Ayman Gouda

Scopus Publications

A Green Simultaneous Stability Indicating Method for a Coenzyme and Vitamins in Parenteral Medications Through a Micro-Scale Sample Preparation
Jin-Kui Ma, Xiao-Yang Chen, Yu-Tong Lin, Ahmed Sobhy Darwish, Ayman A. Gouda, et al.
Food Analytical Methods, 2026
A Simple and New HPLC Technique for the Determination of Monothioglycerol, an Antioxidant, in Raw Materials and Parenteral Preparations: Assessment of Greenness, Blueness, and Whiteness Scores
Ahmed Sobhy Darwish, Ayman A. Gouda, Ragaa El Sheikh, Samya Sh. Alenezia, El‐Sayed I. Ghaith
Biomedical Chromatography, 2026
Monothioglycerol predominantly acts as an antioxidant in injectable solutions, inhibiting the oxidation and degradation of medications that are sensitive to oxygen, alongside other formulation ingredients. It scavenges free radicals and ceases the chemical chain reactions that result in instability. A thorough, swift, straightforward, and eco‐friendly stability‐indicating liquid chromatography (LC) method has been developed and validated, facilitating the measurement of monothioglycerol concentrations in injectable solutions. The antioxidant was studied through several tests in accordance with ICH guidelines, including characteristics such as forced degradation studies. Through isocratic separation, monothioglycerol and its related degradants were effectively resolved. The antioxidant was determined using an end‐capped octadecylsilyl (C18) column, and the method was validated under room temperature conditions. The isocratic mobile phase operates at a flow rate of 1.0 mL/min and consists of fixed ratios of filtered water, acetonitrile, and orthophosphoric acid. The overall AES grade of 86, AGREE grade of 0.64, MoGAPI grade of 76, BAGI grade of 75.0, and ultimate whiteness of 95.8 all highlight the ecological advantages of the HPLC method. The current research indicates that the proposed methodology is unique, precise, accurate, stable, and environmentally beneficial at a microscale, making it suitable for routine quality control analysis.
Gradient Mode HPLC Approach to Quantify Sodium Bisulfite as an Antioxidant in Raw Material and in Oral Pharmaceutical Suspension Containing Parabens and Nystatin; Utilization of Greenness Tools
Ahmed Sobhy Darwish, Ayman A. Gouda, Ragaa El Sheikh, Samya Sh. Alenezia, El-Sayed Ismail Abdulla Ghaith
Results in Chemistry, 2026
Chemisorption of Sm(III) on a trisphosphorylated Schiff-base adsorbent: Statistically verified kinetic, isotherm, and thermodynamic route to closed-loop Sm2O3 recovery from magnet leachates
Ahmed R. A. Weshahy, Ayman A. Gouda, Bahig M. Atia, Ragaa Elsheikh Shohaib, Mohamed A. Gado
Canadian Journal of Chemical Engineering, 2026
A novel trisphosphorylated Schiff‐base adsorbent (PTREN) was developed and statistically validated for targeted samarium(III) recovery from leachates of spent SmCo permanent magnets. Structural and physicochemical characterization via Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), matrix‐assisted laser desorption/ionization–time‐of‐flight–mass spectrometry (MALDI‐TOF‐MS), thermogravimetric and derivative thermogravimetric analysis (TGA/DTG), x‐ray diffraction (XRD), scanning electron microscopy (SEM), and N 2 ‐sorption confirmed successful phosphonate functionalization (Brunauer‐Emmett‐Teller [BET]), thermal stability up to approximately 430°C, and a hierarchical microporous–mesoporous architecture with a BET surface area of 68.47 m 2 g −1 . Batch adsorption studies demonstrated pronounced pH sensitivity, with maximum Sm(III) removal at pH 5.0—proximate to the point of zero charge—and rapid equilibrium within 45 min using 0.05 g adsorbent, yielding a maximum uptake capacity of 456.4 mg g −1 . Kinetic modelling confirmed pseudo‐second‐order behaviour ( R 2 = 0.9938), supported by Elovich and intraparticle diffusion analyses, indicating chemisorption dominance with multi‐stage mass‐transfer contributions. Equilibrium data conformed to the Langmuir isotherm ( R 2 = 0.9948; q max = 454.55 mg g −1 ; R L = 0.011–0.060), while Dubinin–Radushkevich analysis yielded a mean adsorption energy of 28.87 kJ mol −1 , corroborating inner‐sphere SmOP coordination. Thermodynamic parameters indicated a spontaneous (negative Δ G °), endothermic (Δ H ° = +9.097 kJ mol −1 ), and entropy‐driven (Δ S ° = +40.152 J mol −1 K −1 ) process. Response‐surface methodology and ANOVA yielded a robust quadratic predictive model ( R 2 = 0.9874; CV% = 2.85%), identifying initial Sm(III) concentration and adsorbent dosage as dominant variables, with a non‐significant lack‐of‐fit. Stripping with 0.5 mol L −1 HNO 3 enabled crystalline Sm 2 O 3 recovery, while PTREN retained above 85% capacity over nine regeneration cycles, confirming its viability for closed‐loop, industrially scalable samarium recovery.
VORTEX-ASSISTED DISPERSIVE MICROSOLID-PHASE EXTRACTION METHOD FOR PRECONCENTRATION OF COBALT AND NICKEL IN REAL SAMPLES PRIOR TO THEIR FLAME ATOMIC ABSORPTION SPECTROMETRIC DETECTION
Dalia H. Mabrouk, Ayman A. Gouda, Mohamed S. El-Attar, Ibrahim S. Ali, Basant S.A. Emam
Bulletin of the Chemical Society of Ethiopia, 2026
A straightforward and validated vortex-assisted dispersive microsolid-phase extraction method for the separation and preconcentration of cobalt and nickel ions in real samples (water, juice, and food) prior to their determination by flame atomic absorption spectrometry (FAAS) was developed. The suggested technique utilizes adsorbent, modified multiwalled carbon nanotubes, in conjunction with a new complexing agent, 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-thiol, which complexes with cobalt and nickel ions at pH 7.0. The impact of various parameters has been examined and refined. The calibration curves exhibited linearity throughout the ranges of 2.0–500 and 5.0–400 μg L−1, with limit of detections of 0.60 and 1.5 μg L−1 for cobalt and nickel ions, respectively, under optimal circumstances. The preconcentration factor was 200. Cobalt and nickel have maximum sorption capacities of around 400 and 450 mg g–1, respectively. The recovery rates of the analytes varied between 95.0% and 100%. Additionally, the relative standard deviation (RSD%) for intra-day (1.80% and 2.40%) and inter-day (1.50% and 2.0%) measurements indicates the repeatability for determination of cobalt and nickel ions, respectively. Certified reference materials were employed to validate the precision of the suggested preconcentration process. The suggested method effectively determined the concentrations of cobalt and nickel ions in several real environmental samples. KEY WORDS: Vortex-assisted dispersive micro solid-phase extraction, Multiwalled carbon nanotubes, Cobalt, Nickel, Environmental samples, Flame atomic absorption spectrometry Bull. Chem. Soc. Ethiop. 2026, 40(1), 89-104. DOI: https://dx.doi.org/10.4314/bcse.v40i1.8
AN ENVIRONMENTALLY SUSTAINABLE RP-HPLC METHODOLOGY FOR THE QUANTIFICATION OF THE COVID-19 DRUG MOLNUPIRAVIR IN PURE AND DOSAGE FORMS
Samya Sh. Alenezi, Ayman A. Gouda, Mohsen M. Zareh, Ahmed Y. Kilany, Mahmoud Alsayed Almasry, et al.
Bulletin of the Chemical Society of Ethiopia, 2026
A comprehensive eco-friendly stability-indicating RP-HPLC method has been developed and validated for the determination of molnupiravir in dosage forms. Molnupiravir quantification was carried out on the Luna C8 column (4.6 mm × 250 mm, 5 µm, 100 Å) from Phenomenex, USA, and set at 25 ℃. The mobile phase consists of water: ethanol (60:40 v/v), at a flow rate of 0.5 mL/min. The injection volume was 20 µL, and detection was implemented at 236 nm. The devised method was validated in accordance with ICH requirements and was discovered to be linear within the range of 0.25-100 µg/mL with a regression coefficient (R2) equal to 0.9999. Molnupiravir was exposed to acidic, basic, oxidative, thermal, and photolytic stress conditions. The accuracy was about 100.69 ± 0.11%, the limits of detection and quantification are 0.0086 and 0.026 µg/mL, respectively, and the intra- and inter-day precision with RSD% did not exceed 1.0%. The total analysis time was less than 7.0 minutes, establishing this method as proper for regular quality control evaluations of molnupiravir. The inclusion of absolute ethanol was required in order to obtain a sufficient resolution. Three methods were used to assess the sustainability.KEY WORDS: Dosage forms, Molnupiravir, RP-HPLC, Stability-indicating, SustainabilityBull. Chem. Soc. Ethiop. 2026, 40(3), 577-592. DOI: https://dx.doi.org/10.4314/bcse.v40i3.7
Rationally molecular imprinted polymer@CDs sensor “key-and-lock platform” fotabler smart sensing of oxomemazine in different real samples
A.B. Abdallah, Gehad M. Helal, Ayman A. Gouda, Ragaa El-Sheikh
Microchemical Journal, 2025
A straightforward HPLC approach to testing butylated hydroxytoluene, an antioxidant, in pure and topical anti-burn gels; Evaluation of greenness, blueness, and whiteness grades
Jin-Kui Ma, Xiao-Yang Chen, Nan Zhang, Ahmed Sobhy Darwish, Ayman A. Gouda, et al.
Talanta Open, 2025
Enhanced Removal of Nickel and Ferrous Ions Using a Modified, Eco-Friendly Adsorbent: A Kinetics, Isotherms, and Thermodynamics Study
Ibrahim Hegazy, Ragaa El‐sheikh, Ayman A. Gouda, Hani H. Ali, Amany R. Salem
Chemistryselect, 2025
Water contaminated with heavy metal ions can be effectively treated using abundant and available eco‐friendly adsorbent. The synthesized sulphonic‐impregnated Pomegranate peel powder (SIPP) was fully characterized using different techniques and used to remove and decontaminate of heavy metal from water solutions. Various factors affecting the adsorption process of nickel (Ni2+) and ferrous (Fe2+) have been studied. SIPP's sorption capacities for Fe2+ and Ni2+ were determined to be 36 and 165 mg/g, respectively. The obtained equilibrium data proved that Langmuir isotherm was the best and gave satisfactory results. The maximum adsorption capacity according to Langmuir = 50.25 and 373 for Fe2+ and Ni2+, Respectively. Fe2+ (R2 = 0.968) and Ni2+ (R2 = 0.982) were found to be best described by the Freundlich isotherm, which was selected based on the highest R2 value. The adsorption process was physical according to activation energy; ED = 0.171 kJ/mol and 0.189 kJ/mol for Fe2+ and Ni2+, respectively. The experimental data fitted well with pseudo‐second‐order kinetic model. Thermodynamic nature was found to be exothermic from negative free energy for both metal ions. Even after three cycles, SIPP maintains greater metal ion removal efficiency. SIPP demonstrates its ability to adsorb and remove heavy metals from large volumes of solution.
Environmental sustainability profiles assessment of HPLC stability indicating method for quantitation of piracetam and vincamine in pharmaceutical medications
Samya Sh. Alenezi, Ayman A. Gouda, Ragaa El Sheikh, Niaf A. Badahdah, Muneer E Alzuhiri, et al.
Talanta Open, 2025
Development and validation of charge transfer based spectrophotometric method for the quantification of bromocriptine mesylate in pharmaceutical formulations
Chemical Review and Letters, 2025
Tricaprylylmethylammonium chloride-enhanced high sensitivity potentiometric sensor for iodide assessment in antiseptic solutions
Abd-ElNasser A. Mohamed, Mohsen M. Zareh, Nora O. Saleem, Niaf A. Badahdah, Muneer E. Alzuhiri, et al.
Results in Chemistry, 2025
Greenness-integrated analytical quality by design-compliant development of a quasi-HDES-DLLME method for patent blue V preconcentration from various food products, and environmental water samples
Heba Salah Mousa, Ayman A. Gouda, Marwa R. El-Zahry, Magdi Mohamed Ibrahim ElHosary, Marwa H. Hassan
Microchemical Journal, 2025
Adsorption and Recovery of Neodymium and Praseodymium from Magnet Waste NdFeB Using a Novel Pyridine Schiff Base Compound
Ahmed. A. Weshahy, Ayman A. Gouda, Ragaa El Sheikh Shohaib, Bahig M. Atia, Mohamed A. Gado
Chemistryselect, 2025
Development of an innovative colorimetric optical sensor for the detection of silver ions in environmental and biological samples
Mohamed A. Ali, Ahmad O. Babalghith, Ayman A. Gouda, Alaa S. Amin
International Journal of Environmental Analytical Chemistry, 2025
UTILISATION OF CHARGE TRANSFER COMPLEXATION REACTIONS FOR THE QUANTIFICATION OF ANTIFUNGAL DRUG: VORICONAZOL IN PURE AND DOSAGE FORMS
Sabry A. El-Korashy, Alaa S. Amin, Ayman A. Gouda, Mustafa Kh. Alshuwaili, Hoyeda E. Ibrahim
Bulletin of the Chemical Society of Ethiopia, 2025
Extraction of some heavy metal ions from aqueous solutions with new eco-friendly solvents
Ibrahim Hegazy, Ragaa El-Sheikh, Ayman A. Gouda, Hani H. Ali, M. A. Hassanin, et al.
International Journal of Environmental Analytical Chemistry, 2025
Design and utilisation of a novel poly imino-phosphorane composite for the effective removal of Pb2+ and Cr3+ ions from contaminated water sources
Ahmed M. Amin, Hala A. Ibrahium, Ayman A. Gouda, Ragaa El Sheikh, Bahig M. Atia, et al.
International Journal of Environmental Analytical Chemistry, 2025
EVALUATION OF THE GREENNESS PROFILES OF INDIRECT SPECTROPHOTOMETRIC METHODS FOR ESTIMATION OF GEMIFLOXACIN MESYLATE IN PURE AND DOSAGE FORMS UTILIZING N-BROMOSUCCINIMIDE AS A GREEN REAGENT
Samya Sh. Alenezi, Ayman A. Gouda, Ragaa El Sheikh, Ahmed El Sayed, Moataz S. Mahmoud, et al.
Bulletin of the Chemical Society of Ethiopia, 2025
GREEN ULTRASOUND-ASSISTED EMULSIFICATION DISPERSIVE LIQUID-LIQUID MICROEXTRACTION COMBINED WITH SPECTROPHOTOMETRY FOR PRECONCENTRATION AND QUANTIFICATION OF NICKEL IN ENVIRONMENTAL SAMPLES
Samya Sh. Alenezi, Ayman A. Gouda, Ragaa El Sheik, Ahmed H. Moustafa, Fatma A. Ibraheem, et al.
Bulletin of the Chemical Society of Ethiopia, 2025
ASSESSMENT OF THE ECO-FRIENDLINESS PROFILES OF SPECTROPHOTOMETRIC METHODS FOR THE QUANTIFICATION OF VONOPRAZAN FUMARATE IN PHARMACEUTICAL FORMULATIONS UTILIZING N-BROMOSUCCINIMIDE
Samya Sh. Alenezi, Ayman A. Gouda, Ragaa El Sheikh, Niaf A. Badahdah, Muneer E Alzuhiri, et al.
Bulletin of the Chemical Society of Ethiopia, 2025
Development and validation of spectrophotometric methods for estimation of arrhythmias drug-dronedarone hydrochloride in pure and dosage forms
Ragaa El Sheikh, Ayman A. Gouda, Ahmed A. Ghazy, Nesma M. Jumaa, Noha E.M. Elsaify, et al.
Talanta Open, 2024
Validated spectrophotometric approach for the estimation of an antiepileptic drug: retigabine in pure form and pharmaceutical formulations utilizing N-Bromosuccinimide as an oxidant
Mohannad M. Garoub, Ragaa El Sheikh, Sara G. Mohamed, Moataz S. Mahmoud, Ahmed F. Abdel Allem, et al.
Talanta Open, 2024
Development of environmentally friendly catalyst Ag-ZnO@cellulose acetate derived from discarded cigarette butts for reduction of organic dyes and its antibacterial applications
Heba Mousa, Soad S. Abd El-Hay, Ragaa El Sheikh, Ayman A. Gouda, Samar Abd El-Ghaffar, et al.
International Journal of Biological Macromolecules, 2024
Development of Cloud Point Extraction for Preconcentration and Spectrophotometric Determination of Entecavir as Antiviral Drug in Pharmaceutical Formulations and Application to Content Uniformity Testing
Ayman Gouda, Ragaa Shohaib, Mohannad Garoub, Eman Fawzy, Moataz Mahmoud, et al.
Egyptian Journal of Chemistry, 2024
Implementation of analytical quality by design concepts for the optimization of quantitative 1H nuclear magnetic resonance (1H-qNMR) method for quantitation of novel anti-covid drugs (molnupiravir and favipiravir) in their pharmaceutical dosage forms
Marwa H. Hasan, Ayman A. Gouda, Abdalla E.A. Hassan, Shaimaa G. Elsayed, Heba Salah Mousa
Microchemical Journal, 2024
An eco-friendly HPLC method for concurrent determination of carbocisteine, guaifenesin, and oxomemazine in their combined formulations
Soad S. Abd El-Hay, Ragaa El Sheikh, Mohamed Ali, Ayman A. Gouda, Heba M. El-Sayed
Talanta Open, 2023
Utilizing a newly developed carrier element free coprecipitation method for preconcentration and quantification of Co(II), Cu(II), Ni(II), and Zn(II) in environmental samples
Marmar Mabrouk, Ahmed H. Moustafa, Ayman A. Gouda, Hager E. Mohamed, Ali M. Alshehri, et al.
Talanta Open, 2023
Efficiency Enhancement of the Spectrophotometric Estimation of Zinc in Water, Food, Tobacco and Pharmaceutical Preparations Samples Utilizing Cloud Point Extraction
Ahmed Moustafa, Hassan El-Sayed, Alaa Amin, Asmaa El Haggar, Ayman Gouda
Egyptian Journal of Chemistry, 2023
Recovery of W(VI) from Wolframite Ore Using New Synthetic Schiff Base Derivative
Rawan E. Elbshary, Ayman A. Gouda, Ragaa El Sheikh, Mohammed S. Alqahtani, Mohamed Y. Hanfi, et al.
International Journal of Molecular Sciences, 2023
Utilization of cloud point extraction for enhancement the efficiency of spectrophotometric estimation of milnacipran HCl as anti-depression drug in dosage forms and application to its tablets uniformity testing
Mohannad M. Garoub, Ayman A. Gouda, Ragaa ElSheikh, Eman Fawzy, Walid E. ElToukhi
Journal of Umm Al Qura University for Applied Sciences, 2023
DEVELOPMENT OF AN EFFICIENT DISPERSIVE LIQUID-LIQUID MICROEXTRACTION APPROACH COMBINED WITH SPECTROPHOTOMETRY FOR DETERMINATION OF ANTIVIRAL DRUG, VALACYCLOVIR HCl IN PHARMACEUTICAL FORMULATIONS
Amal H. Al-Bagawi, Samya Sh. Alenezi, Ragaa El Sheikh, Ghada Abdel Fattah, Ayman A. Gouda
Bulletin of the Chemical Society of Ethiopia, 2023
Simultaneous preconcentration and determination of zirconium in environmental samples using ultrasound-assisted ionic liquid based dispersive liquid-liquid microextraction combined with spectrophotometry
Ragaa El Sheikh, Enas M. El Sheikh, Mahmoud S. Khalafalla, Lamees I. Mahfouz, Marwa M. El-Gabry, et al.
International Journal of Environmental Analytical Chemistry, 2023
ULTRASOUND-ASSISTED DISPERSIVE LIQUID-LIQUID MICROEXTRACTION APPROACH FOR PRECONCENTRATION OF ACYCLOVIR AS ANTIVIRAL DRUG IN DOSAGE FORMS PRIOR TO SPECTROPHOTOMETRIC DETERMINATION
Amal H. Al-Bagawi, Ragaa El Sheikh, Osama M.A. Salem, Ghada M. Abdel Fattah, Mohannad M. Garoub, et al.
Bulletin of the Chemical Society of Ethiopia, 2023
Preconcentration and separation of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) in environmental samples on cellulose nitrate membrane filter prior to their flame atomic absorption spectroscopy determinations
Ayman A. Gouda, Ragaa El Sheikh, Ahmed O. Youssef, Nancy Gouda, Walaa Gamil, et al.
International Journal of Environmental Analytical Chemistry, 2023
PARAMETERS FOR THE CONDUCTOMETRIC ASSOCIATION FOR LUMP AND NANO CoSO4.7H2O IN THE PRESENCE AND ABSENCE OF FUCHSIN ACID IN WATER AT DIFFERENT TEMPERATURE
Mohamed Fathi, Esam A. Gomaa, Shereen E. Salem, Hamada M. Killa, Ayman A. Gouda, et al.
Bulletin of the Chemical Society of Ethiopia, 2023
Ultrasound-assisted dispersive microsolid-phase extraction approach for preconcentration of trace cobalt and nickel and sensitive determination in water, food and tobacco samples by flame atomic absorption spectrometry
Ayman A. Gouda, Ragaa El Sheikh, Abdalla M. Khedr, Sherehan Abo Al Ezz, Walaa Gamil, et al.
International Journal of Environmental Analytical Chemistry, 2023
Design, spectroscopic, structural characterization, and biological studies for new complexes via charge transfer interaction of ciprofloxacin drug with π acceptors
Mahmoud M. Ali, Ayman A. Gouda, Khaled F. Alshammari, Mubark Alshareef, Ahmed Alharbi, et al.
Journal of Molecular Liquids, 2022
An Eco-Friendly Cloud Point Extraction for Preconcentration of Iron(III) in Water Samples prior to Spectrophotometric Determination
Ayman Gouda, Ragaa Shohaib, Alaa Amin, Mohamed Sherif, Asmaa El lakani
Egyptian Journal of Chemistry, 2022
A New Partially Phosphorylated Polyvinyl Phosphate-PPVP Composite: Synthesis and Its Potentiality for Zr (IV) Extraction from an Acidic Medium
Antoaneta Ene, Hesham M. H. Zakaly, Amany R. Salem, Ayman A. Gouda, Khalid Althumayri, et al.
Separations, 2022
Selective Recovery of Cadmium, Cobalt, and Nickel from Spent Ni–Cd Batteries Using Adogen® 464 and Mesoporous Silica Derivatives
Ahmed R. Weshahy, Ahmed K. Sakr, Ayman A. Gouda, Bahig M. Atia, H. H. Somaily, et al.
International Journal of Molecular Sciences, 2022
A Novel Triazole Schiff Base Derivatives for Remediation of Chromium Contamination from Tannery Waste Water
Ahmad A. Alluhaybi, Ahmed Alharbi, Ahmed M. Hameed, Ayman A. Gouda, Fatma S. Hassen, et al.
Molecules, 2022
Ultrasound-Assisted Dispersive Microsolid-Phase Extraction for Preconcentration of Trace Cobalt and Nickel in Environmental Samples Prior to their Determination by Flame Atomic Absorption Spectrometry
A. A. Gouda, R. El Sheikh, H. M. El Sayed, A. M. Khedr, Sh. Abo Al Ezz, et al.
Journal of Applied Spectroscopy, 2022
Efficient Recovery of Rare Earth Elements and Zinc from Spent Ni–Metal Hydride Batteries: Statistical Studies
Ahmed R. Weshahy, Ayman A. Gouda, Bahig M. Atia, Ahmed K. Sakr, Jamelah S. Al-Otaibi, et al.
Nanomaterials, 2022
Understanding the effect of hydrozincite and witherite nanominerals on the performance and phase composition of alkali-activated slag
Hamdy A. Abdel-Gawwad, Khalil A. Khalil, Ayman A. Gouda, Abdelrahman H. Elkhoresy, Mohammed A. Arif
Journal of Building Engineering, 2022
Simultaneous estimation of pantoprazole and piroxicam by HPLC: Response surface methodology approach
Soad S. Abd El-Hay, Ragaa El Sheikh, Ayman A. Gouda, Mohamed Ali, Heba M. El-Sayed
Microchemical Journal, 2022
VALIDATED SPECTROPHOTOMETRIC METHODS BASED ON CHARGE TRANSFER COMPLEXATION REACTION FOR THE DETERMINATION OF VALACYCLOVIR HYDROCHLORIDE AS ANTIVIRAL DRUG IN PHARMACEUTICAL FORMULATIONS
ALI H. AMIN, RAGAA EL SHEIKH, AHMED O. YOUSSEF, GHADA M. ABDEL FATTAH, AYMAN A. GOUDA
International Journal of Applied Pharmaceutics, 2022
Nano-synthesis approach, elaborated spectral, biological activity and in silico assessment of novel nano-metal complexes based on sulfamerazine azo dye
Abdalla M. Khedr, Ayman A. Gouda, Hoda A. El‑Ghamry
Journal of Molecular Liquids, 2022
The Role of Modified Chelating Graphene Oxide for Vanadium Separation from Its Bearing Samples
A. Alharbi, A. A. Gouda, B. M. Atia, M. A. Gado, A. A. Alluhaybi, et al.
Russian Journal of Inorganic Chemistry, 2022
SPECTROPHOTOMETRIC METHODS FOR THE QUANTITATIVE DETERMINATION OF MEMANTINE HYDROCHLORIDE IN PURE FORM AND PHARMACEUTICAL FORMULATIONS
ALI H. AMIN, RAGAA EL SHEIKH, GHADA M. ABDEL FATTAH, MOHAMMED ALI, BASMA M. ABDELNABY, et al.
International Journal of Applied Pharmaceutics, 2022
Design of a novel optical sensor for determination of trace amounts of tin in food and in environmental samples
Ayman A. Gouda, Alaa S. Amin
International Journal of Environmental Analytical Chemistry, 2022
A new carrier element-free coprecipitation method with 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-thiol for separation, preconcentration, and determination of some metal ions in water and food samples
Ayman A. Gouda, Ragaa El Sheikh, Wafaa S. Hassan, Nancy Gouda, Hameeda A. Khadrajy
International Journal of Environmental Analytical Chemistry, 2022
Eco-friendlyultrasound-assisted ionic liquid-based dispersive liquid-liquid microextraction of nickel in water, food and tobacco samples prior to FAAS determination
Ragaa El Sheikh, Wafaa S. Hassan, Amira M. Youssef, Ahmed M. Hameed, Abdu Subaihi, et al.
International Journal of Environmental Analytical Chemistry, 2022
Hydrochemical characteristics and water quality assessment in Abu-Zaabal area, eastern Nile Delta, Egypt
RAGAA EL-SHEIKH, IBRAHIM HEGAZY, EHAB ZAGHLOOL, MOHAMED E. A. ALI, AYMAN A. GOUDA
International Journal of Applied Pharmaceutics, 2021
Utilization of N-bromosuccinimide for the sensitive spectrophotometric determination of pipazethate HCl as antitussive drug in pure and dosage forms
M.A.S. Abourehab, M.H.K. Shahin, R.E. Sheikh, A. Ellateif, S.M. Fawzi, et al.
Annales Pharmaceutiques Francaises, 2021
Development and validation of spectrophotometric methods for estimation of antimigraine drug eletriptan hydrobromide in pure form and pharmaceutical formulations
A.A. Gouda, A.Y. Hamdi, R. El Sheikh, A.E. Abd Ellateif, N.A. Badahdah, et al.
Annales Pharmaceutiques Francaises, 2021
An eco-friendly ultrasound-assisted emulsification dispersive liquid-liquid microextraction of nickel in environmental samples coupled with spectrophotometry
El Sayed Abo Taleb, Maged Antonious, Ragaa El Sheikh, Ahmed Youssef, Ayman Gouda
Egyptian Journal of Chemistry, 2021
Sensitive spectrophotometric determination of vardenafil HCl in pure and dosage forms
M.M. Mabrouk, A.A. Gouda, S.F. El-Malla, D.S. Abdel Haleem
Annales Pharmaceutiques Francaises, 2021
A green enrichment method of copper, manganese and nickel in water samples via cloud point extraction
Analytical and Bioanalytical Chemistry Research, 2020
Highly Selective Optical Sensor Eu (TTA)3 Phen Embedded in Poly Methylmethacrylate for Assessment of Total Prostate Specific Antigen Tumor Marker in Male Serum Suffering Prostate Diseases
Mohannad Garoub, A. H. Hefny, W. E. Omer, Mostafa M. Elsaady, Mohamed M. Abo-Aly, et al.
Frontiers in Chemistry, 2020
Green vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction for enrichment and determination of cadmium and lead in water, vegetables and tobacco samples
RAGAA EL-SHEIKH, WAFAA S. HASSAN, SARA H. IBRAHIM, AMIRA M. YOUSSEF, AYMAN A. GOUDA
International Journal of Applied Pharmaceutics, 2020
Development of green vortex-assisted supramolecular solvent-based liquid–liquid microextraction for preconcentration of mercury in environmental and biological samples prior to spectrophotometric determination
Ayman A. Gouda, Ali M. Alshehri, Ragaa El Sheikh, Wafaa S. Hassan, Sara H. Ibrahim
Microchemical Journal, 2020
Development and validation of new spectrophotometric methods for estimation of antipsychotic drug asenapine maleate in pure and dosage forms
RAGAA EL-SHEIKH, AHLAM E. ABD ELLATEIF, ESRAA AKMAL, AYMAN A. GOUDA
International Journal of Applied Pharmaceutics, 2020
Validated spectrophotometric methods for determination of montelukast sodium in pure and dosage forms using n-bromosuccinimide and dyes
RAGAA EL-SHEIKH, WAFAA S. HASSAN, Rowaida FAHMY, AYMAN A. GOUDA
International Journal of Applied Pharmaceutics, 2020
Highly Efficient Gold Nano-Flower Optical Biosensor Doped in a Sol-Gel/PEG Matrix for the Determination of a Calcitonin Biomarker in Different Serum Samples
Walaa E. Omer, Maged A. El-Kemary, Mostafa M. Elsaady, Mona N. Abou-Omar, Ahmed O. Youssef, et al.
ACS Omega, 2020
Green supramolecular solvent-based liquid-phase microextraction method for spectrophotometric determination of aluminum in food, water, hair and urine samples
Ayman A. Gouda, Abdu Subaihi, Soad S. Abd El Hay
Current Analytical Chemistry, 2020
Green dispersive micro solid-phase extraction using multiwalled carbon nanotubes for preconcentration and determination of cadmium and lead in food, water, and tobacco samples
Ayman A. Gouda, Ali H. Amin, Ibrahim S. Ali, Zakia Al Malah
Current Analytical Chemistry, 2020
Ultrasound-assisted ionic liquid microextraction for preconcentration of cadmium in water, vegetables and hair samples prior to faas determination
Eman M. Hafez, Ragaa El Sheikh, Ali A. Sayqal, Najla AlMasoud, Ayman A. Gouda
Current Analytical Chemistry, 2020
An environment-friendly supramolecular solvent-based liquid–phase microextraction method for determination of aluminum in water and acid digested food samples prior to spectrophotometry
Eman M. Hafez, Ragaa El Sheikh, Maher Fathallah, Ali A. Sayqal, Ayman A. Gouda
Microchemical Journal, 2019
Reducing and Oxidizing Columns in the Flow Injection Determination of Nitrazepam in Pharmaceutical Formulations
Hind Hadi, Marwa Mouayed, Ayman A. Gouda
Journal of Analytical Chemistry, 2019
Application of cloud point extraction for preconcentration, separation and determination of Aluminum in food samples
Ragaa El Sheikh, Mohammed Atwa, Ayman Gouda, Amira Abdullah
Main Group Chemistry, 2019
Validated spectrophotometric determination of rizatriptan benzoate in pharmaceutical formulations using alizarin derivatives
International Journal of Pharmaceutical Quality Assurance, 2019
Eco-friendly environmental trace analysis of thorium using a new supramolecular solvent-based liquid-liquid microextraction combined with spectrophotometry
Ayman A. Gouda, Manal S. Elmasry, Hisham Hashem, Heba M. EL-Sayed
Microchemical Journal, 2018
A new separation and enrichment method of heavy metals in water and food samples using 2-(2'-benzothiazolylazo)-6-aminophenol impregnated multi-walled carbon nanotubes
Soad S. Abd El-Hay, Hibah Aldawsari, Ayman A. Gouda
Current Analytical Chemistry, 2018
Solid-phase extraction method for preconcentration of cadmium and lead in environmental samples using multiwalled carbon nanotubes
Ayman A. GOUDA, Wael A. ZORDOK
Turkish Journal of Chemistry, 2018
Sensitive spectrophotometric assay of muscarinic receptor antagonist tolterodine tartrate in bulk drug and pharmaceutical formulations
Ragaa El-sheikh, Wafaa S Hassan, Ayman A Gouda, Marwa M El-gabry
Asian Journal of Pharmaceutical and Clinical Research, 2017
Novel spectrophotometric methods for determination of desloratidine in pharmaceutical formulations based on charge transfer reaction
Ayman A. Gouda, Mohamed Kasssem
Arabian Journal of Chemistry, 2016
Determination of thorium(IV) in real samples by spectrophotometry after micelle-mediated cloud point extraction
Soad S. Abd El-Hay, Ayman A. Gouda
Journal of Radioanalytical and Nuclear Chemistry, 2016
Impregnated multiwalled carbon nanotubes as efficient sorbent for the solid phase extraction of trace amounts of heavy metal ions in food and water samples
Ayman A. Gouda, Sheikha M. Al Ghannam
Food Chemistry, 2016
High performance liquid chromatography for simultaneous determination of xipamide, triamterene and hydrochlorothiazide in bulk drug samples and dosage forms
Soad S. Abd El-Hay, Hisham Hashem, Ayman A. Gouda
Acta Pharmaceutica, 2016
A new coprecipitation method without carrier element for separation and preconcentration of some metal ions at trace levels in water and food samples
Ayman A. Gouda
Talanta, 2016
Development of cloud-point extraction method for preconcentration of trace quantities of cobalt and nickel in water and food samples
Ayman A. Gouda, Abdulhadi M. Summan, Ali H. Amin
Rsc Advances, 2016
Application of Cloud Point Extraction for Separation of Iron in Water, Food and Environmental Samples Perior to Determination by Spectrophotometry
Ayman A. Gouda, Ragaa El Sheikh, Alaa S. Amin
Analytical Chemistry Letters, 2016
Optimized and validated spectrophotometric methods for the determination of ezetimibein pharmaceutical formulations using potassium permanganate
Der Pharma Chemica, 2016
Spectrophotometric methods based on charge transfer complexation reaction for the determination of some antifungal drugs in pure and dosage forms
A. A. Gouda, R. El Sheikh, A. S. Amin, S. H. Ibrahim
Bulletin of the Chemical Society of Ethiopia, 2016
Optimized and validated spectrophotometric determination of two antifungal drugs in pharmaceutical formulations using an ion-pair complexation reaction
Ayman A. Gouda, Ragaa El Sheikh, Alaa S. Amin, Sara H. Ibrahim
Journal of Taibah University for Science, 2016
Spectrophotometric estimation of vardenafil HCl and tadalafil in pure forms and tablets using cerium(IV) ammonium sulphate
Der Pharmacia Lettre, 2016
Utilization of alizarin derivatives for the sensitive spectrophotometric determination of two proton pump inhibitors in pharmaceutical formulations
Ayman A. Gouda, Soad S. Abd El-Hay, Hisham Hashem
Main Group Chemistry, 2015
Sensitive spectrophotometric determination of acetylcholinestrase inhibitor donepezil hydrochloride in pure form and pharmaceutical formulations using sulphonphethalin dyes
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Spectrophotometric determination of oxybutinine hydrochloride by ion-pair extractionin in pharmaceutical preparations
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Validated spectrophotometric methods for determination of enalapril maleate in pure and dosage forms
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Utility of certain σ and π-acceptors for the spectrophotometric determination of voriconazol antifugal drug in pharmaceutical formulation
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Spectrophotometric determination of pizotefin maleate in pure form and tablets using π-acceptors
A. S. Amin, A. A. Gouda, R. E. Sheikh, E. H. Youssef
Bulletin of the Chemical Society of Ethiopia, 2015
Development of efficient cloud point extraction method for preconcenration and spectrophotometric determination of nickel in water samples using 2-(benzothiazolylzao)orcinol
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Cloud point extraction, preconcenration and spectrophotometric determination of cobalt in water samples
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Determination of phenolic components and antioxidant activity of some Egyptian tea samples
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Cloud point extraction, preconcentration and spectrophotometric determination of trace amount of manganese(II) in water and food samples
Ayman A. Gouda
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2014
Development and validation of a rapid stability indicating HPLC-method using monolithic stationary phase and two spectrophotometric methods for determination of antihistaminic acrivastine in capsules
Ayman A. Gouda, Hisham Hashem, Thomas Jira
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2014
Solid-phase extraction using multiwalled carbon nanotubes and quinalizarin for preconcentration and determination of trace amounts of some heavy metals in food, water and environmental samples
Ayman A. Gouda
International Journal of Environmental Analytical Chemistry, 2014
Kinetic spectrophotometric determination of gemifloxacin mesylate and moxifloxacin hydrochloride in pharmaceutical preparations using 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole
Mohammed G. Abdel Wahed, Ragaa El Sheikh, Ayman A. Gouda, Sayed Abou Taleb
Journal of Spectroscopy, 2014
Spectrophotometric determination of gemifloxacin mesylate, moxifloxacin hydrochloride, and enrofloxacin in pharmaceutical formulations using acid dyes
Ayman A. Gouda, Alaa S. Amin, Ragaa El-Sheikh, Amira G. Yousef
Journal of Analytical Methods in Chemistry, 2014
Charge transfer spectrophotometric methods for the determination of two antihistaminic drugs in pharmaceutical formulations
International Journal of Pharmacy and Pharmaceutical Sciences, 2014
Cloud-point extraction, preconcentration and spectrophotometric determination of trace quantities of copper in food, water and biological samples
Ayman A. Gouda, Alaa S. Amin
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2014
Sensitive spectrophotometric determination of cypermethrin in its formulations, water and environmental samples
Ayman A. Gouda, Laila S. Al Mazroai
Main Group Chemistry, 2014
Spectrophotometric methods based on charge transfer complexation reactions for the determination of amisulpride in pure form and pharmaceutical formulations
International Journal of Pharmacy and Pharmaceutical Sciences, 2014
Utility of N-bromosuccinimide as an environmental-friendly reagent for sensitive spectrophotometric determination of aripiprazole in tablets
International Journal of Pharmacy and Pharmaceutical Sciences, 2014
Spectrophotometric determination of pizotifen maleate in bulk drug and tablets using N-bromosuccinimide and three dyes
International Journal of Pharmacy and Pharmaceutical Sciences, 2014
Preconcentration, solvent sublation and spectrometric determination of uranium(VI) in water samples using arsenazo III and Tri n-octyl amine
International Journal of Pharmacy and Pharmaceutical Sciences, 2014
Spectrophotometric study on the charge transfer complex between sumatriptan succinate and some π-acceptors and alizarin derivatives
Sheikh El, Ayman Gouda, Rham El-Azzazy
Chemical Industry and Chemical Engineering Quarterly, 2013
Kinetic spectrophotometric determination of some fluoroquinolone antibiotics in bulk and pharmaceutical preparations
M.G. Abdel Wahed, R. El Sheikh, A.A. Gouda, S. Abou Taleb
Bulletin of the Chemical Society of Ethiopia, 2013
Utility of charge transfer and ion-pair complexation for spectrophotometric determination of eletriptan hydrobromide in pure and dosage forms
Ayman A. Gouda, Ragaa El Sheikh, Rham M. El-Azzazy
Journal of Chemistry, 2013
Development and validation of rapid stability indicating HPLC-determinations of antiepileptic drugs phenobarbital in suppositories and phenytoin in capsules as well as in urine sample
Hisham Hashem, Ayman A. Gouda, Hanaa Saleh
Journal of Liquid Chromatography and Related Technologies, 2013
Utilization of a green brominating agent for the spectrophotometric determination of pipazethate HCl in pure form and pharmaceutical preparations
Ayman A. Gouda
Journal of Spectroscopy, 2013
Spectrophotometric and spectrofluorometric methods for the determination of non-steroidal anti-inflammatory drugs: A review
Ayman A. Gouda, Mohamed I. Kotb El-Sayed, Alaa S. Amin, Ragaa El Sheikh
Arabian Journal of Chemistry, 2013
Development and validation of sensitive spectrophotometric method for determination of two antiepileptics in pharmaceutical formulations
Ayman A. Gouda, Zakia Al Malah
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2013
Development and validation of a rapid stability indicating chromatographic determination of cefdinir in bulk powder and dosage form using monolithic stationary phase
Hisham Hashem, Ayman A. Gouda, Wafaa Hassan
Journal of Liquid Chromatography and Related Technologies, 2012
Utility of solid phase spectrophotometry for the modified determination of trace amounts of cadmium in food samples
Alaa S. Amin, Ayman A. Gouda
Food Chemistry, 2012
Extractive spectrophotometric method for the determination of tropicamide
Z.A. Shoaibi, A.A. Gouda
Journal of Young Pharmacists, 2012
Spectophotometric methods for determination of cefdinir in pharmaceutical formulations via derivatization with 1,2-naphthoquinone-4-sulfonate and 4-chloro-7-nitrobenzo-2-oxa-1, 3-diazole
Ayman A. Gouda, Hisham Hashem, Wafaa Hassan
Drug Testing and Analysis, 2012
Extractive spectrophotometric determination of some α-adrenergic--antagonists in pure forms and in pharmaceutical formulations
Sheikh El, Nahla Esmail, Ayman Gouda, Walid Basset
Chemical Industry and Chemical Engineering Quarterly, 2012
Spectrophotometric determination of tadalafil in pure and dosage forms
Kaf Al, Ayman Gouda
Chemical Industry and Chemical Engineering Quarterly, 2011
Utility of inorganic oxidants for the spectrophotometric determination of ganciclovir in dosage forms
Latin American Journal of Pharmacy, 2011
Comparative study between chloramine-T and iodogen to prepare radioiodinated etodolac for inflammation imaging
H. Hussien, A. A. Goud, A. M. Amin, R. EL-Sheikh, U. Seddik
Journal of Radioanalytical and Nuclear Chemistry, 2011
A novel spectrofluorimetric method for the assay of pseudoephedrine hydrochloride in pharmaceutical formulations via derivatization with 4-chloro-7-nitrobenzofurazan
Akram M. El‐Didamony, Ayman A. Gouda
Luminescence, 2011
Copper(II)-neocuproine reagent for spectrophotometric determination of captopril in pure form and pharmaceutical formulations
Ayman A. Gouda, Alaa S. Amin
Arabian Journal of Chemistry, 2010
Kinetic spectrophotometric determination of hyoscine butylbromide in pure form and in pharmaceutical formulations
Ayman A. Gouda
Arabian Journal of Chemistry, 2010
Sensitive spectrophotometric methods for determination of some organophosphorus pesticides in vegetable samples
Ayman Gouda, Alaa Amin, Ragaa El-Sheikh, Magda Akl
Chemical Industry and Chemical Engineering Quarterly, 2010
Utility of certain σ- and π-acceptors for the spectrophotometric determination of ganciclovir in pharmaceutical formulations
Ayman A. Gouda
Talanta, 2009
Radioiodination, purification and bioevaluation of Piroxicam in comparison with meloxicam for imaging of inflammation
A. M. Amin, A. A. Gouda, R. El-Sheikh, U. Seddik, H. Hussien
Journal of Radioanalytical and Nuclear Chemistry, 2009
Spectrophotometric determination of pipazethate HCl and dextromethorphan HBr using potassium permanganate
International Journal of Biomedical Science, 2008
Utility of solid-phase spectrophotometry for determination of dissolved iron(II) and iron(III) using 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline
Alaa S. Amin, Ayman A. Gouda
Talanta, 2008
Spectrophotometric determination of hyoscine butylbromide and famciclovir in pure form and in pharmaceutical formulations
Ayman A. Gouda, Zeineb El Shafey, Nagda Hossny, Rham El-Azzazy
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2008
Spectrophotometric determination of etodolac in pure form and pharmaceutical formulations
Ayman A Gouda, Wafaa S Hassan
Chemistry Central Journal, 2008
Utility of some π-acceptors for spectrophotometric determination of gatifloxacin in pure form and in pharmaceutical preparations
Ayman Abouel Fetouh Gouda, Ragaa El-Sheikh, Alaa Sayed Amin
Chemical and Pharmaceutical Bulletin, 2008
Spectrophotometric determination of some histamine H1-antagonists drugs in their pharmaceutical preparations
Wafaa S. Hassan, Magda M. El-Henawee, Ayman A. Gouda
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2008
Spectrophotometric determination of gatifloxacin in pure form and in pharmaceutical formulation
Alaa S. Amin, Ayman Abou El-Fetouh Gouda, Ragaa El-Sheikh, Faten Zahran
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2007
Spectrophotometric determination of pipazethate HCl, dextromethorphan HBr and drotaverine HCl in their pharmaceutical preparations
Alaa S. Amin, Ragaa El-Sheikh, Faten Zahran, Ayman Abou El-fetouh Gouda
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2007
Spectrophotometric determination of some anti-tussive and anti-spasmodic drugs through ion-pair complex formation with thiocyanate and cobalt(II) or molybdenum(V)
Ragaa El-Shiekh, Faten Zahran, Ayman Abou El-Fetouh Gouda
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 2007
Spectrophotometric determination of pipazethate hydrochloride in pure form and in pharmaceutical formulations
Ragaa El-Shiekh, Alaa S Amin, Faten Zahran, Ayman A Gouda
Journal of AOAC International, 2007
Spectrophotometric determination of dextromethorphan hydrobromide and ketamine hydrochloride in pure and dosage forms
Ragaa El‐Sheikh, Monir Zaky, Faten Zahran Mohamed, Alaa Sayed Amin, Ayman Abou El‐Fetouh Gouda
Journal of the Chinese Chemical Society, 2006

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