rashid kadara | Manchester Metropolitan University (original) (raw)

Papers by rashid kadara

Analytica Chimica Acta, 2003

Single-use sensors, incorporating a three-electrode configuration (graphite carbon-working electr... more Single-use sensors, incorporating a three-electrode configuration (graphite carbon-working electrode; carbon-counter electrode and silver/silver chloride-reference electrode), have been fabricated on a polyester substrate using low cost screen-printing (thick-film) technology. These electrodes coupled with constant current stripping chronopotentiometry (CCSCP), has provided a convenient screening tool for on-site detection of trace levels of copper. Modification of the graphite carbon surface based on in situ deposition of mercury film has been carried out. By appropriate choice of supporting medium and applied constant stripping current, well-resolved and reproducible response for copper was obtained. The stripping response for copper following 2min deposition was linear over the concentration range examined (10–2000ppb) with detection limit of 6ppb using 2M hydrochloric acid (HCl). Successful applications of the sensing device to acetic-acid bioavailable fraction of a certified reference material (CRM 601, a lake sediment) and soil samples are demonstrated.

The Analyst, 2009

We demonstrate, with the example of the electroanalytical sensing of chromium(vi) using ultra-mic... more We demonstrate, with the example of the electroanalytical sensing of chromium(vi) using ultra-microelectrode arrays, that a larger number of microelectrodes comprising an array do not necessarily provide improved electroanalytical performance. Using a low density array, which consists of 256 microdiscs where each microdisc comprising the array has a radius of 10 microns in a cubic arrangement separated from their nearest neighbour by 100 microns, the electroanalytical sensing of chromium(vi) is shown to be possible over the range 13-428 microM with a limit of detection of 3.4 microM readily achievable. Using a high density microelectrode, consisting of 2597 microdiscs where each microdisc has a radius of 2.5 microns in a hexagonal pattern which are separated from their nearest neighbour by 55 microns, the electroanalytical performance, in terms of linear range and sensitivity, is considerably lower going against the misconception that a high density array should produce a superior analytical response. The reason for this disparity is discussed and it is shown that the arrangement of the microelectrodes on the array is critical due to the interaction of diffusion zones between neighbouring electrodes allowing analysts to make informed decisions on the conscientious choice of microelectrode arrays.

Electrochimica Acta, 2008

... Compton and co-workers [8] explored this recent interest in C 60 -modified glassy carbon elec... more ... Compton and co-workers [8] explored this recent interest in C 60 -modified glassy carbon electrodes and elegantly showed that for the electrochemical oxidation of cysteine, graphite impurities present in the C 60 used by Tan et al. ...

Electrochemistry Communications, 2010

We demonstrate that the electron transfer properties of disposable screen printed electrodes can ... more We demonstrate that the electron transfer properties of disposable screen printed electrodes can be readily tailored via the introduction of a polymeric formulation into the ink used to fabricate these electrochemical platforms. This approach allows the role of the binder on the underpinning electrochemical properties to be explored and allows the electrochemical reactivity of the screen printed electrodes to be tailored from that of edge plane to basal plane of highly ordered pyrolytic graphite.

Electroanalysis, 2009

We present a simplified approach for the trace screening of toxic heavy metals utilizing bismuth ... more We present a simplified approach for the trace screening of toxic heavy metals utilizing bismuth oxide screen printed electrodes. The use of bismuth oxide instead of toxic mercury films facilitates the reliable sensing of lead(II), cadmium(II) and zinc(II). A linear range over 5 to 150 mg L À1 with detection limits of 2.5 and 5 mg L À1 are readily observed for cadmium and lead in 0.1 M HCl, respectively. Conducting a simultaneous multi-elemental voltammetric detection of zinc, cadmium and lead in a higher pH medium (0.1 M sodium acetate solution) exhibited a linear range between 10 and 150 mg L À1 with detection limits of 5, 10 and 30 mg L À1 for cadmium, lead and zinc respectively. The sensor is greatly simplified over those recently reported such as bismuth nanoparticle modified electrodes and bismuth film coated screen printed electrodes. The scope of applications of this sensor with the inherent advances in electroanalysis coupled with the negliable toxicity of bismuth is extensive allowing high throughput electroanalysis.

Electroanalysis, 2010

Gold ensembles for the trace level sensing of arsenic(III) in the presence of copper(II) are repo... more Gold ensembles for the trace level sensing of arsenic(III) in the presence of copper(II) are reported. The gold ensembles are fabricated using citrate capped gold nanoparticles which are chemically synthesised in an aqueous solution with an aliquot of this simply cast onto an economical and disposable screen printed electrode. After drying at room temperature, the gold ensembles are ready for use. The gold ensembles are explored towards the sensing of arsenic(III) in the presence of copper(II) using anodic stripping voltammetry where the corresponding stripping peaks are well resolved and using this protocol it is possible to readily detect 3 mg L À1 (3 ppb) with a detection limit of 0.4 mg L À1 (0.4 ppb). Proof-of-concept is also shown for the sensing of arsenic(III) in a canal water sample. Given the low cost of the sensor and ease of fabrication, the gold ensembles hold promise for the sensing of arsenic(III) in water samples where copper(II) may be present.

Electroanalysis, 2008

... Electrodes Sebastian Griese, Dimitrios K. Kampouris, Rashid O. Kadara, Craig E. Banks* ... Co... more ... Electrodes Sebastian Griese, Dimitrios K. Kampouris, Rashid O. Kadara, Craig E. Banks* ... Compton and co-workers [40] explored the reported electrocatalysis of C60 modified carbon electrodes by Tan, Bond and co-workers [14]. ...

Analytical Methods, 2010

The bio-monitoring of heavy metals in biological fluids allows the exposure from anthropogenic so... more The bio-monitoring of heavy metals in biological fluids allows the exposure from anthropogenic sources to be readily assessed. 1–5 The use of oral (saliva) fluid is extremely appealing as a sample media for bio-monitoring as one of its benefits is the ease of collection. In terms of ...

The Analyst, 2010

We demonstrate that graphite screen printed macroelectrodes allow the low ppb sensing of chromium... more We demonstrate that graphite screen printed macroelectrodes allow the low ppb sensing of chromium(VI) in aqueous solutions over the range 100 to 1000 microg L(-1) with a limit of detection of 19 microg L(-1). The underlying electrochemical mechanism is explored indicating an indirect process involving surface oxygenated species. The drawbacks of using hydrochloric acid as a model solution to evaluate the electrochemical detection of chromium(VI) are also pointed out. The analytical protocol is shown to be applicable for the sensing of chromium(VI) in canal water samples at levels set by the World Health Organisation. The protocol is simplified over existing analytical methodologies and given its analytical performance and economical nature, holds promise for the de-centralised screening of chromium(VI).

SpringerBriefs in Applied Sciences and Technology, 2015

SpringerBriefs in Applied Sciences and Technology, 2016

Journal of Agricultural and Food Chemistry, 2009

Analytica Chimica Acta, 2003

Single-use sensors, incorporating a three-electrode configuration (graphite carbon-working electr... more Single-use sensors, incorporating a three-electrode configuration (graphite carbon-working electrode; carbon-counter electrode and silver/silver chloride-reference electrode), have been fabricated on a polyester substrate using low cost screen-printing (thick-film) technology. These electrodes coupled with constant current stripping chronopotentiometry (CCSCP), has provided a convenient screening tool for on-site detection of trace levels of copper. Modification of the graphite carbon surface based on in situ deposition of mercury film has been carried out. By appropriate choice of supporting medium and applied constant stripping current, well-resolved and reproducible response for copper was obtained. The stripping response for copper following 2min deposition was linear over the concentration range examined (10–2000ppb) with detection limit of 6ppb using 2M hydrochloric acid (HCl). Successful applications of the sensing device to acetic-acid bioavailable fraction of a certified reference material (CRM 601, a lake sediment) and soil samples are demonstrated.

The Analyst, 2009

We demonstrate, with the example of the electroanalytical sensing of chromium(vi) using ultra-mic... more We demonstrate, with the example of the electroanalytical sensing of chromium(vi) using ultra-microelectrode arrays, that a larger number of microelectrodes comprising an array do not necessarily provide improved electroanalytical performance. Using a low density array, which consists of 256 microdiscs where each microdisc comprising the array has a radius of 10 microns in a cubic arrangement separated from their nearest neighbour by 100 microns, the electroanalytical sensing of chromium(vi) is shown to be possible over the range 13-428 microM with a limit of detection of 3.4 microM readily achievable. Using a high density microelectrode, consisting of 2597 microdiscs where each microdisc has a radius of 2.5 microns in a hexagonal pattern which are separated from their nearest neighbour by 55 microns, the electroanalytical performance, in terms of linear range and sensitivity, is considerably lower going against the misconception that a high density array should produce a superior analytical response. The reason for this disparity is discussed and it is shown that the arrangement of the microelectrodes on the array is critical due to the interaction of diffusion zones between neighbouring electrodes allowing analysts to make informed decisions on the conscientious choice of microelectrode arrays.

Electrochimica Acta, 2008

... Compton and co-workers [8] explored this recent interest in C 60 -modified glassy carbon elec... more ... Compton and co-workers [8] explored this recent interest in C 60 -modified glassy carbon electrodes and elegantly showed that for the electrochemical oxidation of cysteine, graphite impurities present in the C 60 used by Tan et al. ...

Electrochemistry Communications, 2010

We demonstrate that the electron transfer properties of disposable screen printed electrodes can ... more We demonstrate that the electron transfer properties of disposable screen printed electrodes can be readily tailored via the introduction of a polymeric formulation into the ink used to fabricate these electrochemical platforms. This approach allows the role of the binder on the underpinning electrochemical properties to be explored and allows the electrochemical reactivity of the screen printed electrodes to be tailored from that of edge plane to basal plane of highly ordered pyrolytic graphite.

Electroanalysis, 2009

We present a simplified approach for the trace screening of toxic heavy metals utilizing bismuth ... more We present a simplified approach for the trace screening of toxic heavy metals utilizing bismuth oxide screen printed electrodes. The use of bismuth oxide instead of toxic mercury films facilitates the reliable sensing of lead(II), cadmium(II) and zinc(II). A linear range over 5 to 150 mg L À1 with detection limits of 2.5 and 5 mg L À1 are readily observed for cadmium and lead in 0.1 M HCl, respectively. Conducting a simultaneous multi-elemental voltammetric detection of zinc, cadmium and lead in a higher pH medium (0.1 M sodium acetate solution) exhibited a linear range between 10 and 150 mg L À1 with detection limits of 5, 10 and 30 mg L À1 for cadmium, lead and zinc respectively. The sensor is greatly simplified over those recently reported such as bismuth nanoparticle modified electrodes and bismuth film coated screen printed electrodes. The scope of applications of this sensor with the inherent advances in electroanalysis coupled with the negliable toxicity of bismuth is extensive allowing high throughput electroanalysis.

Electroanalysis, 2010

Gold ensembles for the trace level sensing of arsenic(III) in the presence of copper(II) are repo... more Gold ensembles for the trace level sensing of arsenic(III) in the presence of copper(II) are reported. The gold ensembles are fabricated using citrate capped gold nanoparticles which are chemically synthesised in an aqueous solution with an aliquot of this simply cast onto an economical and disposable screen printed electrode. After drying at room temperature, the gold ensembles are ready for use. The gold ensembles are explored towards the sensing of arsenic(III) in the presence of copper(II) using anodic stripping voltammetry where the corresponding stripping peaks are well resolved and using this protocol it is possible to readily detect 3 mg L À1 (3 ppb) with a detection limit of 0.4 mg L À1 (0.4 ppb). Proof-of-concept is also shown for the sensing of arsenic(III) in a canal water sample. Given the low cost of the sensor and ease of fabrication, the gold ensembles hold promise for the sensing of arsenic(III) in water samples where copper(II) may be present.

Electroanalysis, 2008

... Electrodes Sebastian Griese, Dimitrios K. Kampouris, Rashid O. Kadara, Craig E. Banks* ... Co... more ... Electrodes Sebastian Griese, Dimitrios K. Kampouris, Rashid O. Kadara, Craig E. Banks* ... Compton and co-workers [40] explored the reported electrocatalysis of C60 modified carbon electrodes by Tan, Bond and co-workers [14]. ...

Analytical Methods, 2010

The bio-monitoring of heavy metals in biological fluids allows the exposure from anthropogenic so... more The bio-monitoring of heavy metals in biological fluids allows the exposure from anthropogenic sources to be readily assessed. 1–5 The use of oral (saliva) fluid is extremely appealing as a sample media for bio-monitoring as one of its benefits is the ease of collection. In terms of ...

The Analyst, 2010

We demonstrate that graphite screen printed macroelectrodes allow the low ppb sensing of chromium... more We demonstrate that graphite screen printed macroelectrodes allow the low ppb sensing of chromium(VI) in aqueous solutions over the range 100 to 1000 microg L(-1) with a limit of detection of 19 microg L(-1). The underlying electrochemical mechanism is explored indicating an indirect process involving surface oxygenated species. The drawbacks of using hydrochloric acid as a model solution to evaluate the electrochemical detection of chromium(VI) are also pointed out. The analytical protocol is shown to be applicable for the sensing of chromium(VI) in canal water samples at levels set by the World Health Organisation. The protocol is simplified over existing analytical methodologies and given its analytical performance and economical nature, holds promise for the de-centralised screening of chromium(VI).

SpringerBriefs in Applied Sciences and Technology, 2015

SpringerBriefs in Applied Sciences and Technology, 2016

Journal of Agricultural and Food Chemistry, 2009