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The study aimed to ascertain the levels of trace elements present in the face powders marketed in Ghana. Fifteen different brands of facial makeup powders were purchased from a local market in Ghana. The samples were analyzed using an... more
The study aimed to ascertain the levels of trace elements present in the face powders marketed in Ghana. Fifteen different brands of facial makeup powders were purchased from a local market in Ghana. The samples were analyzed using an X-ray fluorescence (XRF) analyzer to determine the concentrations of 16 elements (Pb, As, Hg, Zn, Fe, Mn, Cr, Ti, Cu, Ni, Co, Sb, Cd, Ag, Sn, and Au). The contents of the trace elements were ordered in the following descending order according to the maximum concentrations: Fe > Zn > Ti > Mn > Cr > Hg > As > Pb > Cu, Ni, Co, Sb, Cd, Ag, Sn, and Au. Pearson correlation statistics showed strong positive relationships between Pb and Zn (r = 0.71), Pb and Cr (r = 0.57), Hg and Zn (r = 0.63), Hg and Fe (r = 0.73), Hg and Cr (r = 0.61), Zn and Fe (r = 0.69), Zn and Cr (r = 0.88), Fe and Cr (r = 0.67), and Fe and Ti (r = 0.62). Except for Pb and Cr, all the other elements had their margin of safety (MOS) values less than 100. The hazard...
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Optimum fish production is greatly dependent on the physical, chemical and biological qualities of water. Hence, successful fish pond management requires an in-depth understanding of water quality. A study to assess heavy metal (Cr, Cd,... more
Optimum fish production is greatly dependent on the physical, chemical and biological qualities of water. Hence, successful fish pond management requires an in-depth understanding of water quality. A study to assess heavy metal (Cr, Cd, Mn, Pb and Zn) contamination and physicochemical parameters of water samples from eight selected fish ponds in Sunyani, Ghana, was conducted. The parameters included temperature, pH, salinity, total hardness, electrical conductivity (EC), chemical oxygen demand (COD) and biological oxygen demand (BOD). The results revealed detectable Mn and Zn levels in all the selected fish ponds; with Mn levels in three ponds being significantly higher than the World Health Organization (WHO) recommended limit (< 0.500 mg/L). Of the three samples, which showed detectable Cr and Cd levels, concentrations of two exceeded the permissible limits. Pb was below the detection limit in all the samples whilst Cu levels detected in two of the ponds were below the permissi...
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The diffusion of potassium in potato (Solanum tuberosum) at different leaching conditions was investigated. Two modes of pretreatment of potato samples (cubes and spheres) by preheating to 80°C and leaching at temperatures of 20-80°C were... more
The diffusion of potassium in potato (Solanum tuberosum) at different leaching conditions was investigated. Two modes of pretreatment of potato samples (cubes and spheres) by preheating to 80°C and leaching at temperatures of 20-80°C were performed using a temperature- and agitation-controlled batch extractor. A Fickian model incorporating the effective diffusion coefficient ( D eff ), partition coefficient ( K ) between the solute concentration in the potato and medium, and mass transfer coefficient ( kl ) was developed to simulate and predict the fraction of potassium leached from the potato at any temperature. Results showed significant reduction in activation energies from 92 to 25.02 kJ/mol for cubes and from 75.02 to 13.40 kJ/mol for spheres culminating in higher extraction rates when samples were preheated to 80°C. The D eff , K , and kl values obtained were in the range of 0.02 − 7.33 × 10 − 9 m 2 / s , 0.63 − 8.00 × 10 − 2 , and 0.01333.00 × 10 − 4 m / s , respectiv...
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Nickel sulfides have unique and diverse structural features, making them ideal for energy conversion and storage. This research focuses on the synthesis and characterization of nickel sulfide thin films and nanocrystals from nickel ethyl... more
Nickel sulfides have unique and diverse structural features, making them ideal for energy conversion and storage. This research focuses on the synthesis and characterization of nickel sulfide thin films and nanocrystals from nickel ethyl xanthate complex using spin-coating and solventless methods. The nickel ethyl xanthate complex (C6H10S4NiO2) was characterized using Fourier-transformed infrared (FT-IR), ultraviolet-visible (UV-Vis), and nuclear magnetic resonance (NMR) spectroscopies as well as thermogravimetric analysis (TGA). The NiS thin films and nanoparticles were analyzed with energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD). Nickel ethyl xanthate was synthesized in an 81.2% yield. The bandgaps of the nickel sulfide obtained from the spin-coating method ranged from 4.35–4.88 eV. For the solventless method, the bandgap of the nickel sulfide ranged from 3.93–3.96 eV. The crystal phase observed from the spin-coating and solventless methods was α-NiS (hexag...
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In this study, [Pb((SePiPr2)2N)(S2CNHexMe)], a novel complex, was synthesised by refluxing [Pb(S2CNHexMe)2] and [Pb((SePiPr2)2N)2] complexes for 2 hours in chloroform and precipitating with methanol. The microelemental analysis, FT-IR,... more
In this study, [Pb((SePiPr2)2N)(S2CNHexMe)], a novel complex, was synthesised by refluxing [Pb(S2CNHexMe)2] and [Pb((SePiPr2)2N)2] complexes for 2 hours in chloroform and precipitating with methanol. The microelemental analysis, FT-IR, and NMR spectroscopies were performed on the complex and the melting point was determined. The crystal structure of this new compound has been determined. The structure showed a distorted square pyramidal geometry with 2 sulphur and 2 selenium atoms coordinating the central atom at the base of the pyramid and a lone pair occupying the axial position of the lead atom. The complex was used to deposit lead chalcogenide thin films by the aerosol-assisted chemical vapour deposition (AACVD) method at 300, 350, 400, and 450°C. The thin films matched with the powder X-ray diffraction (pXRD) pattern for cubic PbSe with a (200) preferred orientation at all the deposition temperatures. The scanning electron microscopy (SEM) and energy dispersive X-ray spectrosco...
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Pharmaceuticals, among the emerging contaminants, are pseudopersistent and recently of serious concern due to universal use, toxicity, and resistance development at low concentrations. This study was aimed at assessing the prevalence and... more
Pharmaceuticals, among the emerging contaminants, are pseudopersistent and recently of serious concern due to universal use, toxicity, and resistance development at low concentrations. This study was aimed at assessing the prevalence and risk of eight pharmaceuticals in surface water used for vegetable irrigation in Ghana’s Kumasi and Sunyani metropolises, which are influenced by hospitals, sewage treatment facilities, and market effluents. Samples were concentrated via solid-phase extraction (SPE) while liquid chromatography was used to identify and quantify the analytes. Ibuprofen, acetaminophen, and diclofenac were the detected analgesics in this study, with concentrations stretching from below detection limit (not detected) to 319.0 ng/L, while amoxicillin, trimethoprim, and cefuroxime were the detected antibiotics with a concentration range of no detection to 840.0 ng/L. Based on the available long-term data, an environmental risk assessment was conducted. Because of the presen...
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A Thesis submitted to the Department of Chemistry, College of Science, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the degree of MPhil in Polymer Science and Technology June, 2013
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An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely... more
An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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Morinda citrifolia, L commonly called noni, has a long history as a medicinal plant and is reported to have a broad range of therapeutic effects, including antibacterial, antiviral, antifungal, antitumor, antihelmin, analgesic,... more
Morinda citrifolia, L commonly called noni, has a long history as a medicinal plant and is reported to have a broad range of therapeutic effects, including antibacterial, antiviral, antifungal, antitumor, antihelmin, analgesic, hypotensive, anti-inflammatory, and immune enhancing effects. Photochemical analyses of ethanol and hexane extracts of noni fruit revealed the presence of flavonoids, terpenoids, alkaloids and steroids. Proximate composition of the noni fruit revealed a moisture content of 54.21, crude protein 2.18, crude fat 3.25, crude fiber 4.49, ash 0.73 and carbohydrate 35.14%. The Vitamin C content was estimated using iodometric titration and found to be 134.10 mg/100g. This suggests that the noni fruit can if consumed can help promote good health.
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The bioactive compounds of the leaves of Carica papaya; solo and solomix were extracted using ethanol and n-hexane, and investigated for the presence of secondary metabolites. Both ethanol and n-hexane extracts revealed the presence of... more
The bioactive compounds of the leaves of Carica papaya; solo and solomix were extracted using ethanol and n-hexane, and investigated for the presence of secondary metabolites. Both ethanol and n-hexane extracts revealed the presence of alkaloids. Flavonoids, glycosides and saponins were present in only the ethanol extract whereas tannins were present in the n-hexane extract. The bioactivities of the leaf extracts were attributed to their phytochemical constituents. Antimicrobial activity of the extracts were determined against some human pathogenic bacteria and fungi such as Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Bacillus subtilis and Candida albicans using the agar well diffusion and broth dilution methods with the polar extract being more effective. The ethanol extract demonstrated a significant broad-spectrum antimicrobial activity against both gram-positive and gramnegative bacteria, with the highest activity having a zone of inhibition of 10 mm. Anti...
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The leaves of Persea americana are widely used for ethno-medicinal purposes worldwide. This study assessed the antimicrobial and antioxidant activities of the methanol, ethyl acetate, chloroform and petroleum ether leaves extracts of P.... more
The leaves of Persea americana are widely used for ethno-medicinal purposes worldwide. This study assessed the antimicrobial and antioxidant activities of the methanol, ethyl acetate, chloroform and petroleum ether leaves extracts of P. americana. Extracts displayed variable antimicrobial activities that were microorganism-specific. The methanolic extract displayed the most potent antimicrobial activities with the largest zones of inhibition (0-1.8 mm) in the agar diffusion assay and with the lowest minimum inhibitory concentration (MIC) in the broth dilution assay against a panel of microorganisms that included Bacillus subtilis, Escherichia coli, Salmonella typhi, Streptococcus aureus, Pseudomonas aeruginosa and Candida albicans. The ethyl acetate extract exhibited the most potent antioxidant potential with the lowest EC50 of 4.15x10-30 g/ml for the peroxide radical scavenging activities. The data supports the ethnomedicinal use of the leaves of P. americana for the management of ...
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A novel complex [Pb((SePiPr2)2N) (S2CNEt2)] has been synthesized and characterized by microelemental analysis, melting point NMR, and FT-IR spectroscopies. Its crystal structure has also been successfully determined using single-crystal... more
A novel complex [Pb((SePiPr2)2N) (S2CNEt2)] has been synthesized and characterized by microelemental analysis, melting point NMR, and FT-IR spectroscopies. Its crystal structure has also been successfully determined using single-crystal X-ray crystallography. The structure indicates a distorted square pyramidal geometry with the four basal atoms being noncoplanar. The complex was used as a single-source precursor for the deposition of lead chalcogenide thin films on glass substrates at 300, 350, 400, and 450°C by AACVD. The films were characterized by SEM, EDX, and XRD. The XRD peaks matched with cubic PbSe at all temperatures. The SEM micrographs showed the formation of cubes with the lower temperatures (300–350°C) showing well-resolved cubes while with the higher temperatures (400–450°C) showing poorly resolved cubes. The EDX analyses confirmed the formation of PbSe thin films at all the deposition temperatures.
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Lead alkyl xanthate (alkyl = octyl, nonyl and dodecyl) complexes have been synthesized and characterized using micro-elemental analyses, infra-red and thermogravimetric analyses. The synthesized complexes were used as molecular precursors... more
Lead alkyl xanthate (alkyl = octyl, nonyl and dodecyl) complexes have been synthesized and characterized using micro-elemental analyses, infra-red and thermogravimetric analyses. The synthesized complexes were used as molecular precursors (SSP) for preparation of PbS nanowires using the hot injection technique in olive oil. The influence of the alkyl chain length on the structural and electronic properties on the PbS nanowires are reported. Powder X-ray diffraction (p-XRD) analyses of the as-synthesized nanowires show a face centred cubic rocksalt structure (halite). Transmission electron microscope (TEM) images of the as-synthesized PbS nanomaterials reveal 1-dimensional growth of nanowires. The estimated optical band gaps from the Tauc plots were 1.34, 1.41 and 1.45 eV for PbS nanowires obtained from the octyl, nonyl and dodecyl chain lengths respectively at 125 °C. The composition and purity of the as-synthesized PbS nanowires was observed by energy dispersive X-ray analysis (EDX) which showed an approximately 1:1 Pb to S ratios in all the as-synthesized nanowires.
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Lead sulphide thin films have been successfully deposited by spin coating lead hexadecyl and octadecyl xanthate onto glass substrates and annealed at moderate temperatures. The thin films were characterized using powder x-ray... more
Lead sulphide thin films have been successfully deposited by spin coating lead hexadecyl and octadecyl xanthate onto glass substrates and annealed at moderate temperatures. The thin films were characterized using powder x-ray diffractometer (p-XRD) and were found to be face centred cubic (FCC) with the (200) being the most preferred orientation. The optical band gaps obtained were 0.93 and 1.00 eV respectively for PbS from complexes (1) and (2) annealed at 350 °C. They were all blue shifted from the bulk value of 0.41 eV.
Research Interests: Materials Science and MRS
A precise composition and band gap tunable PbS1−xSex solid solution was prepared by a single source route.
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Lead(ii) n-alkylxanthates with varying alkyl groups are used in melt reactions to impart size control on the PbS nanocrystals formed.
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Lead(ii) n-alkylxanthates with varying alkyl groups are used in melt reactions to impart size control on the PbS nanocrystals formed.
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Dichalcogenoimidodiphoshinato lead complexes, [Pb((EPiPr2)2N)2] (E=S, Se) have been synthesized and characterized. The crystal structure of [Pb((SeSPiPr2)2N)2]), has been solved by single‐crystal X‐ray crystallography and reported. These... more
Dichalcogenoimidodiphoshinato lead complexes, [Pb((EPiPr2)2N)2] (E=S, Se) have been synthesized and characterized. The crystal structure of [Pb((SeSPiPr2)2N)2]), has been solved by single‐crystal X‐ray crystallography and reported. These complexes have been used as single‐source precursors to synthesise PbS and PbSe nanoparticles by hot‐injection method in an oleylamine/trioctylphosphine mixture. Powder X‐ray diffraction (p‐XRD) studies indicate that the nanoparticles produced are cubic. The optical band gaps estimated from the absorption spectrum fitting curve indicate significant tuning of the bulk band gap, blue shifting towards the visible region of the electromagnetic spectrum.
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The physicochemical and microbial properties of some sachet drinking water sold in the Kumasi Metropolis of Ghana is reported in this study in order to assess the quality of water being consumed by the public. Nine different sachet water... more
The physicochemical and microbial properties of some sachet drinking water sold in the Kumasi Metropolis of Ghana is reported in this study in order to assess the quality of water being consumed by the public. Nine different sachet water samples were taken from different parts (sub- metropolises) of Kumasi and analysed for their odour, colour, turbidity, pH, electrical conductivity, total dissolved solids, alkalinity, total hardness and coliform bacteria. Metals and anions analysed were Ca, Mg, Fe, Mn, NO3−, NO2−, PO42− and Cl−. Microbes determined were faecal and total coliforms. The faecal coliform determined was Escherichia coli. Most of the sachet water samples analysed within the Ghana and WHO standards for drinking water. However, BKD, AHN and DDE water samples failed bacteriological tests and therefore makes them unwholesome and harmful to consumers.