International Journal of Chemistry

International Journal of Chemistry | Vol. 2, No. 6, June 2011 | pp. 68–75

DOI: 10.46882/2011/IJC/000033

Article Type: Original Research Paper

Title: Phytochemical Profiling, Volatile Oil GC-MS Fingerprinting, and Radical Scavenging Traits of Zingiber officinale Varieties

Names of Authors: S. A. Abdulrahman¹, I. K. Bello²*

Authors’ Affiliations:
¹Department of Chemistry, Federal University of Technology, Minna, Nigeria.
²Department of Biochemistry, Ibrahim Badamasi Babangida University, Lapai, Nigeria.

Abstract: Zingiber officinale (Ginger) is highly valued globally for its culinary and medicinal properties, yet geographic variations alter its secondary metabolite concentrations. This research isolates the volatile oil constituents and appraises the free radical scavenging potential of yellow and white ginger rhizome varieties cultivated in Northern Nigeria. Powdered matrices were extracted using hydro-distillation in a Clevenger-type apparatus to yield essential oils. Gas Chromatography-Mass Spectrometry (GC-MS) identified 24 distinct compounds, with gingerol (28.4%), shogaol (16.2%), and alpha-zingiberene (22.5%) making up the dominant bioactive compounds. The antioxidant capacities were monitored in vitro using the DPPH assay and the ferric reducing antioxidant power (FRAP) test, using ascorbic acid as a standard control. The essential oil of the yellow variety displayed higher radical scavenging traits, yielding an IC50 value of 42.6 μg/mL, compared to 54.8 μg/mL shown by the white variety. Total phenolic content (TPC) tracked via the Folin-Ciocalteu method revealed a linear relationship with free radical neutralization capacity, showing that structural plant phenolics drive the antioxidant performance of these culinary rhizomes.

Keywords: Zingiber officinale; Essential oils; GC-MS profiling; Free radicals; DPPH assay; Phenolic antioxidants

Manuscript Timeline: Received: February 10, 2011; Revised: March 24, 2011; Accepted: April 15, 2011; Published: June 08, 2011.

Citation: Abdulrahman, S. A., & Bello, I. K. (2011). Phytochemical Profiling, Volatile Oil GC-MS Fingerprinting, and Radical Scavenging Traits of Zingiber officinale Varieties. International Journal of Chemistry, 2(6), 68–75.

International Journal of Chemistry | Vol. 1, No. 1, January 2010 | pp. 1–8

DOI: 10.46882/2010/IJC/000001

Article Type: Original Research Paper

Title: Synthesis and Characterization of Novel Zinc Oxide Nanoparticles Using Camellia sinensis Leaf Extract for Photocatalytic Degradation of Methylene Blue

Names of Authors: Ananya R. Sharma¹, Michael K. Chen², David O. Okoro¹

Authors’ Affiliations:
¹Department of Chemistry, Faculty of Science, University of Lagos, Akoka, Nigeria
²Department of Chemical Engineering, Tsinghua University, Beijing, China

Abstract: Green synthesis of nanoparticles has gained significant attention due to its eco-friendly and cost-effective nature. In this study, zinc oxide nanoparticles (ZnO NPs) were successfully synthesized using the aqueous leaf extract of Camellia sinensis (Green tea) as a reducing and stabilizing agent. The synthesized nanoparticles were characterized using UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). UV-Vis spectra showed a characteristic absorption peak at 365 nm, confirming the formation of ZnO NPs. XRD analysis revealed a crystalline wurtzite structure with an average crystallite size of 24.5 nm. The photocatalytic activity of the synthesized ZnO NPs was evaluated through the degradation of Methylene Blue (MB) dye under solar light irradiation. The effects of operational parameters, including catalyst dosage (0.1 to 0.5 g/L), initial dye concentration (10 to 50 mg/L), and pH (4 to 10), were systematically investigated. Optimal degradation of 94.2% was achieved within 120 minutes using a catalyst dosage of 0.3 g/L at pH 9. The degradation kinetics followed a pseudo-first-order model with a rate constant of 0.0231 min⁻¹. Reusability tests demonstrated that the catalyst maintained a degradation efficiency of over 85% after four consecutive cycles. These findings suggest that green-synthesized ZnO NPs serve as a highly efficient, sustainable, and reusable photocatalyst for the treatment of textile wastewater containing hazardous organic dyes.

Keywords: Green synthesis, Zinc oxide nanoparticles, Camellia sinensis, Photocatalytic degradation, Methylene blue, Kinetics

Manuscript Timeline: Received: October 12, 2009; Revised: November 20, 2009; Accepted: December 05, 2009; Published: January 02, 2010

International Journal of Chemistry | Vol. 1, No. 9, September 2010 | pp. 70–77

DOI: 10.46882/2010/IJC/000009

Article Type: Original Research Paper

Title: Computational Density Functional Theory (DFT) Insights into the Corrosion Inhibition Efficacy of Imidazole Derivatives on Al(111) Surface

Names of Authors: Razaq A. Balogun¹, Fatma Al-Marzouqi²

Authors’ Affiliations:
¹Department of Chemistry, University of Ilorin, Ilorin, Nigeria
²Department of Chemistry, United Arab Emirates University, Al Ain, UAE

Abstract: Quantum chemical calculations based on density functional theory (DFT) were applied to model the structural, electronic, and corrosion inhibition characteristics of three imidazole derivatives: 2-methylimidazole (2-MI), 2-phenylimidazole (2-PI), and 2-mercaptoimidazole (2-MeI) on an Aluminum (111) surface. The electronic configurations of the inhibitor molecules were optimized at the B3LYP fractional level using the 6-311G(d,p) basis set. Key global quantum chemical parameters were computed, including the highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (Delta E), dipole moment (mu), electronegativity (chi), global hardness (eta), and the fraction of electrons transferred from the inhibitor molecule to the metal surface (Delta N). The calculations demonstrated that 2-MeI exhibited the highest EHOMO (-5.42 eV) and the lowest energy gap (3.12 eV), pointing to its high reactivity and capacity to readily donate lone pair electrons to the vacant d-orbitals of aluminum. Local reactivity trends were evaluated utilizing Fukui functions (f⁺ and f⁻) to identify the specific nucleophilic and electrophilic adsorption active sites within each compound. Molecular dynamics (MD) simulations were executed to model the configurations of the compounds on the Al(111) surface. The binding energies increased in the order of 2-MI < 2-PI < 2-MeI, agreeing with empirical weight loss metrics.

Keywords: Density Functional Theory, Corrosion inhibition, Imidazole, Quantum chemical parameters, Molecular dynamics, Fukui functions

Manuscript Timeline: Received: June 05, 2010; Revised: July 19, 2010; Accepted: August 10, 2010; Published: September 02, 2010

International Journal of Chemistry | Vol. 1, No. 7, July 2010 | pp. 52–60

DOI: 10.46882/2010/IJC/000007

Article Type: Original Research Paper

Title: Speciation and Spatial Distribution of Heavy Metals in Surface Sediments of the Lagos Lagoon System

Names of Authors: Babajide A. Adeisa¹, Ngozi E. Chukwu¹, Hans-Dieter Meier²

Authors’ Affiliations:
¹Department of Marine Sciences, University of Lagos, Akoka, Nigeria
²Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany

Abstract: Heavy metal pollution in coastal lagoons poses a severe ecological threat to benthic organisms and commercial fisheries. Surface sediment samples collected from ten strategically selected stations across the Lagos Lagoon were analyzed to evaluate the total concentrations and chemical speciation of Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), and Zinc (Zn). Spatial distribution patterns showed that heavy metal accumulation was drastically elevated in areas near industrial wastewater discharges and urban runoff channels. A modified Tessier sequential extraction procedure was employed to fractionate the metals into five operational pools: exchangeable, bound to carbonates, bound to iron-manganese oxides, bound to organic matter, and residual. Total metal levels ranged as follows: Zn (112.4–345.8 mg/kg) > Cr (45.2–128.5 mg/kg) > Pb (18.6–94.2 mg/kg) > Cu (12.4–65.3 mg/kg) > Cd (1.1–5.4 mg/kg). Speciation analysis revealed that Cd and Pb were predominantly associated with the exchangeable and carbonate fractions (35% and 28%, respectively), highlighting their high mobility, bioavailability, and potential toxicity to the aquatic ecosystem. Conversely, Cr and Cu were mostly locked within the organic and residual fractions, suggesting lower immediate ecological risk. The pollution load index (PLI) indicated significant anthropogenically driven deterioration across the lagoon system.

Keywords: Heavy metals, Sediment speciation, Tessier extraction, Bioavailability, Lagos Lagoon, Environmental pollution

Manuscript Timeline: Received: April 15, 2010; Revised: May 24, 2010; Accepted: June 15, 2010; Published: July 02, 2010

International Journal of Chemistry | Vol. 1, No. 5, May 2010 | pp. 35–42

DOI: 10.46882/2010/IJC/000005

Article Type: Original Research Paper

Title: Microwave-Assisted Synthesis and Antibacterial Evaluation of Novel Sulfonamide Derivatives Bearing a Schiff Base Moiety

Names of Authors: Marcus A. Gomez¹, Blessing C. Umeh², Tariq M. Al-Alawi³

Authors’ Affiliations:
¹Department of Chemistry, University of Cape Town, Cape Town, South Africa
²Department of Pharmaceutical Chemistry, University of Benin, Benin City, Nigeria
³Department of Chemistry, College of Science, Sultan Qaboos University, Muscat, Oman

Abstract: The development of novel antimicrobial agents is imperative due to the rapid global rise of multi-drug resistant bacterial pathogens. A series of novel sulfonamide derivatives containing a Schiff base core (compounds 4a–4j) were synthesized via an efficient, rapid microwave-assisted condensation reaction of sulfanilamide with various substituted aromatic aldehydes. Compared to conventional heating methods, the microwave-assisted protocol reduced reaction times from 4.5 hours to 6–10 minutes and enhanced product yields from 62% to a range of 88%–95%. The molecular structures of all newly synthesized compounds were validated using elemental analysis, FTIR, 1H-NMR, and 13C-NMR spectroscopy. The in vitro antibacterial activities of the compounds were screened against two Gram-positive strains (Subtilis bacillus, Staphylococcus aureus) and two Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa) utilizing the broth microdilution method to determine Minimum Inhibitory Concentrations (MIC). Compound 4d, possessing a nitro group substitution at the para-position of the aromatic ring, exhibited the most potent antibacterial action, with an MIC value of 7.8 micro-g/mL against S. aureus and 15.6 micro-g/mL against E. coli, matching the efficacy of the standard reference drug Ciprofloxacin.

Keywords: Microwave synthesis, Sulfonamides, Schiff base, Antibacterial activity, Minimum Inhibitory Concentration

Manuscript Timeline: Received: February 14, 2010; Revised: March 20, 2010; Accepted: April 14, 2010; Published: May 06, 2010

International Journal of Chemistry | Vol. 1, No. 10, October 2010 | pp. 78–86

DOI: 10.46882/2010/IJC/000010

Article Type: Original Research Paper

Title: Development and Validation of a RP-HPLC Method for the Simultaneous Quantification of Paracetamol and Ibuprofen in Pharmaceutical Formulations

Names of Authors: Chinyere N. Nwosu¹, Alistair K. Brown²

Authors’ Affiliations:
¹Department of Pharmaceutical Chemistry, University of Port Harcourt, Choba, Nigeria
²School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom

Abstract: A simple, rapid, precise, and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method was engineered and validated for the concurrent analysis of paracetamol and ibuprofen in tablet dosage forms. The chromatographic separation was accomplished on a C18 stationary phase column (250 mm x 4.6 mm, 5 micro-m particle size). The optimized mobile phase consisted of a mixture of water adjusted to pH 3.2 using orthophosphoric acid and acetonitrile in an isocratic ratio of 40:60 (v/v). The flow rate was regulated at 1.0 mL/min, and the analytes were supervised via UV detection at a wavelength of 230 nm. The retention times for paracetamol and ibuprofen were found to be 2.45 minutes and 5.12 minutes, respectively, indicating rapid baseline separation. The method was validated according to International Council for Harmonisation (ICH) guidelines for parameters including linearity, accuracy, precision, specificity, limit of detection (LOD), and limit of quantification (LOQ). Linearity was established over a concentration domain of 5.0–50.0 micro-g/mL for paracetamol and 10.0–100.0 micro-g/mL for ibuprofen, generating correlation coefficients (R²) exceeding 0.999. The recovery percentages fell within 98.5%–101.2%, proving excellent accuracy. The low relative standard deviation (%RSD < 2.0%) obtained for intra-day and inter-day evaluations confirmed the robustness of the methodology for routine quality control assay analysis.

Keywords: RP-HPLC, Isocratic separation, Validation, Paracetamol, Ibuprofen, Pharmaceutical formulation, ICH guidelines

Manuscript Timeline: Received: July 11, 2010; Revised: August 25, 2010; Accepted: September 14, 2010; Published: October 05, 2010.