Solvent-Focused Gas Chromatographic Determination of Thymol and Carvacrol Using Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction through Solidifying Floating Organic Droplets (USA-DLLME-SFO).

An ultrasound-assisted dispersive liquid-liquid microextraction by solidifying floating organic droplets, coupled to a form of temperature-programmed gas chromatography flame ionization detection, has been developed for the extraction and determination of thymol and carvacrol. This method utilizes undecanol as the extraction solvent, offering advantages such as facilitating phase transfer through solidification and enhancing solvent-focusing efficiency. The optimal gas chromatography conditions include a sample injection volume of 0.

Accelerating Surface Photoreactions Using MoS-FeS Nanoadsorbents: Photoreduction of Cr(VI) to Cr(III) and Photodegradation of Methylene Blue.

Nanocubic MoS-FeS, as a photocatalyst, was synthesized with high catalytic active edges and high specific surface areas with the capability of absorbing visible light. The results showed that the photocatalytic efficiency of nanocubic MoS-FeS for adsorption/degradation of methylene blue (MB) as well as the reduction of Cr(VI) was high. The adsorption process was found to follow a kinetic model of a pseudo-second-order kind ( = 464 mg g) along with an isotherm described by the Langmuir model with = 340 mg g.

Introducing hierarchical hollow MnO microspheres as nanozymes for colorimetric determination of captopril.

A simple sensor was developed for the colorimetric determination of captopril (CPT). Herein, hierarchical hollow MnO microspheres (HH-MnO) were applied as nanozymes with peroxidase-mimetic activity. Free cation radicals with a strong absorption signal (λ at 653 nm) were generated via a redox reaction between 3, 3', 5, 5'-tetramethylbenzidine (TMB) and HH-MnO.

A novel selective and sensitive multinanozyme colorimetric method for glutathione detection by using an indamine polymer.

A sensitive and selective novel multinanozyme colorimetric method for glutathione (GSH) detection was developed. MnO-nanozymes can catalyze the oxidation reaction of 3, 3՛-diaminobenzidine (DAB) and produce a brown indamine polymer. In the presence of GSH, this reaction slowly proceeds.

A field-applicable colorimetric assay for notorious explosive triacetone triperoxide through nanozyme-catalyzed irreversible oxidation of 3, 3'-diaminobenzidine.

A field-applicable colorimetric assay for fast detection of notorious explosive triacetone triperoxide (TATP) has been developed through the selective irreversible oxidation of 3, 3'-diaminobenzidine by hydrogen peroxide (HP) liberated during the acidic hydrolysis/degradation of TATP in the presence of MnO nanozymes. The generated HP was detected by probing the absorbance of the product (indamine polymer) of the 3, 3'-diaminobenzidine (DAB) oxidation reaction at 460.0 nm.

Employment of a natural deep eutectic solvent as a sustainable mobile phase additive for improving the isolation of four crucial cardiovascular drugs by micellar liquid chromatography.

Modification of micellar liquid chromatography (MLC) with a natural deep eutectic solvent (NADES) and butanol was effectively performed for analysis of four crucial cardiovascular drugs namely aspirin, atorvastatin, metformin, and metoprolol. The multivariate software tools were employed for screening and optimizing the primary experimental parameters including sodium dodecyl sulphate concentration ([SDS]) as well as the volume percentages of NADES, butanol, and glacial acetic acid (GAC). By using the desirability function, the optimal framework of the mobile phase was obtained at volume ratio of 83:10:3.

Electrochemical sensing of hydrogen peroxide using a glassy carbon electrode modified with multiwalled carbon nanotubes and zein nanoparticle composites: application to HepG2 cancer cell detection.

A nanobiocomposite was prepared from multiwalled carbon nanotubes and zein nanoparticles. It was dispersed in water/ethanol and drop cast onto a glassy carbon electrode. The modified electrode can be used for electroreduction of HO (typically at a working potential of -0.

Designing a sustainable mobile phase composition for melamine monitoring in milk samples based on micellar liquid chromatography and natural deep eutectic solvent.

Modified micellar liquid chromatography (MLC) with a natural deep eutectic solvent (NADES), produced from choline chloride (ChCl) and ethylene glycol (EG), was employed for melamine (MEL) monitoring in milk matrix. This sustainable mobile phase was attained through chemometrical optimization of crucial variables including concentration of sodium dodecyl sulphate ([SDS]) along with volume percentages of both NADES and glacial acetic acid (GAC). The desirability function and central composite design were utilized as chemometrical tools.

Quantitative structure-retention relationship for chromatographic behaviour of anthraquinone derivatives through considering organic modifier features in micellar liquid chromatography.

A simple and informative quantitative structure-retention relationship (QSRR) model has been introduced for prediction of retention times in some anthraquinone derivatives using reversed-phase micellar liquid chromatography (MLC) technique. In the developed multiple linear regression model, the structural descriptors of analytes as well as the empirical parameters of organic modifiers in the applied MLC systems have been considered. Retention times of 77 chromatographic samples (16 anthraquinones were evaluated by using 6 different organic modifiers) were experimentally determined and utilized as the independent variables of the QSRR model.

Analysis of malondialdehyde in human plasma samples through derivatization with 2,4-dinitrophenylhydrazine by ultrasound-assisted dispersive liquid-liquid microextraction-GC-FID approach.

A sensitive and reliable ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) procedure was developed and validated for extraction and analysis of malondialdehyde (MDA) as an important lipids-peroxidation biomarker in human plasma. In this methodology, to achieve an applicable extraction procedure, the whole optimization processes were performed in human plasma. To convert MDA into readily extractable species, it was derivatized to hydrazone structure-base by 2,4-dinitrophenylhydrazine (DNPH) at 40 °C within 60 min.

Simultaneous determination of captopril and hydrochlorothiazide by using a carbon ionic liquid electrode modified with copper hydroxide nanoparticles.

A carbon electrode modified with the ionic liquid octylpyridinium hexafluorophosphate and copper hydroxide nanoparticles was employed in an electrochemical assay for simultaneous determination of captopril (CPT) and hydrochlorothiazide (HCT). The electrode showed two well-defined oxidation peaks for CPT (at 0.22 V) and HCT (at 0.

Green-modified micellar liquid chromatography for isocratic isolation of some cardiovascular drugs with different polarities through experimental design approach.

Bilayer pseudo-stationary phase micellar liquid chromatography (MLC) was developed for simultaneous isocratic isolation of hydrochlorothiazide, as a basic-polar (hydrophilic) cardiovascular drug, as well as triamterene and losartan potassium, as acidic-nonpolar (hydrophobic) cardiovascular drugs. Utilizing a deep eutectic solvent (DES), as a novel green mobile phase additive in combination with acetonitrile (ACN) and acetic acid (ACA), drastically improved the chromatographic behavior of the drugs. Concentration of sodium dodecyl sulphate (SDS), as well as volume percentages of ACN, DES, and ACA were optimized by using a central composite design.

Chiral recognition of tryptophan enantiomers using chitosan-capped silver nanoparticles: Scanometry and spectrophotometry approaches.

A new, fast and inexpensive colorimetric sensor was developed for chiral recognition of tryptophan enantiomers using chitosan-capped silver nanoparticles. The function of the sensor was based on scanometry and spectrophotometry of the colored product of a reaction solution containing a mixture of chitosan-capped silver nanoparticles, phosphate buffer and tryptophan enantiomers. The image of the colored solution was taken using the scanometer and the corresponding color values were obtained using Photoshop software which subsequently were used for optimization of the experimental parameters as the analytical signal.

Chiral recognition of naproxen enantiomers based on fluorescence quenching of bovine serum albumin-stabilized gold nanoclusters.

A simple, fast and green method for chiral recognition of S- and R-naproxen has been introduced. The method was based on quenching of the fluorescence intensity of bovine serum albumin-stabilized gold nanoclusters in the presence of naproxen enantiomers. The quenching intensity in the presence of S-naproxen was higher than R-naproxen when phosphate buffer solution at pH7.

Gas-assisted dispersive liquid-phase microextraction using ionic liquid as extracting solvent for spectrophotometric speciation of copper.

Gas-assisted dispersive liquid-phase microextraction (GA-DLPME) has been developed for preconcentration and spectrophotometric determination of copper ion in different water samples. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate and argon gas, respectively, were used as the extracting solvent and disperser. The procedure was based on direct reduction of Cu(II) to Cu(I) by hydroxylamine hydrochloride, followed by extracting Cu(I) into ionic liquid phase by using neocuproine as the chelating agent.

A rapid and sensitive assay for determination of doxycycline using thioglycolic acid-capped cadmium telluride quantum dots.

A rapid, simple and inexpensive spectrofluorimetric sensor for determination of doxycycline based on its interaction with thioglycolic acid-capped cadmium telluride quantum dots (TGA/CdTe QDs) has been developed. Under the optimum experimental conditions, the sensor exhibited a fast response time of <10s. The results revealed that doxycycline could quench the fluorescence of TGA/CdTe QDs via electron transfer from the QDs to doxycycline through a dynamic quenching mechanism.

A comparative study for adsorption of lysozyme from aqueous samples onto Fe3O4 magnetic nanoparticles using different ionic liquids as modifier.

In this paper, nanoparticles of Fe3O4 as well as their modified forms with different ionic liquids (IL-Fe3O4) were prepared and used for adsorption of lysozyme. The mean size and the surface morphology of the nanoparticles were characterized by TEM, XRD and FTIR techniques. Adsorption studies of lysozyme were performed under different experimental conditions in batch system on different modified magnetic nanoparticles such as, lysozyme concentration, pH of the solution, and contact time.

Highly sensitive colorimetric determination of amoxicillin in pharmaceutical formulations based on induced aggregation of gold nanoparticles.

A novel, simple and highly sensitive colorimetric method is developed for determination of Amoxicillin (AMX). The system is based on aggregation of citrate-capped gold nanoparticles (AuNP) in acetate buffer (pH=4.5) in the presence of the degradation product of Amoxicillin (DPAMX).

Photodegradation study of nystatin by UV-Vis spectrophotometry and chemometrics modeling.

Nystatin, one of the tetraene antifungal antibiotics, is very sensitive to light. Thus, when nystatin is exposed to natural daylight, it is photodegraded to products of lower biological activity. In this work, the photodegradation kinetics of nystatin was monitored by a UV-Vis spectrophotometry method.

A novel methodology for analysis of enantiomers through determination of their critical micelle concentrations using spectrophotometric method.

A novel methodology for analysis of enantiomer composition of chiral compounds based on measuring of their critical micelle concentration by using spectrophotometric technique is introduced. The proposed method does not require any chiral selector and the corresponding process is simple, fast, reproducible, and inexpensive. The procedure was successfully applied for analysis of naproxen.

Characterization of a novel organic solvent tolerant protease from a moderately halophilic bacterium and its behavior in ionic liquids.

An extracellular protease was purified from a novel moderately halophilic bacterium Salinivibrio sp. strain MS-7 by the combination of an acetone precipitation (40-80 %) step and a DEAE-cellulose anion exchange column chromatography. Kinetic parameters of the enzyme exhibited V(max) and K(m) of 130 U/mg and 1.

Construction of an optical sensor for the determination of ascorbic acid using ionic liquids as modifier.

An optode was designed for an indirect determination of ascorbic acid by using neocuproine, which has been coated on transparent triacetylcellulose film as a membrane. The proposed method is based on the oxidation of ascorbic acid to dehydroascorbic acid with the Cu(II) and neocuproine reagent. The increase in the absorbance value of the optode at the maximum wavelength of 455 nm was related to the ascorbic acid concentration in aqueous samples.

Investigating the parameters affecting the adsorption of amino acids onto AgCl nanoparticles with different surface charges.

In this paper, adsorption behaviors of typical neutral (alanine), acidic (glutamic acid) and basic (lysine) amino acids onto the surfaces of neutral as well as positively and negatively charged silver chloride nanoparticles were examined. Silver chloride nanoparticles with different charges and different water content were synthesized by reverse micelle method. The adsorptions of the above mentioned amino acids onto the surfaces of differently charged silver chloride nanoparticles were found to depend strongly on various parameters including pH of the aqueous solution, type of amino acid, water to surfactant mole ratio, and type of charges on the surfaces of silver chloride nanoparticles.

Removal of reactive red-120 and 4-(2-pyridylazo) resorcinol from aqueous samples by Fe3O4 magnetic nanoparticles using ionic liquid as modifier.

The nanoparticles of Fe(3)O(4) as well as the binary nanoparticles of ionic liquid and Fe(3)O(4) (IL-Fe(3)O(4)) were synthesized for removal of reactive red 120 (RR-120) and 4-(2-pyridylazo) resorcinol (PAR) as model azo dyes from aqueous solutions. The mean size and the surface morphology of the nanoparticles were characterized by TEM, DLS, XRD, FTIR and TGA techniques. Adsorption of RR-120 and PAR was studied in a batch reactor at different experimental conditions such as nanoparticle dosage, dye concentration, pH of the solution, ionic strength, and contact time.