مهدی تقدیری

The principle of this research is based on the development of multi-residue method by QuEChERS sample preparation follow by gas chromatography with mass spectrometric detection in the selected ion monitoring mode (GC–MS-SIM) for the routine analysis of 42 pesticides in rice samples. The rice samples were initially extracted with acetonitrile, and the targeted pesticides were purified following the dispersive solid phase extraction (d-SPE) cleanup method. The calibration curve for each analyte quantified by matrix-matched calibration was linear over the concentration range of 10.0–1000.0 μg L−1 with a correlation coefficient range between 0.990 and 0.999. Mean recoveries from three replicates ranged from 79% to 112%, with satisfactory precision (RSD<7%). The limit of detection and the limit of quantification were in the range of 3.04–12.52 μg L−1 and 10.14–41.76 μg L−1 respectively, for all 42 pesticides.

Two new organic hybrids of phosphomolybdic acid (PMA) were prepared by means of hexamine (HMT) and HMT-Ni2+ complex. The effects of hybridization of HMT and Ni2+ were investigated on the photocatalytic activity of PMA. Characterization of hybrids were carried out by elemental analyses, Fourier transform infrared spectroscopy, powder X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry. The band gaps of PMA, phosphomolybdate-hexamine (PMA-HMT) and phosphomolybdate-hexamine-nickel (PMA-HMT-Ni) were determined from the diffuse reflectance spectra using the Tauc plots. Dye adsorption and photocatalytic properties of PMA-HMT and PMA-HMT-Ni hybrids were examined by studying the decolorization of model dyes methylene blue (MB), rhodamine B (RhB) and mixtures of MB and methyl orange (MO) solutions. The results show that the band gap of PMA-HMT-Ni is narrower and hence, its photocatalytic activity is higher for the degradation of dyes under sunlight irradiation. Mechanism of photodegradation was studied by adding scavengers. Removal is via combination of adsorption and then photocatalytic degradation through oxidation by radicals.

In this research, nano-silica coated with phosphotangestic acid was used as a new, effective and heterogeneous high-selectivity catalyst for the diastereoselective synthesis of trans-2,3-dihydrofuran during, multi-component one-pot and solventless reaction. In this reaction, the in-situ production and condensation of pyridinium bromide ylide are carried out with benzaldehyde and 4-hydroxy-coumarin derivatives. The size and shape of the catalyst were studied using detection methods such as scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FT-IR). Also, the BET analysis of this nano-catalyst showed a high surface area, which could be a factor in the good performance of this nano-catalyst. An induction coupled plasma analysis also confirmed the ability to recover of this nanocatalist.The reaction products were evaluated using FT-IR spectroscopy and melting point determination. High efficiency, short reaction time, solventless conditions and easy product separation method are the future advantages of this research.

In this work, a new, simple and fast method for the solid phase extraction-spectrophotometric determination of phosphate using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs) has been developed. The determination of phosphate is based on the molybdenum blue method which was monitored at λmax of 810 nm. MNPs and ACMNPs characterized by SEM, VSM, and XRD spectroscopy. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of CTAB@ACMNPs with an adscititious magnet. Under the optimal experimental conditions, the preconcentration factor (PF), detection limit (DL), linear range (LR) and relative standard deviation (RSD) of phosphate were 80 (for 400 mL of sample solution), 0.038 µg mL−1, 0.8-10.0 µg mL−1 and 2.5 % (for 5.0 µg mL-1, n=7), respectively. The proposed method was successfully applied to the separation/preconcentration and determination of phosphate in different water samples and suitable recoveries were obtained.

In the present research work 5 samples of powder detergent including famous optical brightneer were prepared.Except this optical brightneer, amount of other ingredients were same in all formulation.Then optimum amount of O.B. have been determined.

In the present research work 5 samples of powder detergent including famous optical brightneer were prepared.Except this optical brightneer, amount of other ingredients were same in all formulation.Then optimum amount of O.B. have been determined.