Robust and sensitive analysis of methanol and ethanol from cellulose degradation in mineral oils.

Methanol and ethanol have been identified as oil-soluble by-products generated by the aging of oil-impregnated cellulosic insulation materials of power transformers. Their presence provides useful information for diagnostics and end-of-life transformer estimation. Despite their value as cellulose degradation indicators, their sensitive and accurate determination is challenged by the complex oil matrix.