Amr A. Essawy

Novel application of pyronin Y fluorophore as high sensitive optical sensor of glucose in human serum

This paper presents a novel, high sensitive, facile and rapid spectrofluorimetric method for the direct assessment of glucose in human serum samples. The strong fluorescence intensity of pyronin Y (PY) is found to be selectively quenched substantially by adding solutions of glucose. Therefore, a new quantitative method to determine glucose could be developed. The noticeable and specific quenching effect of glucose on PY emission could be attributed to the increase in the nonradiative interactions as a result of a charge-transfer excited state with the location of the positive charge at the xanthenes moiety. Various parameters namely, the best working solvent, the proper pH medium in addition to the concentration of PY fluorophore corresponding to maximum fluorescence intensity were closely investigated. Under optimal conditions, the standard curve was linear in the glucose concentration ranges from 5.0×10(-9) to 1.0×10(-6)molL(-1) (r=0.994). The detection limit (S:N=3) (LOD) is 2.9×10(-9)molL(-1). Validation of this approach was done by examining glucose concentration in serum samples of twenty patient and ten health donors. Achieved recovery reached 99.63-100.43% and 99.57-100.70%, respectively, in good agreement with those provided from hospital using traditional method. The relative standard deviations (RSD) were estimated between 0.00-0.78% and 0.15-1.91%, respectively.

DFT calculations, spectroscopic, thermal analysis and biological activity of Sm(III) and Tb(III) complexes with 2-aminobenzoic and 2-amino-5-chloro-benzoic acids

The complexes of Sm(III) and Tb(III) with 2-aminobenzoic acid (anthranilic acid, AA) and 2-amino-5-chlorobenzoic acid (5-chloroanthranilic acid, AACl) were synthesized and characterized based on elemental analysis, IR and mass spectroscopy. The data are in accordance with 1:3 [Metal]:[Ligand] ratio. On the basis of the IR analysis, it was found that the metals were coordinated to bidentate anthranilic acid via the ionised oxygen of the carboxylate group and to the nitrogen of amino group. While in 5-chloroanthranilic acid, the metals were coordinated oxidatively to the bidentate carboxylate group without bonding to amino group; accordingly, a chlorine-affected coordination and reactivity-diversity was emphasized. Thermal analyses (TGA) and biological activity of the complexes were also investigated. Density Functional Theory (DFT) calculations at the B3LYP/6-311++G (d,p)_ level of theory have been carried out to investigate the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using SDDALL basis set. Moreover, total energy, energy of HOMO and LUMO and Mullikan atomic charges were calculated. In addition, dipole moment and orientation have been performed and discussed.

A novel method for tyrosine assessment in vitro by using fluorescence enhancement of the ion-pair tyrosine-neutral red dye photo probe

A low cost and accurate method for the detection and analytical determination of tyrosine in tablet and blood serum was developed. The method was based upon measuring the fluorescence intensity of the ion associate of neutral red dye and the tyrosine (NRD+ TYR−) at 610 nm in acetonitrile at (pH 9.5, λex = 350 nm). The influence of the different parameters, e.g., pH, solvent, tyrosine concentration and foreign ions concentrations that control the fluorescence intensity of the produced ion associate was critically investigated. The remarkable enhancement of the fluorescence intensity of NRD+ TYR− ion associate in acetonitrile at 610 nm and the quenching of emission band of NRD at 380 nm by various concentrations of tyrosine was successfully used as a photo-probe for the assessment of tyrosine concentration. The calibration plot was achieved over the concentration range 1 × 10−5 to 5 × 10−9 mol L−1 tyrosine with a correlation coefficient of 0.993 and a detection limit of 2.7 × 10−9 mol L−1. The developed method is simple and proceeds without practical artifacts compared to the other determination methods.

Ultrasonic-mediated synthesis and characterization of TiO2-loaded chitosan-grafted-polymethylaniline nanoparticles of potent efficiency in dye uptake and sunlight driven self-cleaning applications

In the present study, a new sequential process for wastewater remediation in two steps with high durability was presented. Firstly, dye uptake on TiO2-loaded chitosan-graft-poly(2- and 3-methylaniline) nanocomposites was observed in the dark. Secondly, sunlight-assisted photocatalytic self-cleaning for regeneration of the used adsorbent was achieved. Thus a synergic effect of adsorption/photooxidation for successful removal of dye from aqueous solutions was manifested. The nanocomposites were characterized by FTIR, UV-Vis diffuse reflectance, XRD, and TEM. The data of dye adsorption were fitted to Langmuir and Freundlich isotherms. The Langmuir model gave the best fit. The pseudo-first-order and pseudo-second-order were used to analyze the kinetic data. The data fit well with the second-order kinetic model. The adsorptive removal of the dye was highly efficient. Interestingly, the adsorbents were successfully regenerated by photomineralizing the adsorbed dye via solar-assisted self-cleaning. Efficient photocatalytic ability as reflected from the estimated photodegradation rate of the dye was observed. Furthermore, the prepared materials showed good photocatalytic stability after five runs under solar light. The ˙OH detected from the photoluminescence – terephthalic acid technique along with ˙O2− species seem to be the oxidizing species responsible for the sunlight-driven photodegradation reaction.