Iranian Journal of Analytical Chemistry
Volume:10 Issue: 1, Winter and Spring 2023

In recent years, the presence of bisphenol A in food, drinking water, and toys is considered as a toxic compound. In this research, a Fabric-phase sorptive extraction using an organic-inorganic coating as an adsorbent was used to separate bisphenol A in different samples. The isolated bisphenol A was measured by high-performance liquid chromatography. The organic-inorganic coating was done with other methods. Optimal conditions for selecting the type of fabric and bis phenol A extraction were obtained by the central composite design in 3 and 5 variables according to the response surface methodology. At first, the influencing factors in NFPSE such as fabric type, number of sol-gel connections, and binding time were investigated. Also, the effects of different parameters on adsorption such as sample volume, adsorption time, solution desorption volume, desorption time and pH were examined. The calibration curve in the region (0.1-15 ng.mL-1) for bisphenol A was linear with a correlation coefficient of more than 99%.The detection limit (LODs)andthe limit of quantificationwere 0.11 ng.mL-1 and 0.37 ng.mL-1 respectively.Repeatability (RSD) with three replicated experiments was 1.25%.The recovery was obtained for different samples in the range of 95 to 97 %. According to the obtained results, the method mentioned in this research can be introduced as a reproducible method with a high absorption capacity for bisphenol A determination in drinking water and toys.

Effect of fibers of seeds inside Cucumis melon (Persian melon) extract (FE) and Cucumis melon leaves extract (LE) were investigated as descaler and inhibitor. In one part of this research, the effect of LE and FE for the solvent of Ca precipitates was investigated by gravimetric and electrochemical measurements. The decrease in the weight of calcium precipitate in the solution containing the extracts shows that the FE has the best effect as a solvent of Ca precipitate with 62% efficiency due to lower pH. A comparison of the hardness of the solutions after dissolving the calcium precipitate shows an increase of about 3 times the hardness of the solution containing FE compared to the blank. The second part is dedicated to the study of corrosion inhibition behavior of extracts on Cu corrosion in brine and acid solution by Tafel plot and electrochemical impedance spectroscopy (EIS). The solution containing the LE and FE shows higher polarization resistance (Rp) (about 3.5 times) and lower corrosion current density than the blank solution. While the LE shows more positive potential than the FE. Based on the results,the FE can be used to formulate a low-cost and environmentally friendly descaling agent, and the LE can be used as a green corrosion inhibitor.

In this study, the differential pulse voltammetry (DPV) method was used to simultaneously determine bismuth and copper concentrations. A 25 bismuth and copper mixtures at the designed ratio were measured using the DPV technique. However, the overlapping differential pulse voltammograms obtained made it difficult to quantitatively analyze the concentrations based on adaptive peak current selection. To address this issue, the voltammograms were preprocessed using derivatization and peak subtraction. The second derivative voltammogram was found to be highly correlated with the copper-bismuth concentration ratio, resulting in improved fit and prediction accuracy. To further improve the accuracy and precision of the training and prediction results, XGBoost and Gradient Boosting regression models were applied. The XGBoost and Gradient Boosting regression models showed high accuracy and precision with r-squared values of 0.877 and 0.993 for copper, and 0.879 and 0.993 for bismuth, respectively. The mean recoveries of copper were 99.84% and 98.07%, while bismuth recoveries were 93.17% and 90.85% for XGBoost and Gradient Boosting, respectively. Additionally, cross-validation using 10 splits produced a mean score of 45.565 and a mean absolute error of 13.051 for copper, and a mean score of 13.600 and a mean absolute error of 10.920 for bismuth. Overall, the results indicate that the proposed method is an accurate and precise way to simultaneously determine bismuth and copper concentrations.

In this study, the surface of the glassy carbon electrode (GCE) is modified with the nanocomposite of graphene oxide (GO)/ ionic liquid (1-Butyl-3-methylimidazolium tetrafluoroborate; [BMIM]BF4). The electrochemical behavior of ascorbic acid (AA) and dopamine (DA) at the surface of the modified glassy carbon electrode was studied using the differential pulse and cyclic voltammetric methods (DPV and CV). The results show good response sensitivity to AA and DA. The acceleration of the electron transfer rate and enhancement of the electroactive surface area is obtained due to a synergistic effect in the concurrent presence of GO and [BMIM]BF4 at the surface of the electrode. The presence of GO caused to a higher specific surface of the electrode, and ionic liquid ([BMIM]BF4) increased the ion conductivity and dispersibility in the modifier layer at the surface of the GCE. These results obtained in optimum conditions, show good peak separation for AA and DA (more than 300 mV), and the sub-micromolar detection limits for them. The obtained results in this work, make the modified GCE very effective in the manufacture of simple devices for the detection of AA and DA in human urine samples.

For the first time, hollow fiber-solid liquid phase microextraction (HF-SLPME) using multiwalled carbon nanotube- ion exchange polyurethane foam (MWCNT-PUFIX) as adsorbent along with graphite furnace atomic absorption spectrometry was used to extract and measure the anticancer drug cisplatin. In this method, the nanocomposite dispersed in octanol, is located in the pores and lumen of a porous polypropylene hollow fiber, was used as the extracting phase, this method benefits from high selectivity, high sample purification and enrichment, and reducing the consumption of organic solvents. The major factors affecting the extraction efficiency were investigated. The validation of the method was assessed by linearity, limit of detection, and accuracy calculated as relative recovery percent. The calibration curve was constructed under the optimal conditions was linear in the range of 1.00-55.0 µg/mL and the detection limit was 0.5 µg/mL. This method was successfully used for analysis of biological samples and the obtained results showed that the method has good accuracy and precision.

In present work, orange peel derived activated carbon (OPAC) /Fe3O4 loaded into polyurethane biocomposites were synthesized with different weight fractions of (OPAC)/Fe3O4 via, 0.5, 1 and 2 wt%  filler in the biocomposites. The physico – mechanical, thermal characteristics and magnetic properties  of fabricated (OPAC)/Fe3O4 filled biocomposites  have been measured by using DSC, TGA, DMA and VSM. A slight improvement in thermal stability was noticed for (OPAC)/Fe3O4 loaded biocomposites. The PU/(OPAC)/Fe3O4biocomposites are thermally stable up to 250ºC and completely degraded above 520 ºC. The biocomposites degradation kinetic parameters for each step of the thermal degradation processes have been studied using two mathematical models namely, Coats–Redfern and Broido's methods. The PU/(OPAC)Fe3O4 biocomposites showed high mechanical, magnetic, thermal properties at a low loading of 2 wt.%, and could potentially be used for a wide range of applications.

In this research, Fe3O4 and Fe3O4/Graphene materials were prepared and characterized via different techniques such as X-ray diffractometer (XRD), Vibrating Sample Magnetometer (VSM), and energy-dispersive X-ray spectroscopy (EDX). The efficiency of prepared samples were investigated by elimination of methylene blue as a cationic dye from aqueous solutions via different methods such as adsorption, photodegradation and sonodegradation processes. The results indicated that the degradation rate of methylene blue by Fe3O4/Graphene nanocomposite under sonocatalytic process was considerably higher than the adsorption and photocatalytic procedures. Sonocatalytic degradation of methylene blue by Fe3O4/Graphene nanocomposite could be explained by the mechanisms of hot spots and sonoluminescence. The degradation pathways between sonocatalytic oxidation and methylene blue solution was described. The results showed that the conjugate structure of nitrogen-sulfur heterocyclic material was broken and aromatic ring was oxidized to open the ring. Methylene blue molecules were finally mineralized to H2O and CO2 in the sonocatalytic degradation process. Furthermore, the figures-of-merit based on electric energy consumption (electrical energy per order (EEO)) were estimated in the degradation of methylene blue in the presence of Fe3O4/Graphene nanocomposite. The results showed that less energy is consumed during the sonodegradation of methylene blue in the presence of Fe3O4/Graphene nanocomposite in comparison with photodegradation procedure.

In this paper, liquid phase microextraction technique based on deep eutectic solvent was used for preconcentration of trace levels of Cu2+ followed by its determination by flame atomic absorption spectrometry (FAAS). 8-Hydroxy quinolone (oxine) was used as a complexing agent and the mixture of choline chloride-phenol with a mole ratio of 1:3 was used as an extraction solvent. By using ultrasonicated dispersive liquid phase microextraction technique, the extraction solvent was dispersed in the sample solution and extracted the hydrophobic complex in a short time. Different parameters affecting the relative recovery including pH of sample solution, concentration of complexing agent, mole ratio of extraction solvent component, volume of extraction solvent, extraction time and volume of aprotic solvent (tetrahydrofuran) were completely investigated and optimized. Under the optimum conditions, the calibration curve was linear in the range of 20-300 µg L-1 Cu2+ with a limit of detection of 4.5 µg L-1 Cu2+ (n=8). Also, the relative standard deviation based on seven replicate analysis of solution containing 50 µg L-1 Cu2+ was 3.1%.  Finally, the proposed efficient, rapid and green liquid phase microextraction was successfully used for determination of trace levels of Cu2+ in different water samples.

In this study, a dispersive magnetic solid phase extraction (DMSPE) was described by combining graphene oxide (GO) with Fe3O4 and CuO (Fe3O4@CuO&GO) for extraction and preconcentration of aspirin (ASP) in biological samples. The morphology and structure of the prepared nanocomposite was characterized and analyzed by XRD, SEM and FTIR techniques. Ion mobility spectrometry (IMS) method equipped to a corona discharge ionization source was exploited to determine ASA. The extraction parameters (desorption solvent, pH, adsorbent amount, extraction time and temperature) and also the operational parameters of IMS were investigated and optimized. Under the optimum conditions, the DMSPE–IMS method provided a linear range 6.0–40.0 ng for ASA with coefficient of determination R2 = 0.99. The LOD and LOQ values were 0.9 and 3.0 ng for ASA, respectively. The repeatability of developed method was evaluated as relative standard deviation (RSD% = 2.7). The proposed method was also used to determine ASA in human plasma and serum as biological samples, which recovery results were within 89.0–100.0%.