The interest in experimental data regarding thermal fuel decomposition as well as the release behavior of ash-forming elements of biomass fuels for modeling and simulation purposes is continuously increasing. On the basis of combustion experiments with lab-scale reactors and single-particle reactors, integral release data regarding ash-forming vapors can be obtained, whereby the release is calculated on the basis of analysis data of the fuel and the ash residues. At the moment, almost no time-resolved release data of ash-forming elements from single particles exist. Therefore, a single-particle reactor was designed, which has been coupled to an inductively coupled plasma mass spectrometer (ICP-MS). This reactor can be used for targeted experiments in a temperature range of 250–1050 °C under inert, reducing, and oxidizing conditions. With this reactor, it is possible to simultaneously determine the surface and center temperatures of a biomass particle, weight loss of the particle, and flue gas composition....