Electroanalytical sensing of chromium(iii) and (vi) utilising gold screen printed macro electrodes

Abstract

We report the fabrication of gold screen printed macro electrodes which are electrochemically characterised and contrasted to polycrystalline gold macroelectrodes with their potential analytical application towards the sensing of chromium(III) and (VI) critically explored. It is found that while these gold screen printed macro electrodes have electrode kinetics typically one order of magnitude lower than polycrystalline gold macroelectrodes as is measured via a standard redox probe, in terms of analytical sensing, these gold screen printed macro electrodes mimic polycrystalline gold in terms of their analytical performance towards the sensing of chromium(III) and (VI), whilst boasting additional advantages over the macro electrode due to their disposable one-shot nature and the ease of mass production. An additional advantage of these gold screen printed macro electrodes compared to polycrystalline gold is the alleviation of the requirement to potential cycle the latter to form the required gold oxide which aids in the simplification of the analytical protocol. We demonstrate that gold screen printed macro electrodes allow the low micro-molar sensing of chromium(VI) in aqueous solutions over the range 10 to 1600 μM with a limit of detection (3σ) of 4.4 μM. The feasibility of the analytical protocol is also tested through chromium(VI) detection in environmental samples.

Manganese oxide nanoflakes/multi-walled carbon nanotubes/chitosan nanocomposite modified glassy carbon electrode as a novel electrochemical sensor for chromium (III) detection

“…The detection limit (S/N=3) and sensitivity were 0.3 µM and 18.7 nAµM -1 , respectively. The detection limit, linear calibration range and sensitivity for Cr(III)determination at this modified electrode are comparable with those obtained by using other modified electrodes[33,[68][69][70].…”

“…Due to the high redox potential of the Cr(VI)/Cr(III) couple, different oxidants such as cerium(IV), Mn-oxide and Fe(III) have been used for oxidation of Cr(III) to Cr(VI) [17][18][19][20][21]. Furthermore, oxidation of Cr(III) to Cr(IV) in alkaline solution at Au (111), Pt and gold screen printed macro electrode was also investigated [22][23][24][25]. The electrooxidation of Cr (III) at the proposed electrode has been done in alkaline solution and sensitivity of detection methods was low.Therefore, for oxidation of Cr(III) in natural solution and improving sensitivity, the introducing of novel materials and methods for electrode modification overcomes these limitations.…”

Back‐to‐Back Screen‐Printed Electroanalytical Sensors: Extending the Potential Applications of the Simplistic Design

“…Due to the natureo fs creen-printing with the range of inks that are currently available [22,23,43] the electrode composition can be readily changed which demonstrates the versatility of the backto-back configuration;s uch work can bee xtended to other inks containing catalytic mediators and other nanomaterials and as new inks are developed, the back-toback configuration can be easily implemented. www.electroanalysis.wiley-vch.de…”

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[a] 1IntroductionOver recentd ecades the utilisationo fscreen-printed derived electrochemical sensorsh ave modernised the field of electroanalysis,w ith their ability to bridge the gap between laboratory experiments and in-field applications [1][2][3][4][5][6].T he incorporationo fs creen-printed electrodes has allowed scientists to take their knowledge and theoretical interpretations and place it into ad evice that possess great scales of economy allowing for simple,i nexpensive disposable electrochemical platforms [1,[7][8][9].T hrough carefuls elections of screen-printing inks and designs, unique sensors can be produced with different geometries such as screen-printed arrays [10][11][12][13],r ecessed electrodes [14] and microbands [15,16].I na ddition to this,t he ease of the mass production of screen-printed sensors enables their use as one-shot sensors, allowing possible contamination to be avoided, and alleviates the need for electrode pre-treatment as is the case for solid electrodes prior to theiru se [1,13,[17][18][19].Screen-printing technologies can be readily adapted to create sensors that can contain beneficial electrode materials such as carbon nanotubes whichh ave au seful geometric structure that provides the enhanced sensing of capsaicin [20] and the cobalt pthalocyanine mediator which has shown electrocatalytic signals towards hydrazine [21].A dditionally upon carefuls election of the screen-printing inks,s ensors can be readily produced containing metallic compoundss uch as palladium [19] Recently the concept of the back-to-back screen-printed graphite electrodec onfiguration has been introduced for the first timew hereathree-electrode system is printed upon both sides of ap olyester substrate,a sp resented in Figure 1[ 24].T his novel electrochemical sensor has been demonstrated to be usefulf or the electroanalytical sensing of NADH and nitritee xhibiting at wo-fold increase in the analytical sensitivity,a dditionally with improvements in the limit of detection [ 24].I nt his paper we build upon such report of the back-to-back electrode configuration

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“…Screen-printing technologies can be readily adapted to create sensors that can contain beneficial electrode materials such as carbon nanotubes whichh ave au seful geometric structure that provides the enhanced sensing of capsaicin [20] and the cobalt pthalocyanine mediator which has shown electrocatalytic signals towards hydrazine [21].A dditionally upon carefuls election of the screen-printing inks,s ensors can be readily produced containing metallic compoundss uch as palladium [19],g old [22] and platinum, [23],f or ar ange of variouse lectroanalytical applications,o ffering the potential of one-shot low cost metallics ensors.…”