CHAPTER 9: Recent Approaches to Enhance the Selectivity of Peroxynitrite Detection

This chapter critically discusses recent approaches to enhance the selectivity of peroxynitrite (PON) electrochemical detection against other reactive nitro-oxidative species (RNOS) or electro-active interference molecules. Two selectivity issues that are especially important during fast detection in biological matrices are reviewed: (i) chemical resolution and (ii) chemical selectivity. In addition, new detection methods, sometimes coupled with mathematical models, to discriminate the PON-specific response from the overall sensor response are examined. Furthermore, the selectivity is improved by using permeable membranes to prevent the access of some interference species to the working electrode. In addition, improvements in deposition methods can be advantageous. In particular, pulsed laser evaporation (PLE) has been utilized for the first time to prepare PON-sensitive films of reduced graphene oxide with iron porphyrin directly from solution mixtures. These PLE hybrid films were characterized by atomic force microscopy and electrochemistry. An alternative approach to achieve selectivity is to utilize distinct sensors integrated in a microsensor array for each RNOS of interest, such as PON anion (ONOO⁻), hydrogen peroxide (H₂O₂), nitric oxide (NO) and superoxide (O₂⁻). The correct attribution of the PON electrochemical signal is essential, especially when dealing with unknown PON levels within cells or tissue. One such example is to use a PON decomposition catalyst as a PON “scavenger” and follow the decrease in the PON signal. By using one or more of these approaches, the selectivity of PON electrochemical detection can be enhanced.