17 research outputs found
The fabrication, characterisation and electrochemical investigation of screen-printed graphene electrodes
We report the fabrication, characterisation (SEM, Raman spectroscopy, XPS and ATR) and electrochemical
implementation of novel screen-printed graphene electrodes. Electrochemical characterisation of the fabricated
graphene electrodes is undertaken using an array of electroactive redox probes and biologically relevant
analytes, namely: potassium ferrocyanide(II), hexaammine-ruthenium(III) chloride, N,N,N0 ,N0-tetramethyl-pphenylenediamine
(TMPD), b-nicotinamide adenine dinucleotide (NADH), L-ascorbic acid (AA), uric acid (UA)
and dopamine hydrochloride (DA). The electroanalytical capabilities of the fabricated electrodes are also
considered towards the sensing of AA and DA. The electrochemical and (electro)analytical performances of
the fabricated screen-printed graphene electrodes are considered with respect to the relative surface
morphologies and material compositions (elucidated via SEM, Raman, XPS and ATR spectroscopy), the density
of electronic states (% global coverage of edge-plane like sites/defects) and the specific fabrication conditions
utilised. Comparisons are made between two screen-printed graphene electrodes and alternative graphite
based screen-printed electrodes. The graphene electrodes are fabricated utilising two different commercially
prepared ‘graphene’ inks, which have long screen ink lifetimes (43 hours), thus this is the first report of a true
mass-reproducible screen-printable graphene ink. Through employment of appropriate controls/comparisons
we are able to report a critical assessment of these screen-printed graphene electrodes. This work is of high
importance and demonstrates a proof-of-concept approach to screen-printed graphene electrodes that are
highly reproducible, paving the way for mass-producible graphene sensing platforms in the future
The fabrication, characterisation and electrochemical investigation of screen-printed graphene electrodes
We report the fabrication, characterisation (SEM, Raman spectroscopy, XPS and ATR) and electrochemical
implementation of novel screen-printed graphene electrodes. Electrochemical characterisation of the fabricated
graphene electrodes is undertaken using an array of electroactive redox probes and biologically relevant
analytes, namely: potassium ferrocyanide(II), hexaammine-ruthenium(III) chloride, N,N,N0 ,N0-tetramethyl-pphenylenediamine
(TMPD), b-nicotinamide adenine dinucleotide (NADH), L-ascorbic acid (AA), uric acid (UA)
and dopamine hydrochloride (DA). The electroanalytical capabilities of the fabricated electrodes are also
considered towards the sensing of AA and DA. The electrochemical and (electro)analytical performances of
the fabricated screen-printed graphene electrodes are considered with respect to the relative surface
morphologies and material compositions (elucidated via SEM, Raman, XPS and ATR spectroscopy), the density
of electronic states (% global coverage of edge-plane like sites/defects) and the specific fabrication conditions
utilised. Comparisons are made between two screen-printed graphene electrodes and alternative graphite
based screen-printed electrodes. The graphene electrodes are fabricated utilising two different commercially
prepared ‘graphene’ inks, which have long screen ink lifetimes (43 hours), thus this is the first report of a true
mass-reproducible screen-printable graphene ink. Through employment of appropriate controls/comparisons
we are able to report a critical assessment of these screen-printed graphene electrodes. This work is of high
importance and demonstrates a proof-of-concept approach to screen-printed graphene electrodes that are
highly reproducible, paving the way for mass-producible graphene sensing platforms in the future
Disposable Screen-printed Bismuth Electrode Modified with Multi-walled Carbon Nanotubes for Electrochemical Stripping Measurements
Screen printed recessed microelectrode arrays
The construction and characterisation of screen printed recessed microelectrode arrays are reported. This screen printing approach results in the fabrication of shallow recessed microelectrode arrays which are characterised by microscopy and cyclic voltammetry. The analytical utility of the shallow recessed microelectrode arrays is demonstrated with the cathodic stripping of manganese (II) allowing nano-molar levels to be readily detected exhibiting a superior performance over conventional carbon based electrodes. The limitations of using screen printing technology to fabricate microelectrode arrays are also discussed
Disposable bismuth oxide screen printed electrodes for the high throughput screening of heavy metals
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 g L-1 with detection limits of 2.5 and 5 g L-1 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 g L-1 with detection limits of 5, 10 and 30 g L-1 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
High throughput screening of lead utilising disposable screen printed shallow recessed microelectrode arrays
The cathodic stripping voltammetry of lead at disposable screen printed shallow recessed microelectrode arrays has been developed for the first time. The array comprises 6 microdiscs which have radii of 116 (±6) microns which are recessed by 4 microns and are separated by 2500 microns from their nearest neighbour in a hexagonal arrangement. The electroanalytical determination of lead was explored in 0.1 M nitric acid and found that using a 120 s deposition time, a detection limit of 3 M is feasible which is not possible utilising a screen printed graphite macro-electrode. The sensitivity of this analytical protocol can be tailored by varying the deposition time and it is found that increasing this to 320 s facilitates a limit of detection of 39 nM. This methodology is shown to be feasible for the portable and economical screening of lead in river water samples at the levels indicated by the EC Dangerous Substances Directive (76/464/EEC)
Disposable highly ordered pyrolytic graphite-like electrodes: tailoring the electrochemical reactivity of screen printed electrodes
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