Monitoring of low levels of hydrogen peroxide is of great importance for modern medicine, environmental control and various branches of industry. In particular, H₂O₂ is the most valuable marker for oxidative stress.
We reported the specially deposited Prussian Blue (PB) to be the most advantageous hydrogen peroxide transducer allowing its low-potential detection down to 10^-7 M in flow-injection mode [1]. However, in certain cases including medicine and environmental control, the detection of lower H₂O₂ levels is required.
We report on the possibility for nano-structuring of Prussian Blue by its electrochemical deposition through liquid crystalline templates, which is noticed from AFM images of the resulting surfaces.
Analytical performance of the resulting Prussian Blue based nano-electrode arrays have been studied in course of hydrogen peroxide detection in FIA mode. They demonstrate a sub-ppb detection limit (1×10^-8 M) and a linear calibration range starting exactly from the detection limit and extending over six orders of magnitude of H₂O₂ concentrations (1×10^-8 - 1×10^-2 M), which are the most advantageous analytical performances in hydrogen peroxide electroanalysis.
The developed sensors were applied for clinical research in pulmanology. Hydrogen peroxide was detected in patients condensates of breathing air.

Acknowledgements: The financial support through NATO Linkage SA (PST.CLG.978764) 6607/FP is greatly acknowledged.
References:
1. A.A. Karyakin (review). Electroanalysis, 13(2001) 813.