Njagi Njomo
University of the Western Cape
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Publication
Featured researches published by Njagi Njomo.
Sensors | 2014
Milua Masikini; Stephen N. Mailu; Abebaw Tsegaye; Njagi Njomo; Kerileng M. Molapo; Chinwe O. Ikpo; Christopher E. Sunday; Candice Rassie; Lindsay Wilson; Priscilla Gloria Lorraine Baker; Emmanuel Iheanyichukwu Iwuoha
An impedimetric immunosensor for fumonisins was developed based on poly(2,5-dimethoxyaniline)-multi-wall carbon nanotubes doped with palladium telluride quantum dots onto a glassy carbon surface. The composite was assembled by a layer-by-layer method to form a multilayer film of quantum dots (QDs) and poly(2,5-dimethoxyaniline)-multi-wall carbon nanotubes (PDMA-MWCNT). Preparation of the electrochemical immunosensor for fumonisins involved drop-coating of fumonisins antibody onto the composite modified glassy carbon electrode. The electrochemical impedance spectroscopy response of the FB1 immunosensor (GCE/PT-PDMA-MWCNT/anti-Fms-BSA) gave a linear range of 7 to 49 ng L−1 and the corresponding sensitivity and detection limits were 0.0162 kΩ L ng−1 and 0.46 pg L−1, respectively, hence the limit of detection of the GCE/PT-PDMA-MWCNT immunosensor for fumonisins in corn certified material was calculated to be 0.014 and 0.011 ppm for FB1, and FB2 and FB3, respectively. These results are lower than those obtained by ELISA, a provisional maximum tolerable daily intake (PMTDI) for fumonisins (the sum of FB1, FB2, and FB3) established by the Joint FAO/WHO expert committee on food additives and contaminants of 2 μg kg−1 and the maximum level recommended by the U.S. Food and Drug Administration (FDA) for protection of human consumption (2–4 mg L−1).
Journal of Nano Research | 2016
Nomxolisi Dywili; Njagi Njomo; Chinwe O. Ikpo; Anne Lutgarde Djoumessi Yonkeu; Suru Vivian John; Ntuthuko Wonderboy Hlongwa; Naledi Raleie; Emmanuel Iheanyichukwu Iwuoha
Nanostructured anilino-functionalized reduced graphene oxide intercalated with Pt metal nanoparticles was successfully synthesized. Graphene oxide nanosheets were synthesized using a modified Hummers method with simultaneous in-situ functionalization with aniline and ionic Pt reduction and dispersion through sonication. The nanomaterial was characterised with FTIR, UV-visible, SEM, TEM, EDX, XRD and Raman spectroscopy to ascertain surface, chemical, elemental and crystalline properties, composite structures, size, morphology and successful entrapment of metal nanoparticles while the electro-conductivity of the nanomaterial was interrogated using CV. The graphene oxide was successfully functionalized with aniline with new peaks belonging to the N-H and C-N group being present and calculated band gaps of 5.35 eV and 4.39 eV which are attributed to functionalization of graphene oxide. The functionalized graphene oxide was successfully loaded with platinum nanoparticles as TEM revealed that the Pt particles are spread out on the graphene sheets and when magnified a uniform distribution of the nanoparticles can be observed. The material (functionalized graphene oxide loaded with platinum nanoparticles) was used in the design of an asymmetric supercapacitor cell using 6M KOH aqueous electrolyte. On testing by galvanostatic charge/discharge, a high specific capacitance value of 605 F/g with a corresponding energy and power densities of 0.021kWh/Kg and 0.372kW/Kg respectively, were obtained.
Nano Hybrids Vol. 3 | 2013
Chinwe O. Ikpo; Njagi Njomo; Kenneth I. Ozoemena; Tesfaye Waryo; Rasaq A. Olowu; Milua Masikini; Abd Almonam Baleg; Nazeem Jahed; Priscilla G.L. Baker; Emmanuel I. Iwuoha
The electrochemical dynamics of a film of FeCo nanoparticles were studied on a glassy carbon electrode (GCE). The film was found to be electroactive in 1 M LiClO4 containing 1:1 v/v ethylene carbonate dimethyl carbonate electrolyte system. Cyclic voltammetric experiments revealed a diffusion-controlled electron transfer process on the GCE/FeCo electrode surface. Further interrogation on the electrochemical properties of the FeCo nanoelectrode in an oxygen saturated 1 M LiClO4 containing 1:1 v/v ethylene-carbonate-dimethyl carbonate revealed that the nanoelectrode showed good response towards the electro-catalytic reduction of molecular oxygen with a Tafel slope of about 120 mV which is close to the theoretical 118 mV for a single electron transfer process in the rate limiting step; and a transfer coefficient (α) of 0.49. The heterogeneous rate constant of electron transfer (ket), exchange current density (io) and time constant (τ) were calculated from data obtained from electrochemical impedance spectroscopy and found to have values of 2.3 x 10-5 cm s-1, 1.6 x 10-4 A cm-2 and 2.4 x 10-4 s rad-1, respectively.
Archive | 2012
Stephen M Mailu; Rachel Fanelwa Ajayi; Kerileng M. Molapo; Njagi Njomo; Milua Masikini; Priscilla Baker; Peter M. Ndangili; Gcineka Mbambisa; Emmanuel I. Iwuoha
Electrochimica Acta | 2014
Oluwakemi Tovide; Nazeem Jaheed; Nurali Mohamed; Ezo Nxusani; Christopher E. Sunday; Abebaw Tsegaye; Rachel Fanelwa Ajayi; Njagi Njomo; Hlamulo R. Makelane; Mawethu P. Bilibana; Priscilla Baker; Avril Williams; Sibulelo Vilakazi; Robert Tshikhudo; Emmanuel I. Iwuoha
Electrochimica Acta | 2014
Njagi Njomo; Tesfaye Waryo; Milua Masikini; Chinwe O. Ikpo; Stephen N. Mailu; Oluwakemi Tovide; Natasha Ross; Avril Williams; Nolubabalo Matinise; Christopher E. Sunday; Noluthando Mayedwa; Priscilla G.L. Baker; Kenneth I. Ozoemena; Emmanuel I. Iwuoha
Electrochimica Acta | 2014
Abd Almonam Baleg; Nazeem Jahed; Anne Lutgarde Djoumessi Yonkeu; Njagi Njomo; Gcineka Mbambisa; Kerileng M. Molapo; Xolile Fuku; Gertrude Fomo; Hlamulo R. Makelane; Abebaw Tsegaye; Tesfaye Waryo; Priscilla Baker; Sibulelo Vilakazi; Robert Tshikhudo; Emmanuel I. Iwuoha
Electrochimica Acta | 2014
Natasha Ross; Emmanuel I. Iwuoha; Chinwe O. Ikpo; Priscilla Baker; Njagi Njomo; Stephen N. Mailu; Milua Masikini; Nolubabalo Matinise; Abebaw Tsegaye; Noluthando Mayedwa; Tesfaye Waryo; Kenneth I. Ozoemena; Avril Williams
Archive | 2013
Chinwe O. Ikpo; Charl J. Jafta; Kenneth I. Ozoemena; Natasha West; Njagi Njomo; Nazeem Jahed; Priscilla G.L. Baker; Emmanuel I. Iwuoha
Archive | 2012
Kenneth Ozoemena; Njagi Njomo; Emmanuel I. Iwuoha; Priscilla Baker; Peter M. Ndangili; Rasuq Adewale