Iranian Journal of Analytical Chemistry
Volume:7 Issue: 1, Winter and Spring 2020

The use of a polymer inclusion membrane (PIM) as a sensing material is a novel approach to overcome the selectivity and stability of the optical chemical sensor (optode). In this work, non-plasticized PIM containing poly vinyl chloride (PVC) as a support base, 2-(2-benzothiazolylazo)phenol (BTAP)  as a reagent and Aliquat 336 as a fixed carrier (ionophore) was prepared and its performance was tested for application in an optode to determine Fe3+‏ ions. The results showed that PIM properties are greatly affected by the membrane composition. The studies revealed that the optode response was dependent on film thickness, the presence of plasticizer, stirring effect, concentration of BTAP, concentration of Aliquat 336 and pH of the aqueous solution used. A linear calibration curve in the range from 5.0–210 ng mL−1 of Fe3+, with a detection and quantification limits of 1.60 and 4.95 ng mL−1, respectively were obtained. The maximum wavelength (λmax) for the PIM based optical optode was 581 nm. The PIM developed in this investigation was found to be stable, has good mechanical strength, sensitive and reusable. Lastly, the PIM was successfully applied as an optical sensor to determine Fe3+ ions in natural water, food, biological and environmental samples, and the obtained result is comparable to atomic absorption spectrometry method.

In present work Hengam island sands were used for preparation of new magnetic nano-adsorbent. These sands have intrinsic magnetic properties due to possess specific compounds such as Fe3O4. It was modified by surface activator agent namely 3-(Glycidyloxypropyl)trimethoxysilane to produce effective nano-adsorbent. After preparation of this nano-adsorbent, Its physical and chemical properties was verified using several techniques such as FTIR, TGA/DTG, XRD and SEM. Nano-adsorbent was used as a solid phase to extraction of cetirizine from aqueous solutions and then its determination was done by HPLC. Effective analytical parameters such as pH of sample solution (pH=4), dosage of nano-adsorbent (100 mg), zero charge (pHz=5), breakthrough volume (500 mL) and contact time (15 min) were evaluated and optimized. Furthermore, figures of merit parameters such as precision (RSD=1.44%), limit of detection (LOD=1.1 µg L-1) and linear dynamic range (LDR=0.01-250 mg L-1) were obtained. Also for validation the accuracy of method, amount of cetirizine in two real samples were successfully determined.

In this research a graphene oxide/zinc oxide nanocomposite (GO/ZnO) was synthesized and employed for simple and sensitive pipette tip-based micro-solid phase extraction (PT-µSPE) of nalidixic acid (NA) from seawater and human blood plasma samples following by its determination by spectrophotometry. Several parameters affecting the suggested protocol were optimized, namely type and volume of eluent, amount of sorbent, sample volume, number of cycles of extraction and elution, pH of sample solution and type and amount of salt. The optimization performed by both response surface methodology (RSM) and one-variable-at-a-time techniques. Figures of merit were achieved as: detection limit; 0.30 µg L-1, enrichment factor 40 for NA, linear calibration curve in the range of 1.0-200.0 µg L-1; and reproducibility (as RSD %) better than 4.4%. Results for the application of the technique in seawater and human blood plasma showed that this analysis method can be applied for the determination of the analyte in complex real samples successfully.

Physicochemical characterization was carried out for the determination of the quality of drinking tap water from Masha, and Mizan-Aman town southwest Ethiopia. Known volume of tap water samples were digested by Standard Method 3030K microwave digestion system using 5 mL concentrated of HNO3 for 20 minutes at variable temperature (160-170 oC). After digestion with microwave acid digestion, some selected metals (Mg, Ca, Cu, Mn, Fe, Zn, Cd & Pb) were determined by Flame Atomic Absorption Spectrophotometer and the common anions were determined as follows, Ortho phosphorous (PO43-) by APHA4500-PC.Vanadomolybdphosphoric method, Chloride (Cl-) by APHA4500-Cl-B. Argentometric method, Carbonate(CO3-2) by APHA 2330B.Titration method, Nitrate (NO3-) and ammonia (NH3) by WTD photometer method (WAG PHOT-24).The concentration of these metals and common anions obtained in this study were found to be within the range of WHO and other international guideline lines except Cd. Levels of these metals concentration in this study was that, in all water samples, Mg was found in higher concentration followed by Ca, Fe, Mn, Zn, Cu and Cd respectively. Concentration of Pb was below the method detection limit in all water samples. Under this investigation, at p = 0.05, the physicochemical parameters of all water samples which were taken from different sites were significantly different among the distribution points and distribution systems. The concentrations of the selected metals and common anions were significantly different in between the distribution points and distribution systems except Zn in Mizan, Mn, Fe and Cd in Aman, NH3 in Masha, and Aman sites and in respective of the physical parameters, temperature and electrical conductivity of all the water samples were significantly different except in Masha site. pH and total hardness of all water samples were not significantly different in all sites except total hardness in Masha site.

A simple, green and sensitive method namely in situ solvent formation microextraction (ISFME) based on the use of 1-Octyl-3-methylimidazolium hexafluorophosphate [Omim][PF6] as an ionic liquid/green extractant (eco-friendly) was proposed for the concentration and deternination trace levels of cadmium(II) ions as dangerous pollution agent in some real and saline samples. In this method, cadmium(II) ions was complexed with a Schiff bases ligand (L) as complexing agent and then extracted into an ionic liquid phase (secoundary phase) as green/eco-friendly extractant. After phases separation, the enriched Cd(II) ions in the secoundary phase was determined by flame atomic absorption spectrometer (FAAS). The effect of some analytical parameters were investigated and optimized. In the optimum conditions, the limit of detection (LOD), relative standard deviation (RSD) and enhancement factor (EF) were 0.05 µg L−1, 1.2% and 93, respectively. The accuracy of the method was confirmed by analyzing of a certified reference matter. Based on the obtained results, the method was successfully applied for the determination of cadmium(II) ions in several real and saline samples.

In this research study Polypyrrole nanoparticles were synthesized on the copper surface using the amperometry technique, and their morphology, particle size, and thermal properties were investigated. Titanium dioxide particles were added to the texture of polypyrrole nanoparticles as the filler in order to increase electron transfer in the active layer of the solar cell. Polypyrrole nanoparticles were electrochemically synthesized in the shortest time possible with an ideal morphology and a particle size of less than 40 nm using a new multi-step amperometry technique. The results of EDAX analysis confirmed the existence of titanium particles in the texture of polypyrrole. The crystal size was determined through XRD analysis. SEM images confirmed the uniform and spherical appearance of polypyrrole nanoparticles with spongy and porous structures. Based on the results, the increase in the efficiency of the prepared solar cell based on polypyrrole/TiO2 nanocomposite coated on the copper surface (compared to common polymeric solar cells) was 39.7%. Application of copper as the conductive metal surface improves the electrical conductivity .

In this study, Magnetic Fe3O4-walnut sawdust nanocompositewas synthesized and used for removal of lead from aqueous solution. The size, structural, optical and morphological properties of nanoparticles have been analyzed by Scanning Electron Microscope )SEM) and Dynamic Light Scattering method. The effect of pH, contact time, adsorbent dose, initial concentration, ionic strength and the effect of temperature on the adsorption was checked out in a batch process mode. Using the equilibrium constants obtained at different temperatures, the thermodynamic results parameters were calculated as ∆G, ∆H and ∆S. The thermodynamic parameters showed that the uptake of lead is spontaneous and endothermic. The data were fitted with the Langmuir and Freundlich equations to describe the adsorption equilibrium. The maximum adsorption capacity by using Langmuir equation was calculated 12.99 mg/g. The kinetic data followed by Pseudo second. Owing to such outstanding features, Magnetic Fe3O4-walnut sawdust nanocompositeproved the great potential in adsorption lead removal from aqueous solutions.

N-salicyloyl tryptamine derivatives as anti-neuroinflammatory agents have a potent strategy to cure neuroinflammatory diseases including Alzheimer and Parkinson. Computational methods of quantitative structure properties relationships (QSPR) and molecular dynamics were successfully used to design of four novel N-salicyloyl tryptamine with improved properties. The QSPR model of five variables was presented to predict anti- neuroinflammatory activity of N-salicyloyl tryptamine derivatives. The quantum descriptors as Hartree Fock energy, ionization energy, softness, dipole moment and the thermal energy, were calculated with density functional theory at the B3LYP/6-311G level. Cross validation of multivariate linear regression (MLR) was used to build and evaluate the model QSPR. The model possesses coefficients of the highest squared correlation coefficient (R2) of 0.900 for the training set and 0.817 for the test set. The statistical results exhibited high internal and external consistency as demonstrated by the validation methods. Three of designed compounds showed good pharmacokinetic properties by QSPR predictions. These results provided strong guidance for the discovery and design of novel potential anti- neuroinflammatory compounds. Also, the adsorption of the designed compounds on functionalized carbon nanotube (8, 0) was investigated using molecular dynamics simulation with COMPASS force field. Results indicated that the adsorption of designed N-salicyloyl tryptamine derivatives on f-CNT involves a partial π–π interaction and hydrogen bonding. The study of investigation the interactions of N-salicyloyl tryptamine with f-CNT (8, 0) can be useful for finding the main CNT-based carriers for these derrivatives.

In this study a new method by using graphene oxide (GO) Nano sheets-melamine composites and derivation of Poly (Styrene –alternative- Maleic Anhydride) (SMA), (SMA+Melamine) (SMA-M) were presented as Sorbents for the elimination of Lead ions from aqueous solutions. The adsorbents have the sufficiency to adsorb the Lead ions. Through the immobilization of melamine onto GO Nano sheets, the desired composite was synthesized and identified by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy and absorption atomic spectroscopy (AAS) techniques. The various experimental parameters such as pH and concentration of the aqueous solution of Lead (II) ion, the content of the Lead (II) ion the grapheme oxide-Melamine and SMA-M have been optimized. It was shown that the uptake efficiency of Lead (II) ion considerably increased after immobilization of Melamine on the GO Nano sheets and SMA.

In this research, a new modeling method based on three-layer artificial neural network (ANN) technique was applied to predict the extraction yield of copper-morin complex from aqueous samples by means of molecularly imprinted stir bar sorptive extraction. Input variables of the model were pH of the solution, absorption and desorption times, stirring rate, temperature, and amount of morin ligand; while the output was extraction yield of copper ions. It was found that a network with 12 hidden neurons is highly accurate in predicting extraction recovery of copper-morin complex. The mean squared error and correlation coefficient between the experimental data and the ANN predictions were achieved as 0.0009 and 0.9999 for training, 0.0032 and 0.976 for validation and 0.0030 and 0.96666 for testing data sets. Under the optimum conditions, the linear range found to be in the range of 5-1000 μg L-1 with the detection limit of 0.38 μg L-1. The relative standard deviation was obtained to be below 5.3%. The method was successfully applied for preconcentration and determination of Cu in a few real samples.

In this study, a simple and sensitive method was developed for pre-concentration of spirotetramat (SPT) using the ionic liquid-based dispersive liquid-liquid microextraction. After extracting of SPT into 1-butyl-3-methylimidazolium hexafluorophosphate (ionic liquid), the insecticide was injected into HPLC system for determining. Under the optimum conditions, the developed method provided a linearity in the range of 0.05–2.0 µg mL-1 with R2= 0.9987, and also enrichment factor was 250. The detection limit and relative standard deviation of the developed method were 0.01 µg mL-1 and 2.7%, respectively. The proposed method was successfully applied to the pre-concentration and determination of SPT in spiked water samples with mean recoveries 94.0-96.0%.