Nonconducting polymers on Prussian Blue modified electrodes: improvement of selectivity and stability of the advanced H/sub 2/O/sub 2/ transducer

Abstract

An approach to improve the analytical performance of a Prussian Blue (PB)-based hydrogen peroxide transducer is described. In support of this objective, both the stabilizing and anti-interferent properties of nonconducting films were used. Electropolymerization on the top surface of PB modified electrodes is possible due to the high oxidizing ability of Berlin Green, and the growth of nonconductive polymers may be independently monitored by investigating the redox activity of the inorganic polycrystal. The best performance characteristics, which are advantageous over existing H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensors, were obtained for PB electrodes covered with electropolymerized o-phenylenediamine (1,2-diaminobenzene). The reported transducer remained at the 100% response state for more than 20 h under continuous flow of 0.1-mM hydrogen peroxide (flow rate 1 mlmin/sup -1/), which improves the stability level among the selective H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensors by one order of magnitude. The selectivity factor of the PB-poly (1,2-diaminobenzene) based transducer relative to ascorbate is nominally 600. PB-poly(1,2-diaminobenzene) modified electrode allows the detection hydrogen peroxide in the flow-injection mode down to 10/sup -7/ M with sensitivity of 0.3 AM/sup -1/cm/sup -2/, which is two times lower compared to the uncovered PB-based transducer.