Ojodomo J. Achadu

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The fabrication of maleimide-derivatized graphene quantum dots (M-GQDs) and zinc phthalocyanine (2) as novel sensor probes for the selective detection of biothiols (cysteine, homocysteine or glutathione) through the rapid and specific Michael addition reaction between biothiols and the maleimide-derivatized probes is presented in this study. GQDs directly(More)
We report on the interaction of graphene quantum dots (GQDs) with 4-acetamido-2,2,6,6-tetramethylpiperidine-oxyl (4-acetamido-TEMPO) free radicals. The GQDs were N and S, N doped. The fluorescence quantum yields were higher for the doped GQDs compared to the undoped. The interaction is assessed by spectrofluorimetric, steady state/time resolved fluorescence(More)
In this study, we report on the fabrication of simple and rapid graphene quantum dots (GQDs)-based fluorescence “turn-ON” nanoprobes for sensitive and selective detection of ascorbic acid (AA). Pristine GQDs and S and N co-doped-GQDs (SN-GQDs) were functionalized with 4-amino-2,2,6,6-tetramethylpiperidine-N-oxide (4-amino-TEMPO, a nitroxide free radical).(More)
This study reports the development of functional optical limiting materials composed of pristine graphene (GQDs), nitrogen-doped (NGQDs) and sulfur-nitrogen co-doped (SNGQDs) graphene quantum dots covalently linked to mono-amino substituted zinc phthalocyanine (Pc). Open aperture Z-scan technique was employed to monitor the behaviour of the conjugates under(More)
Graphitic carbon nitride quantum dots (gCNQDs) when alone or containing embedded 4-amino-2,2,6,6-tetramethyl(piperidin-1-yl)oxyl) (4-AT) (gCNQDs-4-AT(embedded)) were synthesized via low temperature in situ one-pot process from diaminomaleonitrile (DAMN). The blue emission of both gCNQDs and gCNQDs-4-AT were excitation wavelength-dependent with very high(More)
This study reports on the design of novel nanoconjugates of graphene quantum dots (GQDs) and tetra or octa-mercaptopyridine-substituted zinc and aluminium phthalocyanines (Pcs) deployed as fluorescence "turn ON" nanoprobes. The phthalocyanines were separately adsorbed onto the planar structure of graphene quantum dots (GQDs) via π-π stacking interaction to(More)
Simple and novel spectrophotometric method is described for simultaneous determination of aluminium and iron. The method is based on the metal ions complexes formed by aluminium and iron with mixed chromogenic reagents of 1, 10 phenanthroline and 8-hydroxyquinoline (oxine). The derivatives have absorption maxima at 400 nm and 510 nm respectively in the(More)
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