Browsing by Author "Baker, P.G.L"

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    Molecularly imprinted polypyrrole sensors for the detection of pyrene in aqueous solutions
    (Springer Nature, 2021) Ngwanya, O.W; Ward, M; Baker, P.G.L
    Recently, electrochemical sensors have emerged as tools for polyaromatic hydrocarbons (PAH) detection that are cost-effective, easy to produce and use, highly selective and sensitive, and with good reproducibility. Polypyrrole may be easily produced from polymerization of pyrrole, by chemical as well as electrochemical methods, to produce dimensionally stable semi-conductive polymer materials, under mild synthesis conditions. In this study, polypyrrole was used as the stable molecular framework within which to create an imprint of the desired polyaromatic hydrocarbon, in situ, at glassy carbon electrodes. The molecularly imprinted polymer (MIP) sensors were washed to remove the imprint and subsequently characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and cyclic voltammetry (CV). The MIP sensors were then applied to the detection of pyrene and non-imprinted polymers (NIP) sensors were also evaluated for comparison with the MIP sensors. Calibration curves obtained for the detection of the pyrene at the MIP sensors in aqueous media reported limits of detection (LOD) of 2.28 × 10−7 M for pyrene and limit of quantification (LOQ) of 6.92 × 10−7 M (n = 3). The sensitivity of the MIP sensors (32.53 A/M) determined from the slopes of the calibration curves reported twice the value measured for NIP sensors (14.48 A/M).
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    Voltammetric determination of metformin and its derivatives using Cu modified polymer electrode.
    (University of the Western Cape, 2020) Ngwekazi, Andisiwe; Baker, P.G.L; Mciteka, L.P
    Diabetes, a worldwide disease, is classified into two types, type 1 or insulin-dependent and type 2 or noninsulin-dependent. Based on reports published by the International Diabetes Federation, the total number of those suffering from diabetes is growing every year. Statistics predict that type 2 diabetes, currently affecting about 8% of the adult population, would spread at such a pace that by 2030, more than 40 million cases of diabetes would be found throughout the world. On the other hand, studies revealed that patients with type 2 diabetes mellitus (T2DM) have a lower incidence of tumour development than healthy controls and that patients diagnosed with cancer have a lower risk of mortality when treated with metformin. However, the frequent use of metformin with low oral bioavailability ranging between 40-60% in the intestinal environment leads to large accumulation on the enterocytes.