Browsing by Author "Saah, Selina Ama"

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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 and characterization of lead sulphide nanoparticles from lead alkyl xanthate single source precursors using a solventless method
    (2013-12-02) Saah, Selina Ama
    Xanthates have been successfully investigated as single source precursors for producing metal sulphide nanoparticles. These offer advantages over other precursors because they have low decomposition pathways, they are cheap, they are clean and they have pre-formed M-S bond. Although ethyl xanthates have been investigated with much success, there are few or no reports on the syntheses of higher alkyl xanthates. In this work a series of lead alkyl xanthates have been synthesized with the alkyl groups being ethyl, n-butyl, 1- hexyl and 1-octyl. The purities of the precursors were confirmed by micro-elemental analyses. Infra-red, 1H NMR, 13C NMR, melting point, and mass spectroscopy were also used to characterize the precursors. The thermal behaviours of the precursors were determined by TGA and DSC. The crystal structure of lead hexyl xanthate was determined. The low melting points recorded for the precursors confirmed that the lead alkyl xanthates could be used as single source precursors in low thermal decomposition for the syntheses of lead sulphide nanoparticles. The PbS nanoparticles were then produced using the melt method which is a rapid, less toxic and cheap process. The as-prepared lead sulphide nanoparticles were characterized by XRD and TEM which confirmed a growth towards cubic PbS phases. The calculated particle sizes from the Debye Scherer equation were 26.45, 25.17, 24.79 and 23.32 nm for the PbS nanoparticles obtained from the decomposition of ethyl, butyl, hexyl and lead octyl xanthate respectively. SEM and EDX were also used to determine the morphology and purity of the as-prepared PbS nanoparticles respectively.
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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