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Wyszukujesz frazę "Elsayed, M. A." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Factors Affecting of Porous Properties of Carbon Gel Microsphere
Autorzy:
Elsayed, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/1194052.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
base catalysts
carbon microsphere
nitrogen adsorption
sol-gel polycondensation
Opis:
Carbon microsphere with high porosity and surface area were synthesized via the sol-gel polycondensation of resorcinol with formaldehyde in a slightly basic medium and followed by drying and pyrolysis. The effects of different parameters during synthesis were investigated. The porous properties of carbon microsphere were evaluated by nitrogen adsorption method and scanning electron microscopy (SEM). By changing both the catalyst species and resorcinol to catalyst ratio (R/C), it was possible to prepare ultramicroporous carbon sphere with pore size about 1.8 nm. The samples evolve from micro-mesoporous solid (RF-Na2CO3: combination of types I and IV isotherms) with 24.2% micropore to an exclusively microporous material (RF-NH4HCO3: type I isotherm) with 98.7% micropore. The results show that it is possible to tailor the morphology of these materials by varying the initial pH of the precursor’s solution in a narrow range and that the micropore surface area and micropore volume are independent from the initial pH, while the BET surface area vary from 582 m2/g (pH = 3.2) to 680 m2/g (pH = 6). However, as the pH increases over pH = 6 the surface area is decreases. These materials can be used as packing for separation columns or as catalysts supports.
Źródło:
World Scientific News; 2015, 13; 80-94
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the Effect of Air to Fuel ratio Parameter on the Organophosphorus – Pesticide Analysis by GC-FPD
Autorzy:
Kilany, A. Y.
Elsayed, M. A.
Abd Elmegid, M. K.
Powiązania:
https://bibliotekanauki.pl/articles/412130.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
sensitivity
minimum detectability
dynamic range
linear range
organophosphorus pesticides
malathion
dimethoate
GC/FPD
Opis:
In the present contribution, sensitive and precise method for the quantification of Organophosphorus / Pesticides (Malathion and Dimethoate) in nanograms range has been developed. The performance of flame photometric detector (FPD), a selective detector (P&S-mode) that can be used in the analysis of organophosphorus compound, is evaluated in terms of sensitivity, selectivity and reproducibility. The performance of flame photometric detector was strongly depending on the absolute and relative flow rate of air and hydrogen gases. The optimum air-to-fuel ratio for detection of Malathion and Dimethoate was 0.4 and 0.3 (FPD-P mode). At this ratio, low picogram amounts of phosphor can be detected accurately (0.18 pgP) with a wide linear dynamic range of 0.18 pgP to 298 ngP. While, the optimum air-to-fuel ratio, for detection of Malathion and Dimethoate was 0.6 (FPD-S mode). In addition to, the method is precise with 4.5 % relative standard deviation (RSD). In conclusion, it could be proposed that this procedure can be recommended as a suitable method for the quantification of Malathion and Dimethoate in cases of acute poisoning.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 17, 3; 236-248
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation of UV Spectrophotometric and HPLC Methods for Quantitative determination of chlorpyrifos
Autorzy:
Zalat, O. A.
Elsayed, M. A.
Fayed, M. S.
Abd El Megid, M. K.
Powiązania:
https://bibliotekanauki.pl/articles/412092.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
chlorpyrifos
HPLC
UV-spectrophotometric
liner range
Opis:
A specific and sensitive HPLC and UV spectrophotometric methodwere developed for determination and analysis of chlorpyrifos. Chromatographic separation was achieved on a 150 mm x 10 mm I.D. reversed phase column Zorbax SB C-18. usingdeionizedwater: acetonitrile in the ratio of 10:90 v/v respectively as mobile phase. The effluent was monitored at 290 and 230 nm. Two sharp peaks were obtained for the solvent and chlorpyrifos at 2.7 and 3.45 min respectively. UV spectrophotometric method was performed at 290 nm using Isopropanol as the solvent. Linear range was 0.025-3500 ppm (r2 = 0.9986 ±0.0009) for HPLC method and 2.229 to 200 ppm (r2 = 0.9988) for UV spectrophotometric method. Validation guidelines and statistical analysis showed that both the methods were precise, accurate, sensitive, and can be used for the routine quality control of chlorpyrifos in waste discharges.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 2; 58-63
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sources of uncertainty for the Determination of Chlorpyrifos by Gas Chromatography Equipped with Flame Photometric Detector
Autorzy:
Zalat, O. A.
Elsayed, M. A.
Fayed, M. S.
Abd El Megid, M. K.
Powiązania:
https://bibliotekanauki.pl/articles/411973.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
sensitivity
Minimum detectability
Chlorpyrifos
injection
Opis:
Analysts are increasingly being required to evaluate the uncertainty associated with methods. Estimating the uncertainty of an analytical result is an essential part of quantitative analysis. This paper discusses the sources of uncertainty of chlorpyrifos determination by gas chromatography equipped with flame photometric detector (GC-FPD). The analysis was performed on HP-5 MS, 30 m x 0.32 mm capillary column with a 0.25 μm stationary film thickness using ultra pure nitrogen (99.9999 %) as a carrier gas at 25 psi constant pressure. The method has been optimized. Factors affecting quantization of chlorpyrifos such as injector temperature, carrier gas inlet pressure, air to hydrogen ratios and initial temperature program have been studied to get the best sensitivity, minimum delectability. The liner range of the detector was from 0.15 ng/ml to 1200 ppm, the minimum detection limit was 0.15 ng/ml and the relative standard deviation was 0.839.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 6; 8-55
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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