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2002

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Articles 2941 - 2970 of 3454

Full-Text Articles in Physical Sciences and Mathematics

Alteration Of Three Turkish Bentonites By Treatment With Na_{2}Co}_{3} And H}_{2}So}_{4}, Nuray Yildiz, Ayla Çalimli Jan 2002

Alteration Of Three Turkish Bentonites By Treatment With Na_{2}Co}_{3} And H}_{2}So}_{4}, Nuray Yildiz, Ayla Çalimli

Turkish Journal of Chemistry

In this study, fine fractions of bentonites from the Çankırı and Kütahya regions were treated with Na_{2}CO_{3} and H_{2}SO_{4}. The resulting materials were analysed by X-ray diffraction (XRD), thermogravimetric and differential thermal analyses (TGA, DTA) and infrared (IR) spectroscopy. Surface areas of the samples were also measured. The results showed that structural changes were observed by treatment with Na_{2}CO_{3} and H_{2}SO_{4}. These changes showed differences depending on exchangeable cations, clay type and the ratio of additives.

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The Effects Of Benzoic Acid In Chloride Solutions On The Corrosion Of Iron And Aluminum, Si̇bel Zor Jan 2002

The Effects Of Benzoic Acid In Chloride Solutions On The Corrosion Of Iron And Aluminum, Si̇bel Zor

Turkish Journal of Chemistry

In this work, the corrosion behavior of iron and aluminum was investigated in 0.1 M NaCl solutions with an initial pH value of 8 and containing various concentrations (0, 30, 150, 300 ppm) of benzoic acid. For this purpose, the anodic and cathodic semilogarithmic current-potential curves, weight loss and pH of the solution were determined over time. The changes in the concentrations of benzoic acid in the solutions with time were determined by a UV spectrophotometer. According to the results obtained in this investigation, benzoic acid in 0.1 M NaCl acts on iron and aluminum as an inhibitor. This effect …

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Production Of Mesophase Pitch From Coal Tar And Petroleum Pitches Using Supercritical Fluid Extraction, Mustafa Zafer Özel, Keith D. Bartle Jan 2002

Production Of Mesophase Pitch From Coal Tar And Petroleum Pitches Using Supercritical Fluid Extraction, Mustafa Zafer Özel, Keith D. Bartle

Turkish Journal of Chemistry

Supercritical fluid extraction (SFE) is currently being investigated as a possible technique in the production of high quality mesophase pitch from coal tar and petroleum pitches. Mesophase pitch is used to make high technology products, such as carbon fibre. The conventional production of mesophase pitch initially involves the removal of low molecular weight species from coal tar and petroleum pitches. The remaining residue is then transformed into a mesophase pitch through a polymerisation process. The aim of this study involves the extraction of light molecular weight species using SFE. Both petroleum and coal tar pitch contain complex aromatic molecules with …

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Simultaneous Determination Of Fe(Ii) And Fe(Iii) In Pharmaceutical Samples By Post-Column Derivatization/Hplc, Hami̇de Z. Şenyuva, Deni̇z Yurtsever Sarica, Tuncel Özden Jan 2002

Simultaneous Determination Of Fe(Ii) And Fe(Iii) In Pharmaceutical Samples By Post-Column Derivatization/Hplc, Hami̇de Z. Şenyuva, Deni̇z Yurtsever Sarica, Tuncel Özden

Turkish Journal of Chemistry

A post-column derivatization HPLC method with visible absorbance detection at 521 nm was modified for the simultaneous determination of Fe(II) and Fe(III) in mixtures. The method was applied to pharmaceuticals marketed in Turkey. Iron species were separated on a post-column derivatization HPLC, IonPac CS5A (4x250 mm) analytical column using a pyridine-2,6-dicarboxylic acid based eluent. The determinations of Fe(II) and Fe(III) were also realized by the most common method of FAAS, total iron determination. Detection limits (3S) were found to be 0.109 \mu g/L for Fe(II) and 0.217 \mu g/L for Fe(III), respectively. The mean recovery of the HPLC and AAS …

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Chemical Exfoliation Characteristics Of Karakoç Phlogopite In Hydrogen Peroxide Solution, Erol Üçgül, İsmai̇l Gi̇rgi̇n Jan 2002

Chemical Exfoliation Characteristics Of Karakoç Phlogopite In Hydrogen Peroxide Solution, Erol Üçgül, İsmai̇l Gi̇rgi̇n

Turkish Journal of Chemistry

The chemical exfoliation characteristics of phlogopite samples taken from Sivas - Yıldızeli-Karakoç (Turkey) ore were investigated. H_{2}SO_{4}, HCl, HNO_{3}, H_{3}PO_{4} and H_{2}O_{2} solutions at varying concentrations were tested for chemical exfoliation and the best reagent for this purpose was determined to be hydrogen peroxide. In the exfoliation tests performed, hydrogen peroxide concentration, temperature and reaction time were observed to be important parameters, with solid/liquid ratio being of minor importance. The exfoliation characteristics of the material increased with increases in hydrogen peroxide concentration and depending on the reaction time (1-30 hours) a maximum value of a 49-fold increase in swelling was …

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Phytochemical Studies At The Bulbs Of Ornithogalum Umbellatum L., Temi̇ne Şabudak, Ülkü Oyman Jan 2002

Phytochemical Studies At The Bulbs Of Ornithogalum Umbellatum L., Temi̇ne Şabudak, Ülkü Oyman

Turkish Journal of Chemistry

Phytochemical examination of the bulbs of Ornithogalum umbellatum L. led to the isolation a new steroidal compound. Its structure was determined to be 3-O-(2'-methoxy-4'-(2-pentenal))-phenyl sitosterol (1) by spectroscopic data and chemical evidence.

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Terpenoids And Aromatic Compounds From Euphorbia Heteradena, Sevi̇l Öksüz, Ayhan Ulubelen, Asli Barla, Wolfgang Voelter Jan 2002

Terpenoids And Aromatic Compounds From Euphorbia Heteradena, Sevi̇l Öksüz, Ayhan Ulubelen, Asli Barla, Wolfgang Voelter

Turkish Journal of Chemistry

Euphorbia heteradena Jaub. & Spach (Euphorbiaceae), a plant endemic to Turkey, has not been investigated previously. The CH_{2}Cl_{2} extract of the aerial parts of Euphorbia heteradena yielded 24-methylenecycloartanol, cycloart-25-en-3\beta ,24-diol, cycloart-22-en-3\beta ,25-diol, vomifoliol, vomifoliol 9-O-\beta -D-glucopyranoside, 3,4,3'-tri-O-methoxy ellagic acid, syringic acid and scopoletin. The structures of the isolates were identified by high field spectroscopic methods including 1D and 2D NMR techniques.

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Vapour Liquid Equilibrium In Asymmetric Mixtures Of N-Alkanes With Ethane, Anca Duta, Dan Geana Jan 2002

Vapour Liquid Equilibrium In Asymmetric Mixtures Of N-Alkanes With Ethane, Anca Duta, Dan Geana

Turkish Journal of Chemistry

The paper presents a vapour liquid equilibria study in binary mixtures of n-alkanes with high dimensional asymmetry. Each mixture contains ethane and alkanes higher than eicosane. Calculations were done using two equations of state, Peng-Robinson (PR) and Soave (SRK), in combination with van der Waals mixing rules, corrected with two interaction parameters. A limited temperature dependence of the interaction parameters was found. The correlations between the interaction parameters and the number of carbon atoms of the higher n-alkane led to equations valid for systems ethane + C_{3} up to C_{44}. The results of the prediction calculations were good, both with …

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The Simultaneous Determination Of Quinoline Yellow (E-104) And Sunset Yellow (E-110) In Syrups And Tablets By Second Derivative Spectrophotometry, Mahmure Üstün Özgür, İkbal Koyuncu Jan 2002

The Simultaneous Determination Of Quinoline Yellow (E-104) And Sunset Yellow (E-110) In Syrups And Tablets By Second Derivative Spectrophotometry, Mahmure Üstün Özgür, İkbal Koyuncu

Turkish Journal of Chemistry

A very simple spectrophotometric method using measurements at zero-crossing wavelength is described for resolving binary mixtures of the food dyes, Sunset Yellow (E-110) and Quinoline Yellow (E-104). Calibration graphs are linear up to 15.0 \mu gml^{-1} of Sunset Yellow (r = 0.9998), and Quinoline Yellow (r = 0.9999). The assay procedure for E-110 and E-104 in pharmaceutical products involves the extraction of the dyes with AcOH/NaOAc buffer solution (pH = 4.5), filtration, and measurement of the second derivative absorbance values at 410.0 nm for E-104 and 533.1 nm for E-110. This method was used for determining synthetic mixtures of these …

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Trypsin-Catalyzed Peptide Synthesis In Acetonitrile With Low Water Content, Yeşi̇m Yeşi̇loğlu, Ayten Sağiroğlu Jan 2002

Trypsin-Catalyzed Peptide Synthesis In Acetonitrile With Low Water Content, Yeşi̇m Yeşi̇loğlu, Ayten Sağiroğlu

Turkish Journal of Chemistry

Trypsin was immobilized to alumina by adsorption from its aqueous solutions. The activity of trypsin was increased by immobilization for peptide synthesis. With these immobilized enzymes Bz-Arg-Leu-NH_{2} dipeptide synthesis was carried out. Iso amylalcohol, tetrahydrofuran and acetonitrile were used as solvents giving the highest yield in the peptide formation reaction. The yield of the peptide was strongly dependent on water content in the reaction medium. The stability of alumina-immobilized trypsin is described.

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Synthesis And Protection Of Some Amidines, Kadi̇r Dabak Jan 2002

Synthesis And Protection Of Some Amidines, Kadi̇r Dabak

Turkish Journal of Chemistry

A series of benzamidine derivatives were synthesized from substituted benzonitrile compounds and protected with the tert-butoxycarbonyl group.

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Titrimetric And Spectrophotometric Determinations Of Some Phenothiazine Psychotropics Using Chloramine-T, Kanakapura Basavaiah, Javarappa Manjunathaswamy Jan 2002

Titrimetric And Spectrophotometric Determinations Of Some Phenothiazine Psychotropics Using Chloramine-T, Kanakapura Basavaiah, Javarappa Manjunathaswamy

Turkish Journal of Chemistry

A simple, convenient and accurate indirect titrimetric method and a rapid, sensitive and precise indirect spectrophotometric method for the determination of six phenothiazine drugs using chloramine-T as an oxidant are described. The titrimetric method is based on the oxidation of the drugs in sulphuric acid medium by a known excess of chloramine-T and iodometric determination of the unreacted chloramine-T. In the spectrophotometric method, the unreacted oxidant is made to react with metol in the presence of an aromatic amine to produce a purple-red product with the absorption maximum at 520 nm. The absorbance is found to decrease linearly with increasing …

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Synthesis Of New Substituted 6-(Morpholin-4-Yl)-1h-Benzimidazole Derivatives, Canan Kuş Jan 2002

Synthesis Of New Substituted 6-(Morpholin-4-Yl)-1h-Benzimidazole Derivatives, Canan Kuş

Turkish Journal of Chemistry

A series of various substituted benzimidazole derivatives containing fluoro and morpholino substituents at the 5 and 6 positions was synthesized and their structures were identified by spectroscopic techniques.

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Synthesis, Spectral And Thermal Degradation Kinetics Of Divalent Cadmium Complexes Of Dothiepine And Diphenhydramine, Halehatty S. Bhojya Naik, Parasuramapuma R. Chetana, Hosakere D. Revanasiddappa Jan 2002

Synthesis, Spectral And Thermal Degradation Kinetics Of Divalent Cadmium Complexes Of Dothiepine And Diphenhydramine, Halehatty S. Bhojya Naik, Parasuramapuma R. Chetana, Hosakere D. Revanasiddappa

Turkish Journal of Chemistry

Cadmium(II) complexes with 3-(6H-dibenzo[b,e] thiepin-11-ylidene) propyl dimethyl amine chloride (dot) and 2-diphenyl methoxy--N,N-dimethylamine hydrochloride (dp) were synthesised and characterised by reflectance, IR, ^{1}H NMR, magnetic moments and conductivity measurements. The new complexes studied for kinetics of thermal degradation by thermogravimetric analyses (TGA) and derivative thermogravimetric studies (DTG) in a static nitrogen atmosphere at a heating rate of 10°C min^{-1}. The kinetic and thermodynamic parameters such as energy of activation (Ea), frequency factor (lnA), enthalpy (\Delta H), free energy (\Delta H), and entropy (\Delta S) evaluated. The energy of activation values for the degradation of (dot) and (dp) complexes were found …

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Synthesis And Magnetic, Spectral And Thermal Studies On Metal 1,3,8,10,15,17,22,24-Octanitrophthalocyanines, Kallam R. Venugopala Reddy, Jathi Keshavayya Jan 2002

Synthesis And Magnetic, Spectral And Thermal Studies On Metal 1,3,8,10,15,17,22,24-Octanitrophthalocyanines, Kallam R. Venugopala Reddy, Jathi Keshavayya

Turkish Journal of Chemistry

A simple and novel method for the preparation of 1,3,8,10,15,17,22,24-octanitrophthalocyanine derivatives, MPcON's (M = Fe (III)Cl, Zn(II), Co(II), Cu(II) and Ni(II)), was developed. The dark green complexes were characterized by elemental analysis, electronic spectra, IR spectra, thermogravimetry, differential thermal analysis, powder X-ray diffraction and magnetic susceptibility.

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Phenolic Compounds From Scutellaria Pontica, Tayfun Ersöz, Ü. Şebnem Harput, İclal Saracoğlu, İhsan Çaliş, Yukio Ogihara Jan 2002

Phenolic Compounds From Scutellaria Pontica, Tayfun Ersöz, Ü. Şebnem Harput, İclal Saracoğlu, İhsan Çaliş, Yukio Ogihara

Turkish Journal of Chemistry

From the aerial parts of Scutellaria pontica, a phenolic glucoside, 3,5-dihydroxyphenyl \beta -D-glucopyranoside (1); as well as a C-glucosyl flavon, isovitexin (2); flavones and flavone glycosides, 5-hydroxy-7,3',4'-trimethoxyflavone (3); apigenin (4); apigenin-7-O-\beta-D-glucopyranoside (5); and apigenin-7-O-\beta-D-glucopyranoside-4'-O-methylether (6) were isolated in addition to two phenylethanoid glycosides, martynoside (7) and verbascoside (= acteoside) (8). The structures of the isolated compounds were established on the basis of spectroscopic evidence.

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Synthesis, Characterization And Thermal Analysis Of Organotin(Iv) Derivatives Of 4-(N-Maleoyl)Butanoate, Khadija Shahid, Saqib Ali, Moazzam H. Bhatti, Muhammad Mazhar, Sohail Mahmood, Sadiqur Rehman Jan 2002

Synthesis, Characterization And Thermal Analysis Of Organotin(Iv) Derivatives Of 4-(N-Maleoyl)Butanoate, Khadija Shahid, Saqib Ali, Moazzam H. Bhatti, Muhammad Mazhar, Sohail Mahmood, Sadiqur Rehman

Turkish Journal of Chemistry

Organotin(IV) derivatives of the type R_{4 - n}SnL_{n} where R = Me, n-Bu, Ph, L = 4 - (N-maleoyl)butanoate and n = 1 or 2 were synthesized by refluxing R_{3}SnCl and R_{2}SnCl_{2} with (4-(N-maleoyl)butanoate in the presence of triethylamine using dry toluene as solvent. These compounds were characterized by IR, multinuclear NMR and mass spectrometry. We also studied their thermal behavior and calculated the degradation pattern, energy of activation (E_{a}) and order of reaction (n).

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Solid-Phase Extraction Of Copper With Lead 4-Benzylpiperidinedithiocarbamate On Microcrystalline Naphthalene And Its Spectrophotometric Determination, Hasan Cesur, Beki̇r Bati Jan 2002

Solid-Phase Extraction Of Copper With Lead 4-Benzylpiperidinedithiocarbamate On Microcrystalline Naphthalene And Its Spectrophotometric Determination, Hasan Cesur, Beki̇r Bati

Turkish Journal of Chemistry

Using lead 4-benzylpiperidinedithiocarbamate complex (Pb(4-BPDC)_{2}), a solid-phase extraction method was developed for pre-concentration and spectrophotometric determination of copper in water samples. In this method, copper in large volume liquid phase quantitatively replaces lead on colorless Pb(4-BPDC)_{2} complex and naphthalene solid phase mixture forming Cu-4-benzylpiperidinedithiocarbamate complex (Cu(4-BPDC)_{2}). The solid phase containing colored Cu(4-BPDC)_{2} is dissolved in chloroform and its absorbance is measured at 437 nm against the reagent blank. The range of linearity is 0.4 -10 \mu gml^{-1} of copper in chloroform, the molar absorptivity of the complex determined from the linear portion of Beer's law plot is 8.197x10^{3} lmol^{-1}cm^{-1} and …

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Electrochemical Behavior Of Benzo[C]Cinnoline And Its Bromo Derivatives, Ni̇lgün Seçken, M. Levent Aksu, Ali̇ Osman Solak, Emi̇ne Kiliç Jan 2002

Electrochemical Behavior Of Benzo[C]Cinnoline And Its Bromo Derivatives, Ni̇lgün Seçken, M. Levent Aksu, Ali̇ Osman Solak, Emi̇ne Kiliç

Turkish Journal of Chemistry

The electrochemical behavior of benzo[c]cinnoline and some of its bromo derivatives was studied. Two discrete 2-electron reduction waves in acidic and only one wave in basic media in ethyl alcohol-BR buffer system (l:5 v/v) were observed. A mechanism for the electrode reaction is proposed. Diffusion coefficients, formal potentials for and the derivatives, the number of electrons transferred were determined by using sampled current polarography, cyclic voltammetry, chronoamperometry, chronocoulometry and constant potential coulometry. Adsorption of the molecules on the surface of the mercury drop was analyzed and this phenomena was exploited to calculate the formal potentials and the diffusion coefficients of …

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Molecular Dynamics Simulation Of Phase Transitions In Binary Lj Clusters, Adem Teki̇n, Mi̇ne Yurtsever Jan 2002

Molecular Dynamics Simulation Of Phase Transitions In Binary Lj Clusters, Adem Teki̇n, Mi̇ne Yurtsever

Turkish Journal of Chemistry

The structures of small clusters are studied extensively by classical simulation methods because of their interesting thermodynamic behavior. In this work, we study the thermodynamic properties of binary mixtures of noble gas atoms. Interatomic interactions are defined by 6-12 Lennard-Jones (LJ) potential. Starting from the global minimum of the potential energy surfaces, the systems are heated by increasing the total energy until melting occurs. The melting is observed by monitoring the Lindemann factor. The effects of the relative sizes of A and B atoms and the interaction strength of A-A, A-B, and B-B on the melting temperature of clusters containing …

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The Use Of Chloranilic Acid For The Spectrophotometric Determination Of Three Antihistamines, Kanakapura Basavaiah, V. S. Charan Jan 2002

The Use Of Chloranilic Acid For The Spectrophotometric Determination Of Three Antihistamines, Kanakapura Basavaiah, V. S. Charan

Turkish Journal of Chemistry

Cyproheptadine hydrochloride (CPH), methdilazine hydrochloride (MDH) and promethazine theoclate (PMT) were determined in their pure state and in pharmaceutical formulations by a simple spectrophotometric method. The determination was based on the formation of a charge-transfer complex between chloranilic acid as a \pi-acceptor and the studied drugs as n-donors in an acetonitrile-chloroform mixture. The spectra, various experimental parameters, the stoichiometry and the stability of the complexes formed were investigated. The complexes formed were found to absorb at 520 nm. Beer's law is obeyed in the concentration ranges 25-125, 20-100 and 25-150 \mu g ml^{-1}, for CPH, MDH and PMT respectively. The …

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Application Of Proton Conducting Polymer Electrolytes To Electrochromic Devices, Ayhan Bozkurt Jan 2002

Application Of Proton Conducting Polymer Electrolytes To Electrochromic Devices, Ayhan Bozkurt

Turkish Journal of Chemistry

Electrochromic display devices have been fabricated using Polydiallyldimethylammonium dihydrogenphosphate (PAMA^+ H_2PO_4^-) blended with H_3PO_4 as the electrolyte and WO_3 as the electrochromic film. The WO_3 deposited glass electrodes were doped with protons to form H_xWO_3 in which color depends on the charge density (CD) ranging from 0.01 to 0.04 C/cm^2. Proton conducting films of PAMA^+ H_2PO_4^- 2 H_3PO_4 (2 moles of acid per polymer repeat unit) were sandwiched between two electrodes to obtain the following symmetric configuration: Glass/ITO/WO_3/H^+ -electrolyte film/H_xWO_3 /ITO/Glass. Prior to construction of the electrochromic windows, the electrochemical stability of polymer/acid blends was determined via cyclic voltammetry (CV).

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Determination Of Linear Alkylbenzene Sulphonates And Their Biodegradation Intermediates By Isocratic Rp-Hplc, Mehmet Akyüz, David J. Roberts Jan 2002

Determination Of Linear Alkylbenzene Sulphonates And Their Biodegradation Intermediates By Isocratic Rp-Hplc, Mehmet Akyüz, David J. Roberts

Turkish Journal of Chemistry

An HPLC method was developed to determine linear alkylbenzene sulphonates (LASs) and their biotransformation products sulphophenyl carboxylates by isocratic chromatography using two C_{18} columns in series. Solid-phase extraction with a (C_{18}) cartridge was employed to isolate LAS from sediment and sewage effluent samples. Sodium perchlorate and ammonium perchlorate were used as ion pair agents. The recovery of the compounds was 94% \pm 2 and 98% \pm 2 respectively for sediment and sewage effluent. It was demonstrated that it is possible to separate LAS compounds and their isomers and homologues using this system.

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Determination Of Oxygen And Nitrogen Impurities In Magnesium Metal By Vacuum Distillation And Icp-Oes Techniques, Javed Akhtar, S. K. Durrani, N. A. Chughtai, M. Munir, Bashir Mohammad Jan 2002

Determination Of Oxygen And Nitrogen Impurities In Magnesium Metal By Vacuum Distillation And Icp-Oes Techniques, Javed Akhtar, S. K. Durrani, N. A. Chughtai, M. Munir, Bashir Mohammad

Turkish Journal of Chemistry

Due to the various promising properties of magnesium as a structural material and certain other applications such as a reducing agent for refractory metals, magnesium metal has great commercial importance in many technical industries but the presence of oxygen and nitrogen impurities adversely affects its physico-chemical and mechanical properties. Therefore, the exact measurement of oxygen and nitrogen impurities is essential. The accuracy of analytical values of micro amounts of nitrogen and oxygen (\mu g.g^{-1} level) in magnesium metal has been measured indirectly. The conditions for the vacuum distillation (VD) method were optimized. Analysis of residue for magnesium content was studied …

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A Spectrophotometric Method For The Determination Of Prazosin Hydrochloride In Tablets, Mahmure Üstün Özgür, Sidika Sungur Jan 2002

A Spectrophotometric Method For The Determination Of Prazosin Hydrochloride In Tablets, Mahmure Üstün Özgür, Sidika Sungur

Turkish Journal of Chemistry

A rapid and sensitive analytical method was developed for the spectrophotometric assay of prazosin hydrochloride. The method is based on the formation of a coloured derivative between the drug and 1,2-naphthoquinone-4- sulphonic acid sodium salt (NQS). The reaction proceeds quantitatively at pH 4.5 and 70°C for 40 min. After the extraction of the derivative with chloroform: n-butanol (3:1), the absorbance was measured at 400 nm. The method was applied to commercially available tablets and the results were statistically compared with those obtained by ultraviolet spectrophotometric and differential pulse polarographic methods using t- and F-tests.

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Determination Of Ascorbic Acid In Vegetables By Derivative Spectrophotometry, Zeynep Aydoğmuş, S. Müge Çeti̇n, Mahmure Üstün Özgür Jan 2002

Determination Of Ascorbic Acid In Vegetables By Derivative Spectrophotometry, Zeynep Aydoğmuş, S. Müge Çeti̇n, Mahmure Üstün Özgür

Turkish Journal of Chemistry

Determination of ascorbic acid (AA) in garlic, green pepper and chestnut was performed by derivative spectrophotometry without using any pre-separation or background correction techniques. The method is based on the measurement of the distances between two extremum values (peak-to-peak amplitudes) in second and third order derivative spectra of the extracts. Ten percent trichloroacetic acid was found to be the most suitable extraction solution. In the second order derivative spectrum the extrema of 253.2 and 259 nm for garlic, and in the third order derivative spectrum, the extrama of 256.4 and 261.6 nm for green pepper and chestrut samples were used …

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Determination Of Fatty Acid Composition And Total Trans Fatty Acids In Cereal-Based Turkish Foods, Orhan Dağlioğlu, Murat Taşan, Bariş Tunçel Jan 2002

Determination Of Fatty Acid Composition And Total Trans Fatty Acids In Cereal-Based Turkish Foods, Orhan Dağlioğlu, Murat Taşan, Bariş Tunçel

Turkish Journal of Chemistry

The fatty acid composition and trans fatty acids of 13 cereal-based foods produced by Turkish companies were analysed by capillary gas-liquid chromatography. The total fat contents of the samples ranged from 1.8 to 37.9%. Traditional Turkish white bread and bulgur had the lowest fat content (1.8% and 2.3% respectively) and wafer the highest (37.9%). The major fatty acids in the samples were C_{16:0}, C_{18:0}, trans C_{18:1}, C_{18:1} and C_{18:2}. Total unsaturated fatty acid contents varied between 49.0 and 80.3% of total fatty acids, and bulgur had the highest percentage among the samples. Except for bulgur, all the samples contained trans …

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Electrodeposition Of Zinc From Chloride Solution, Yanjerappa Arthoba Naik, Thimmappa V. Venkatesha, Perdur Vasudeva Nayak Jan 2002

Electrodeposition Of Zinc From Chloride Solution, Yanjerappa Arthoba Naik, Thimmappa V. Venkatesha, Perdur Vasudeva Nayak

Turkish Journal of Chemistry

The electroplating of zinc is carried out in the presence of 3,4,5-Trimethoxy benzaldehyde from a chloride bath. The bath constituents are optimized through Hull cell experiments. Operating parameters such as pH, temperature, and current density are also optimized. The current efficiency and throwing power are measured at different current densities. Polarization study is carried out under galvanostatic conditions. Corrosion resistance test indicated good protection of steel by the coating. The consumption of brightener is determined in the laboratory scale. SEM photomicrographs revealed fine-grained structure of the deposit from the optimum bath. IR spectrum of the scratched deposit showed inclusion of …

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The Effect Of Nicotinamide On Iron Corrosion In Chloride Solutions, Tunç Tüken, Bi̇rgül Yazici, Mehmet Erbi̇l Jan 2002

The Effect Of Nicotinamide On Iron Corrosion In Chloride Solutions, Tunç Tüken, Bi̇rgül Yazici, Mehmet Erbi̇l

Turkish Journal of Chemistry

The use of nicotinamide ``3-pyridineamide'' as an iron corrosion inhibitor was tested in aerated aqueous solutions of NaCl and Na_2SO_4 for different pH values. Polarization resistance (R_p) measurements, polarization curves and AC impedance spectroscopy techniques were used to obtain experimental data. Nicotinamide (ND) was found to exhibit a cationic-type inhibitor behaviour in acidic solution of NaCl (pH 3) and also a weak inhibitory effect in acidic sulphate solution (pH 3). The impedance spectra at open circuit potential showed that the corrosion process of the metal was characterized by two distinguishable capacitive loops. The charge transfer resistance (R_t) and the polarization …

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Novel Method For The Spectrophotometric Determination Of Isoniazid And Ritodrine Hydrochloride, Padmarajaiah Nagaraja, Kallanchira Sunitha, Ramanathapura Vasantha, Hemmige Yathirajan Jan 2002

Novel Method For The Spectrophotometric Determination Of Isoniazid And Ritodrine Hydrochloride, Padmarajaiah Nagaraja, Kallanchira Sunitha, Ramanathapura Vasantha, Hemmige Yathirajan

Turkish Journal of Chemistry

A simple, rapid and sensitive spectrophotometric method for the determination of isoniazid (INH) and ritodrine hydrochloride (RTH) in pure form as well as dosage forms is described. The method is based on the diazotisation of 4,4'-sulphonyldianiline (dapsone, DAP) followed by a coupling reaction with either INH or RTH in sodium hydroxide medium. Beer's law is obeyed in the concentration range of 0.5-20 \mu g ml^{-1} for INH at 440 nm and 0.5-18 \mu g ml^{-1} for RTH at 460 nm. The method is successfully employed for the determination of INH/RTH in pharmaceutical preparations and the results agree favourably with the …

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