Browsing by Author "Boadi, Nathaniel Owusu"

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    Determination of levels of cyanide in soils, water and cassava at Bibiani- a gold mining town in Ghana
    (2005-11-03) Boadi, Nathaniel Owusu
    Bibiani is a gold mining town in the Western Region of Ghana and the method of mining used is surface mining. The main leaching agent used is sodium cyanide which is toxic and when not properly managed could contaminate the soil, water and foodstuff which serve as the basis of livelihood for the natives living in the mining communities. Total cyanide concentrations in the soil, water and cassava samples from Bibiani were determined. Total cyanide concentrations were also determined in the soil, cassava and water samples from KNUST, Kumasi in the Ashanti Region to serve as control samples. Two analytical methods were adopted for cyanide determination of the samples. They are the argentometric method using potassium iodide as indicator and colorimetric method using pyridine-barbituric acid reagent as coupling agent and UV-Visible spectrophotometer to measure cyanide concentration. The research was conducted between October 2004 and May 2005 . Zinc, cadmium, copper and iron concentrations were determined in all the samples using the flame atomic absorption spectrometer. Sodium was also determined using the flame photometer. The mean total cyanide concentrations in raw cassava ranged from 84.74 to 149.99 mg/kg fresh weight using argentometric method and 82.45 to 142.91 mg/kg fresh weight using colorimetric method. The cassava peels had levels of cyanide ranging from 360 to 510 mg/kg for the argentometric method and 360.05 to 509.51 mg/kg for the colorimetric method. The cooked cassava had cyanide concentrations ranging between 6.79 and 24.91 mg/kg. The mean total cyanide levels in the soil samples ranged from 6.04 to 26.17 mg/kg and the mean total cyanide levels in water samples ranged from 2.17 to 7.83 mg/L. Sodium concentrations ranged from 998.1 to 1794.7 mg/kg in the soil, 25.94 to 29.92mg/L in the water and 114.7 to 159.6 mg/kg in the cassava samples. The concentration of iron in the soil samples ranged from 77.88 to 302.08mg/kg while in the cassava and water samples, iron was below detection limit. Copper concentrations ranged from 12.4 mg/kg to 115.4mg/kg in the soil, 4.6 to 6.0 mg/kg in the cassava and below detection in the water samples. The zinc concentrations ranged from 24.1 to 170.3 and 7;6 to 11.6 mg/kg. in soil and cassava samples respectively. Zinc was below detection in most of the water samples. however, two of the water samples had traces of it. Cadmium was generally low in all the samples. The pH of the soil, water and cassava samples ranged from 3.88 to 6.95, 3.14 to 7.44 and 5.42 to 5.60 respectively. The moisture content of the soil samples ranged between 2.47 and 35.40% and that of cassava. 56.08 to 56.87 %. Conductivity and total dissolved solids of water ranged from 34 to 155.5cm and 31 to 89mg/L respectively. The toxicological implications of these findings are discussed.
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    Nutritional composition and antioxidant properties of three varieties of carrot (Daucus carota)
    (Elsevier, 2021) Boadi, Nathaniel Owusu; Badu, Mercy; Kortei, Nii Korley; Saah, Selina Ama; Annor, Benjamin; Mensah, Michael Baah; Okyere, Harry; Fiebor, Alphonse; 0000-0002-8080-4812
    Carrots are a potentially rich source of antioxidants in addition to their nutritional proper ties. In this study, the nutritional composition and antioxidant properties of three varieties of carrots, namely Kuroda, Pamela and Amazonia cultivated in Ghana were determined. The peroxide scavenging method was used to determine the antioxidant properties of the ethanolic extracts of the carrot varieties at different concentrations. The protein, crude fi bre, fat and carbohydrate contents of the carrot varieties ranged 6.46 – 10.73 %, 7.18 – 8.87 %, 1.97 – 4.31 % and 6.25 – 8.39 % respectively. The three varieties had high moisture contents ranging from 69.06 to 75.30 %. The antioxidant properties were high even at low concentrations of extract, and their activity increased with time in the order Amazonia > kuroda > pamela. Amazonia had the highest fibre, protein and carbohydrate contents and the lowest moisture content, making it the most preferred variety.
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    Risk of Exposure to Trace Elements through the Application of Facial Makeup Powders
    (Hindawi, 2022) Saah, Selina Ama; Boadi, Nathaniel Owusu; Sakyi, Patrick Opare; Darko, Godfred; Mensah, Michael Baah; 0000-0002-8080-4812
    e study aimed to ascertain the levels of trace elements present in the face powders marketed in Ghana. Fifteen di erent brands of facial makeup powders were purchased from a local market in Ghana. e samples were analyzed using an X-ray uorescence (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). e 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. e hazard indices (HIs) for Pb, Mn, Cr, and Ti were less than 1, indicating no risk. However, the HIs for As, Hg, Zn, and Fe were more than 1, indicating a potential risk of usage in adults. As a result, using face powders could put users at risk of exposure to trace elements. Dermal exposure to trace elements from cosmetics resulted in a lifetime cancer risk (LCR) that was higher than what was considered tolerable (LCR >10−6 ) due to the presence of Pb, As, and Cr. Mercury was identi ed as a potential skin sensitizer in the cosmetic samples examined by an exposure-based sensitization quantitative risk assessment (SQRA)
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    Synthesis of Lead Chalcogenide Nanoparticles and thin Films from Single-Source Precursors
    (December, 2014) Boadi, Nathaniel Owusu
    The work described herein deals with the synthesis and characterisation of lead chalcogenide thin films and nanocrystals from Single-source precursors. Single-source precursors of type imidodiisopropyl –dithio, -diseleno and -thioselenophosphinato complexes of lead have been synthesised and characterised. The as-synthesised compounds have been used for the fabrication of lead sulphide and lead selenide thin films by aerosol-assisted chemical vapour deposition and for the synthesis of nanocrystals by colloidal hot injection method. The as- grown thin films and nanoparticles of lead sulphide and lead selenide have been characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray (EDAX) analyses. Optical band gaps of the nanoparticles produced have been evaluated using the absorption spectrum fitting procedure. The band gaps of the nanoparticles were wider than those of their respective bulk particles, indicating a significant tuning. PbSxSe1-x thin films have also been prepared by aerosol assisted chemical vapour deposition (AACVD) using novel Single-source precursors synthesised, characterised and their structures elucidated in this project. The complexes are [Pb((SePiPr2)(SPiPr2)N)2], [Pb((SePiPr2)2N)(S2CNEt2)] and [Pb((SePiPr2)2N)(S2CNHexMe)]. The thin films deposited from all three complexes showed the formation of PbSxSe1-x at temperatures ranging from 300 °C to 400 °C and PbSe at 450 °C. Distribution of sulphur and selenium within alloyed thin films is confirmed by scanning electron microscope studies and EDAX analysis.
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    Synthesis of Nickel Sulfide Thin Films and Nanocrystals from the Nickel Ethyl Xanthate Complex
    (Hindawi, 2022) Kotei, Patience Adei; Boadi, Nathaniel Owusu; Saah, Selina Ama; Mensah, Michael Baah; 0000-0002-8080-4812
    Nickel sul des have unique and diverse structural features, making them ideal for energy conversion and storage. is research focuses on the synthesis and characterization of nickel sul de thin lms and nanocrystals from nickel ethyl xanthate complex using spin-coating and solventless methods. e 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). e NiS thin lms and nanoparticles were analyzed with energy dispersive X-ray (EDX) spectroscopy and X-ray di raction (XRD). Nickel ethyl xanthate was synthesized in an 81.2% yield. e bandgaps of the nickel sul de obtained from the spin-coating method ranged from 4.35–4.88 eV. For the solventless method, the bandgap of the nickel sul de ranged from 3.93–3.96 eV. e crystal phase observed from the spin-coating and solventless methods was α-NiS (hexagonal). A direct correlation was observed between annealing temperature, bandgap, and particle size
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    Transesterification of palm kernel oil using calcium oxide as catalyst
    (International Scientific Organization, 2021) Badu, Mercy; Boateng, Ransford Appianin; Padevoah, Mary Magdalene; Agbemade , Agbemade; Quainoo, Timothy; Mensah, Micheal Baah; Boadi, Nathaniel Owusu; 0000-0002-8080-4812
    The study focused on using locally produced palm kernel oil, palm ethanol and CaO catalyst from guinea fowl eggshells for biodiesel production. The physicochemical properties such as density (0.8936±0.00008165 g/ml), viscosity (83.32±0.193cP/P), refractive index (1.4540±0.00036), pH (5.89±0.084 mol/L H+), acid value (13.9±0.3 mgKOH/g), saponification value (283.305±23.24 mgKOH/g) and iodine value (20.7±5.77 mgI2/g) of the crude oil was determined. The transesterification process was carried out by optimizing reaction conditions using the One-Factor (OFAC) at a time method. The biodiesel produced from optimum conditions had density (0.877±0.001g/ml), iodine value (13.97±1.037 mgI2/g) and cetane index (76.215±0.531). The results also gave a kinematic viscosity (7.87±0.531 mm²/s), pour point (8.667±0.943°C), acid value (0.92±0.145 mgKOH/g) and saponification value (161.75±11.017 mgKOH/g).