Simple and fast self-polymerization of benzidine using anodic exfloated graphene oxide nanosheet.

Nowadays, researchers are looking for green synthesis methods of polymers that solve the disadvantages of polymerization with different initiators and traditional methods. In this work, the self-polymerization process of benzidine by anodic exfloated graphene oxide Nanosheet electrode (AEGO Nsh) is reported for the first time in the world. The self-polymerization of benzidine onto AEGO Nsh electrode was done by an easy and simple method by anodizing the graphite sheet followed by immersing the AEGO Nsh electrode inside the benzidine monomer dissolved in organic and inorganic acid media.

Sensitive and Selective Determination of Benzidine by Synthesized tragacanth-poly (Acrylic acid-co-acrylamide-GQD) Hydrogel Nanocomposite as a Highly Stable Fluorescent Probe.

Benzidine is known as a toxic and highly carcinogenic substance, so its determination is an essential issue. Until now, no effective and stable fluorescent probe based on hydrogel nanocomposite has been reported for the determination of this substance. In this work, for the first time, the synthesis and use of tragacanth-poly (acrylic acid-co-acrylamide-GQD) hydrogel nanocomposite (H-GQD) as a novel, high-stable, and selective fluorescence hydrogel nanocomposite for the identification of benzidine is reported.

Area of Feasible Figures of Merit (AF-FOMs) for second-order multivariate calibrations in Multivariate Curve Resolution (MCR).

Background: The significance and necessity of using powerful multivariate curve resolution (MCR) techniques in the study and investigation of chemical systems are clear and obvious. It has long been recognized the importance of using second-order data to extract both quantitative and qualitative information in analytical chemistry through multivariate calibration instead of univariate calibration. Although the calculation of analytical figures of merit (AFOMs) in multivariate calibrations seems to be complicated, in recent years these parameters have been reported for each developed analytical method based on multivariate calibrations.

Photodecoration of tungsten oxide nanoparticles onto eggshell as an ultra-fast adsorbent for removal of MB dye pollutant.

Nowadays, the use of natural wastes and adsorbents along with their modification by simple and new methods based on metal oxides to remove dye pollutants has been the focus of many researchers. In this study, for the first time, simple and low-cost modification of eggshell (EGS) with tungsten oxide (WO) based on the photochemical modification method as a green, ultra-fast, cost-effective, and biodegradable adsorbent is reported to remove of methylene blue (MB) dye pollutant. The EGS modified by WO was investigated by EDX, EDX mapping, XRD, FE-SEM, and UV-Vis Diffuse Reflectance (DRS) analyses.

A near-infrared plasmonic biosensor for detection of morphine and codeine in biological samples based on the end-to-end assembly of modified gold nanorods.

The analytical determination of opiates in biological samples is a critical mission and remains a challenge for almost all judicial and clinical drug testing panels due to their high abuse potential. Based on the high sensitivity of the longitudinal surface plasmon resonance (LSPR) peak of gold nanorods (AuNRs), we successfully developed a novel and simple refractive index sensing platform for detection of morphine (MOR) and codeine (COD) by means of 2-amino-5-mercapto-1,3,4-thiadiazole functionalized gold nanorods (AMTD-AuNRs) in aqueous solution, which is, to the best of our knowledge, the first report on the assay of MOR and COD using AuNRs. AMTD molecules strongly anchor onto the tips of AuNRs the mercapto group and subsequent hydrogen-bonding interactions between AMTD and the analytes induced end-to-end chain assembly of AuNRs and a consequent decrease of the LSPR absorption band at 850 nm along with a bathochromic shift and emergence of a new hybridized plasmon mode at 1050 nm which was characterized using a Vis-NIR spectrophotometer.

Photochemical modification of tea waste by tungsten oxide nanoparticle as a novel, low-cost and green photocatalyst for degradation of dye pollutant.

So far, many adsorbents and nanocomposites have been synthesized by different methods and used to remove or degradation of dye pollutants. Nowadays, the use of natural adsorbents and their modification with simple methods based on metal oxides are of interest to many researchers. In this study, for the first time, we report the simple and low-cost modification of tea pomace waste (TPW) with tungsten oxide (WO) based on the photochemical method as a green, cost-effective, and biodegradable photocatalyst for the degradation of Rh B dye pollutant.

The study of the removal of penconazole fungicide from surface water using carboxymethyl tragacanth-based hydrogel grafted with poly (acrylic acid-co-acrylamide).

In this study, a polymeric adsorbent based on carboxymethyl tragacanth (CMT) grafted by poly acrylic acid-co-acrylamide (AAc-co-AAm) synthesized by radical polymerization for the first time was used to remove the fungicide penconazole (PEN) or Topas 20% from surface water. The parameters of solution pH, adsorption isotherm, and adsorption kinetics of PEN were studied by the synthetic adsorbent. The surface morphology and functional groups of CMT-g-poly (AAc-co-AAm) were confirmed by XRD, SEM and FT-IR techniques.

Comparison of volatile compounds of anal sac secretions between the sexes of domestic dog ().

Volatile compounds of anal sac secretions are odorant chemicals used across the carnivores for social communication such as identifying individuals and group membership. Odor profiles taken from expressed anal sac secretions of some species of carnivores have been detected in previous studies. In this study, the volatile compounds of anal sac secretions between five male and five female domestic dogs () were compared.

Highly-sensitive and fast detection of human telomeric G-Quadruplex DNA based on a hemin-conjugated fluorescent metal-organic framework platform.

The formation of G-quadruplex (G4) structures in Human telomeric DNA (H-Telo) has been demonstrated to inhibit the activity of telomerase enzyme that is associated with the proliferation of many cancer cells. Accordingly, G-quadruplex structures have become one of the well-established targets in anticancer therapeutic strategies. And, the development of simple and selective detection platforms for G4 structures has become a significant focus of research in recent years.

Modeling and optimization of simultaneous degradation of rhodamine B and acid red 14 binary solution by homogeneous Fenton reaction: a chemometrics approach.

This study aimed to propose a mathematical method to investigate and optimize the simultaneous elimination process of multiple organic pollutants using the Fenton process. Hence, the treatment of rhodamine B (RB) and acid red 14 (AR14) dyes in their binary solution was studied. Multivariate curve resolution alternating least square (MCR-ALS), a novel chemometric method, was applied along with correlation constraints to resolute the UV-Vis spectrophotometric data, enabling quantification of investigated dyes despite a high spectral overlapping.

Development of magnetic solid phase microextraction method for determination of the endocrine disrupting chemicals leached from reused plastic bottles.

Reuse of polyethylene terephthalate (PET) bottles for storage of water and liquid food is so common in some countries of the world. However, it can result in the migration of plastic components or additives into the stored liquids and threatening of human health. In this respect, the present study developed a method for determination of endocrine disrupting chemicals (EDCs) that might be released from reused disposable plastic containers.

Simultaneous colorimetric determination of morphine and ibuprofen based on the aggregation of gold nanoparticles using partial least square.

In this work a new method is presented for simultaneous colorimetric determination of morphine(MOR) and ibuprofen(IBU) based on the aggregation of citrate-capped gold nanoparticles (AuNPs). Citrate-capped gold nanoparticles were aggregated in the presence of morphine and ibuprofen. The difference in kinetics of AuNPs aggregation in the presence of morphine / ibuprofen was used for simultaneous analysis of morphine and ibuprofen.

Highly selective and sensitive determination of dopamine in biological samples via tuning the particle size of label-free gold nanoparticles.

Herein, a rapid, sensitive and selective approach for the colorimetric detection of dopamine (DA) was developed utilizing unmodified gold nanoparticles (AuNPs). This assay relied upon the size-dependent aggregation behavior of DA and three other structurally similar catecholamines (CAs), offering highly specific and accurate detection of DA. By means of this study, we attempted to overcome the tedious procedures of surface premodifications and achieve selectivity through tuning the particle size of AuNPs.

Hydrogen bonding recognition and colorimetric detection of isoprenaline using 2-amino-5-mercapto-1,3,4-thiadiazol functionalized gold nanoparticles.

In this paper, we describe a rapid, low-cost and highly sensitive colorimetric method for the detection of isoprenaline, based on 2-amino-5-mercapto-1,3,4-thiadiazol (AMTD) functionalized gold nanoparticles (AMTD-AuNPs) as a sensing element. Hydrogen bonding interaction between isoprenaline and AMTD resulted in the aggregation of AuNPs and a consequent color change of AuNPs from red to blue. The concentration of isoprenaline could be detected with the naked eye or a UV-visible spectrometer.

Second-order advantage obtained from standard addition first-order instrumental data and multivariate curve resolution-alternating least squares. Calculation of the feasible bands of results.

In order to achieve the second-order advantage, second-order data per sample is usually required, e.g., kinetic-spectrophotometric data.

Development of cloud point extraction using pH-sensitive hydrogel for preconcentration and determination of malachite green.

A novel and sensitive cloud point extraction procedure using pH-sensitive hydrogel was developed for preconcentration and spectrophotometric determination of trace amounts of malachite green (MG). In this extraction method, appropriate amounts of poly(styrene-alt-maleic acid), as a pH-sensitive hydrogel, and HCl were added respectively into the aqueous sample so a cloudy solution was formed. The cloudy phase consists of hydrogel particles distributed entirely into the aqueous phase.

Optimization of dispersive liquid-liquid microextraction of Co(II) and Fe(III) as their oxinate chelates and analysis by HPLC: Application for the simultaneous determination of Co(II) and Fe(III) in water samples.

In this study, dispersive liquid-liquid microextraction method was used for the preconcentration and simultaneous determination of Co(II) and Fe(III) in water samples as their oxinate chelates. In dispersive liquid-liquid microextraction process, methanol and chloroform were used as disperser and extracting solvents, respectively, and the ligand 8-hydroxy quinoline was used as a chelating agent for the extraction of Co(II) and Fe(III). HPLC was applied for the quantitation of the analytes after preconcentration.

Rank annihilation factor analysis using mean centering of ratio spectra for kinetic-spectrophotometric analysis of unknown samples.

In this work rank annihilation factor analysis (RAFA) using mean centering of ratio spectra was used to analyze the kinetic-spectrophotometric data. Annihilation of the contribution of one chemical component from the original data matrix is a general method in RAFA. However, sometimes, RAFA is not suitable for studying rank-deficient data such as kinetic-spectrophotometric measurements which involves closure rank deficiency.

A novel spectrophotometric method for the simultaneous kinetic analysis of ternary mixtures by mean centering of ratio kinetic profiles.

In this paper, a novel and very simple method was developed for the simultaneous spectrophotometric determination of ternary mixtures, without prior separation steps. The method is based on the mean centering of ratio kinetic profiles. The mathematical explanation of the procedure is illustrated.

Mean centering of ratio spectra as a new spectrophotometric method for the analysis of binary and ternary mixtures.

In this paper a new and very simple method was developed for the simultaneous determination of binary and ternary mixtures, without prior separation steps. This method is based on the mean centering of ratio spectra. The mathematical explanation of the procedure is illustrated.

Optimization and application of homogeneous liquid-liquid extraction in preconcentration of copper (II) in a ternary solvent system.

In this study a homogeneous liquid-liquid extraction based on the Ph-dependent phase-separation process was investigated using a ternary solvent system (water-acetic acid-chloroform) for the preconcentration of Cu(2+) ions. 8-Hydroxy quinoline was used as the chelating agent prior to its extraction. Flame atomic absorption spectrophotometry using acetylene-air flame was used for the quantitation of analyte after preconcentration.

Optimization of polymeric triiodide membrane electrode based on clozapine-triiodide ion-pair using experimental design.

Central composite design (CCD) and response surface methodology (RSM) were developed as experimental strategies for modeling and optimization of the influence of some variables on the performance of a new PVC membrane triiodide ion-selective electrode. This triiodide sensor is based on triiodide-clozapine ion-pair complexation. PVC, plasticizers, ion-pair amounts and pH were investigated as four variables to build a model to achieve the best Nernstian slope (59.

Optimization of dispersive liquid-liquid microextraction of copper (II) by atomic absorption spectrometry as its oxinate chelate: application to determination of copper in different water samples.

In this study a dispersive liquid-liquid microextraction (DLLME) method based on the dispersion of an extraction solvent into aqueous phase in the presence of a dispersive solvent was investigated for the preconcentration of Cu(2+) ions. 8-Hydroxy quinoline was used as a chelating agent prior to extraction. Flame atomic absorption spectrometry using an acetylene-air flame was used for quantitation of the analyte after preconcentration.

A new strategy for solving matrix effect in multivariate calibration standard addition data using combination of H-point curve isolation and H-point standard addition methods.

This work presents a new and simple strategy for solving matrix effects using combination of H-point curve isolation method (HPCIM) and H-point standard addition method (HPSAM). The method uses spectrophotometric multivariate calibration data constructed by successive standard addition of an analyte into an unknown matrix. By successive standard addition of the analyte, the concentrations of remaining components (interferents) remain constant and therefore give constant cumulative spectrum for interferents in the unknown mixture.

Artificial neural networks for determination of enantiomeric composition of alpha-phenylglycine using UV spectra of cyclodextrin host-guest complexes: comparison of feed-forward and radial basis function networks.

In this work feed-forward neural networks and radial basis function networks were used for the determination of enantiomeric composition of alpha-phenylglycine using UV spectra of cyclodextrin host-guest complexes and the data provided by two techniques were compared. Wavelet transformation (WT) and principal component analysis (PCA) were used for data compression prior to neural network construction and their efficiencies were compared. The structures of the wavelet transformation-radial basis function networks (WT-RBFNs) and wavelet transformation-feed-forward neural networks (WT-FFNNs), were simplified by using the corresponding wavelet coefficients of three mother wavelets (Mexican hat, daubechies and symlets).