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Spectrokinetics study of probable effects of diverse inorganic ions on bleaching of dye

Frontiers of Chemical Science and Engineering 2011年第1期5卷 131-138页

作者： rafia azmat Masooda QADRI Fahim UDDIN Department of Chemistry Jinnah University for Women5C NazimabadKarachi 74600Pakistan Department of Chemistry University of KarachiKarachi 75270Pakistan

Toluidine blue(TB)is an important anticoagulant metachromasia molecule showing a pronounced variation in the visible spectrum due to the aggregation phenomenon and electrostatic interaction with the charged synthetic and biologic *** current study describes the interactive role of diverse inorganic material ions on the bleaching of toluidine blue(tolonium chloride)(TB^(+))with urea in acidic and basic media using the spectrophotometric *** spectra of TB and urea with different cations and anions were monitored and their characteristic features are presented *** negative effect of added cations on reduction may be the result of altered electron pathways which led to suppression of the reduction/bleaching of TB,while a slight decrease in dye reduction by added anions may be due to the scavenging of the OH**** has been observed in the case of Co^(2+)that in addition to the electron-transfer reaction,other processes like layer and precipitate formation also appear to be taking *** dye bleaching process followed pseudo first order kinetics with respect to TB,urea,and H^(+)ion,whereas significant decoloration in the presence of urea proved that reductants control the redox *** decoloration in acidic medium with diverse ions was seen compared to alkaline media,showing that water pH played an important role in the bleaching of *** reduction/bleaching of dye was investigated at different temperatures,and energy parameters were evaluated for a TB^(+)-Urea reaction,including the energy of activation(Ea=39.60 kJ·mol^(–1)),enthalpy of activation(ΔH#=34 kJ$mol^(–1)),entropy of activation(ΔS#=146.5 kJ mol^(–1)·K^(–1)),and free energy of activation(ΔG*=–52.35 kJ·mol^(–1)).A mechanism of interaction of diverse ions in dye bleaching and a mechanism of reduction based on the above findings is proposed.

关键词： TB diverse ions suppress decoloration

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Kinetics of Reduction of Thionine with Ribose and the Structural Properties of the Dye at Different pH Using DFT Method

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Chinese Journal of Chemistry 2011年第4期29卷 643-649页

作者： Ahmed, Khalid azmat, rafia Uddin, Fahim Fatmi, M. Qaiser Department of Chemistry University of Karachi Karachi 752 70 Pakistan Department of Chemistry Jinnah University for Women Nazimabad Karachi Pakistan Department of Chemistry University of California at Riverside California 92521 USA

The reaction between the thionine （Th） and the ribose was observed spectrophotometrically and changes in absorbance of Th were recorded at variable concentration of dye, reductant and pH. A pseudo first order rate of reaction was found to establish the reduction kinetics of the dye, studied at a pH range of 0.34 to 12.8. Absorption spectrum of Th at different pH, with ribose showed a pH （12.8） dependent introversion. The reduction most probably took place with enediol intermediate of the sugar at high pH. A full geometry optimization of predominant species of Th namely, mono-deprotonated, di-deprotonated Th, and LTh （leuco thionine） respectively, at low and high pH, was performed at B3LYP level of theory. The data obtained from the energy minimization were in excellent agreement with other experimental and theoretical observations. The calculated enthalpies of formation for both reduction reactions （mono-deprotonated Th＋H＋→leucothionine and di-deprotonated Th＋2H＋→leucothionine） provided evidences for maximum reduction of the dye at high pH.

关键词： thionine ribose pH enediol geometry optimization reduction

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Thionine sensitized areobic photooxidation of thiourea in acidic medium

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Frontiers of Chemistry in China 2011年第2期6卷 120-126页

作者： rafia azmat Nida SALEEM Department of Chemistry Jinnah University for WomenKarachi 74600Pakistan

An investigation of the thionine sensitized aerobic photooxidation of thiourea was observed spectrophotometrically at a wavelength of 598 *** reported two types of reactions which generally occur in the presence of oxygen:1)Singlet oxygen,produced by dye sensitization due to the hydrolysis that reacts with thiourea to form oxidative products like urea and other sulfur-containing fragments and 2)bleaching of dye,which leads to the *** rate of reaction in all studied parameters followed first order kinetics with respect to maximum absorption of the dye in the visible band *** kinetics was significantly dependent upon the medium and the reaction accelerated more rapidly at low pH.A direct relation was exhibited between the thiourea concentration and dye sensitizer,which was not pragmatic with the concentration of *** reaction was effected by the temperature,and the values of energy parameters suggested that the energy of activation was low while the entropy of activation increases with the rise in temperature,which indicated a highly solvated state of intermediate *** value of ΔH* and ΔG*at elevated temperature showed that free energy is the driving force for the completion of reaction.A mechanism based on the above findings has been suggested.

关键词： thionine sensitized photo oxidation thiourea singlet oxygen fragment

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A natural chemical technology for reducing fluoridation through chloride contents in muscles of fish

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Journal of Chemistry and Chemical Engineering 2009年第8期3卷 57-63页

作者： rafia azmat Department of Chemistry Jinnah University for Women 5C Nazimabad Karachi 74600 Pakistan

Accumulation trend of fluoride ion was carried out in 25 fish species, collected randomly from fresh water and marine water, Sindh, Pakistan to ensure the level of chloride contents by Selective Ion Electrode （SIE） method. Results showed an inverse relation in between chloride and fluoride concentration in muscles of fish under investigation, It was observed that chloride ions contents of marine water fish were significantly higher as compared with fresh water fish. This may be related with the habitat of marine water fish while no appreciable divergence in fluoride concentration in both regions was observed. This indicated that the deliberation of fluoride is the phenomena of nature of fish and self-determining. Highest concentration of fluoride ion in fresh water fish and marine water fish showed an inverse level of chloride ion in it, reflects water body conditions of both resources. A probable mechanism of accumulation of fluoride with respect to essential chloride ion which may be related with the size of ionic radii of both halides ion is described in relevant section of this article. Where a larger ionic radii of chloride ion believed to play an imperative role in reducing fluoridation in fishes. This may be regarded as natural chemical technology for reducing fluoride in muscle （edible part） of fish of both regions.

关键词： fluoride chloride inverse relation ionic radii chemical technology

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Pre-oxidative catalytic treatment of toluidine blue with potassium permanganate in acidic solution

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Frontiers of Chemistry in China 2011年第2期6卷 84-90页

作者： rafia azmat Faryal Vali MOHAMMED Tehseen AHMED Qurat-ul-Ain TANWIR Department of Chemistry University of KarachiKarachi 75270Pakistan International Chemical and Biological Sciences Center H.E.J Reaseach Institute of ChemistryUniversity of KarachiKarachi 75270Pakistan Department of Chemistry Jinnah University for WomenKarachi 74600Pakistan

This article describes the potential of KMnO4 for oxidation of the thiazine dye(Toluidine blue TB)in an acidic *** effect of different operational parameters like initial concentration of dye,potassium permanganate,pH,ionic strength,catalyst,acids and temperature were investigated spectrophotometrically at λ_(max)=613 *** results showed a complete removal of the TB with mineralization of the dye *** and complete decoloration was observed in the presence of monobasic acid(HCl)as compared to the H_(2)SO_(4) where little color removal was *** was found to be an effective catalyst in oxidation for complete and fast decolorization with *** significant change at elevated temperatures showed that an intermediate complex degraded with slight change in the ***/visible spectrophotometry and GC mass analysis showed an intermediate activated complex demethylated sulophooxide of TB which later on degraded into smaller fragments.

关键词： oxidation TB potassium permanganate decoloration Pb

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Marine Green Algae as a Supplement for Chlorophyll and Other Nutrients in Vigna Radiata under UV-C Radiation-Induced Stress

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Journal of Chemistry and Chemical Engineering 2010年第5期4卷 1-7页

作者： rafia azmat Hajra Nasreen Department of Chemistry Jinnah University for Women 5C Nazimabad Karaehi 74600 Pakistan Department Of Botany Jinnah University for Women 5C Nazimabad Karachi 74600 Pakistan

The potential protective effect of marine green algae （Codium iyengerii） was examined in UV-C treated seedlings of Vigna radiata. The study comprises of three treatments of UV-C radiation （100-290 nm） dose for one min in alternative days. This results in deformed morphological parameters, including： decrease in plant height, fresh mass of leaves, shoots and roots, as well as leaf areas, which may be attributed with decreased in the relative growth rate, carbohydrate, amino acids, and protein contents of plant. A drastic effect of UV-C radiation was found on the photosynthetic apparatus where increase in red pigmentations on the leaves surface indicates the presence of UV-C absorbing pigments instead of chloroplast pigments. Visible spectrum of leaves chlorophyll showed reduced concentration of visible absorbing pigments which showed the deleterious effect of these radiations on physiological processes of seedlings. These negative effects of UV-C radiation on plant growth were found to be decreased by the application of green seaweed （Codium iyengerii）, and absorption spectrums of chloroplast contents showed that UV-C radiation inducing damages were appropriately managed by enhanced concentration of seaweeds which significantly increased morphological and physiological parameters like leaf, stem, root biomass, and plant height under UV-C radiation were observed.

关键词： Survival UV-C radiation codium iyengerii spectrums morphological and physiological parameterss.

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A new approach for reduction of methylene green withascorbic acid by de-oxygenation through carbondioxide

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Natural Science 2011年第7期3卷 566-572页

作者： rafia azmat Noshab Qamar Raheela Naz 不详

Reduction kinetics of the methylene green (MG) with ascorbic acid (AA) in acidic medium at λmax 660 nm was monitored through visible spectrophotomtry in absence and presence of sodium carbonate. CO2 release through reaction of sodium carbonate and oxalic acid, created deoxygenated atmosphere for reduction of dye which greatly boosted the reaction rate. Initially slow reaction in presence of atmospheric oxygen proceeded rapidly when sodium carbonate was added. The reaction followed fractional order kinetics with AA and zero order kinetics with MG. The rate of reaction shows no linear dependence on [H+] concentration as an acidic medium. The rate of reaction is directly related with the elevated concentration of salt, which suggests that the two same charged species are involved in the rate determining step. Secondary reactions at elevated temperature showed complex kinetics.

关键词： Ascorbic Acid Methylene Green Sodium Carbonate Charged Species Secondary Reactions Elevated Temperature

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Kinetics and mechanisms of oxidation of d-fructose and d-lactose by permanganate ion in acidic medium

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Natural Science 2012年第7期4卷 466-478页

作者： rafia azmat Raheela Naz Noshab Qamar Imran Malik Department of Chemistry University of Karachi Department of Chemistry Jinnah University for Women 5-C Nazimabad Karachi Pakistan International Centre of Chemical and Biological Sciences (ICCBS) University of Karachi

The oxidations of D-fructose and D-lactose were monitored spectrophotometrically by potassium permanganate in acidic medium at λmax 545 nm. Reaction demonstrated that the two oxidative species of permanganate were involved in an acidic oxidation of the sugars. It was established that respective acids of sugars as well as arabinonic and formic acid were the oxidation products. Respective acids of sugars were the results of reactive oxygen species of permanganate ions in acidic conditions while arabinonic and formic acids due to the cleavage of C__C bond through MnO-4 species. It was first order kinetics with respect to [MnO-4 ], [fructose], [lactose] and [H+]. Hg was used to accelerate the slow oxidation of lactose. Effect of varying salt electrolyte concentration was insignificant showing that the molecular species was involved in the rate determining step. Formic and arabinonic acids and respective acids were analyzed through spot and spectroscopic studies respectively. Reaction was monitored at different temperatures and thermodynamics activation parameters were determined. A mechanism consistent with kinetic studies, spectral evidences, stoichiometry of the reactions and product analysis has been proposed for the oxidation of fructose and lactose in absence and presence of catalyst respectively.

关键词： Fructose Lactose KMnO4 Hg Formic Acid Arabinonic Acid

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第13届亚洲化学大会论文摘要——Spectrokinetics Study of Probable Interaction of Diverse Inorganic Material Ions on Bleaching of Dye

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华东理工大学学报（自然科学版） 2010年第1期36卷 87-87页

作者： azmat rafia Department of Chemistry Jinnah University for Women 5C Nazimabad 74600 Pakistan

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