جستجوی مقالات مرتبط با کلیدواژه « magnetic solid phase extraction » در نشریات گروه « شیمی »

In this study, an attempt was made to synthesize a new sorbent based on the second generation of silica coated magnetic poly(amidoamine) (Fe3O4@SiO2@PAMAM) to improve the performance of magnetic solid phase extraction (MSPE) of some antifungal drugs including miconazole, clotrimazole and ticonazole in various real samples such as urine and human plasma. The extracted analytes were measured by high performance liquid chromatography equipped with ultraviolet detection (HPLC-UV). Field emission-scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), Thermogravimetric analysis (TGA), Transmission electron microscopy (TEM) and Fourier transform-infrared spectroscopy (FT-IR) were used to study the morphology and structure of the prepared sorbent. The various factors such as: extraction time, sorbent amount, solvent desorption volume, desorption time, ionic strength and pH were studied and optimized. The method is validated according to ICH guidelines with respect to precision, accuracy, linearity, specificity, robustness, and limits of detection and quantification. Under the optimized condition, the linearity of the method was in the range of 1–500 µg L-1 (miconazole= 1-200 µg L-1, clotrimazole = 1-500 µg L-1 and ticonazole = 1-200 µg L-1). The obtained correlation coefficients (r^2) were between 0.9871-0.9977. The limits of detection (LODs) were also calculated to be 0.14-0.18 µg L-1 (miconazole= 0.16 µg L-1, clotrimazole = 0.18 µg L-1 and ticonazole=0.14 µg L-1). The limits of quantification (LOQs) were also in the range of 0.46-0.60 µg L-1 for the selected analytes. The relative standard deviations (RSDs%), were obtained in the range of 4.6 to 5.9%. Moreover, the calculated enrichment factors were between 85 and 93. The proposed method was also employed for the analysis of various real samples such as urine and plasma samples. The obtained recoveries indicated that the method was useful and applicable in complicated real samples

Mercury exposure can produce toxic organic compounds in the body. Also, mercury can potentially cause oxidative damage and cellular disorders. In this study, the determination of mercury values in urine and air of chloralkali workers based on copper nanoparticles functionalized in carboxylic carbon nanotubes (CuNPs@CNT-COOH) were obtained by cold vapor atomic absorption spectrometer (CV-AAS). The urine samples were determined by magnetic solid-phase extraction (MSPE) at pH 8.0. By measuring the mercury level in the air and the urine sample of workers, the level of oxidative stress (Malondialdehyde (MDA), Superoxide Dismutase (SOD) and Catalase (Cat)), Interleukin-6 (IL-6), and Tumor Necrosis Factor α (TNF-α) as the proinflammatory cytokines were measured in the subject group. The results revealed statistically significant differences in the mercury level of the urine samples in the case and control groups (p<0.001). Similarly, the malondialdehyde (MDA) level was significantly different between the two research groups (p<0.001). Catalase concentration was not significantly different in the two groups (p=0.059). The LOD and linear range for mercury determination in urine were achieved at 0.012 μg L−1 and 0.05-7.0 μg L−1, respectively. Workers’ exposure to mercury can significantly increase oxidative stress and inflammatory cell signaling molecules such as cytokines.

Carbonized cotton fabric/zeolite imidazolate framework-71/Fe3O4/polythionine (CCF/ZIF-71/Fe3O4/PTh) was fabricated, characterized, and applied as efficient magnetic sorbent in magnetic solid-phase extraction (MSPE) of cadmium from water and food samples before determination by flame atomic absorption spectrometry (FAAS). This modification of carbonized cotton fabric led to making a great surface area and porosity, increase extraction efficiency, and acceptable selectivity. The characterization of this proposed sorbent was performed by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and Fourier transform-infrared (FT-IR) spectroscopy analysis techniques. The impact of several analytical parameters including pH, sorbent dosage, time of extraction, desorption condition, chelating agent concentration, the amount of salt and effect of potentially interfering ions on the selectivity and extraction recoveries of cadmium, were evaluated and optimized. In this proposed methodology, the limit of detection (LOD), the limit of quantification (LOQ), and relative standard deviation (RSD, n = 3) were found to be 0.21ng mL−1, 0.6 ng mL−1and lower than 3.0%,respectively. The validation and accuracy of the new advanced procedure were confirmed by applying the proposed procedure for certified reference materials (SRM1570A). Eventually, CCF/ZIF-71/Fe3O4/PTh can be utilized as a selective sorbent, for the rapid, accurate and sensitive determination of Cd (II) by magnetic solid-phase extraction tandem flame atomic adsorption spectroscopy (MSPE-FAAS) in water, tomato and cabbage samples.

In this work, an effective and simple method was utilized for the synthesis of zinc(II)-doped manganese ferrite magnetic nanoparticles (Zn0.2Mn0.8Fe2O4 MNPs). The prepared Zn0.2Mn0.8Fe2O4 MNPS was studied and characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction spectroscopy and Brunauer–Emmett–Teller analysis. The prepared Zn0.2Mn0.8Fe2O4 nanomaterial was applied as an applicable magnetic nano-sorbent for solid-phase extraction of cadmium(II) (Cd(II)) ions. The enriched Cd(II) ion was desorbed from the surface of the MNPs using a diluted HNO3 solution, and quantified by flame atomic absorption spectrometry. The influential variables, including the adsorbent mass, sample volume, pH, extraction time, and desorption conditions were investigated and optimized. Based on the method validation, the limit of detection for the developed method was 0.03 ng mL‒1 and the calibration curve is linear in the range of 0.1‒30.0 ng mL‒1. The method’s repeatability based on intra-day and inter-day precisions are 1.9% and 3.3%, respectively. For evaluation of the method accuracy, a certified reference material, natural waters, and industrial wastewater samples were analyzed.

A mesoporous silica SBA-15/iron oxide (Fe3O4-SBA-15) nanocomposite was fabricated and employed as a magnetic solid-phase extraction (MSPE) sorbent to determine three types of organophosphorus pesticides (OPPs) in fruit samples. The fabricated nanocomposite was analysed using high-performance liquid chromatography with an ultraviolet detector (HPLC-UV). Meanwhile, the optimisation of extraction efficiency on three OPPs analyses used three different parameters, viz. desorption conditions, extraction time, and sorbent amount. The experimental results showed that the Fe3O4-SBA-15 nanocomposite achieved high analyte recoveries ranging from 89 to 118% with a relative deviation of less than 8.0%. By combining the optimised MSPE conditions with HPLC-UV, a suitable method for determining three OPPs was developed. This study revealed that the proposed method exhibits good coefficients of determination varying from 0.9942 to 0.9980, with low limit detection (LODs) ranging from 0.03 - 0.08 mgL-1 and low limit quantifications (LOQs) of 0.10 - 0.24 mgL-1. Based on these findings, the fabricated Fe3O4-SBA-15 nanocomposite is a suitable sorbent with excellent adsorption capacity for the selected OPPs from fruit matrices.

An efficient method was developed for the synthesis of amino functionalized magnetic metal organic framework composite (Fe3O4-NH2@MOF-235) and the prepared composite was used as an adsorbent in magnetic solid-phase extraction (MSPE) for the separation and enrichment of Bisphenol A (BPA) from water samples followed by high performance liquid chromatography analysis. The prepared framework composite was characterized using transmission electron microscopy, x-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer-Emmett-Teller and vibrating sample magnetometer techniques. Several parameters affecting the efficiency of magnetic separation including the amount of absorbent, extraction time, desorption solvent, and desorption volume were optimized. Under optimum conditions, the response of the method was linear over the concentration range of 0.1 to 20 ng ml-1 for studied BPA. The limit of detection of the method was 0.03 ng ml-1 at a signal-to-noise ratio of 3 with an RSD of lower than 6.5%. Finally, the proposed method was successfully applied for the determination of trace amounts of target analyte in mineral water samples.

A simple and a green methodology has been developed for the preconcentration of Ni2+ based on the adsorption of its dimethylglyoximate complex on polydopamine coated Fe3O4 nanoparticles. The adsorbed complex was easily desorbed using 1.0 mL of CHCl3 and the concentration of nickel was determined by UV-Vis spectrophotometry. The effects of pH, sorbent mass, extraction time on the sorption of nickel dimethylglyoximate complex were investigated using Box–Behnken design. In optimal experimental conditions, a wide linear range of 5.0-600.0 μg/L with detection limit of  1.49 μg/L was obtained. The proposed method was applied for extraction and preconcentration of Ni2+ in various food samples and the results were compared with the official AOAC method.