Prussian Blue and Its Analogues: Electrochemistry and Analytical Applications

This article reviews fundamental aspects of deposition, structure and electrochemistry of Prussian Blue and its analogues. Special attention is given to the metal hexacyanoferrates with potential analytical applications. Prussian Blue and its analogues as advanced sensing materials for nonelectroactive ions are discussed. In contrast to common ‘smart materials’, the sensitivity and selectivity of metal hexacyanoferrates to such ions is provided by thermodynamic background. Prussian Blue itself is recognized as the most advantageous low-potential transducer for hydrogen peroxide over all known systems. Both high sensitivity (ca. 1 A M−1 cm−2) and selectivity in relation to oxygen reduction are more than three orders of magnitude higher, than for platinum electrodes. Biosensors based on different transducing principles containing enzymes oxidases are compared, and the devices operated due to hydrogen peroxide detection with the Prussian Blue based transducer are shown to be the most advantageous ones. The future prospects of chemical and biological sensors based on metal hexacyanoferrates are outlined.