A common-sense observation would be to free-air burn (low temp combustion) a liter of each of the following:
GASOLINE
ADDITIVE OF CHOICE
ETHANOL
Then observe what remains as residue. Higher combustion temperatures and pressures of course modify the process somewhat but not in a fundamental manner. Degradation of a sensor would be caused by laminar sealing, thermal, erosive (ablative), or corrosive action. Erosive includes electrolytic. Try as I might I cannot imagine alcohol entering into any of the foregoing.