"Carbonyl value (CV)" is used as an index to evaluate the degradation of fat. Benzene was conventionally used for the measurement of carbonyl value. Because the use of benzene is hazardous, the butanol is now used.
FUJIFILM Wako offers "1-Butanol" assuring the "Suitability for carbonyl value determination"* for carbonyl value determination.
* This product is tested according to the Standard Methods for the Analysis of Fats, Oils and Derivatives (2.5.4.2-2013) specified by the Japan Oil Chemists' Society.