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Articles 2281 - 2310 of 2720
Full-Text Articles in Chemistry
Synthesis, Characterization And Biological Activity Of Triorganotin Carboxylates Containing Germanium, Muhammad Aziz Choudhary, Muhammad Mazhar, Saqib Ali, Umm-E Salma, Saima Ashraf, Abdul Malik
Synthesis, Characterization And Biological Activity Of Triorganotin Carboxylates Containing Germanium, Muhammad Aziz Choudhary, Muhammad Mazhar, Saqib Ali, Umm-E Salma, Saima Ashraf, Abdul Malik
Turkish Journal of Chemistry
Some new triorganotin carboxylates containing germanium with general formulae (R^{1}GeCHR^{2}CH_{2}COO) Sn(CH_{2}C(CH_{3})_{3})_{3} where R^{1} = N(CH_{2}CH_{2}O)_{3} and C_{6}H_{5}, R^{2} = C_{6}H_{5}, p-C_{6}H_{4}OCH_{3} and o-/p-C_{6}H_{4}F were synthesized and characterized by elemental analysis, infrared, multinuclear (^{1}H, ^{13}C, ^{119}Sn) NMR and mass spectrometry. Antibacterial activity of these compounds was evaluated against the standard drugs ampicilline and amoxicilline, and found to be more active in some cases than the standard drugs.
Phenolic Constituents From Phlomis Lycia, İclal Saracoğlu, Ü. Şebnem Harput, İhsan Çaliş, Yukio Ogihara
Phenolic Constituents From Phlomis Lycia, İclal Saracoğlu, Ü. Şebnem Harput, İhsan Çaliş, Yukio Ogihara
Turkish Journal of Chemistry
From the aerial parts of Phlomis lycia L. (Labiatae) a lignan glucoside, (-)-dihydrodehyrodiconiferyl alcohol-9-O-\beta -D-glucopyranoside (1); a caffeic acid ester, chlorogenic acid (2); three phenylethanoid glycosides, forsythoside B (3), alyssonoside (4) and leucosceptoside B(5); and two iridoid glucosides, lamiide (6) andauroside (7), were isolated. The structure elucidation of the isolated compounds was carried out by spectroscopic (UV, IR, 1D- and 2D-NMR, FAB-MS) methods. (-)-Dihydrodehyrodiconiferyl alcohol-9-O-\beta -D-glucopyranoside (1) and chlorogenic acid (2) were isolated for the first time from Phlomis species in this study.
An Investigation Of The Interaction Of 4-Membered Rings With Adjacent Carbanion Centers, Özden Özel Güven, N. Beki̇r Peyni̇rci̇oğlu
An Investigation Of The Interaction Of 4-Membered Rings With Adjacent Carbanion Centers, Özden Özel Güven, N. Beki̇r Peyni̇rci̇oğlu
Turkish Journal of Chemistry
A series of cyclobutylcarbinyl phenyl ketones was prepared and the rates of base catalyzed hydrogen-deuterium exchange of \alpha -hydrogen atoms were compared with those of appropriate model compounds, to test the validity of an earlier finding, which suggested that a four-membered ring, like the three-membered ring, has the ability to stabilize an adjacent carbanion center. In this study, unlike the cyclopropyl group, no clearly defined stabilization of the adjacent carbanion center was detected by the 1-phenyl- and 1-p-nitrophenyl- substituted cyclobutyl groups and only a very slight rate enhancement by the 3-phenylcyclobutyl group was detected. Attempts to detect a stabilization of …
Iridoid And Phenylethanoid Glycosides From Euphrasia Pectinata, Tayfun Ersöz, M. Zi̇ver Berkman, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Iridoid And Phenylethanoid Glycosides From Euphrasia Pectinata, Tayfun Ersöz, M. Zi̇ver Berkman, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Turkish Journal of Chemistry
Two specimens of Euphrasia pectinata collected from different regions of northern Anatolia were studied to determine their iridoid and phenylethanoid glycosides. Four iridoid glucosides, aucubin (1), euphroside (2), ixorodoside (3), and boschnaloside (4), and two phenylethanoid glycosides, acteoside (5) and leucosceptoside A (6), were isolated, and characterized from the aerial parts of E. pectinata} collected from Zigana pass (Trabzon). From the aerial parts of E. pectinata} collected from Kartalkaya (Bolu), a phenethyl alcohol glycoside, decaffeoylacteoside (7), was isolated in addition to previously isolated compounds. The structures of the isolated compounds were established by spectroscopic evidence.
Diterpenes From Sideritis Sipylea And S. Dichotoma, Gülaçti Topçu, Ahmet C. Gören, Turgut Kiliç, Y. Kemal Yildiz, Gülendam Tümen
Diterpenes From Sideritis Sipylea And S. Dichotoma, Gülaçti Topçu, Ahmet C. Gören, Turgut Kiliç, Y. Kemal Yildiz, Gülendam Tümen
Turkish Journal of Chemistry
Two Sideritis species afforded eleven kaurene and one beyerene diterpenes. Structures of the compounds from Sideritis sipylea} were elucidated as linearol (1), 7-epicandicandiol (2), sideridiol (3), siderol (4), isolinearol (5), isosidol (6) and epoxyisolinearol (7). Linearol was treated with m -chloroperbenzoic to afford its analogues ent-3\beta ,7\alpha ,17-trihydroxy-18-acetoxykaur-15-ene (1a) and ent}-7\alpha ,17,18-trihydroxy-3\beta -acetoxykaur-15-ene (1b) as new compounds. From the second species, Sideritis dichotoma, the kaurenes sideridiol (3) siderol (4), ent-7\alpha ,18-dihydroxy-15\beta ,16\beta -epoxykaurane (8)}, ent}-7\alpha -acetoxy,18-hydroxy-15\beta ,16\beta -epoxykaurane (9), ent-7\alpha -acetoxy-15,18-dihydroxy-kaur-16-ene (10), ent-7\alpha ,15,18-trihydroxykaur-16-ene (11) and the beyerene ent-7\alpha ,18-dihydroxybeyer-15-ene (12) were isolated. Structural elucidation is based on NMR techniques …
Pyrrolizidine Alkaloids From Symphytum Sylvaticum Boiss. Subsp. Sepulcrale. (Boiss.& Bal.) Greuter & Burdetvar. Sepulcrale And Symphytum Aintabicum Hub.- Mor. & Wickens, Semra Kurucu, Murat Kartal, Muhammad Iqbal Choudhary, Gülaçti Topçu
Pyrrolizidine Alkaloids From Symphytum Sylvaticum Boiss. Subsp. Sepulcrale. (Boiss.& Bal.) Greuter & Burdetvar. Sepulcrale And Symphytum Aintabicum Hub.- Mor. & Wickens, Semra Kurucu, Murat Kartal, Muhammad Iqbal Choudhary, Gülaçti Topçu
Turkish Journal of Chemistry
Pyrrolizidine alkaloid (Echimidine-N-oxide) was isolated from Symphytum sylvaticum Boiss. subsp. sepulcrale (Boiss. & Bal.) Greuter & Burdet var. sepulcrale and pyrrolizidine alkaloid (Echimidine) was isolated from Symphytum aintabicum Hub. - Mor. & Wickens. The structures of the isolated compounds were elucidated based on IR, EIMS, ^{1}H, and ^{13}C NMR analysis and also on 2D NMR (COSY, HMBC, HMQC) experiments.
Thermodynamic And Kinetic Parameters Concerning Complex Formation Between 3-Hydroxy- And 1-Aminopyrene And Pyridine, Nursel Acar, Özgül Koçak
Thermodynamic And Kinetic Parameters Concerning Complex Formation Between 3-Hydroxy- And 1-Aminopyrene And Pyridine, Nursel Acar, Özgül Koçak
Turkish Journal of Chemistry
Systems formed by the pyrene derivatives 3-hydroxypyrene and 1-aminopyrene with pyridine were studied. The thermodynamic and kinetic parameters of the systems were calculated using the changes in the absorption and emission spectra which occur due to hydrogen bond or complex formation. The decrease of the formation rate constant in the series methylcyclohexane, benzene, and o-chlorotoluene may be due to a more difficult formation of the hydrogen bond complex due to the increase of the dielectric constant in the solvent series.
Glycine Transport Through A Charged Polysulfone Cation Exchange Membrane, Nuri̇ Ünlü, Hüseyi̇n Kara, Mustafa Ersöz
Glycine Transport Through A Charged Polysulfone Cation Exchange Membrane, Nuri̇ Ünlü, Hüseyi̇n Kara, Mustafa Ersöz
Turkish Journal of Chemistry
The transport of glycine through a charged polysulfone cation exchange membrane was studied as a function of pH at different initial conditions of less than pH 5.9 and the glycine permeability was explained under the experimental conditions as pH dependent interfacial transport. The glycine permeability increases with a decreasing pH in the receiver phase. The largest permeability was obtained if the initial pH on the source side was pH 5.9 and that on the opposite side was pH 2.0. The transport phenomena can be explained by the interfacial transport based on the interfacial chemical reaction (protonation, deprotonation or ion-exchange) between …
Solvent, Temperature And Concentration Effects On The Adsorption Of Poly(N-Butyl Methacrylate) On Alumina From Solutions, Nursel Pekel, Olgun Güven
Solvent, Temperature And Concentration Effects On The Adsorption Of Poly(N-Butyl Methacrylate) On Alumina From Solutions, Nursel Pekel, Olgun Güven
Turkish Journal of Chemistry
Adsorption of poly(n-butyl methacrylate) (PnBMA) on alumina from solution was studied by UV and FT-IR Photoacoustic Spectroscopy techniques. The effects of the solvent, temperature, concentration, and molecular weight of the polymer on adsorption were investigated. Three solvents, cyclohexane, carbon tetrachloride and benzene, were employed. The adsorption was dependent on molecular weight and much more polymer was adsorbed in cyclohexane than in other solvents on the alumina surface. A decrease in adsorption was observed with increasing temperature. The results are in conformity with Langmuir's isotherm. The differences observed in Langmuir parameters were explained by polymer-polymer, polymer-solvent, polymer-adsorbent, and solvent-adsorbent interactions.
The Kinetics And Mechanism Of Oxidation Of Vanillin By Diperiodatonickelate(Iv) In Aqueous Alkaline Medium, Chandrashekhar Kathari, Pandurang Pol, Sharanappa Nandibewoor
The Kinetics And Mechanism Of Oxidation Of Vanillin By Diperiodatonickelate(Iv) In Aqueous Alkaline Medium, Chandrashekhar Kathari, Pandurang Pol, Sharanappa Nandibewoor
Turkish Journal of Chemistry
The title reaction was investigated in aqueous alkaline medium. A first order dependence in diperiodatonickelate (IV) (DPN) and an apparent fractional order in both vanillin and alkali were obtained. Periodate has a retarding effect on the reaction. The effect of added products and the ionic strength of the reaction medium have no significant effect on the reaction rate. A decrease in the dielectric constant of the medium decreases the rate of reaction. Effects of temperature on the rate of reaction were studied. A mechanism based on experimental results was proposed, and constants involved in the mechanism were evaluated. A good …
Synthesis, Spectral And Fungicidal Studies On Dioxobridged Binuclear Niobium(V) And Tantalum(V) Complexes Of N-Alkylphenothiazines, Boregowda Keshavan, Hunasegala Kempe Gowda
Synthesis, Spectral And Fungicidal Studies On Dioxobridged Binuclear Niobium(V) And Tantalum(V) Complexes Of N-Alkylphenothiazines, Boregowda Keshavan, Hunasegala Kempe Gowda
Turkish Journal of Chemistry
Six new dioxobridged binuclear complexes of the type [MO(L)Z]_{2}Z, where M=niobium(V) or tantalum(V), L=N-alkylphenothiazines (NAPs) and Z=tartrate and oxalate for niobium and tantalum respectively, were synthesized. The stoichiometry of the complexes was proposed on the basis of elemental analyses, molar conductance, magnetic and thermal data. The coordination behaviour of the ligands was determined with the help of spectroscopic studies. The fungicidal activity of the complexes was evaluated.
Aspertins A-D: Further Piperidine Alkaloids From Andrachne Aspera} (Euphorbiaceae), Viqar Uddin Ahmad, Arshad Kamal, Muhammad Shaiq Ali
Aspertins A-D: Further Piperidine Alkaloids From Andrachne Aspera} (Euphorbiaceae), Viqar Uddin Ahmad, Arshad Kamal, Muhammad Shaiq Ali
Turkish Journal of Chemistry
The aerial parts of Andrachne aspera belonging to the family Euphorbiaceae yielded four new piperidine alkaloids: aspertin-A (1), aspertin-B (2), aspertin-C (3) and aspertin-D (4). The structures of isolated alkaloids were elucidated by NMR, mass spectrometery and chemical means.
Diels-Alder Reactions Using 5 M Liclo_{4} -Diethyl Ether Catalyst, Mesut Kacan, H. R. Ferhat Karabulut
Diels-Alder Reactions Using 5 M Liclo_{4} -Diethyl Ether Catalyst, Mesut Kacan, H. R. Ferhat Karabulut
Turkish Journal of Chemistry
The rate acceleration of Diels-Alder reactions in 5.0 M lithium perchlorate-diethyl ether was re-examined using itaconic anhydride and itaconic acid. Rate acceleration was observed for non-functionalised dienes, but functionalised dienes gave the starting or polymeric materials.
Synthesis Of 2'-Deoxy-2'-Fluoro-L-Arabinofuranosyl Imidazole Derivatives, Süreyya Ölgen
Synthesis Of 2'-Deoxy-2'-Fluoro-L-Arabinofuranosyl Imidazole Derivatives, Süreyya Ölgen
Turkish Journal of Chemistry
A new series of imidazole nucleosides was synthesized via direct condensation and construction of heterocyclic moiety from glycosyl amine templates. The characterization of the compounds was accomplished by elemental analysis, ^{1}H-NMR, ^{13}C-NMR, IR, UV-VIS spectral data and optical rotation.
Determination Of Zinc In Aerosol Samples By Discrete Nebulization Flame Atomic Absorption Spectrometry, Deni̇z Yurtsever Sarica, Di̇lek Akim, Tuncel Özden
Determination Of Zinc In Aerosol Samples By Discrete Nebulization Flame Atomic Absorption Spectrometry, Deni̇z Yurtsever Sarica, Di̇lek Akim, Tuncel Özden
Turkish Journal of Chemistry
A well-known analytical method, ``discrete nebulization'', which is suitable for samples having a limited amount like body fluids, high solid content or salt solutions, and less volatile metals, has been further developed for zinc determination in aerosol samples. The effects of injection volume and nebulizer aspiration rate on absorbance and precision were studied. A calibration graph was obtained linearly up to 1.75 mg/L Zn with a 0.9988 correlation coefficient and 3.09\% RSD using 50 \mu L injection volume, values comparable to conventional continuous nebulization. The detection limit (3S) achieved by the method was calculated to be 1.09 ng or 0.020 …
A Comparative Study For Basic Characterization Of Three Clinoptilolite Specimens, Eva Chmielewska, Eva Samajova, Jan Kozac
A Comparative Study For Basic Characterization Of Three Clinoptilolite Specimens, Eva Chmielewska, Eva Samajova, Jan Kozac
Turkish Journal of Chemistry
Physicochemical and mineralogical characteristics of the clinoptilolite tuffs of Chinese, Slovakian and American origin were investigated using various techniques, i.e. X - ray powder diffraction, water vapour desorption, ion exchange and chemical analysis.
Effects Of Ozonation On Characteristics Of Aquatic Fulvic Acid, Şermi̇n Gül
Effects Of Ozonation On Characteristics Of Aquatic Fulvic Acid, Şermi̇n Gül
Turkish Journal of Chemistry
Aquatic fulvic acid (FA) treated with ozone was characterized by physical/chemical (dissolved organic carbon-DOC), spectroscopic (UV/VIS, IR, fluorescence), chromatographic (gel permeation chromatography-GPC) methods. The influence of ozonation on the subsequent water treatment process such as flocculation and chlorination was also examined. The DOC concentration of the 20 min ozonated FA samples was reduced only a small amount (5%) whereas the UV absorption reduced to a higher percent (40%). The IR spectra of ozonated samples showed a moderate attenuation of the double band and aromatic character of FA. Ozonation of the FA caused the fluorescence intensities to increase steadily with ozonation …
Stabilization Of Papain By Modification With Chitosan, Ali̇ Kilinç, Seçi̇l Önal, Azmi̇ Telefoncu
Stabilization Of Papain By Modification With Chitosan, Ali̇ Kilinç, Seçi̇l Önal, Azmi̇ Telefoncu
Turkish Journal of Chemistry
Papain (EC 3.4.22.2) was immobilized on chitosan by adsorption and subsequent cross-linking with glutaraldehyde. The immobilized papain displayed a lower specific activity than did the native enzyme. The thermal stability of the immobilized papain, relative to that of the free enzyme, was markedly increased. The storage stability of the conjugated enzyme was enhanced such that more than 85% of the initial activity remained after a month storage at 45°C. The optimum pH of immobilized papain was shifted to the acidic region and enzyme stability was increased at pH levels below 3.5.
Steric Effects On The Oxidation Potential Of 1-Aryl Thioglycosides, Mehmet A. Oturan, Maurice Medebielle, Shirish A. Patil, Robert S. Klein
Steric Effects On The Oxidation Potential Of 1-Aryl Thioglycosides, Mehmet A. Oturan, Maurice Medebielle, Shirish A. Patil, Robert S. Klein
Turkish Journal of Chemistry
The electrochemical oxidation of several 1-arylthioglycosides has been studied by cyclic voltammetry in acetonitrile. We found that the oxidation potential of the \alpha anomer always occurs at a less positive oxidation potential than of the \beta anomer. The difference in the oxidation potential depends on the substituent attached on the C-3 of the sugar moiety and is greatly influenced by the stability of the radical cation obtained after the first electron transfer.
Ft-Ir And Ft-Raman Studies On 3-Aminophthalhydrazide And N-Aminophthalimide, N. Puviarasan, V. Arjunan, S. Mohan
Ft-Ir And Ft-Raman Studies On 3-Aminophthalhydrazide And N-Aminophthalimide, N. Puviarasan, V. Arjunan, S. Mohan
Turkish Journal of Chemistry
The FT-infrared (400-4000 cm^{-1} ) and FT-Raman (100-3500 cm^{-1} ) spectra of N-aminophthalimide and 3-aminophthalhydrazide were recorded. The observed frequencies were assigned to various modes of vibrations on the basis of normal coordinate analysis, assuming C_{S} point group symmetry. The potential energy distribution associated with normal modes is also reported. The assignments of fundamental vibrations agree well with the calculated frequencies.
Application Of Quantitative Structure-Retention Relationships (Qsrr) To A Set Of Organic Bromo And Nitrile Derivatives, Gustavo P. Romanelli, Juan Carlos Autino, Eduardo A. Castro
Application Of Quantitative Structure-Retention Relationships (Qsrr) To A Set Of Organic Bromo And Nitrile Derivatives, Gustavo P. Romanelli, Juan Carlos Autino, Eduardo A. Castro
Turkish Journal of Chemistry
The retention times are studied for two sets of 1-bromo-2-aryiloxyetanes and 3- aryloxypropiononitriles derivatives by means of Quantitative Structure-Retention Relationships (QSRR}). Five quantum mechanical molecular descriptors are used to calculate the regression equations. The fitting polynomials are computed in several-variable at first, second, and third order equations. Results are only significant when resorting to several-variable formulae which seems to point out the rather complex physical chemistry nature of the property under study.
Flow Injection Extraction - Spectrophotometric Determination Of Bismuth With Di-(Hydrogenated Tallow Alkyl) Dimethylammonium Chloride, S. A. Barakat
Flow Injection Extraction - Spectrophotometric Determination Of Bismuth With Di-(Hydrogenated Tallow Alkyl) Dimethylammonium Chloride, S. A. Barakat
Turkish Journal of Chemistry
Bismuth(III) (0-25 \mu g/ml) is determined spectrophotometricaly at 513 nm after extraction into dichloromethane of the ion associate di-(hydrogenatedtallowalkyl)dimethylammonium tetraiodobismuthate. The reagent stream is distilled water, merged with 1.0 M sulfuric acid, 5% potassium iodide and 5% (w/v) ascorbic acid solution. The reagent stream is 0.2% (w/v) di-(hydrogenatedtallowalkyl)dimethylammonium chloride solution. The injection rate is 15 h^{-1}. The calibration graph is linear up to 25 \mu g/ml. The detection limit is 0.35 \mu g/ml Bi. The system is applied on water samples and copper-based alloys.
Spectrophotometric Studies Of The Behavior Of P-Amino-N, N-Dimethyl Aniline With Ferric Nitrate In Methanol, Ali Hassoon Al-Taiar, Suhad K. Shubber, A. Megherbi
Spectrophotometric Studies Of The Behavior Of P-Amino-N, N-Dimethyl Aniline With Ferric Nitrate In Methanol, Ali Hassoon Al-Taiar, Suhad K. Shubber, A. Megherbi
Turkish Journal of Chemistry
The UV-visible absorption bands of the new complex were obtained using p-amino-N, N-dimethyl aniline as an electron donor with ferric nitrate as an electron acceptor in methanol at 25°C. The values of association constant K^{AD}, molar extinction coefficient \varepsilon^{AD}, and absorption band energy of charge transfer complex h \varepsilon_{CT} were calculated. The ionization potential of the donor I^{D}, was calculated from the complex band energy. The kinetics of the above association reaction were studied. This reaction was found to be a first order. The values of the rate constant of the forward reaction k_{1}, the rate constant of the reverse …
A Study Of The Adsorption Of Phenol By Activated Carbon From Aqueous Solutions, Riaz Qadeer, Abdul Hameed Rehan
A Study Of The Adsorption Of Phenol By Activated Carbon From Aqueous Solutions, Riaz Qadeer, Abdul Hameed Rehan
Turkish Journal of Chemistry
A commercial active carbon was tested as an adsorbent for the removal of phenol from aqueous solutions. The optimum conditions for maximum adsorption in terms of shaking time, amount of the adsorbent, and concentration of the adsorbate were identified. The adsorption data fitted the Langmuir isotherm equation in the whole range of concentrations studied. The adsorption of picric acid, pyrogallol and salicylic acid at selected conditions for phenol was also studied. Elution studies to recover the adsorbed phenol from active carbon were performed with distilled water, NaOH and HCl solutions.
An Indirect Lectin Affinity Bioassay For Uromodulin, Zeki̇ Topcu
An Indirect Lectin Affinity Bioassay For Uromodulin, Zeki̇ Topcu
Turkish Journal of Chemistry
Uromodulin is a monomeric glycoprotein excreted in large amounts in urine. Most of the assay methods for quantifying uromodulin rely on the availability of antibodies to this glycoprotein. This study reports a new bioassay for uromodulin without requiring the presence of antibodies. The bioassay is based on the lectin affinity of the glycoprotein and the known interaction between uromodulin and the tumor necrosis factor. The measuring range of the bioassay described in this paper is between 0.13 and 1.25 \mu g/ml, which makes it a potential method for clinical use.
Efficient Synthesis Of 1-Alkoxycarbonyl-Methyl-2-Alkylpyrroles From Dichloro- And Methoxychloropropylalkyl Ketones, Raik A. Gadzhili, Raya A. Nadzhafova, Özge Şeşenoğlu
Efficient Synthesis Of 1-Alkoxycarbonyl-Methyl-2-Alkylpyrroles From Dichloro- And Methoxychloropropylalkyl Ketones, Raik A. Gadzhili, Raya A. Nadzhafova, Özge Şeşenoğlu
Turkish Journal of Chemistry
The condensation reaction of 2,3-dichloropropyl- and 2-methoxy-3-chloropropyl alkyl ketones with alkyl 2-aminoacetate salts leads to 1-alkoxy-carbonylmethyl-2-alkylpyrroles. These compounds, with various bases, gave 1-carbamoylmethyl-, 1-dialkylaminocarbonylmethyl-, 1-carbazoyl methyl-2-alkylpyrroles and potassium salt of 2-alkyl-pyrrolyl-1-acetic acid.
Determination Of Ternary Mixtures Of Vitamins (B_{1}, B_{6}, B_{12}) By Zero-Crossing Derivative Spectrophotometry, Mahmure Üstün Özgür, İkbal Koyuncu
Determination Of Ternary Mixtures Of Vitamins (B_{1}, B_{6}, B_{12}) By Zero-Crossing Derivative Spectrophotometry, Mahmure Üstün Özgür, İkbal Koyuncu
Turkish Journal of Chemistry
A new method for determining ternary mixtures of vitamin B_{1}, B_{6} and B_{12} using second derivative spectrophotometry is described. The procedure is accurate, nondestructive and does not require any separation step or the solving of equations. Calibration graphs were linear up to 20 \mu gml^{-1} of vitamin B_{1} at 228.9 nm (r=0.9999), vitamin B_{6} at 309.6 nm (r=0.9999) and vitamin B_{12} at 361.7 nm (r=0.9998). The method was successfully applied for analyzing synthetic mixtures and commercial pharmaceutical preparations.
The Effects Of Benzoic Acid In Chloride Solutions On The Corrosion Of Iron And Aluminum, Si̇bel Zor
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 …
Simultaneous Determination Of Fe(Ii) And Fe(Iii) In Pharmaceutical Samples By Post-Column Derivatization/Hplc, Hami̇de Z. Şenyuva, Deni̇z Yurtsever Sarica, Tuncel Özden
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 …
Chemical Exfoliation Characteristics Of Karakoç Phlogopite In Hydrogen Peroxide Solution, Erol Üçgül, İsmai̇l Gi̇rgi̇n
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 …