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ABSTRACT: A new method is reported for sensitive determination of tartrazine in the food samples. The method is based on the catalytic effect of silver nanoparticle (AgNPs) on the oxidation reaction of tartrazine by potassium iodate in the acetate buffer medium. The reaction is followed spectrophotometrically by measuring the change in absorbance (ΔA) at 420nm using a fixed time method (70s). The reaction variables were optimised in order to achieve the highest sensitivity. The thirty six criterion detection limit was 0.3ng/mL, and the relative standard deviation for ten replicate measurements of 30ng/mL of tartrazine was 0.98% (n=10). The method was successfully applied to the determination of tartrazine in lemon, and papaya-flavoured gelatin, candy, and in fruit syrup.
Food Chemistry 06/2013; 138(2-3):1239-42. · 3.65 Impact Factor
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ABSTRACT: In this paper, a new spectrophotometric method is reported for the determination of nanomolar levels of Eriochrome black T in environmental samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of Eriochrome black T by hexacyanoferrate (III) in acetate-acetic acid medium and at 25 °C. The absorbance is measured at 512 nm with the fixed-time method. It relies on the linear relationship between the absorbance difference (∆A) and Eriochrome black T amounts in the range of 40-1,250 nM. Under optimum conditions, the sensitivity of the proposed method, i.e., the detection limit corresponding to 80 s, is about 25 nM. The method is featured with good accuracy and reproducibility for Eriochrome black T determination in river water samples without any pre-concentration and separation step.
Environmental Monitoring and Assessment 01/2013; · 1.40 Impact Factor
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ABSTRACT: A new spectrophotometric method is reported for the determination of nanomolar level of malachite green in surface water samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of malachite green by hexacyanoferrate (III) in acetate-acetic acid medium. The absorbance is measured at 610 nm with the fixed-time method. Under the optimum conditions, the linear range was 8.0 × 10(-9)-2.0 × 10(-7) mol L(-1) malachite green with a correlation coefficient of 0.996. The limit of detection (S/N = 3) was 2.0 × 10(-9) mol L(-1). Relative standard deviation for ten replicate determinations of 1.0 × 10(-8) mol L(-1) malachite green was 1.86 %. The method is featured with good accuracy and reproducibility for malachite green determination in surface water samples without any pre-concentration and separation step.
Environmental Monitoring and Assessment 12/2012; · 1.40 Impact Factor
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ABSTRACT: A new kinetic method has been developed for the determination of nitrite in fruit juice samples. The method is based on the catalytic effect of nitrite with the oxidation of Nile Blue A (NBA) by KBrO(3) in the sulfuric acid medium. The optimum conditions obtained are 1.2 mM sulfuric acid, 0.034 mM of NBA, 2.8 × 10(-3) M KBrO(3), reaction temperature of 20 °C, and reaction time of 100 s at 595.5 nm. Under the optimized conditions, the method allowed the quantification of nitrite in a range of 0.2-800 μg/mL with a detection limit of 0.02 μg/mL. The method was applied to the determination of nitrite in 15 brands of fruit juice samples.
Environmental Monitoring and Assessment 07/2012; · 1.40 Impact Factor
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ABSTRACT: A direct method for calculating the temperature of a hawking particle is carried out. Study of the quantum gravity effects
on the hawking radiation is made by imposing a generalized time energy uncertainty principle. It is shown that the Hawking
radiation of mini black hole is hotter than the hawking calculations.
KeywordsGeneralized time-energy uncertainty–Black hole–Temperature
Astrophysics and Space Science 04/2012; 334(1):161-163. · 1.69 Impact Factor
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ABSTRACT: Although the tunneling approach is fully established for black hole radiation, much work has been done to support the extension
of this approach to more general settings. In this letter the Parikh-Kraus-Wilczeck tunneling proposal of black hole tunneling
radiation is considered. The Reissner-Nordström-de Sitter black hole thermodynamics is studied according to the generalized
uncertainty principle and the modified dispersion relation analysis. It is shown that entropy, temperature and the original
Parikh-Kraus-Wilczek calculations of the black hole tunneling probability receive new corrections. The results are compared
and it is shown that these two alternative approaches lead to the same results if one uses the suitable expansion coefficients.
KeywordsBlack hole radiation-Black hole thermodynamics-Tunneling radiation-Generalized uncertainty principle-Modified dispersion relation-Reissner-Nordström-de Sitter black hole
International Journal of Theoretical Physics 04/2012; 49(7):1633-1640. · 0.85 Impact Factor
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ABSTRACT: A new kinetic method has been developed for the determination of iodine in water samples. The method is based on the catalytic effect of I(-) with the oxidation of Indigo Carmine (IC) by KBrO(3) in the sulfuric acid medium. The optimum conditions obtained are 0.16 M sulfuric acid, 1 × 10(-3) M of IC, 1 × 10(-2) M KBrO(3), reaction temperature of 35°C, and reaction time of 80 s at 612 nm. Under the optimized conditions, the method allowed the quantification of I(-) in a range of 12-375 ng/mL with a detection limit of 0.46 ng/mL. The method was applied to the determination of iodine in river and city water samples with the satisfactorily results.
Environmental Monitoring and Assessment 03/2012; · 1.40 Impact Factor
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ABSTRACT: A quantitative structure-property relationship (QSPR) study based on an artificial neural network (ANN) was carried out for the prediction of the microemulsion liquid chromatography polar surface area (PSA) of a set of 32 drug compounds. The genetic algorithm-kernel partial least squares (GA-KPLS) method was used as a variable selection tool. A KPLS method was used to select the best descriptors and the selected descriptors were used as input neurons in neural network model. For choosing the best predictive model from among comparable models, square correlation coefficient Q(2) for the whole set calculated based on leave-group-out predicted values of the training set and model-derived predicted values for the test set compounds is suggested to be a good criterion. Finally, to improve the results, structure-property relationships were followed by nonlinear approach using artificial neural networks and consequently better results were obtained. Also this demonstrates the advantages of ANN. Copyright © 2011 John Wiley & Sons, Ltd.
Drug Testing and Analysis 05/2011; · 2.54 Impact Factor
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ABSTRACT: Genetic algorithm and partial least square (GA-PLS), kernel PLS (GA-KPLS) and Levenberg- Marquardt artificial neural network (L-M ANN) techniques were used to investigate the correlation between dissociation constant (pK(a) ) and descriptors for 60 drug compounds. The applied internal (leave-group-out cross validation (LGO-CV)) and external (test set) validation methods were used for the predictive power of models. Descriptors of GA-KPLS model were selected as inputs in L-M ANN model. The results indicate that L-M ANN can be used as an alternative modeling tool for quantitative structure-property relationship (QSPR) studies. Copyright © 2011 John Wiley & Sons, Ltd.
Drug Testing and Analysis 04/2011; · 2.54 Impact Factor
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ABSTRACT: A novel selective and sensitive method is developed for determination of Penicillin G by Differential Pulse Adsorptive Stripping Voltammetry (DPAdSV). Penicillin G gave well-resolved diffusion-controlled cathodic peaks at -0.42 and -0.584 V, respectively (vs Ag/AgCl) in pH 7.50 of borate buffer. Optimal conditions were obtained as pH 7.50, accumulation potential of -0.2 V (vs Ag/AgCl), accumulation time of 120 s, and scan rate of 100 mV/s. Under the optimized conditions, a linear calibration curve was established for the concentration of Penicillin G in the range of 0.007-2.13 µg/ml with a detection limit of 0.000717 µg/ml. The procedure was successfully applied to the determination of Penicillin G in various medicine and biological samples. The relative standard deviation of the method at 0.05 and 0.5 µg/ml Penicillin G, for 10 runs, was 2.55% and 2.06%, respectively.
Drug Testing and Analysis 03/2011; 4(2):140-4. · 2.54 Impact Factor
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ABSTRACT: The Exp-function method is applied to construct a new type of solution of the coupled (2+1)-dimensional nonlinear system of Schrödinger equations. It is shown that the method provides a powerful mathematical tool for solving nonlinear evolution equations in mathematical physics.
The ANZIAM Journal 06/2010; 52(01):110 - 121. · 0.25 Impact Factor
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ABSTRACT: Using the modified Hawking radiation of a Schwarzschild black hole (based on the generalized uncertainty principle) we obtained the Bekenstein– Hawking entropy of a higher dimensional Schwarzschild black hole. Further-more, the thermodynamics of such black hole is studied.
01/2008; 114.
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ABSTRACT: The Parikh–Wilczek tunneling proposal of black hole radiation is considered in de Sitter–Schwarzschild space–time. The semi-classical black hole tunneling radiation is calculated under a minimal length uncertainty analysis. It is shown that the original calculation of Parikh–Wilczek receives a new correction.
Physics Letters B.
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ABSTRACT: A generalized formulation of non-commutative geometry for the Bargmann–Fock space of quantum field theory is presented. The analysis is related to the symmetry of the simplistic space and a minimal length uncertainty.
Chaos, Solitons & Fractals.
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ABSTRACT: Perturbed Numbo-Goto membrane at the equatorial plane of Reissner-Nordstrøm de-Sitter space-time is studied. It is shown that, the space-time geometry of the black-brane is non-commutative.
Chaos, Solitons & Fractals.
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ABSTRACT: An analytic approximate solution is presented for the natural convective dissipative heat transfer of an incompressible, third grade, non-Newtonian fluid flowing past an infinite porous plate embedded in a Darcy–Forchheimer porous medium. The mathematical model is developed in an (x,y) coordinate system. Using a set of transformations, the momentum equation is rendered one-dimensional and a partly linearized heat conservation equation is derived. The viscoelastic formulation presented by Akyildiz [Akyildiz FT. A note on the flow of a third grade between heated parallel plates. Int J Non-Linear Mech 2001;36:349–52] is adopted, which generates lateral mass and viscoelastic terms in the heat conservation equation, as well as in the momentum equation. A number of special cases of the general transformed model are discussed. A homotopy analysis method (HAM) is implemented to solve, with appropriate boundary conditions, the coupled third-order, second degree ordinary differential equation for momentum and the second-order, fourth degree heat conservation equation.
Communications in Nonlinear Science and Numerical Simulation.
