Electrochemical detection of TNT at cobalt phthalocyanine mediated screen-printed electrodes and application to detection of airborne vapours

We describe the use of cobalt phthalocyanine as a mediator to improve the sensitivity for the electrochemical detection of TNT. Commercial screen-printed electrodes containing cobalt phthalocyanine were employed for determination of TNT. Improved sensitivities compared to screen-printed carbon electrodes without phthalocyanine were observed, current response for cyclic voltammetric measurements at modified electrodes being at least double that of unmodified electrodes. A synergistic effect between oxygen and TNT reduction was also observed. Correlation between TNT concentrations and sensor output was observed between 0–200 µM TNT. Initial proof-of-concept experiments combining electrochemical determinations, with the use of an air-sampling cyclone, are also reported

Screen-printed platinum electrodes for measuring crevice corrosion: Nickel aluminium bronze as an example

Screen-printed platinum electrodes were used to monitor crevice corrosion processes. The electrodes, printed on an inert alumina substrate, formed the bottom of an artificial crevice when mechanically clamped to a rectangular block of nickel-aluminium bronze (NAB). Cyclic differential pulse voltammetry was used to detect corrosion products over time whilst the assembly was immersed in a 3.5% by weight aqueous solution of sodium chloride. Cupric (Cu2+), ferric (Fe3+) and ferrous (Fe2+) ions were detected with evolution profiles indicative of selective phase corrosion

Electrochemical Sensors with Screen Printed Ag|AgCl|KCl Reference Electrodes

This paper presents the printed thick film Ag|AgCl|KCl reference electrodes for electrochemical or biosensors application and their electrochemical and analytical performance. The reference electrode exhibits a stable potential against standard glass reference electrode with a potential difference of 5 mV in the deionized water. The anodic and cathodic peak current of the electrode increase with the increase in scan rate in the range of 25-150 mVs-1. The open circuit potential response of thick film reference electrode in the NaCl concentrations range (30-100 mM) was measured and it shows a stable potential in each test solution. The fabricated reference electrode shows an excellent application for an electrochemical pH sensor

Modified screen-printed carbon electrodes application for protein tumor markers determination

Screen-printed carbon electrodes were modified with gold nanoparticles bound with DNA-aptamers by two different methods. Aptamers can selectively bind protein tumor markers from the blood plasma. The electrodes were tested. Signals obtained via squire-wavy voltammetry from modified electrodes covered with blood plasma of the healthy donors and donors with lung cancer can be distinguished

Mercury films on commercial carbon screen-printed devices for the analysis of heavy metal ions: a critical evaluation

The suitability of mercury films on commercial screen-printed electrodes for the analysis of heavy metal ions is critically tested for the particular case of Pb(II)-ions. Although determination is possible by anodic stripping voltammetry with a reasonable detection limit (8.9 µg L-1), important drawbacks are noticed as a consequence of the heterogeneous deposition of mercury on the rough surface of screen-printed devices

Modified screen-printed carbon electrodes application for protein tumor markers determination

Screen-printed carbon electrodes were modified with gold nanoparticles bound with DNA-aptamers by two different methods. Aptamers can selectively bind protein tumor markers from the blood plasma. The electrodes were tested. Signals obtained via squire-wavy voltammetry from modified electrodes covered with blood plasma of the healthy donors and donors with lung cancer can be distinguished

Engine oil acidity detection using solid state ion selective electrodes

Initial results from oil acidity measurements using thick film electrodes are presented. The results suggest that as the oil degrades, its pH/acidity follows a specific trend. Furthermore, an investigation into the feasibility of detecting changes in oil acidity (i.e. TAN value) using ion selective electrodes fabricated utilising thick film technology is presented. The thick-film (screen printing) technique is a decent means for the mass production of rugged, compact and disposable sensors as many such devices can be printed at the same time making them very cost effective to manufacture. Thick-Film ion selective and reference electrodes were fabricated, calibrated and tested in different oil samples varying its acidity. Ruthenium oxide (RuO2) pH sensitive electrodes were screen printed and were used against silver/silver chloride (Ag/AgCl) reference electrodes as well as a commercial glass Ag/AgCl reference electrode. The potentiometric sets of electrodes were calibrated in pH 4, 7 and 10 buffers in a cyclic manner and the voltage was recorded using a high input impedance voltmete

Aqueous UV–VIS spectroelectrochemical study of the voltammetric reduction of graphene oxide on screen-printed carbon electrodes

Two graphene oxide (GO) materials with different layer size and proportion of functional groups in the basal planes (hydroxyl and epoxy) and in the edges (carbonyl and carboxyl) were used to modify the surface of commercially available screen-printed electrodes. Cyclic voltammetry in 0.1 M KNO3 was evaluated as an easy to use electrochemical methodology to reduce GO attached to the surface of screen-printed electrodes (SPEs). A cathodic peak related to the reduction of GO was identified, and the peak potential was correlated to the difficulty to reduce GO to electrochemically reduced graphene oxide (ERGO) depending on the functional groups present in the basal plane and in the edges of the original GO monolayers. Time-resolved UV–VIS absorption spectroelectrochemistry in near-normal reflection mode on a screen-printed electrode is used for the very first time as an in situ characterization technique for real-time monitoring unambiguously the electrochemical reduction of graphene oxide.projects CTQ2014-55583-R and CTQ2014-61914-EXP funded by Ministerio de Economía y Competitivida

Screen-printed platinum electrodes for the detection of cupric and ferric ions in high chloride backgrounds

Screen-printed platinum electrodes developed for use in corrosion monitoring applications have been used to detect cupric and ferric ions both individually and as mixtures in a background of 3.5% by weight sodium chloride and in the presence of dissolved oxygen. In single species detection linear responses for the Fe3+/Fe2+ couple were observed over the concentration range 0.3 to 100mM. By contrast, the small size of the working electrode caused a current limiting response for cupric ions over the same concentration range. In mixtures of these ions, the sensors show good differentiation and are able to separate the individual metal ion responses