Quantification of crystalline cellulose in lignocellulosic biomass using sum frequency generation (SFG) vibration spectroscopy and comparison with other analytical methods

► Sum frequency generation spectroscopy is used to characterize crystalline cellulose. ► A correlation is obtained between cellulose in model biomass and SFG signal intensity. ► SFG signal intensity is sensitive to a wide range of cellulose crystallinity. ► SFG signal varies non-linearly with the mass fraction of cellulose in model biomass. ► SFG can be used as a complementary tool to assess cellulose crystallinity in biomass.