A Novel Sustainable Process for Multilayer Graphene Synthesis Using CO from Ambient Air.

Graphene produced by different methods can present varying physicochemical properties and quality, resulting in a wide range of applications. The implementation of a novel method to synthesize graphene requires characterizations to determine the relevant physicochemical and functional properties for its tailored application. We present a novel method for multilayer graphene synthesis using atmospheric carbon dioxide with characterization.

Assessment of heavy metals in benthic macroinvertebrates, water and sediments in River Isiukhu, Kenya.

A major ecological challenge facing freshwater resources such as rivers is the influx of chemical contaminants from anthropogenic sources. A report on the levels of heavy metals, namely Zn, Cu, Cr, Cd and Pb in benthic macroinvertebrates, sediments and water along River Isiukhu, within Lake Victoria catchment area in Kenya is presented. Families of benthic macroinvertebrates that were investigated included Gerridae, Baetidae and Unionidae.

Electrochemical detection of glyphosate herbicide using horseradish peroxidase immobilized on sulfonated polymer matrix.

This paper describes the use of horseradish peroxidase (HRP) based biosensor for novel detection of glyphosate herbicide. The biosensor was prepared by electrochemically depositing poly(2,5-dimethoxyaniline) (PDMA) doped with poly(4-styrenesulfonic acid) (PSS) onto the surface of a gold electrode followed by electrostatic attachment of the enzyme HRP onto the PDMA-PSS composite film. Fourier transform infrared (FTIR) and UV-Vis spectrometry inferred that HRP was not denatured during its immobilization on PDMA-PSS composite film.

Electrochemical Immunosensor Based on Polythionine/Gold Nanoparticles for the Determination of Aflatoxin B₁.

An aflatoxin B₁ (AFB₁) electrochemical immunosensor was developed by the immobilisation of aflatoxin B₁-bovine serum albumin (AFB₁-BSA) conjugate on a polythionine (PTH)/gold nanoparticles (AuNP)-modified glassy carbon electrode (GCE). The surface of the AFB₁-BSA conjugate was covered with horseradish peroxidase (HRP), in order to prevent non-specific binding of the immunosensors with ions in the test solution. The AFB₁ immunosensor exhibited a quasi-reversible electrochemistry as indicated by a cyclic voltammetric (CV) peak separation (ΔE) value of 62 mV.

An Electrochemical DNA Biosensor Developed on a Nanocomposite Platform of Gold and Poly(propyleneimine) Dendrimer.

An electrochemical DNA nanobiosensor was prepared by immobilization of a 20mer thiolated probe DNA on electro-deposited generation 4 (G4) poly(propyleneimine) dendrimer (PPI) doped with gold nanoparticles (AuNP) as platform, on a glassy carbon electrode (GCE). Field emission scanning electron microscopy results confirmed the codeposition of PPI (which was linked to the carbon electrode surface by C-N covalent bonds) and AuNP ca 60 nm. Voltammetric interrogations showed that the platform (GCE/PPI-AuNP) was conducting and exhibited reversible electrochemistry (E°' = 235 mV) in pH 7.

Modelling of the impedimetric responses of an aflatoxin B(1) immunosensor prepared on an electrosynthetic polyaniline platform.

Aflatoxins are a group of mycotoxins that have deleterious effects on humans and are produced during fungal infection of plants or plant products. An electrochemical immunosensor for the determination of aflatoxin B(1) (AFB(1)) was developed with AFB(1)antibody (AFB(1)-Ab) immobilized on Pt electrodes modified with polyaniline (PANi) and polystyrene sulphonic acid (PSSA). Impedimetric analysis shows that the electron transfer resistances of the Pt/PANi-PSSA electrode, the Pt/PANi-PSSA/AFB(1)-Ab immunosensor and Pt/PANi-PSSA/AFB(1)-Ab incubated in bovine serum albumin (BSA) were 0.