Hydrogen sulfide, along with carbon monoxide and nitric oxide, is a gaseous signaling molecule known as a gasotransmitter. These molecules all help to regulate ion channels within the body, however there is particular interest in selectively detecting H2S in vivo due to its physiological significance in the central nervous and cardiovascular systems. Unfortunately there is currently no method that allows for selective in vivo detection of H2S. Our group has been actively investigating cyanide coordinated to electropolymerized ferriprotoporphyrin (FePP) as an electrocatalytic material that can selectively oxidize H2S in the presence of NO and CO, with the intent to implement in a future amperometric sensor. When polymerized onto a Pt microelectrode surface, this material exhibited 100-1000x higher sensitivity towards H2S compared to CO and NO, respectively. However, the response towards H2S was not stable enough for practical applications, as the sensitivity towards H2S significantly decreased during the first several trials. The research presented here utilized electrochemical atomic force microscopy, electrochemical methods of analysis, and computational methods in order to fundamentally understand how the FePP interacts and eventually polymerizes onto electrode surfaces. The intent is that this knowledge will help advance this material to be a selective and stable electrocatalyst for H2S detection.

Fundammental studies of ferriprotoporphyrin polymerization on electrode surfaces for H2S detection

253rd National Meeting (2017)

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