AbstractLignocellulosic biomass comprises wood and agricultural residues, which are sources of cellulose, hemicellulose, and lignin (the lignocellulosic fractions), and represents the major biomass source. Each of these types of lignocellulosic fractions has its own particular structural characteristics and chemistry, which can be exploited in chemical analyses. For a general approach, the quality of the biomass used determines the product quality. Therefore, reliable information is required about the chemical composition of the biomass to establish the best use (e.g., most suitable conversion process and its conditions), which will influence harvest and preparation steps. Then, analytical chemistry is required to understand and control these processes, their raw materials, products, and residues.