Fluorophores “turned-on” by corrosion reactions can be used to monitor corrosion in non-aqueous environments at the single-molecule level.

Super-resolution fluorescent techniques have been used to monitor interfacial processes such as corrosion, catalysis, and DNA sequencing at the single-molecule level in aqueous environments. These reactions are often relevant to non-aqueous environments, where super-resolution methods have yet to be employed.

Here, we demonstrate that fluorogenic “turn-on” probes that we have previously used to sense the corrosion of iron at the single-molecule scale in water can be applied to organic environments. We first observe the cathodic reduction of non-fluorescent resazurin to fluorescent resorufin in the presence of iron in bulk solutions of ethanol and acetone. We then show that the fluorescent signal is directly proportional to the amount of electrons available due to the progression of corrosion. Using fluorescent microscopy instrumentation we determine single-molecule photophysical properties of resorufin in ethanol and acetone. We then detect real-time, single-molecule “turn-on” of resazurin by corrosion in organic environments. Analysis of the total number and properties of individual resorufin molecules shows heterogeneities not observed in ensemble measurements. We show super-resolution fluorescent methods can be applied to study reactions in non-aqueous environments.