Abdallah A. Shaltout

FTIR spectroscopic, thermal and XRD characterization of hydroxyapatite from new natural sources

The inorganic constituents of 5 different plants (leaves and stalks) were investigated by using Fourier transformer infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal analysis including thermal gravimetric analysis (TGA), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC). These plants are Catha edulis (Khat), basil, mint, green tea and trifolium. The absorption bands of carbonate ions CO(3)(2-) was exhibited at 1446 cm(-1), and the phosphate ions PO(4)(3-) was assigned at 1105 and 1035 cm(-1). At high temperatures (600, 700 and 600°C) further absorption bands of the phosphate ions PO(4)(3-) was assigned at the frequencies 572, 617, 962, 1043 and 1110 cm(-1) and the vibrational absorption band of the carbonate ions CO(3)(2-) was assigned at 871, 1416 and 1461 cm(-1). X-ray diffraction and thermal analysis confirm the obtained results of FITR. Results showed that the main inorganic constituents of C. edulis and basil leaves are hydroxyapatite whereas the hydroxyapatite content in the other plant samples is less than that in case of C. edulis and basil plant leaves.

Determination of Cd, Cu, Ni, and Pb in Black Tea from Saudi Arabia using Graphite Furnace Atomic Absorption Spectrometry after Microwave-Assisted Acid Digestion

A method has been developed for the determination of Cd, Cu, Ni, and Pb in black tea samples from Saudi Arabia using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). It was found that chemical modifiers were not required for this analysis. The determination of Cd and Cu was free of spectral interferences. In the case of Ni, a strong iron line appeared close to the main nickel line, and in the case of Pb, the well-known absorption spectrum of the PO molecule was present, both of which would cause spectral interferences when deuterium background correction is used. This kind of fine-structured absorption does not cause any problems in HR CS GFAAS, as the analytical lines were separated from the background absorption. The optimum pyrolysis temperatures were 600, 1100, 1300, and 700°C and the atomization temperatures were 1200, 2000, 2550, and 1700°C for Cd, Cu, Ni, and Pb, respectively. The limits of detection were 0.03 µg L−1, 11 µg L−1, 0.9 µg L−1, and 0.27 µg L−1 for Cd, Cu, Ni, and Pb, respectively; the limits of quantification were 0.1 µg L−1, 33 µg L−1, 2.8 µg L−1, and 0.8 µg L−1 for Cd, Cu, Ni, and Pb, respectively. The results of the analysis of a green tea certified reference material confirmed the validity of the proposed method. The concentrations of Cd, Cu, Ni, and Pb found in this study were among the lowest reported in the literature for tea samples.

In vitro surface biocompatibility of high-content silicon-substituted calcium phosphate ceramics

AbstractThe present work investigates surface biocompatibility of silicon-substituted calcium phosphate ceramics. Different silicon-substituted calcium phosphate ceramic bodies were prepared from co-precipitated powders by sintering at 1300°C. The in vitro bioactivity of the ceramics was assessed in simulated body fluid (SBF) at 37°C for periods up to 4 weeks. The changes in the surface morphology and composition were determined by scanning electron microscopy (SEM) coupled with electron probe microanalysis and energy dispersive spectrometer (EDX). Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to observe the change in ionic concentration of SBF after removal of the samples. The bioactivity of the ceramics increased with an increasing silicate ion substitution in a systematic way. The surface of ceramics with 2.23% silicon substitution was partially covered with apatite layer after one week, while ceramics with 8.1% silicon substitution were completely covered with apatite in the first week. The porous microstructure of high-concentration Si-substituted ceramics helps the dissolution of surface ions and the leaching process. This allows SBF to reach supersaturation in a short time and accelerate the deposition of apatite layer.

Spectroscopic Study of Heavy Metals at Different Depths in Southeastern Soil of Nile Delta, Egypt

ABSTRACT The present work has been conducted to study the level of pollutants in six sectors at southeastern soil of Nile delta of Egypt. The level of major, minor and trace metals were surveyed by conventional atomic emission spectroscopy. Flame atomic absorption spectroscopy was used to study Cd, Cu, Ni, and Pb in both soil and irrigating water at different depths up to 100 cm. Results indicate that heavy metals were found with higher concentrations in soil that is irrigated with untreated wastewater. Some samples from locations irrigated with clean surface water also showed higher metal concentrations because of uncontrolled use of fertilizers. The level of metals in surface samples down to 100 cm depth, indicate the possible mobilization of heavy metals that subsequently transported to groundwater and/or the drainage water in these areas. The possible pollution of groundwater and/or drainage water leads to further contamination of soil in other areas through infiltration and diffusion causing wide deterioration of Nile delta agricultural land.

Method Development and Quantitative Elemental Analysis of Mentha Longifolia L. Leaves from Saudi Arabia by Total Reflection X-Ray Fluorescence

ABSTRACT A method has been developed for the quantitative elemental analysis of Mentha longifolia L. leaves collected from different cities in Saudi Arabia using total reflection X-ray fluorescence. Using a microwave digestion system, 100 mg of each sample was completely digested using 3 mL of nitric acid and 2 mL of hydrogen peroxide. The stabilization of the digested samples on the silicon reflectors was studied using a silicone solution and polyvinyl alcohol. 5 µL of either silicone solution or polyvinyl alcohol (1% m/v) was pipetted and dried on the silicon reflector prior to the deposition of the digested samples. It was recognized that there is some enhancement on the intensity of the peak area with the silicone solution at photon energies less than 11 keV. However, the obtained results confirm the ability of using silicone solution or polyvinyl alcohol (1% m/v) as the stabilizer prior to the deposition of the sample droplet on the quartz reflector. However, the silicone solution was more applicable. Based on the developed method, 15 elements were quantified, namely, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Br, Rb, Sr, and Ba. Based on the present quantitative analysis results, M. longifolia samples collected from Al-Madina city had the highest concentration of P, Cl, K, Ti, Fe, Ni, and Cu. The lowest concentrations of P, S, Cl, K, Mn, Ni, and Br were found in Taif-Shafa.

WITHDRAWN: The challenges of selenium determination in biological samples with graphite furnace using line source and high resolution continuum source atomic absorption spectrometry.

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