Chemical composition of the essential oils of Citrus sinensis cv. valencia and a quantitative structure-retention relationship study for the prediction of retention indices by multiple linear regression

The chemical composition of the volatile fraction obtained by head-space solid phase microextraction (HS-SPME), single drop microextraction (SDME) and the essential oil obtained by cold-press from the peels of C. sinensis cv. valencia were analyzed employing gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The main components were limonene (61.34 %, 68.27 %, 90.50 %), myrcene (17.55 %, 12.35 %, 2.50 %), sabinene (6.50 %, 7.62 %, 0.5 %) and α-pinene (0 %, 6.65 %, 1.4 %) respectively obtained by HS-SPME, SDME and cold-press. Then a quantitative structure-retention relationship (QSRR) study for the prediction of retention indices (RI) of the compounds was developed by application of structural descriptors and the multiple linear regression (MLR) method. Principal components analysis was used to select the training set. A simple model with low standard errors and high correlation coefficients was obtained. The results illustrated that linear techniques such as MLR combined with a successful variable selection procedure are capable of generating an efficient QSRR model for prediction of the retention indices of different compounds. This model, with high statistical significance (R2 train = 0.983, R2 test = 0.970, Q2 LOO = 0.962, Q2 LGO = 0.936, REP(%) = 3.00), could be used adequately for the prediction and description of the retention indices of the volatile compounds

Removal of permethrin pesticide from water by chitosan–zinc oxide nanoparticles composite as an adsorbent

AbstractSynthesis of chitosan–ZnO nanoparticles (CS–ZnONPs) composite beads was performed by a polymer-based method. The resulting bionanocomposite was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) spectroscopy and infrared spectroscopy (FT-IR). Adsorption applications for removal of pesticide pollutants were conducted. The optimum conditions, including adsorbent dose, agitating time, initial concentration of pesticide and pH on the adsorption of pesticide by chitosan loaded with zinc oxide nanoparticles beads were investigated. Results showed that 0.5 g of the bionanocomposite, in room temperature and pH 7, could remove 99% of the pesticide from permethrin solution (25 ml, 0.1 mg L−1), using UV spectrophotometer at 272 nm. Then, the application of the adsorbent for pesticide removal was studied in the on-line column. The column was regenerated with NaOH solution (0.1 M) completely, and then reused for adsorption application. The CS–ZnONPs composite beads appear to be the new promising material in water treatment application with 56% regeneration after 3 cycles

5,5′-Dimeth­oxy-2,2′-[4,5-dimethyl-o-phenyl­enebis(nitrilo­methyl­idyne)]diphenol

In the crystal structure of the title compound, C24H24N2O4, the dihedral angles between the central and the two outer benzene rings are 48.12 (8) and 21.44 (8)°. Intra­molecular O—H⋯N hydrogen bonding generates S(6) rings

Determination of Residual Nonsteroidal Anti-Inflammatory Drugs in Aqueous Sample Using Magnetic Nanoparticles Modified with Cetyltrimethylammonium Bromide by High Performance Liquid Chromatography

A simple and sensitive solid-phase extraction method for separation and preconcentration of trace amount of four nonsteroidal anti-inflammatory drugs (naproxen, indomethacin, diclofenac, and ibuprofen) using Fe3O4 magnetic nanoparticles modified with cetyltrimethylammonium bromide has been developed. For this purpose, the surface of MNPs was modified with cetyltrimethylammonium bromide (CTAB) as a cationic surfactant. Effects of different parameters influencing the extraction efficiency of drugs including the pH, amount of salt, shaking time, eluent type, the volume of solvent, amount of adsorbent, sample volume, and the time of desorption were investigated and optimized. Methanol has been used as desorption solvent and the extracts were analysed on a reversed-phase octadecyl silica column using 0.02 M phosphate-buffer (pH = 6.02) acetonitrile (65 : 35 v/v) as the mobile phase and the effluents were measured at 202 nm with ultraviolet detector. The relative standard deviation (RSD%) of the method was investigated at three concentrations (25, 50, and 200 ng/mL) and was in the range of 3.98–9.83% (n=6) for 50 ng/mL. The calibration curves obtained for studied drugs show reasonable linearity (R2>0.99) and the limit of detection (LODs) ranged between 2 and 7 ng/mL. Finally, the proposed method has been effectively employed in extraction and determination of the drugs in biological and environmental samples

A comprehensive study on removal of cadmium from aqueous solution by using mesoporous SBA-15 functionalized by 1,5-diphenyl carbazide: experimental design, kinetic, thermodynamic, and isotherm aspects

In this study, a new adsorbent, which was synthesized by using SBA-15Santa Barbara Amorphous. modified with 1,5-diphenyl carbazide, was employed to extract cadmium (Cd) from aquatic systems. First, the sorbent was identified via various characterization techniques, and then the response surface methodology approach was applied for modeling and optimizing the adsorption performance of the sorbent. Under optimum conditions ($\mathrm{pH}=5.75$, an adsorbent dose of 4.55 mg, and a Cd concentration of 25.39 mg/L), an adsorption capacity of 160 mg/g was obtained. In addition, the sorption process was fast; it attained equilibrium in 25.39 min. Furthermore, the sorbent regenerated by nitric acid was reused without any significant loss of adsorption capacity. Finally, the experimental data were studied by different isotherm models and well described by the Langmuir model

Essential oil composition and in vitro antibacterial activity of Chenopodium album subsp. striatum

The objective of this study was to identify the bioactive compounds of essential oil and evaluate the antibacterial activity of the essential oil extracted from Chenopodium album subsp. striatum against multidrug-resistant bacterial strains (MDR) which were isolated from clinical specimens by conventional methods. Furthermore, eight different Gram-negative and Gram-positive multidrug-resistant bacterial strains were used to investigate the antibacterial potential of the essential oil. The antibacterial activity was tested using MIC and MBC microdilution method, well and disc diffusion in different concentration. The hydro-distillation of aerial parts powder yield was 0.466% (v/w). Essential oil showed bactericidal activity against both MDR Gram-negative and Gram-positive bacterial strains. MIC and MBC results were ranged from 0.31 to 2.5 and 0.62 to 5.0 mg/mL. The inhibition zones in well-diffusion method were ranged from 7 ± 0.6 mm to 15 ± 1.0 mm. Disc diffusion method was ranged from 7 ± 0.0 mm to 16 ± 0.6 mm depending on the type of bacteria strain and essential oil concentration. Essential oil of Ch. album had the greatest potential to be considered as an antibacterial agent against MDR bacteria strain. This potential was due to different biological and bioactive compounds like phytol, linalool, α-terpineol and linolenic acid in the plant

Simultaneous reduction of Cr (VI) and degradation of azo dyes by F-Fe-codoped TiO2/SiO2 photocatalysts under visible and solar irradiation

A new TiO2/SiO2 photocatalyst codoped with fluorine and iron was synthesized using sol-gel process and immobilized onto glass beads using coupling two methods of dip-coating and heat attachment. The prepared samples were characterized by XRD, FT-IR, DRS-UV/Vis, FESEM, EDX, TEM and N2 Adsorption/Desorption analysis. The effective parameters of pH, flow rate and photoreactor vesselsâ angle against solar irradiation on degradation performance were optimized. Subsequently, the photocatalytic activity of the prepared nanocomposites was investigated in an innovative fabricated photoreactor using a four-component pollutant mixture of Cr (VI), basic red 29, basic blue 41 and basic yellow 51, under visible and solar irradiation. Furthermore, the effectiveness of photoreactor performance was assessed under various outdoor climate conditions as natural irradiation source. Consequently, UV/Vis spectrophotometry results showed significant efficiency of photocatalytic removal of the pollutants mixture. TOC results of 74.39% and 78.04% for removal of organic content of the sample under visible and solar light, respectively, were also confirmed the great capability of the designed system for the simultaneous removal of some hazardous inorganic and organic contaminants under natural light sources.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author