Amir Hossein Saeidnejad; Rooholla Moradi
Abstract
Evaluation of plant responses under different environmental conditions is a principal step towards a better understanding of their function and performance. In this investigation, cumin (Cuminum cyminum), which is known as an important medicinal plant, was examined under three different growing conditions ...
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Evaluation of plant responses under different environmental conditions is a principal step towards a better understanding of their function and performance. In this investigation, cumin (Cuminum cyminum), which is known as an important medicinal plant, was examined under three different growing conditions including natural habitat, field and greenhouse conditions in order to clarify the effects of growing conditions on essential oil properties. Essential oil (EO) content was higher in natural habitat samples, but the composition of EO was varied along the three samples extracted from the above three conditions. Overall, 17 compounds were detected and the key component in all samples was thymol, with the highest amount of 18.03% in natural habitat samples. Cuminaldehyde, γ-terpinene, α-thujene and limonene were other substantial compounds of the EO. Some elements were not detected in all samples such as p-cymene which was not extracted from the EO of natural habitat sample and acetoxylinalool which was not observed in greenhouse sample analysis. Regards to phenol content, natural habitat samples showed the highest amount and the lowest value was obtained on field sample. Radical scavenging activity of EO was also higher in natural habitat samples and with respect to phenolic content analysis, it could be considered as a substantial advantage rather than the others. To sum up, results indicated some advantages of natural habitat samples, although field samples also showed superiority in some parameters.
Alaa S. Amin; Hesham El-Feky
Abstract
A highly selective optical sensor for V(IV) ions was established depended on entrapment of a sensitive reagent, 5-(2`,4`-dimethylphenylazo)-6-hydroxy-pyrimidine-2,4-dione (DMPAHPD), in a silica sol–gel thin film coated on a glass substrate. The thin films fabricated depended on tetraethoxysilane ...
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A highly selective optical sensor for V(IV) ions was established depended on entrapment of a sensitive reagent, 5-(2`,4`-dimethylphenylazo)-6-hydroxy-pyrimidine-2,4-dione (DMPAHPD), in a silica sol–gel thin film coated on a glass substrate. The thin films fabricated depended on tetraethoxysilane (TEOS) as precursor, sol–gel of pH = 2.5, water: alkoxyde ratio of 4: 1 and DMPAHPD concentration of 2.5 × 10−4 M. The effect of sol–gel parameters on sensing behavior of the fabricated sensor was also illustrated. The fabricated sensor can be used to detect V(IV) ion with an outstanding high selectivity over a wider dynamic range of 5.0–145 ng mL−1 and a detection limit of 1.35 ng mL−1. It also recorded reproducible results with relative standard deviation of 1.75% and 1.02% for 20 and 70 ng mL−1 of V(IV), respectively, along with a fast response time of two min. Total vanadium was determined after reduction of V(V) to V(IV) using ascorbic acid as reducing agent. The V(V) amounts were estimated by subtracting the concentration of V(IV) from the total vanadium concentration. Interference studies reported a good selectivity for V(IV) with trapping DMPAHPD into sol–gel matrix and appropriately adjusting the structure of doped sol–gel. The proposed sensor was compared with others and was applied to define vanadium in different environmental samples with good results.
Ahmed Alharbi; Alaa S. Amin
Abstract
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) ...
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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.
Ahmadreza Amraei; Mohammad Hosseini; Rouhollah Heydari; Ali Niazi
Abstract
Simultaneous spectrophotometric determination of some polycyclic aromatic hydrocarbons (PAHs) in wastewater samples after preconcentration by salting-out assisted liquid-liquid extraction was achieved using a doolittle multivariate calibration algorithm (DMCA). The DMCA was applied by lower and upper ...
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Simultaneous spectrophotometric determination of some polycyclic aromatic hydrocarbons (PAHs) in wastewater samples after preconcentration by salting-out assisted liquid-liquid extraction was achieved using a doolittle multivariate calibration algorithm (DMCA). The DMCA was applied by lower and upper (LU) triangular matrix decomposition which is efficient, powerful and easily. Results were shown that DMCA has advantages such as, simplicity, rapidness, avoiding matrix inverting and reducing the orders of matrices. The influence of various parameters, such as extraction solvent and volume, type and amount of salt, vortex time and sample pH were studied and optimized. The net analyte signal (NAS) method was used for calculating figures of merit. Linear range (LR) of calibration graphs for naphthalene, anthracene and pyrene were between 0.20 - 2.00, 0.10 - 1.50 and 0.07 -1.00 µg mL-1, respectively. The root mean square errors of prediction (RMSEP) for naphthalene, anthracene and pyrene using DMCA model were 0.0367, 0.0331 and 0.0305, respectively.
Mahmood Payehghadr; Homa Shafieekhani; Ali Morsali
Volume 4, Issue 1 , March 2017, , Pages 12-17
Abstract
A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene)({2-(E)-(Pyridine-2-ylmethylidene)amino]ethyl}has been synthesized and kf value of its complexes with Cu2+, Ni2+, Cd2+, Zn2+, Hg2+ and Co2+has been determined by spectrophotometric and conductometric methods in acetonitrile at various temperatures. ...
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A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene)({2-(E)-(Pyridine-2-ylmethylidene)amino]ethyl}has been synthesized and kf value of its complexes with Cu2+, Ni2+, Cd2+, Zn2+, Hg2+ and Co2+has been determined by spectrophotometric and conductometric methods in acetonitrile at various temperatures. The formation constants (Kß = K1 × K2) of the 1:1 and 1:2 (metal ion to ligand) complexes were calculated by computer fitting of the absorbance-mole ratio data, and molar conductance-mole ratio data at different temperatures, and found that complexes to vary in acetonitrile solvent in the order of Cu2+ >Hg2+>Zn2+>Co2+> Cd2+> Ni2+>Ag+. The enthalpy and entropy changes of the complexation reaction were evaluated from the temperature dependence of formation constants.
Kumble Divya; Badiadka Narayana
Volume 1, Issue 1 , March 2014, , Pages 29-35
Abstract
New, simple and cost effective spectrophotometric methods have been developed for the quality assessment of isoniazid (INH), in bulk and in pharmaceutical formulations by using novel reagents. The proposed methods involve the utility of ethyl 2-[(E)-(4-hydroxyphenyl) diazenyl]-3-oxobutanoate and benzil ...
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New, simple and cost effective spectrophotometric methods have been developed for the quality assessment of isoniazid (INH), in bulk and in pharmaceutical formulations by using novel reagents. The proposed methods involve the utility of ethyl 2-[(E)-(4-hydroxyphenyl) diazenyl]-3-oxobutanoate and benzil as novel reagents for the determination of INH. Developed methods are based on the condensation reaction of INH with reagents to give orange colored chromogen with an absorption band at 454 nm (for method A) and 436 nm (for method B). The applicability of these methods is demonstrated by the determination of the studied drug in commercial tablets and the results are statistically evaluated. The new procedures described in this paper are fast, convenient and have the novelty of carrying out the quantitative determination of INH in pure and in pharmaceutical formulation.
