Electrochemiluminescent detection of hydrogen peroxide with an imaging sensor array

In this paper, we report a novel imaging sensor array for the electrochemiluminescent (ECL) detection of hydrogen peroxide. An ordered array of opto-electrochemical sensors was fabricated on the distal face of a coherent optical fiber bundle. The analytical performance and the ability to perform concomitantly ECL imaging and white-light imaging via the sensor array are described. Luminol ECL was generated at the distal face of the sub-micrometer sensor array by applying an adequate positive potential. The electrochemically-initiated light is transmitted through the coherent imaging sensor array and acquired on the proximal face with a microscope/charge coupled device (CCD) camera system. The influence of the potential applied to the sensor array on the light intensity collected via the array itself was investigated. The variation of the ECL intensity with hydrogen peroxide concentration is linear between 50 μM and 2 mM with a detection limit of 10 μM. The ECL sensor array also showed good temporal stability. Finally, the optical performance and the resolution of the sensor array were demonstrated in the micrometer range by imaging carbon fibers of 10 μm diameter.