Journal of the Chilean Chemical Society
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Open Access journal
ISSN (Online) 0717-9324
Published by SciELO [717 journals]
- ESTIMATION OF ARSENIC(III) IN ORGANIC ARSINES AND ITS COMPLEXES USING
POTASSIUM BROMATE AND POTASSIUM IODATE AS OXIDANTS
Abstract: Oxidimetric quantitative determination of arsenic(III) in organic arsines and their complexes with tin(IV) and mercury(II) has been attempted visually, potentiometrically and conductometrically. In each method, standard potassium bromate and potassium iodate oxidants were used in absolute alcohol medium. In these methods, known weight of organic arsines was dissolved in a mixture of absolute alcohol and concentrated hydrochloric acid. The resulting solution was titrated with standard potassium bromate/iodate solutions as oxidants using CCl4 as indicator in visual method. In case of conductometric and potentiometric titrations using potassium iodate/bromated, the results obtained were comparable to visual method. The percentage of arsenic for 1/10 mol L-1 KIO3 and 1/10 mol L-1 KBrO3 were found to be 11.73% and 11.71%, respectively. It led to the authenticity of the results obtained by visual method. 10 mg to 20 mg of the compound under test gave the results within the standard deviation error. The estimation of arsenic (III) was achieved within half an hour.
- HYDROXYL RADICAL BASED DEGRADATION OF CIPROFLOXACIN IN AQUEOUS
Abstract: This study reports the degradation of ciprofloxacin (CIP) by means of ionizing radiations. Kinetic studies with aqueous concentrations of 4.6, 10, 15, 17.9 mg/L reveals that degradation of CIP follows pseudo-first order kinetics and the decay constant increased with decrease in initial concentration of CIP. The removal efficiency, represented by G-value, decreased with increasing absorbed dose and increased with higher [CIP]0 concentration at a given absorbed dose. The effects of bubbling CIP solution with N2, N2O or air on CIP degradation were also studied. The influence of various radical scavengers like tert-butanol, iso-propanol, HCO3- , CO3(2-) , NO3- and NO2- as radical scavengers in N2- saturated solutions of CIP indicated that 'OH were more closely associated with the radiolytic decomposition of CIP than other radicals, such as e-aq or ·H. The pH value of aqueous media played a crucial role in the degradation of CIP. It was observed that degradation efficiency was higher under acidic condition compared to degradation in natural or alkaline media. F-, CH3COO- and HCOO- were formed as a result of CIP degradation that were analyzed by ion-chromatography.
- SOLVENT EFFECT ON THE STRUCTURAL, ELECTRONIC, SPECTRA PROPERTIES AND FIRST
HYPERPOLARIZABILITY OF W(CO)5L, L=(4-PYRIDYLMETHYLENE)MALONONITRILE
Abstract: In this work, the structural, electronic properties, 14N NQR parameters and first hyperpolarizability of W(CO)5L, L=(4-pyridylmethylene)malononitrile complex were computed in gas phase by hybrid functional PBE method with LanL2DZ, and 6-311G(d,p) basis sets for transition metal and man group elements, respectively. Also, the solvent effect on structural parameters, frontier orbital energies of complexes has been carried out based on Polarizable Continuum Model (PCM). The results indicate that the polarity of solvents has played a significant role on the structures and properties of complex. ¹H and 13C NMR chemical shifts were calculated by using the Gauge-invariant atomic orbital (GIAO) method. By analyzing the structural characteristics of this structure, W-C and W-N bonds were identified and characterized in details by topological parameters such as electron density ρ(r) and Laplacian of electron density 2® ∇2ρ(r) from Bader's atom in molecules theory.
- EXPERIMENTAL AND THEORETICAL STUDY OF STABLE PHOSPHORUS YLIDES DERIVED
FROM INDAZOLE IN THE PRESENCE OF DIFFERENT DIALKYL
ACETYELENEDICARBOXYLATES: FURTHER INSIGHTS INTO THE REACTION MECHANISM
Abstract: In the recent work, kinetics studies were made of the reactions between triphenylphosphine 1, dialkyl acetylenedicarboxylates 2 in the presence of NH-acid, such as indazole 3. The kinetic parameters of all reactions determined by UV spectrophotometry. The second order fits were drawn and the values of the second order rate constant (k) were calculated using standard equations. All reactions repeated at different solvents and temperatures. Furthermore, useful information was obtained from studies of the effect of solvent, the structure of the reactants (dialkyl acetylenedicarboxylates) and also the concentration of reactants on the reaction rates. Theoretical studies were performed for evaluation of potential energy surfaces of all structures participated in the reaction mechanism. The first step of all reactions was recognized as a rate-determining step in the reaction mechanism, on the basis of experimental and theoretical data. Theoretical studies performed for evaluation of potential energy surfaces of all structures participated in the reaction mechanism. Quantum mechanical calculations were clarified that how the ylides exist, in solution, as a mixture of two geometrical Z- and E-isomers as a minor or major form.
- APPLICATION of SBA-Pr-SO3H IN THE GREEN SYNTHESIS OF ISATINHYDRAZONE
DERIVATIVES: CHARACTERIZATION, UV-Vis INVESTIGATION AND COMPUTATIONAL
Abstract: An efficient and green synthesis is developed for the preparation of the arylidene isatinhydrazone derivatives 4a-m using a heterogeneous mesoporous acid catalyst of SBA-Pr-SO3H with a pore size of 6 nm under solvent free conditions. The hydrazones 4a-m were then analyzed by UV-Vis spectroscopy and the results were used for the calculation of the HOMO-LUMO band gap. In addition, the quantum chemical calculations were performed to provide an illustrative explanation for the obtained band gap; it is found that probably these molecules have a high tendency to donate electrons to the appropriate small-molecule acceptors with low energy and empty molecular orbital.
- NEW SPECTROPHOTOMETRY METHOD FOR THE DETERMINATION OF MIRTAZAPINE IN
Abstract: A simple extractive spectrophotometric method has been developed for the quantification of mirtazapine. This method is based on the formation of ion-association complex of mirtazapine drug with bromocresol purple dye. The absorbance of the complex was measured at 400 nm. The method was successfully applied to the determination of mirtazapine in their pharmaceutical formulations. The method shows a linear range from 0.2-10 μg mL-1 with a molar absorptivity of 1.53 '10 4 L mol-1 cm-1. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.096 μg mL-1 and 0.32μg mL-1 respectively. The developed methodology was successfully applied for the determination of mirtazapine in commercial formulation and the percentage recovery was found 99.91 ± 0.15. The developed methodology promises a feasible, low cost and an efficient method for the routine analysis.
- ISOLATION STUDIES FROM STEM EXTRACT OF PISTACIA INTEGERRIMA
STEW. EX BRAND
Abstract: Plants have been source of fantastic natural compounds that range in complexity. Chemical studies on traditional medicinal plants have led to discovery of potent bioactive components. Pistacia integerrima belonging to family Anacardiaceae has been traditionally effective for rheumatic pain, analgesic and antipyretic effects and used in treatment of coughs, phthisis, asthma and dysentery. Natural products have served as basis for compounds to be utilized in drug discovery. Stem extract of Pistacia integerrima was investigated with the aim to find some novel components that can later be used as drugs or active pharmaceutical intermediates. Plant material was collected from Margalla Hills Islamabad, shade dried and subjected to cold maceration technique for extraction. Crude extract was partitioned into different fractions on polarity basis. Repeated normal and reverse phase column chromatography of ethyl acetate fraction supported by Thin Layer Chromatography have led to the isolation of pure single compound. Isolated compound was further analyzed towards structural elucidation using LC-MS, IR and NMR spectroscopy. Present finding will be a useful and novel addition in already known chemical components from Pistacia integerrima.
- CHARACTERIZATION OF THE DISSOLVED ORGANIC MATTER PRESENT IN THE WATER OF
THE BÍO-BÍO RIVER, VIII REGION OF CHILE
Abstract: The dissolved organic matter in rivers has different origin and its composition can vary both by natural conditions and the anthropic activity that takes place near rivers. This mobile fraction of the organic matter is composed of sub-fractions of different molecular weight and polarity, which confer different complexing capacity for the pollutants and thus a different impact on the environment. The aim of this study was to isolate and characterize the organic matter dissolved in a representative basin of a temperate zone in South America, such as Bio Bio River located in the VIII region of Chile. The material was characterized chemically and spectroscopically after fractionating by molecular weight and polarity. It is concluded that the dissolved organic matter of the Rucalhue sector has a terrestrial origin, with a high aromatic carbon content, in contrast with that from Laja and Concepción, which has a greater anthropic impact. The dissolved organic matters from the sectors with high anthropic activity have larger molecular size and higher organic carbon content and conductivity.
- SIGNIFICANCE OF CHITOSAN TO IMPROVE THE SUBSTANTIVITY OF REACTIVE
Abstract: Chitosan (polysaccharide) is used for cationization of cotton and to increase the uptake of reactive dye by the cationized cotton. Four different concentration of chitosan (0.5, 1.0, 1.5 and 2.0%) were applied for 0.5 and 4.0% shades of C.I. Reactive Red and C.I. Reactive Yellow dye, respectively. Different properties e.g. K/S value, washing fastness, light fastness and rubbing fastness of the dyed cotton (untreated and treated with chitosan) were recorded for comparison. The K/S values of chitosan treated fabrics (6.1-13.9 and 18.3-22.8 for both dye shades, respectively) were considerably better than untreated fabric (4.7-5.3 and 16.8-17.0). The results of present study clearly demonstrated that the use of chitosan as an exhausting agent not only reduced the amount of dye for dyeing the cotton fabric but also improved the washing and rubbing fastness properties. The present study further demonstrated that the use of chitosan in textile industry can minimize the dyeing cost, effluent treatment cost and other auxiliary utilization.
- STUDY OF THE REMOVAL OF 4-NITROPHENOL FROM AQUEOUS MEDIA BY ADSORPTION
ON DIFFERENT MATERIALS
Abstract: The removal of 4-Nitrophenol (4-NP) from aqueous media by adsorption is studied in a batch system using different porous materials: activated carbon, zirconia, alumina, sepiolite, natural zeolite and 13X zeolite. Depending on their adsorption capacities, the best adsorbent was chosen to be impregnated with different levels of nickel (Ni) in order to study the adsorption by π-complexation in batch and continuous systems. The samples of Ni(x)/support (x= 2, 4, 6%) were prepared by wet impregnation and were characterised using the same method as with all the materials, by N2 adsorption-desorption using the BET method, surface acidity and Z potential measurements by electrophoretic migration. The samples were measured in a UV-Vis electrophotometer at a wavelength of 318 nm, while the adsorption capacity of the material in the batch system was determined by calculating the difference in concentration once the adsorbent became saturated after an initial concentration of ~20 ppm, and in the continuous system this was done by integrating the area under the adsorption curve. The results suggest that adsorption capacity depends on the specific BET area, apparent acid strength and the IEP of each support, and that it varies with the addition of Ni.
- PHENOLIC COMPOSITION AND BIOLOGICAL (ANTI DIABETIC AND ANTIOXIDANT)
ACTIVITIES OF DIFFERENT SOLVENT EXTRACTS OF AN ENDEMIC PLANT (HELIOTROPIUM
Abstract: Heliotropium strigosum plant is widely used in traditional medicines for treatment of various ailments. In current study, an effort was made to evaluate phenolic profile as well as antidiabetic and antioxidant activities of crude methanol extract and different solvent (n-hexane, ethyl acetate, chloroform and aqueous) fractions of H. strigosum. Total phenolic contents were determined by spectrophotometric assay. Polyphenolic compounds in crude methanol extract and each solvent fraction were identified by reverse phase high performance liquid chromatography (RP-HPLC). Antioxidant and antidiabetic activities were determined using DPPH and a-amylase inhibition assays, respectively. The outcome of spectrophotometric assay showed that methanol extract had higher amount of total phenolic (84.50 ± 0.06 μg GAE/ mg of plant extract) contents than aqueous, ethyl acetate, chloroform and n-hexane fractions, respectively. The RP-HPLC analysis revealed the maximum number of phenolic (chromotropic acid, quercetin, trans-4-hydroxy-3-methoxy cinnamic acid, vanillic acid, gallic acid, caffeic acid, m-coumaric acid, p-coumaric acid, syringic acid, sinapic acid and ferulic acid) compounds in methanol extract. Methanol extract (IC50 = 8.97 μg/mL) exhibited the maximum antidiabetic activity followed by aqueous (IC50 = 20.04 μg/mL), ethyl acetate (IC50 = 27.79 μg/mL), chloroform (IC50 = 56.87 μg/mL) and hexane (IC50 = 32.16 μg/mL) fractions, respectively. The outcome of antioxidant assay revealed that methanol extract was the leading one with regard to antioxidant activity at different doses (10 to 250 μg/mL). The current study concludes that H. strigosum solvents extracts with significant phenolic profile and potent biological activities could be explored for potential uses in neutraceutical and pharmaceutical industries.
- SOLVENT FREE, ONE POT SYNTHESIS OF SYMMETRIC XANTHENE DYES AND THEIR
Abstract: The present paper reports the synthesis of xanthene dyes derivatives from 4, 4'-oxydiphthalic anhydride and 1, 4, 5, 8-naphthalenetetracarboxylic dianhydride (3a-e and 6a-e) with different substituted phenols via Friedel-Crafts acylation reaction in the presence of an ammonium chloride catalyst. The structures of all newly synthesized derivatives were confirmed by the chromatographic, spectral and microelemental data. Dianhydride derivatives with 3-N', N'-dimethylaminophenol (3d and 6d) and resorcinol (3e and 6e) have been found to be highly fluorescent. Electrochemical study was done to determine band gap energy, LUMO and HOMO level energy. Band gap and LUMO energy levels were found to be lowest in xanthene derivatives 3c and 6c. Dyes 3d, 3e, 6d and 6e were found useful for differential staining of plant cells.
- VARIATION IN ANTIOXIDANT ATTRIBUTES AND INDIVIDUAL PHENOLICS OF CITRUS
FRUIT PEELS IN RELATION TO DIFFERENT SPECIES AND EXTRACTION SOLVENTS
Abstract: Major objective of this study was to appraise the variation of antioxidant activity, total phenols, total flavonoids and individual phenolic acids among fruit peels from five species of Citrus namely C. sinensis 'Valancia' (Mausami), C. sinensis 'Maltaise Sanguine' (Red blood), C. reticulata (Kinnow), C. reticulata Blanco 'Merisol' (Fruiter), and C. paradisi 'Macfadyen' (Grapefruit) as function of extraction solvents. The extract yield from the fruit peels of the selected Citrus species by using four solvents varied significantly (p
- NANOSTRUCTURAL CHARACTERIZATION AND LATTICE STRAIN OF TiO2-Al2O3-SiO2
COATING ON GLASS AND SI (100) SUBSTRATES
Abstract: Synthesis of TiO2-Al2O3-SiO2 nanopowder composite, as well as composite coating on soda lime glass and Si (100) by sol-gel method is reported. The morphology and the crystal structure of composite are characterized by the use of field emission scanning electron microscopy (FE-SEM), Energy dispersive X-ray (EDAX), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The effects of chemical compositions and Calcination temperature on surface topography and the crystallization of phases are studied. In addition, the lattice strain and coating roughness parameters are calculated during thermal treatment.
- CHARACTERIZATION OF TEMPORAL BIODEGRADATION OF RADIATA PINE BY
GLOEOPHYLLUM TRABEUM THROUGH PRINCIPAL COMPONENT ANALYSIS-BASED
TWO-DIMENSIONAL CORRELATION FTIR SPECTROSCOPY
Abstract: Brown rot fungi produce a special pattern of wood decay. In the first stages of biodegradation, fast depolymerisation of holocellulose causes a rapid loss of wood strength while lignin is not substantially depolymerized. Fourier Transform Infrared Spectroscopy (FTIR) is a powerful tool for examining changes in wood chemistry. FTIR is an accurate, non-destructive technique, which usually requires a minimum of sample preparation and sample size. Principal component analysis-based two-dimensional (PCA2D) correlation spectroscopy of a spectral data set was applied to assess temporal brown-rot wood decay. Pinus radiata with soil support was degraded by brown rot fungi Gloeophyllum trabeum for a period of 0, 1, 2, 3, 4, 8, 12 and 16 weeks simulating the natural process of biodegradation. Decayed samples were monitored and analyzed periodically by FTIR. Most of the autopeaks had contributions from lignin, cellulose, and hemicelluloses. The main effect observed by PCA2D correlation was the significant decrease in the intensities of bands predominantly in the region of 2000-1000 cm-1, associated with polysaccharides in the biodegraded wood. An increase in the intensities of bands at 1698 and 1664 cm-1 associated with the oxidation of wood components, mostly lignin, was also observed. Detailed analysis of asynchronous map showed that the wood oxidation began after the depolymerisation of polysaccharides.
- SOLVENT EXTRACTION OF PALLADIUM(II) FROM ALKALINE CYANIDE SOLUTION BY THE
DODECYL DIMETHYL-2-PHENOXYETHYL AMMONIUM BROMIDE
Abstract: The direct extraction of Pd(CN)4(2-) from alkaline cyanide solutions with dodecyl dimethyl-2-phenoxyethyl ammonium bromide (DDPB) was investigated. Several factors affecting extraction efficiency, including DDPB concentration, modifier content, equilibrium time, phase ratio (O/A), pH and palladium concentration in aqueous phase, were studied. The results indicated that nearly all of the Pd(II) (>98%) was transferred from the aqueous phase into the organic phase. N-pentanol was the most appropriate modifier for the extraction of Pd(CN)4(2-). Palladium can be separated efficiently by DDPB over base metals (Fe ,Co, Ni and Cu) from alkaline cyanide medium. The extraction was quite fast and equilibrium could be established within 3 min. Most of Pd(II) (>96%) in the organic phase could be stripped with ammonium thiocyanate aqueous solutions, from which elemental palladium could potentially be recovered by the addition of hydrazine hydrate. The organic phase after stripping can be recycled for a continuous extraction-stripping operation. The extraction mechanism can be deduced based on FTIR spectrum and slope analysis while the mechanism of stripping can be explained by the principle of minimum charge density and Le Chatelier's principle. The proposed method was applied to extract palladium from real cyanide leaching liquor of Pd flotation concentrate with satisfactory results.
- SYNTHESIS AND STUDY ON MAGNETIC RESONANCE IMAGING PERFORMANCE OF
Abstract: In this paper, 2-hydrazino-6-methoxy-1,3-benzothiazole was introduced into diethylenetriamine pentaacetic (DTPA) by acylation reaction. The corresponding non-ion Gd(III) complex holding promise of a single molecule magnetic resonance imaging (MRI) contrast agent was obtained by treating this ligand with GdCl3·6H2 O. The efficacy of the contrast agent was assessed by measuring the longitudinal relaxivity (r1), the r1 of Gd(III)-DTPA-bisbenzothiazole hydrazide was up to 6.44 mM-1,s-1, which was 1.8 times higher than that of the analogous MRI contrast agent Gd(III)-DTPA (r1 = 3.64 mM-1s-1) in commercial use. In addition, in vitro MR images on a 0.5 T magnetic field exhibited a remarkable enhancement of signal contrast for Gd(III)-DTPA-bisbenzothiazole hydrazide than Gd(III)-DTPA. These results demonstrate that this non-ion Gd(III) complex acts as a potentially MRI contrast agent.
- DEVELOPMENT AND VALIDATION OF RP- HPLC METHOD FOR THE SIMULTANEOUS
ESTIMATION OF TRAMADOL HYDROCHLORIDE AND DICYCLOMINE IN BULK AND
Abstract: A simple, specific, accurate and precise reversed phase high pressure liquid chromatography (RP-HPLC) method has been developed for the simultaneous estimation of tramadol hydrochloride (TRA) and dicyclomine (DCY) in bulk and tablet dosage form. Chromatography was carried on Phenomex Gemini C column (4.6 x 250 mm, 5u particle size) using mixture of methanol, acetonitrile and 0.1% triethylamine (TEA) pH 3.0 (adjusted with orthophophoric acid) in the ratio of 35:5:60 (v/v/v) respectively as a mobile phase. The flow rate 1.0mL min-1 and detection wavelength 275 nm was selected for the present study. The retention time of tramadol hydrochloride and dicyclomine were 4.13 min and 9.06 min respectively. The linear regression analysis data for the calibration plots showed a good linear relationship over the concentration range of 50-300 μg mL-1 for tramadol hydrochloride and 10-60 μg mL-1 for dicyclomine. The proposed method was validated with respect to linearity, precision, accuracy, specificity and robustness. The proposed method was found to be simple, rapid, accurate, precise and reproducible. Thus it can be applied for routine quality control analysis of tramadol hydrochloride and dicyclomine in tablet dosage form.
- DESIGN, SYNTHESIS AND ANTIMICROBIAL ACTIVITIES OF
Abstract: A new series of 1-(4-oxo-3-(4-fluorophenyl)-3H-quinazolin-2-yl)-4-(substituted) thiosemicarbazides (AR1-AR10) were obtained by the reaction of 2-hydrazino-3-(4-fluorophenyl) quinazolin-4(3H/)-one (6) with different dithiocarbamic acid methyl ester derivatives. The key intermediate 3-(4-fluorophenyl)-2-thioxo-2,3-dihydro-1H-quinazolin-4-one (4) was obtained by reacting 4-fluoroaniline (1) with carbon disulphide and sodium hydroxide in dimethyl sulphoxide to give sodium dithiocarbamate, which was methylated with dimethyl sulfate to yield the dithiocarbamic acid methyl ester (2) and condensed with methyl anthranilate (3) in ethanol yielded the desired compound (4) via the thiourea intermediate. The SH group of compound (4) was methylated for the favorable nucleophilic displacement reaction with hydrazine hydrate, which afford 2-hydrazino-3-(4-fluorophenyl)-3H-quinazolin-4-one (6). All synthesized compounds (AR1-AR10) were also screened for their antimicrobial activity against selective gram positive and gram negative by agar dilution method. In the present study compounds AR8 and AR9 were emerged as the most active compounds of the series.
- SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL PROPERTIES OF NEW CODEINE
Abstract: The reaction of FeCl3 hexahydrate with C18H20NO3.PO4 in acetonitrile produced new complex with general formula [Fe(L)]Cl2, (L= codeine). Characterization of the ligand and its complex were made by elemental analysis, FT-IR, ¹H-NMR, Raman and UV-visible spectroscopy. This new complex showed antitumor activity against two kinds of cancer cell lines: AGS (Stomach) and MCF-7 (Breast). Cell cytotoxic effects of the ligand and its complex were assayed by MTT and Natural-red tests. The antibacterial activity of ligand and complex against Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes and Escherichia coli were also examined.
- DEVELOPMENT AND VALIDATION OF HPTLC METHOD FOR SIMULTANEOUS ESTIMATION OF
TERBINAFINE HYDROCHLORIDE AND MOMETASONE FUROATE IN COMBINED DOSAGE FORM
Abstract: A new simple, precise, accurate, specific and selective high performance thin layer chromatographic (HPTLC) method has been developed for the simultaneous estimation of Terbinafine hydrochloride (TH) and Mometasone furoate (MF) in cream dosage form. The chromatographic separation was achieved on Merck precoated silica gel aluminium plate 60 F254 using Toluene: Ethyl acetate: Glacial acetic acid (8: 4: 0.1 v/v) as mobile phase. The densitometric scanning was carried out at 248 nm. Response was found to be linear in the concentration range of 1000-3000 ng/band with correlation coefficient (r² = 0.999) for Terbinafine hydrochloride and 100-300 ng/band with correlation coefficient (r² = 0.998) for Mometasone furoate. All parameters of method, repeatability, precision, LOD, LOQ, % recovery were validated as per ICH guidelines. The proposed procedure was successfully applied for the simultaneous determination of both drugs in commercial cream preparation. The advantage of the method is simplicity, reasonable sensitivity, rapidity, excellent resolving power, low cost and is a more effective option than other chromatographic techniques in routine quality control.
- BOX-BEHNKEN SUPPORTED DEVELOPMENT AND VALIDATION OF ROBUST RP-HPLC METHOD:
AN APPLICATION IN ESTIMATION OF PRAVASTATIN IN BULK AND PHARMACEUTICAL
Abstract: Pravastatin, a natural bioactive compound inhibits cholesterol biosynthesis which is isolated from fungus by fermentation process. A rapid, sensitive and robust novel reversed phase-HPLC method with UV detection set at 238 nm was developed and validated for quantification of pravastatin in pure drug form and pharmaceutical formulation (Pravachol). A liquid-liquid extraction technique was applied for the preparation samples and chromatographic separation was performed on Symmetry® C (5pm, 3.9 x 150 mm) column with a retention time of 1.95 min using isocratic elution of mobile phase. The mobile phase used in this work consisted of a mixture of methanol and phosphate buffer (70:30%, v/v, pH 4) which was delivered at a flow rate at 1.5 ml/min. Developed HPLC-UV method was validated for linearity (R² = 0.999), accuracy, precision, sensitivity, system suitability, selectivity, and robustness. Box-Behnken experimental design was applied in the validation of robustness. Three independent variables such as the composition of mobile phase, flow rate and pH of mobile phase were investigated. The results indicated that a slight change in the mobile phase composition and flow rate affects the responses, while pH had no significant effect on the response. Overall, the proposed HPLC-UV method was found to be simple, sensitive, and highly robust for routine analysis of pravastatin.
- SYNTHESIS OF ORGANOPHOSPHORUS COMPLEXES AND STRUCTURAL CHARATERIZATION OF
TWO DIMERIC TRIPHENYLPHOSPHINNE COMPLEXES OF MERCURY(II) IONS FROM DIMERIC
COMPLEXES OF [4-METHYLBENZOYLMETHYLENETRI- P -TOLYLPHOSPHINE
Abstract: The organophousphorus complexes of [(PPh3)2Hg2Cl4] (4), [(PPh3)2Hg2Br4] (5) and [(PPh3)2Hg2I4] (6) were resulted from nucleophilic substitution of triphenylphosphine ligand with tri-p-tolylphophine complexes (1-3). The crystal structures of two organophousphorus complexes of mercury(II) ions 4 and 6 have been determined by means of the X-ray diffraction. Both complexes were crystallized in the monoclinic space groups P2(1)/c, and have very similar bond lengths, angles pattern and same substituted triphenylphosphine ligand. Single crystal X-ray analysis of title structures reveal the presence of a centrosymmeteric dimeric structure containing the ligand and mercury halides.
- MODELING AND OPTIMIZATION OF IN SYRINGE MAGNET STIRRING
ASSISTED-DISPERSIVE LIQUID-LIQUID MICROEXTRACTION METHOD FOR EXTRACTION OF
CADMIUM FROM FOOD SAMPLES BY ARTIFICIAL NEURAL NETWORK AND GENETIC
Abstract: For the first time, artificial neural network (ANN) and genetic algorithm (GA) have been employed to modeling and optimization of in syringe magnet stirring assisted dispersive liquid-liquid microextraction (IS-MSA-DLLME) method for extraction of cadmium from food samples and determined by flame atomic absorption spectrometry. Based on one factor at a time optimization method, the different input variables for modeling were chosen as pH of the solution, extraction volume, stirring rate and extraction time. The ANN techniques fitted a model for extraction of cadmium with 8, 0.9988 and 6.4x10-4 neurons, correlation coefficient and mean standard error (MSE), respectively. By using the GA technique, the optimal conditions were achieved at pH 7, extraction volume at 250 μL, stirring rate of 500 rpm and extraction time of 10 min. Under the optimum conditions, the calibration graph was linear over the range of 0.05 - 1.00 μg L-1 and the limits of detection (LOD) were as small as 0.015 μg mL-1. The relative standard deviation was ±2.11% (n = 7) and the enrichment factor was 280. The developed method was successfully applied to the extraction and determination of cadmium in food samples.
- DEVELOPMENT AND VALIDATION OF SIMPLE, RAPID AND SENSITIVE UV, HPLC AND
HPTLC METHODS FOR THE ESTIMATION OF PIRFENIDONE IN TABLET DOSAGE FORM
Abstract: UV, HPLC and HPTLC methods were developed and validated for the quantitative determination of Pirfenidone, a novel antifibrotic agent used in idiopathic pulmonary fibrosis. Chromatography was carried out by isocratic technique on reversed phase Eclipse XDB-C18 column (150 x 4.6 mm, 5 μm) with mobile phase consisting of phosphate buff acetonitrile (pH 3.5) 72:28 v/v at flow rate 1 mL/min. TLC was carried out by stationary phase precoated Silica Gel 60 F254 TLC Plate using mobile phase Toluene: Methanol, 8:2 v/v. The UV spectrophotometric determination was performed at 311 nm using solvent methanol. The proposed methods were validated according to ICH Q2-(R1) guidelines. The linearity range for Pirfenidone was 5-70 μg/mL for HPLC, 800-1600 ng/spot for HPTLC and 10-60 μg/mL for UV method. These methods were accurate and precise with recoveries in the range of 98.2-102.32 and relative standard deviation < 2%. The developed methods were successfully applied for determination of Pirfenidone in tablets.
- COMPARATIVE STUDIES OF DIFFERENT EXTRACTION METHODS OF ESSENTIAL OIL FROM
MATRICARIA RECUTITA L. IN IRAN
Abstract: Chamomile, Matricaria recutita L. from family of Asteracae, is a well-known medicinal plant in folk medicine cultivated all over the world. Chamomile essential oil is widely used in pharmaceutical, cosmetic, and food industries. This paper focuses on isolation methods and chemical constituents of essential oils from Matricaria recutita L. in Iran as to optimize these methods and achieving the proper economic procedures. The volatile constituents of Matricaria recutita L. cultivated in Iran were extracted by different methods of extraction by microwave usage, pilot plants and laboratory scale. The oil yields obtained from microwave was 0.08%, laboratory scale 0.06%, pilot 0.06% and pilot with heating element 0.07% . Essential oils were identified by GC and GC/MS. A total of 34 components were identified and significant qualitative and quantitative differences were observed amongst the studied. The main constituents of the essential oils of the studied three different methods were as follows: Microwave were α-bisabolol oxide A (42.3%), chamazulene (15.1%), α-bisabolol oxide B (9.6%), (Z,Z)-farnesol (8.1%) and in laboratory scale were cis-pinocamphone (73.5%), α-bisabolol oxide A (7.9%), in pilot were α-bisabolol oxide A (62.1%), chamazulene (10.2%), (Z,Z)-farnesol (8.3%) and in pilot with heating element were α-bisabolol oxide A (50.5%), E- β - farnesene (12.8%), chamazulene (12.3%) . The best method of extraction was pilot method ,because α-bisabolol oxide A (62.1%), chamazulene (10.2%), were major components, which are showing different pharmacological activities like anti-inflammatory, anti-cancer, anti-allergic, a treatment for stress and depression.
- THE EFFECT OF DIFFERENT RETINA DISEASES ON CHOLESTEROL AND FATTY ACID
CONTENT OF SILICONE OIL FROM VITRECTOMIZED EYES
Abstract: The differences of cholesterol and fatty acid content of silicone oils that were removed from vitrectomized eyes due to different retinal diseases were investigated. The silicone oils were removed from 25 cases after 4-8 months and classified in two groups; Group A consists of 11 patients who had undergone pars plana vitrectomy combined with phacoemulsification and intraocular lens implantation due to diabetic tractional retinal detachment and Group B consists of 14 patients who was treated for phakic primary rhegmatogenous retinal detachment. The removed material from vitrectomized eyes in Group A was opacified and gelatinous on the other hand in Group B it was transparent. Hexan extracts were prepared from liquid and emulsified phases. The extracts were taken into vials, after that, hexane was removed. The chemical structure of each extracted material was investigated by spectroscopic techniques. The concentration of unsaturated fatty acids (FAs) in both groups were compared statistically. In conclusion, in Group A, epoxy and hydroxy-epoxy FAs were determined. The mean amount of unsaturated FAs in Group A was significantly lower than Group B. Cholesterol was not detected in any samples. The type of FAs in removed silicone oils may differ depending on the oxidative stress of retina.
- SIMULTANEOUS PRECONCENTRATION AND DETERMINATION OF Cu2+, Ni2+ AND Cd2+ BY
MICELLE MEDIATED EXTRACTION IN FOOD AND WATER SAMPLES
Abstract: An effective extraction procedure based on the complexation of Cu2+, Cd2+, and Ni2+ with dithizone and extraction of these complexes by Tergitol NP-7 surfactant was developed. Micelle mediated extraction parameters such as pH, ligand and surfactant concentration, incubation time and temperature were investigated and optimized. Effects of external and internal interfering ions, linear dynamic range, detection and quantitation limits were examined and determined under optimal conditions. Detection limits were found as 0.5, 1.8 and 2.0 mg L-1 for Cu2+, Ni2+ and Cd2+, respectively. Linear dynamic range values were between 0.125-2, 0.125-2.5 and 0.05-1.4 pg mL-1 for Cu2+, Ni2+ and Cd2+ ions, respectively. Applicability, accuracy and precision of the method were checked with standard reference materials and real sample analyses by analyte addition technique. Finally, optimized method was applied to determine Cu2+, Ni2+ and Cd2+ contents of standard reference materials, mushrooms and water samples. Quantitative and accurate results were obtained from the analysis of standard reference materials and real samples.
- THE USAGE OF CARROT POMACE FOR BIOETHANOL PRODUCTION
Abstract: The lignocellulosic substances such as agricultural wastes are promising feedstocks for bioethanol production. Because they are cost effective, renewable, abundant and not having primary value for food and feed. The current study suggests that improvements in polysaccharide hydrolysis of under-utilized biomass of carrot pomace may find practical use in its conversión to bioethanol by Saccharomyces cerevisiae and Pichia stipitis fermentation. Some important parameters for bioethanol production such as pretreatment procedures (CaO and activated charcoal treatments), nitrogen sources ((NH)2SO4, soy wheat, cheese whey), and pomace loading amount (15-120 g/L) were optimized in the study. The highest bioethanol production could be achived when the saccharification and fermentation conditions were optimized in order to increase monosaccharide yield and fermentation of both six-carbon and five-carbon monosaccharides. The bioethanol production was 1.9 -fold higher for S. cerevisiae and 4.6 -fold higher for P. stipitis when (NH4)2SO4 was added in addition to the trace nitrogen substances, vitamins and minerals present in carrot pomace. The highest bioethanol production values were obtained as 6.91 and 2.66 g/L in the presence of 120 g/L pomace loading, 1 g/L (NH)2SO4 at the end of 72 hours incubation time at pH 6 by S. cerevisiae and P. stipitis, respectively.
- REVERSE PHASE HPLC AND DERIVATIVE SPECTROPHOTOMETRIC METHODS FOR
SIMULTANEOUS ESTIMATION OF FENBENDAZOLE AND NICLOSAMIDE IN PHARMACEUTICAL
Abstract: The present study narrates the developed and validated simple, reliable, sensitive, precise and accurate Spectrophotometric and RP-HPLC methods for the simultaneous estimation of Fenbendazole and Niclosamide in pharmaceutical dosage form. In the first order derivative method 0.1 N methanolic HCl was used as diluent. The zero crossing point wavelengths selected for the analysis were 226 nm and 317 nm for Fenbendazole and Niclosamide, respectively and RP-HPLC method has been developed using 1% methanolic HCl as diluent. Separations of drugs were achieved on L1 C18 100 A° column (250 x 4.6 mm, 5 μ) using 2 gm potassium dihydrogen phosphate and acetonitrile (70:30, v/v) as mobile phase with flow rate 1.0 mL/min. The detection wavelength was 290 nm. Validation of developed methods was done according to ICH Q2 (R1) guideline. Calibration curve was linear over the concentration range of 3-9 μg/mL (Fenbendazole) and 10-30 μg/mL (Niclosamide) for spectrophotometric method and 24-39 μg/mL (Fenbendazole) and 80-130 μg/mL (Niclosamide) for RP-HPLC method. The developed RP-HPLC and derivative spectrophotometric method were successfully applied for the quantitative determination of cited drugs in pharmaceutical dosage form. The correlation coefficients (r²) value greater than 0.995. Accuracy of methods were determined by recovery studies and it was found to be 98 to 102 %. The % RSD values for all the validation parameters were less than 2.0 % for both the methods. The developed UV and RP-HPLC methods were compared by t - test and it was found that t stat value was less than t critical, value for all. Hence there was no significant difference between the developed methods.
- FOUR-DIMENSIONAL INCOMMENSURATELY MODULATED STRUCTURE OF THULIUM
Abstract: Single crystal of rare-earth polyphosphate Tm(PO3)3 has been grown under high temperature molten-salt method and structurally characterized by single crystal X-ray diffraction analysis. Using the four-dimensional superspace formalism for aperiodic structures, we performed the crystal structure refinement of Tm(PO3)3 as (3+1)-dimensional incommensurately modulated structure with monoclinic superspace group C2/c(0, 0.358, 0)s0 and α = 14.0620 (12) Å, b = 6.6612 (6) Å, c = 10.0191 (9) Å, β = 127.6043 (9)°, V = 743.51 (11) Å³, Z = 4, Mr = 405.8, Dc = 3.626 g/cm³, F(000) = 744, μ(MoKα) = 12.60 mm'¹, R = 0.048 and ωR = 0.050. The structure features infinite chains of corner-sharing PO4 tetrahedra which are affected by positional modulation running along the b-axis. The final structure model was reasonable and did not show any unusual features.
- A NOVEL ACENTRIC CHAR SULFATE INORGANIC-ORGANIC HYBRID FRAMEWORK:
PHOTOLUMINESCENT, NLO AND SEMICONDUCTOR PROPERTIES
Abstract: A novel acentric char sulfate compound, [Cd(S2O7)(4,4,-bipyridine)(H2O)2]n (1), has been solvothermally synthesized and characterized by single-crystal X-ray diffraction method. Compound 1 is characterized by a three-dimensional (3-D) inorganic-organic hybrid framework structure. Solid-state photoluminescent spectra indicate that compound 1 displays a strong violet emission. The second-order nonlinear optical measurements reveal that compound 1 has modest powder SHG efficiency of about 0.02 times than that produced by a potassium dihydrogen phosphate (KDP) powder. Optical absorption spectrum discovers that the presence of an optical gap of 3.41 eV, suggesting that compound 1 is a wide bandgap semiconductor.