based on the formation of cationic complexes between Fe(III) and Al(III) and 3,5,7,2',4'-pentahydroxyflavone (morin) which were extracted into 1-undecanol as ion pairs with perchlorate ions. The absorbance of the extracted complexes was then measured in the wavelength range of 300-450 nm.

Spectrophotometric determination of iron species using a combination of artificial neural networks and dispersive liquid-liquid microextraction based on solidification of floating organic drop.

A dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) and artificial neural networks method was developed for the simultaneous separation/preconcentration and speciation of iron in water samples. In this method, an appropriate mixture of ethanol (as the disperser solvent) and 1-undecanol (as the extracting solvent) containing appropriate amount of 2-thenoyltrifluoroacetone (TTA) (as the complexing agent) was injected rapidly into the water sample containing iron (II) and iron (III) species. At this step, the iron species interacted with the TTA and extracted into the 1-undecanol.

Speciation and determination of ultra trace amounts of chromium by solidified floating organic drop microextraction (SFODME) and graphite furnace atomic absorption spectrometry.

Solidified floating organic drop microextraction (SFODME) method in combination with graphite furnace atomic absorption spectrometry (GFAAS) has been used for the determination of chromium species in water and urine samples. 1-undecanol containing 2-thenoyltrifluoroacetone (TTA) was used as a selective chelating agent for the extraction of Cr(III). The total Cr was determined after the reduction of Cr(VI) to Cr(III) with hydroxylamine.

Chemometric-assisted kinetic-spectrophotometric method for simultaneous determination of ascorbic acid, uric acid, and dopamine.

A chemometric-assisted kinetic spectrophotometric method has been developed for simultaneous determination of ascorbic acid (AA), uric acid (UA), and dopamine (DA). This method relies on the difference in the kinetic rates of the reactions of analytes with a common oxidizing agent, tris(1,10-phenanthroline) and iron(III) complex (ferritin, [Fe(phen)(3)](3+)) at pH 4.4.