Majid Soleimani

Using a new ligand for solid phase extraction of mercury.

The octadecyl silica cartridge as a sorbent and 4-bp db (1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) as a ligand is a simple, rapid and reliable method for extracting and preconcentrating of Hg(II) in real samples prior to cold vapor atomic absorption spectrometry. Sample solutions were passed through a column at pH 4.5 then retained mercury ions on the column were eluted with minimal amount of 0.01 M nitric acid with 3 mL min(-1) flow rate. The effect of pH, type of buffer, flow rate of sample and eluent, type and volume of the eluent were investigated and optimized. At optimum effective parameters, concentration factor and detection limit were achieved 128 and 1.87 ng L(-1), respectively.

Amino-Functionalization of Multiwall Carbon Nanotubes and Its Use for Solid Phase Extraction of Mercury Ions from Fish Sample

We describe here the amino-functionalization of multiwall carbon nanotubes (MWCNTs) and also its application as an adsorbent of solid phase extraction (SPE). The amino-functionalized MWCNTs have a good capacity to retain Hg2

A new and simple method for sulfur nanoparticles synthesis

Sulfur nanoparticles were successfully synthesized via novel water-in-oil microemulsion system. The microemulsion system contained cyclohexane as an oil phase, Triton X-100 as a surfactant, butanol as a co-surfactant and sodium polysulfide solution or hydrochloric acid solution as aqueous phase, respectively. The sulfur nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The results showed that the as-prepared monoclinic sulfur nanoparticles exhibited high purity and spherical shape with an average size of about 22 nm.

Ghezeljeh montmorillonite nanoclay as a natural adsorbent for solid phase extraction of copper ions from food samples

We demonstrate here the extraction and removal of Cu2+ ion from aqueous solutions by Ghezeljeh montmorillonite nanoclay as a new natural adsorbent material. A copper measurement is carried out by applying the solid phase extraction method in batch mode followed by atomic absorption spectroscopy. The clay is characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The results of XRD and FTIR of nanoclay confirm that montmorillonite is the dominant mineral phase. Based on SEM images of clay, it can be seen that the distance between the plates is nano. The limits of detection and quantification are 1 and 10 μg/L, respectively. The dynamic linear range is within the range of 10 to 50 μg/L. The adsorption capacity and preconcentration factor are 0.65 mg/g and 102, respectively. The experimental method has been successfully applied for the determination of Cu2+ ion in a variety of real water and food samples without interfering effect of various cations and anions.

Highly selective solid phase extraction of mercury ion based on novel ion imprinted polymer and its application to water and fish samples

A novel ion imprinted polymer (IIP) material has been synthesized for mercury ion. The IIP material is applied to the solid phase extraction (SPE) of Hg2+ from complex matrixes including water and fish samples. The IIP-SPE method is operated prior to cold vapor atomic absorption spectroscopy (CV-AAS) to determine mercury ion. In the polymer synthesis, mercury ion, 2-vinylpyridine, ethyleneglycol dimethacrylate and 2,2′-azobisisobutyronitrile are used as target, Hg2+ complexing reagent monomer, cross-linker and initiator, respectively. The polymer is characterized on the basis of FT-IR and thermal analysis (thermogravimetric, TGA; differential thermic, DTA; and differential scanning calorimetry, DSC). The obtained polymer block is ground, sieved and Hg2+ ions are removed from polymer particles by leaching with EDTA, which leaves a cavity in the polymer particles. The maximum Hg2+ adsorption capacity of IIP is 24.6 mg/g. Effective parameters on retaining Hg2+ such as pH, flow rate of sample and eluent, nature of the eluent, ionic strength, selectivity coefficient and retention capacity are investigated. The detection limit and the relative standard deviation are 5 × 10−4 ng/mL and 2.4%, respectively. After 20 adsorption cycles, the recovery of Hg2+ on IIP is only decreased by 3.2%. The column selective adsorption experiments of Na+, Cu2+, Pb2+, Cd2+, Ca2+ and Mg2+ ions with respect to mercury are conducted by using imprinted and non-imprinted polymer. These results showed that the IIP is highly selective for Hg2+ over the other metals.

Ligand-Capped CdTe Quantum Dots as a Fluorescent Nanosensor for Detection of Copper Ions in Environmental Water Sample

AbstractIn this work, as a novel fluorescent nano-sensor, a ligand-capped CdTe QDs (CdTe-L QDs) was designed for the detection and quantification of Cu2+ ions in environmental water samples. The synthesized QDs were characterized by transmission electron microscopy (TEM), thermo-gravimetric (TG) analysis, Fourier transform infrared (FTIR), UV–Vis spectrophotometry and fluorescence spectroscopy. Optical properties of the produced nanosensor were monitored by UV–Vis and fluorescence spectrophotometry. It was observed that fluorescence intensity of the produced nano-sensor selectively quenched by adding Cu2+ ions in comparison to other metal ions tested. Using CdTe-L QDs, a rapid and facile analytical method was developed to determine Cu2+ ions in the concentration range of 5.16 ± 0.07 × 10− 8 mol L− 1–1.50 ± 0.03 × 10− 5 mol L− 1 with a detection limit of 1.55 ± 0.05 × 10− 8 mol L− 1. The nanosensor was successfully applied for the determination of Cu2+ ions in various water samples, and the results were compared with the standard method. Graphical Abstract

PARTIAL LEAST SQUARES FOR SIMULTANEOUS DETERMINATION OF FE(III) AND HG(II) IN WATER AND PHARMACEUTICAL PREPARATIONS BY RP-HPLC USING 1,4-BIS-(4-PYRIDIL)-2,3-DIAZO-1,3-BUTADIENE CHELATING AGENT

A method has been developed for simultaneous determination of Fe(III) and Hg(II) by RP-HPLC, utilizing partial least squares technique. Vertex C 18 , with UV-visible detector was applied in reversed phase high performance liquid chromatography, while 1,4-bis-(4-Pyridil)-2,3-diazo-1,3-butadiene (4-bpdb) was added to the mobile phase as the chelating agent. Several effective parameters e.g. mobile phase make up, buffers, concentration of 4-bpdp and pH salts were investigated in order to optimize the quantification conditions. The optimum condition was achieved at 25°C, 10% methanol containing mobile phase, 30 mmol L -1 acetate buffer, 0.05 mmol L-1 4-bpdb and pH=4.5. Partial least squares chemometric technique was applied. The root mean square error (RMSE) of independent test set in the optimized model was 0.024 and 0.393 for Fe(III) and Hg(II) respectively.

Octaethylporphyrin as an ionophore for aluminum potentiometric sensor based on carbon paste electrode

A new sensor to quantitatively sense aluminum in real sample conditions is presented that uses the potentiometric ion selective electrodes. Aluminum is a cation that plays an important role in the environmental process. This approach is proposed to determine aluminum levels in real samples in the required range (10−6–10−2 M). Carbon paste electrode (CPE) is introduced here as a potentiometric sensor to measure free concentration of aluminum ion. Octaethylporphyrin (OEP) acts as a selective aluminum recognition agent in the CPE. The suitable selectivity coefficient is obtained for the CPEs compare to interfering cation. The Nernstian slope and detection limit are achieved 18.4 mV/decade and 2.5 × 10−6 M Al3+, respectively. Finally, the proposed method is applied to determine aluminum concentration in real water samples and the result of this method is in agreement with the result of atomic absorption spectroscopy (AAS).

Catalytic performances of copper and lead (2-guanidino-benzimidazoliume) complexes in polybutadiene (PB) and hydroxyl-terminated PB epoxidation

Polybutadiene (PB) and hydroxyl-terminated PB were epoxidized using in situ-generated dimethyl dioxirane as an oxidant in the attendance of different concentrations of copper and lead (2-guanidinobenzimidazoliume) (GBH) complexes as the catalyst at 25°C. The potential of cis, trans, and vinyl double bonds toward epoxidation was considered in detail at various reaction times. The products were characterized using proton nuclear magnetic resonance and Fourier transform infrared spectroscopy techniques and data revealed that the formation of desired products were obtained without any side reaction. The results indicated the performance of calculated 0.252 mmol of GBH complexes in obtaining maximum epoxidation yield as well as selectivity in the epoxidation of cis double bonds in comparison with trans and vinyl ones.

A Simple and High Resolution Ion-Pair HPLC Method for Separation and Simultaneous Determination of Nitrate and Thiocyanate in Different Water Samples

An ion-pair reversed-phase high-performance liquid chromatography method with isocratic elution and ultraviolet detection was developed and validated for the separation and simultaneous determination of nitrate and thiocyanate. The separation was performed on a C18 analytical column with mobile phase containing 0.08 mM hexadecyltrimethylammonium bromide as an ion-pair reagent, 40 mM of acetate buffer and 30% methanol at pH 3.2. The detection was monitored at 206 nm. The response was linear from 1 to 10 mM for nitrate, with a detection limit of 0.05 mM, and 1 to 10 mM for thiocyanate, with a detection limit of 0.31 mM. Calibration curves were found to be linear in these concentration ranges with correlation coefficient better than 0.99.