A sensitive and rapid detection of hydrogen peroxide (H₂O₂) is important in biomedical, food, and environmental analysis. The enzyme-based electrochemical detection of H₂O₂ may provide simple, accurate, and rapid process; however, due the thermal and chemical deformation of enzymes during the fabrication process, these sensors may suffer from instability [1]. Recently, some particles which has electrocatalytic properties toward H₂O₂ has been employed to develop electrochemical sensors.  Of these, iron oxide (Fe₃O₄) and copper oxide (CuO) nanoparticles have shown good electrocatalytic properties toward H₂O₂ [2, 3]. However, one common drawback of these sensors is lack of selectivity owing to the fact that these catalysts shows electrocatalytic properties toward various analytes in the solution. Here, we present a novel paper-based electrochemical sensor based on modified carbon nanotube electrode, which can reduce the matrix effect in multi-analyte solutions. Paper-based sensors have become of great interest for fabricating inexpensive, simple, and disposable sensors. Carbon nanotube electrode ink has been modified using CuO and Fe₃O₄, and an electrode array made of modified and bare carbon ink solutions is developed by utilizing screen-printing of carbon ink solutions on paper. Figure shows the developed paper-based sensor array design. Moreover, a multichannel potentiostat circuit has been developed in order to investigate the amperometric response of the sensor array on H₂O₂ solution. The potentiostat can control three working electrodes independently, and it is also working with a USB port as power source. Since these modified electrodes show a unique response to different electroactive species, the results can be interpreted using a statistical method to compromise the interference from other electroactive species in the solution. Further, solutions with various concentration of H₂O₂ and interfering species has been tested using the portable potentiostat in order to assess the matrix effect originated from the interfering species in H₂O₂ detection.

References

[1] M. Song, S. Hwang and D. Whang, “Non-enzymatic electrochemical CuO nanoflowers sensor for hydrogen peroxide detection,” Talanta, vol. 80, no. 5, pp. 1648-1652, 2010.

[2] M. Lin and H. Leu, “A Fe₃O₄-based chemical sensor for cathodic determination of hydrogen peroxide,” Electroanalysis, vol. 17, no. 22, pp. 2068-2073, 2005.

[3] X. Miao, R. Yuan, Y. Chai, Y. Shi and Y. Yuan, “Direct electrocatalytic reduction of hydrogen peroxide based on Nafion and copper oxide nanoparticles modified Pt electrode,” Journal of Electroanalytical Chemistry, vol. 612, no. 2, pp. 157-163, 2008.