Paper-Based Electrochemical Detection of Chlorate

Abstract

We describe the use of a paper-based probe impregnated with a vanadium-containing polyoxometalate anion, [PMo11VO40]5−, on screen-printed carbon electrodes for the electrochemical determination of chlorate. Cyclic voltammetry (CV) and chronocoulometry were used to characterize the ClO3− response in a pH = 2.5 solution of 100 mM sodium acetate. A linear CV current response was observed between 0.156 and 1.25 mg/mL with a detection limit of 0.083 mg/mL (S/N > 3). This performance was reproducible using [PMo11VO40]5−-impregnated filter paper stored under ambient conditions for as long as 8 months prior to use. At high concentration of chlorate, an additional catalytic cathodic peak was seen in the reverse scan of the CVs, which was digitally simulated using a simple model. For chronocoulometry, the charge measured after 5 min gave a linear response from 0.625 to 2.5 mg/mL with a detection limit of 0.31 mg/mL (S/N > 3). In addition, the slope of charge vs. time also gave a linear response. In this case the linear range was from 0.312 to 2.5 mg/mL with a detection limit of 0.15 mg/mL (S/N > 3). Simple assays were conducted using three types of soil, and recovery measurements reported.

Paper-Based Screen-Printed Electrodes: A New Generation of Low-Cost Electroanalytical Platforms

“…As mentioned before, besides being a flat substrate, paper can have other utilities such as storage of reagents or sample [84,85], support for (biological) reactions [42,[86][87][88][89], or platform for taking [67,90] or treating the sample (e.g., preconcentration [81,91] or separation [79,92,93]). Taking this into account, paper-based electroanalytical devices integrating SPEs can be designed in different formats: (i) combining paper with a SPE card fabricated on ceramic or polymeric materials [79,[84][85][86][87][88][89]91,92,[94][95][96][97][98][99][100][101][102]; (ii) combining one electrode of the electrochemical cell (e.g., WE) made on paper with other electrodes (e.g., RE and CE) of a SPE card printed on a conventional material [42,[103][104][105]; and (iii) printing the SPE directly on paper [5,[106][107][108]. In the last case, 2D devices are the most basic but, by stacking and/or folding the paper along the vertical axis, devices with 3D formats (multilayer and origami) can be easily constructed.…”

Cytokine and Cancer Biomarkers Detection: The Dawn of Electrochemical Paper-Based Biosensor

“…Apart from NMNPs, non-NMNPs such as carbon nanotubes and graphene have also been reported as alternatives for surface modification of electrodes for improved detection [71][72][73][74][75]. For instance, an amplified signal was recorded when graphene oxide nanoflakes and zeolite nanocrystals were introduced onto the electrode surface of a paper sensor due to high electron transfer kinetics and larger surface area of the nanocomposites [76].…”

Electrochemical Biosensors: A Solution to Pollution Detection with Reference to Environmental Contaminants

“…Moreover, the developed paper-based analytical tool was used for simultaneous detection of Pb 2+ and Hg 2+ in lake water and human serum samples, respectively. Very recently, Shriver-Lake [ 131 ] produced a paper-based probe by impregnating a vanadium-containing polyoxometalate anion, [PMo 11 VO 40 ] 5− on carbon electrodes for the electrochemical determination of chlorate ( Figure 6 ).…”

“…(Reproduced from Ref. [ 131 ], an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( )).…”