 In this study, Fourier transform infrared, FTR, spectroscopy was used to analyze the composition of biomass and its derivatives during processing. The presence of solvents, chemicals, enzymes, and potentially formed degradation byproducts were identified. These findings will help to avoid misinterpretations of FTR data from processed biomass. This article was authored by Jingxian Zhuang, Mili, Yunchia Pu, and others.