Screen-printed electrodes for electroanalytical sensing, of chromium VI in strong acid media

Abstract

Highlights• Acid-resistant screen-printed electrodes (SPEs) for Cr(VI) detection were developed.• Carbon-based thick-film SPE pastes were formulated in-house with known composition.• A batch fabrication process allowed simple fabrication of robust sensors.• Cr(VI) at pH 1 was electroanalytically quantified with high sensitivity.• High reproducibility, wide linear range and low detection limit were achieved. AbstractSimple, low-cost and acid-resistant carbon-based screen-printed electrodes (SPEs) addressed to detection of hexavalent chromium species, Cr(VI), in sulfuric acid at pH about 1, were prepared and characterized. Working and counter electrodes were prepared jointly on the same substrate in a single strip (working-counter electrodes pair). The batch printing process allowed obtaining many working-counter electrode pairs in a unique step. The developed working electrodes are comprised of several layers deposited on an alumina substrate: (1) bottom silver conductor, (2) dense organic graphite composite conductor, (3) active layer consisting of a porous organic graphite composite which contains a Cr(III) ionophore for testing Cr(III) obtained after reducing Cr(VI), and (4) an insulating and protective dielectric. All materials except the bottom Ag conductor were made on an organic matrix based on a thermoplastic polymer, polyvinylbutyral (PVB). The amperometric determination of Cr(VI) species at pH 1 was performed over a wide concentration range (dynamic range 3 M 40 mM). The range for linear amperometric response is 3 M 10 mM, with sensitivity about 0.08 mA mM at the electrode surface after the reduction of Cr(VI) when diethylenetriamine-pentaacetic acid (DTPA), a complexing agent for Cr(III) is incorporated into the pastes.

A review on detection of heavy metal ions in water – An electrochemical approach

“…Screen printed electrodes are used to detect Cr(VI) metal ions [165]. In these kind of electrodes, working electrode was fabricated with two pads to measure the conductivity of the graphite paste [143].…”

Disposable plastic electrode for electrochemical determination of total chromium and hexavalent chromium

“…However, as is listed in Table 1, only a few methods based on disposable electrodes had been reported for the Cr speciation [25][26][27][28][29][30]. And all these electrodes were prepared based on screen-printed electrodes (SPEs).…”

Untitled

“…High sensitivity, low detection limit, and no requirement of large volume of sample also other important advantages using screen-printed electrode [32]. Previously reported copper ion sensors based ionophore o-xc with PVC or pBA membranes are non-screen-printed solid-state sensors [15][16][17].…”