Direct process accompanying analysis of plant-based biomass samples for critical elements in combusting processes with ETV-ICP-OES

Plant-based biomass is an increasingly valuable renewable resource for the energy and material usage, but it often contains harmful elements based on coatings on construction wood. Knowing the chemical composition is crucial for recycling, phosphorus recovery, meeting emission limits, and achieving efficient combustion without slagging or fouling. In order to analyze macro- and micronutrients (B, Ca, Cu, Fe, K, Mg, Mn, Ni, P, Zn), environmentally relevant heavy metals (As, Cd, Co, Cr, Pb) and further elements relevant to the combustion process (Al, Ba, Li, Na, S, Si, Sr, Ti), a fast and direct method for the analysis of solids is required. As a robust solid sampling method, the electrothermal vaporization (ETV) as a sample introduction system for inductively coupled plasma optical emission spectrometry (ICP-OES) was found to be qualified. Method parameters, including reaction gas (e.g., CHF 3 , NF 3 , H 2 as alternatives to restricted chlorofluorocarbons like CCl 2 F 2 ), plasma settings, temperature program, and emission lines, were optimized to handle varying sample matrices and cover a concentration range from low ppm to percent. Calibration was also refined for the diverse sample types including the possibility of matrix-free calibration with liquid ICP standard solutions. This optimization enables the simultaneous measurement of all relevant elements from trace to main constituents in a single analysis without time-consuming sample preparation.