Abstract
Lignocellulosic biomass from agricultural and forestry residues is a sustainable yet underutilized source for bioenergy and bioproducts, but efficient use requires detailed chemical characterization and fast analytical tools. This thesis compared wheat middlings, corn stover, soybean hulls, and beetle-killed pine using proximate analysis, extractives quantification, lignin analysis, carbohydrate profiling, fatty acid methyl ester (FAME) analysis, and the use of handheld laser induced breakdown spectroscopy (LIBS) for inorganic elements analysis in biomass ashes. Results showed clear compositional differences: agricultural residues had higher ash content (2–5.2%) and hemicellulosic sugars (e.g., xylose up to 14.8% in corn stover), while pine had higher lignin (26.7% Klason) and extractives (5%), affecting thermal stability and conversion potential. LIBS calibration using 22 inductively coupled plasma optical emission spectroscopy and X-ray fluorescence spectroscopy elemental analyzed validated ash standards achieved R² > 0.94 and ≤5% RSD for major elements (Si 6–58 wt%, Mg 0.6–4.1 wt%) and trace metals (Cr, Ti, V), despite some Fe self-absorption. These findings support targeted feedstock use of agricultural residues for biochemical processes, pine for thermochemical applications and showed the use of portable LIBS as a reagent-free rapid tool for field ash profiling, aiding slagging/fouling prediction and supply chain quality control.