Papers by Abdallah Shaltout
Energy-dispersive X-ray fluorescence (EDXRF) spectrometry is not adequate for the determination o... more Energy-dispersive X-ray fluorescence (EDXRF) spectrometry is not adequate for the determination of some potentially
hazardous trace elements, such as Cd, Cu, Ni and Pb at low concentration in PM2.5 atmospheric aerosol
particles. Therefore, a method has been developed for the determination of these elements in atmospheric aerosol
particles using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CSGF-
AAS) without using modifiers. The pyrolysis and atomization temperatures were optimized for this analysis.
The samples were collected from industrial and urban areas of Greater Cairo, Egypt. Atmospheric aerosol particles,
PM2.5, have been collected on polycarbonate filters loaded by a cyclone sampler. The duration of the collection
was 24 h at an air flow-rate of 3 L min−1.Microwave-assisted acid digestion with ultra-pure nitric acid was
used to dissolve the polycarbonate filters, including the atmospheric aerosol particles. For the validation of the
methods, the results were compared with those obtained by total reflection X-ray fluorescence (TXRF) and inductively
coupled plasma mass spectrometry (ICP-MS). Good agreement between the results of the different
spectrometric techniques was found. The measured concentrations of Cd, Cu, Ni, and Pb were below the limits
defined by international guidelines and national standards of ambient air quality.
Antibacterial capabilities of nanocrystalline cadmium sulfide (CdS) thin films have been develope... more Antibacterial capabilities of nanocrystalline cadmium sulfide (CdS) thin films have been developed against Gram-positive and Gram-negative bacteria in dark and sunlight at 60 °C. For this purpose, a strain of Gram-positive Staphylococcus aureus, and two strains of Gram-negative bacteria (Pseudomonas aeruginosa, and Escherichia coli) were used. The nanocrystalline CdS thin films have been prepared using a chemical bath deposition (CBD) method at different thicknesses (50, 80 and 100 nm). The different deposition parameters including the speed of rotation of substrate, temperature of chemical bath, pH of solution and time of the deposition were optimized. The Polyvinylpyrrollidone (PVP) was successfully used as capping agent in order to stop the agglomeration in the CdS thin films. It was found that, CdS thin films have remarkable antibacterial activity in dark and sunlight and it could be applied as antimicrobial agent in medical field. In order to confirm the crystalline structure of CdS thin films, the polycrystalline nature of the deposited CdS thin films with hexagonal structure was obtained. Furthermore, the structural parameters including lattice parameters, cell volume, the space group, average grain size, dislocation density and the strain have been calculated. The topography and surface roughness of the CdS thin films have been studied before and after the bacteriostatic effect using Scanning Electron Microscopy (SEM). Furthermore, the compositions of nanocrystalline CdS thin films have been evaluated using Energy Dispersive X-ray emission (EDX) and a Transmission Electron Microscope (TEM). Based on the optical measurements in the range of 300–2500 nm, the band gap energy of the prepared CdS thin films was found to be 2.4 eV.
he present work aims at detecting and characterizing the semiquione free radicals and inorganic c... more he present work aims at detecting and characterizing the semiquione free radicals and inorganic composition of atmospheric aerosol particles, PM2.5, collected at three different sites (industrial, residential, and traffic dominated) in Taif city, Saudi Arabia, during 2011/2012. PM2.5 particles have been collected on polycarbonate filters in a collection cartridge in a cyclone. The duration of the collection was 24 h at an air flow of 3 L min−1. The average PM2.5 mass concentration was 37±22 μg/m3, 57±22 μg/m3 and 50±31 μg/m3 at the residential, industrial and traffic sites, respectively. These values are higher than the target value for air quality standards of European Union (25 μg/m3). Energy dispersive X-ray fluorescence (EDXRF) and electron paramagnetic resonance (EPR) spectroscopic techniques were chosen for sample analysis. Fourteen elements were quantified by EDXRF: Si, S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Rb, Sr and Pb. The measured concentrations of the potentially hazardous trace elements As, Cu, Sb, Cr, Mn, Ni and Pb were either below the detection limit or below the limits defined by international guidelines and national standards of ambient air quality. Furthermore, electron paramagnetic resonance (EPR) technique was used for testing and identifying paramagnetic species in the PM2.5 particles. The EPR spectra of PM2.5 from the three sites have a g-value in the range from 2.0033 to 2.235 which is characteristic for semiquinone radicals. The PM2.5 samples showed three EPR signals indicate the presence of semiquinone radical anion.
Spectrochimica Acta Part B-atomic Spectroscopy, 2010
In this work we compare the analytical results obtained by traditional calibration curves (CC) an... more In this work we compare the analytical results obtained by traditional calibration curves (CC) and multivariate Partial Least Squares (PLS) algorithm when applied to the LIBS spectra obtained from ten brass samples (nine standards of known composition and one 'unknown'). Both major (Cu and Zn) and trace (Sn, Pb, Fe) elements in the sample matrix were analyzed. After the analysis, the composition of the 'unknown' sample, measured by X-ray Fluorescence (XRF) technique, was revealed. The predicted concentrations of major elements obtained by rapid PLS algorithms are in very good agreement with the nominal concentrations, as well as with those obtained by the more time-consuming CC approach. A discussion about the possible effects leading to discrepancies of the results is reported. The results of this study open encouraging perspectives towards the development of cheap LIBS instrumentation which would be capable, despite the limitations of the experimental apparatus, to perform fast and precise quantitative analysis on complex samples.
Journal of Applied Spectroscopy, 2011
Commercial low-cost laser induced breakdown spectroscopy (LIBS) has been successfully employed fo... more Commercial low-cost laser induced breakdown spectroscopy (LIBS) has been successfully employed for the quantitative analysis of a Cu-based alloy using a Nd:YAG laser at 1064 nm. The main aim of the present investigation is to explore the benefits of a commercial low-cost LIBS setup. It was recognized that some trace elements such as Al and S could not be detected by LIBS even with a high-resolution spectrometer. The main difficulties in quantifying Cu as a basic component of a brass alloy are related to the self-absorption of Cu spectral lines, with the effect complicated at Cu concentrations higher than 65%. However, few Cu lines such as that at 330.795 nm would be helpful to use due to their lower susceptibility to self-absorption. LIBS, flame atomic absorption spectrometry (FAAS), and wavelength dispersive X-ray fluorescence (WDXRF) were compared for the detection of major and trace metals in the Cu-based alloy. In the case of WDXRF, the brass samples were identified by using a standardless quantitative analysis program depending on a fundamental parameter approach. The quantitative analysis results were acceptable for most of the major and minor elements of the brass sample. Therefore, commercial low cost LIBS would be useful for quantitative analysis of most elements in different types of alloys.
Spectroscopy Letters, 2011
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2011
The inorganic constituents of 5 different plants (leaves and stalks) were investigated by using F... more 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 32- was exhibited at 1446 cm -1, and the phosphate ions PO 43- was assigned at 1105 and 1035 cm -1. At high temperatures (600, 700 and 600 °C) further absorption bands of the phosphate ions PO 43- was assigned at the frequencies 572, 617, 962, 1043 and 1110 cm -1 and the vibrational absorption band of the carbonate ions CO 32- 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.
Microchemical Journal, 2011
In multichannel wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) the fluorescence in... more In multichannel wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) the fluorescence intensity might depend on grain size and heterogeneity of the sample. Six river Nile sediment samples were collected two meters below the water surface from different locations covering the greater Cairo, Egypt. Each sample was dried at 65°C for 48 h and divided into four grain size fractions: b 32 μm, 32-63 μm, 63-125 μm and 125-200 μm using different sieves. The dry sediment samples were mixed with low contamination binder (Wax, C 6 H 8 O 3 N 2 ) in a mass ratio of wax:sample = 4:0.9 g. Sample pellets were made using a hydraulic press at a pelletizing pressure of 120 KN cm − 2 . The results show that the XRF intensities of the K α radiation might increase or decrease with decreasing grain size, depending on the atomic number of the analyte. In the present thick pelletized samples, the penetration depth of the characteristic radiation increases at low grain sizes, and consequently the probability of the grain-size effect on the characteristic radiation decreases. Depending on the experimental data, a general theoretical equation, relating fluorescence intensity, grain size and atomic number, was derived by using cubic spline interpolation. The fractions were identified by WDXRF using standardless quantitative analysis, depending on the fundamental parameter approach. According to the present statistical analysis and the Certified Reference Material (CRM) results, the quantitative analysis results were found acceptable when the grain size of the river Nile sediments less than 32 μm. At a grain size N 63 μm, standardless analysis using fundamental parameter approach was found to be useful for qualitative and semi-quantitative analysis only whereas there are a strong positive correlations.
Materials & Design, 2010
A general ceramics processing scheme by cold uniaxial pressing and conventional sintering process... more A general ceramics processing scheme by cold uniaxial pressing and conventional sintering process have been used to prepare ceramics from mixtures of blast furnace slag (BFS) and kaolin (10%, 30% and 50% kaolin). The properties of the ceramics were studied by measuring linear shrinkage, bulk density, apparent porosity and mechanical properties of samples heated at temperatures from 800°C to 1100°C. The formed crystalline phases were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). Slag melt formed at relatively low temperatures (800-900°C) modified the sintering process to liquid phase sintering mechanism. Combination of BFS with 10% kaolin gave the highest mechanical properties, densification and shrinkage at relatively low firing temperatures. The crystalline phases were identified as gehlenite (Ca 2 Al 2 SiO 7 ) in both BFS and BFS with 10% kaolin samples. Anorthite (CaAl 2 Si 2 O 8 ) phase increased with increasing kaolin contents. In the case of kaolin-rich mixtures (30% and 50% kaolin), increased expansion took place during firing at temperatures in the range 800-1000°C. This effect could be attributed to the entrapment of released gases.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2011
The inorganic constituents of 5 different plants (leaves and stalks) were investigated by using F... more 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.
Talanta
The present investigation is the first part of an initiative to prepare a regional map of the nat... more The present investigation is the first part of an initiative to prepare a regional map of the natural abundance of selenium in various areas of Brazil, based on the analysis of bean and soil samples. Continuous-flow hydride generation electrothermal atomic absorption spectrometry (HG-ET AAS) with in situ trapping on an iridium-coated graphite tube has been chosen because of the high sensitivity and relative simplicity. The microwave-assisted acid digestion for bean and soil samples was tested for complete recovery of inorganic and organic selenium compounds (selenomethionine). The reduction of Se(VI) to Se(IV) was optimized in order to guarantee that there is no back-oxidation, which is of importance when digested samples are not analyzed immediately after the reduction step. The limits of detection and quantification of the method were 30 ng L −1 Se and 101 ng L −1 Se, respectively, corresponding to about 3 ng g −1 and 10 ng g −1 , respectively, in the solid samples, considering a typical dilution factor of 100 for the digestion process. The results obtained for two certified food reference materials (CRM), soybean and rice, and for a soil and sediment CRM confirmed the validity of the investigated method. The selenium content found in a number of selected bean samples varied between 5.5 ± 0.4 ng g −1 and 1726 ± 55 ng g −1 , and that in soil samples varied between 113 ± 6.5 ng g −1 and 1692 ± 21 ng g −1 .
Mikrochimica Acta, 2006
In open air and without any type of inert gas, stable and bright micro plasma was successfully ob... more In open air and without any type of inert gas, stable and bright micro plasma was successfully obtained using Liquid Sampling Atmospheric Pressure Glow Discharge (LS-APGD). The discharge current varied between 20 to 80 mA with a maximum voltage 550 V, discharge gap 0.5–2 mm and solution pH of 1. The produced plasma operates in the normal glow discharge region at a low power (11–40 W). For analytical application the linear dynamic range is obtained up to 500 µg mL−1. Limits of detection based on 3σ of the background intensity determined for Ca I (422.673 nm), Cu I (324.754 nm), Fe I (497.5 nm), and Zn I (213.856 nm) are 0.3, 0.65, 0.1, 0.7 µg mL−1 respectively.
X-ray Spectrometry, 2006
As a result of a systematic analysis of the compilation of McMaster's x-ray cross-sections, the p... more As a result of a systematic analysis of the compilation of McMaster's x-ray cross-sections, the polynomial coefficients of the N range (from edges N7 to M5) of elements Z = 61–69 have to be corrected. Furthermore, no detailed information on position and jumps of M edges of elements Z > 53 and N edges of elements Z > 85 are given. Elements Z = 84, 85, 87, 88, 89, 91 and 93 are missing. We have corrected the wrong values of polynomial coefficients and added missing M- and N-edge data and missing elements. Copyright © 2005 John Wiley & Sons, Ltd.
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Papers by Abdallah Shaltout
hazardous trace elements, such as Cd, Cu, Ni and Pb at low concentration in PM2.5 atmospheric aerosol
particles. Therefore, a method has been developed for the determination of these elements in atmospheric aerosol
particles using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CSGF-
AAS) without using modifiers. The pyrolysis and atomization temperatures were optimized for this analysis.
The samples were collected from industrial and urban areas of Greater Cairo, Egypt. Atmospheric aerosol particles,
PM2.5, have been collected on polycarbonate filters loaded by a cyclone sampler. The duration of the collection
was 24 h at an air flow-rate of 3 L min−1.Microwave-assisted acid digestion with ultra-pure nitric acid was
used to dissolve the polycarbonate filters, including the atmospheric aerosol particles. For the validation of the
methods, the results were compared with those obtained by total reflection X-ray fluorescence (TXRF) and inductively
coupled plasma mass spectrometry (ICP-MS). Good agreement between the results of the different
spectrometric techniques was found. The measured concentrations of Cd, Cu, Ni, and Pb were below the limits
defined by international guidelines and national standards of ambient air quality.
hazardous trace elements, such as Cd, Cu, Ni and Pb at low concentration in PM2.5 atmospheric aerosol
particles. Therefore, a method has been developed for the determination of these elements in atmospheric aerosol
particles using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CSGF-
AAS) without using modifiers. The pyrolysis and atomization temperatures were optimized for this analysis.
The samples were collected from industrial and urban areas of Greater Cairo, Egypt. Atmospheric aerosol particles,
PM2.5, have been collected on polycarbonate filters loaded by a cyclone sampler. The duration of the collection
was 24 h at an air flow-rate of 3 L min−1.Microwave-assisted acid digestion with ultra-pure nitric acid was
used to dissolve the polycarbonate filters, including the atmospheric aerosol particles. For the validation of the
methods, the results were compared with those obtained by total reflection X-ray fluorescence (TXRF) and inductively
coupled plasma mass spectrometry (ICP-MS). Good agreement between the results of the different
spectrometric techniques was found. The measured concentrations of Cd, Cu, Ni, and Pb were below the limits
defined by international guidelines and national standards of ambient air quality.