Publications by authors named "Nora Hamad Al-Shaalan"

6 Publications

  • Page 1 of 1

An efficient and magnetically recoverable g-CN/ZnS/CoFeO nanocomposite for sustainable photodegradation of organic dye under UV-visible light illumination.

Environ Res 2021 Jun 17;201:111429. Epub 2021 Jun 17.

Advanced Materials Research Chair, Chemistry Department, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.

Effective improvement of an easily recoverable photocatalyst is equally vital to its photocatalytic performance from a practical application view. The magnetically recoverable process is one of the easiest ways, provided the photocatalyst is magnetically strong enough to respond to an external magnetic field. Herein, we prepared graphitic carbon nitride nanosheet (g-CN), and ZnS quantum dots (QDs) supported ferromagnetic CoFeO nanoparticles (NPs) as the gCN/ZnS/CoFeO nanohybrid photocatalyst by a wet-impregnation method. The loading of CoFeO NPs in the g-CN/ZnS nanohybrid resulted in extended visible light absorption. The ferromagnetic g-CN/ZnS/CoFeO nanohybrid exhibited better visible-light-active photocatalytic performance (97.11%) against methylene blue (MB) dye, and it was easily separable from the aqueous solution by an external bar magnet. The g-CN/ZnS/CoFeO nanohybrid displayed excellent photostability and reusability after five consecutive cycles. The favourable band alignment and availability of a large number of active sites affected the better charge separation and enhanced photocatalytic response. The role of active species involved in the degradation of MB dye during photocatalyst by g-CN/ZnS/CoFeO nanohybrid was also investigated. Overall, this study provides a facile method for design eco-friendly and promising g-CN/ZnS/CoFeO nanohybrid photocatalyst as applicable in the eco-friendly dye degradation process.
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http://dx.doi.org/10.1016/j.envres.2021.111429DOI Listing
June 2021

Mixed-mode open tubular column for peptide separations by capillary electrochromatography.

J Sep Sci 2021 Jul 31;44(13):2602-2611. Epub 2021 May 31.

Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.

Mixed-mode chromatography open tubular column has been developed for peptide separation in electrochromatography. A column with 92 cm effective length and 50 μm internal diameter is fabricated internally with a copolymer sheet of restricted thickness. Catalyst facilitated binding of the coupling agent 3,5-bis (trifluoromethyl) phenyl isocyanate has been carried out at the interior surface of the column. The initiator sodium diethyldithiocarbamate was bound to the coupling agent. A small amount of N-[2-(acryloylamino) phenyl] acrylamide was used along with methacrylic acid and styrene in the monomer mixture to induce a little polar character in the stationary phase fabricated inside the column. Twenty-three peptides have been separated from a chemically digested protein mixture present in cytochrome C in capillary electrochromatography, in addition to the separation of six commercial peptides. We achieved an average plate count of over 1.5 million/m with the column of current study both for the digested protein components and commercial peptides using 70/30% v/v (acetonitrile/20 mM ammonium formate) at pH 6.5. In addition, the column resulted in baseline separation of all the peptides with very good resolution, enhanced peak capacity, and better retention time span.
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http://dx.doi.org/10.1002/jssc.202100116DOI Listing
July 2021

Visible light driven reduced graphene oxide supported ZnMgAl LTH/ZnO/g-CN nanohybrid photocatalyst with notable two-dimension formation for enhanced photocatalytic activity towards organic dye degradation.

Environ Res 2021 06 26;197:111079. Epub 2021 Mar 26.

Chemistry Department P. O. Box 84428, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, 11671, Saudi Arabia.

In this study, 2D/2D/2D heterostructured r-GO/LTH/ZnO/g-CN nanohybrid were synthesized through hydrothermal method. The strong electrostatic interaction between the negatively charged g-CN and r-GO nanosheets with positively charged layered triple hydroxide (LTH) nanosheets are effectively influences the successful formation of heterojunction. The LTH nanosheets are well spread on the g-CN nanosheets combined with r-GO. In particular, the as prepared heterojunction shows a better photocatalytic degradation activity compared to pristine samples and the significant enhancement in the photocatalytic performance is mainly accredited to the large interfacial charge transition of photogenerated charge carriers under the visible light irradiation. Although the 2D/2D/2D heterojunction effectively hinders the charge carrier recombination resulting high photocatalytic activity with good stability. In addition, the r-GO supported LTH/ZnO/g-CN heterojunction shows high photo-stability after sequential experimental runs with no obvious change in the dye degradation process. Consequently, the role of active species was investigated over the r-GO/LTH/ZnO/g-CN heterojunction with the help of different scavengers.
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http://dx.doi.org/10.1016/j.envres.2021.111079DOI Listing
June 2021

Sustainable environment-friendly quantitative determination of three anti-hyperlipidemic statin drugs and ezetimibe in binary mixtures by first derivative Fourier transform infrared (FTIR) spectroscopy.

Spectrochim Acta A Mol Biomol Spectrosc 2020 Aug 17;237:118332. Epub 2020 Apr 17.

Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.

FTIR spectrometry is considered a sustainable green analytical chemistry procedure. Its use in quantitative analysis of pharmaceutical compounds in their raw resources and in their dosage forms is growing currently. The current research offers an environment-friendly, speedy, cost-effective, reliable and easy method for the simultaneous estimation of anti-hyperlipidemic drugs. No sample preparation was required except for grinding and mixing with KBr for making pellets used for acquisition of the FT-IR spectra. First-derivative FTIR spectroscopy is used to assess quantitatively atorvastatin (ATR), rosuvastatin (RSV) and simvastatin (SMV) in their binary mixtures with ezetimibe (EZT). For the first mixture, EZT and ATR were determined at 1733.18 cm and 1647.74 cm, respectively. In the second mixture, the zero-crossing wave numbers selected for the determination of EZT and RSV were 1733.18 cm and 955.69 cm, correspondingly. Whereas, the third mixture was quantified at the wavenumbers of 1520.93 and 3569.68 cm for EZT and SMV, respectively. Validation of the procedure has been performed complying with recommendations of the International Conference of Harmonization (ICH) presenting linearity, accuracy, precision, robustness and selectivity. The linear range for all drugs was 2-30 mg/g. It was found that the LOD was 0.607, 0.311, 0.491 and 0.395 mg/g and the LOQ was found to be 1.839, 0.942, 1.490 and 1.190 mg/g for EZT, ATR, RSV, and SMV, correspondingly. The proposed technique was found to be accurate and precise in terms of percentage error and percentage relative standard deviation among intraday and interday measurements. It was also found selective through comparison of the results of standard drugs with results of binary mixtures and of pharmaceutical tablets. It was found robust through making slight variations in the working conditions and the results obtained remained statistically equivalent. The technique was applied effectively for the estimation of the binary mixtures under study in their tablets. Comparing the found outcomes to those of reference derivative UV spectrophotometric methods gave no significant difference between them. Analytical eco-scale and the scale of Green Analytical Procedure Index (GAPI) are the two scales utilized for evaluation of the greenness of the technique and it was found to be excellent green.
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http://dx.doi.org/10.1016/j.saa.2020.118332DOI Listing
August 2020

Application of Composite NanoMaterial to Determine Phenols in Wastewater by Solid Phase Micro Membrane Tip Extraction and Capillary Electrophoresis.

Molecules 2019 Sep 23;24(19). Epub 2019 Sep 23.

Department of Chemistry, P. O. Box 84428, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia.

Composite nanoparticles were used in solid phase micro membrane tip extraction and capillary electrophoresis to determine phenol and -amino-phenol in wastewater. The optimized conditions were 100 g/L concentration, 40 min contact time, 11 pH, 5 mg/mL nanoparticles amounts, 60 min desorption time, 9 desorption pH and 298 K temperature. Capillary electrophoresis conditions were phosphate buffer (15 mM, pH 7.0) background electrolyte, 18 kV applied voltage, 214 nm UV detection, 30 s sample loading at 23 ± 1 °C. The maximum percent uptakes of -amino-phenol and phenol were 80.0 and 85.0%. High ratio recoveries of -amino-phenol and phenol from nanomaterial were 99.0 and 98. Consequently, the actual extractions of -amino-phenol and phenol from wastewater were 79.2 and 83.30 percent. The migration times of phenol and -amino-phenol and were 9.0 and 12.0 min. The detection limits of phenol and -amino-phenols were 0.1 and 0.2 µg/L after extraction and CE. Therefore, this combination of solid phase micro membrane tip extraction and capillary electrophoresis may be considered as the ideal one for monitoring of toxic phenol and -amino-phenol in water sample.
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http://dx.doi.org/10.3390/molecules24193443DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6804077PMC
September 2019

Extractive spectrophotometric assay of cyclizine in a pharmaceutical formulation and biological fluids.

Saudi Pharm J 2012 Jul 21;20(3):255-62. Epub 2012 Feb 21.

Chemistry Department, Faculty of Science, Princess Nora Bint Abdul Rahman University, P.O. Box 240549, Riyadh 11322, Saudi Arabia.

Two highly sensitive and simple spectrophotometric methods were developed to quantitate the drug cyclizine (CYC) in its pure form and in a pharmaceutical formulation. The two methods involved ion-associate formation reactions (method A) with mono-acid azo dyes, i.e., sudan (I) and sudan (II), as well as ion-pair reactions (method B) with bi-azo dyes, i.e., sudan (III), sudan (IV) and sudan red 7B (V). The reactions were extracted with chloroform, and the extraction products were quantitatively measured at 480, 550, 500, 530 and 570 nm using reagents I-V, respectively. The reaction conditions were monitored and optimised. The Beer plots for reagents I-V showed linear relationships for the concentrations of 4.2-52.0, 5.4-96.0, 3.5-43.0, 4.4-80.0 and 0.6-18.0 μg mL(-1), respectively, with molar absorptivities of 2.2 × 10(4), 4.1 × 10(4), 3.6 × 10(4), 2.5 × 10(4) and 1.3 × 10(4) L mol(-1) cm(-1), respectively. Sandell sensitivities and detection limits were calculated and analysed. The implementation of the two methods to the analysis of a commercial tablet (Valoid) succeeded, and the recovery study suggested that there was no interference from common excipients in the tablet. Regarding the accuracy and precision of the methods, a statistical comparison of the results was performed using Student's t-test and the F-test at the 95% confidence level. The accuracy and precision of the proposed methods were not significantly different.
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http://dx.doi.org/10.1016/j.jsps.2012.02.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3792629PMC
July 2012
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