I am working on lignin removal with various concentration of sodium hydroxide for wheat straw. I have sharp peak at 2360 cm-1 wavelength in both 3 and 4% NaOH pretreated wheat straw and 3 and 4% pretreated hydrolyzed wheat straw. What is this peak denotes as i have confusions like is this carboxyl group? or it belongs to amino acids? It stands out odd. Do Help me out