Chemical Indicators of Self-Heating and Spontaneous Combustion in Stored Grains Investigated by HS-GC-MS

The self-heating and spontaneous combustion of grains represent a significant fire risk in agricultural storage systems, frequently occurring in the absence of external ignition sources. In this study, volatile organic compounds (VOCs) were investigated as chemical markers to reconstruct the evolution of the deterioration and thermal escalation processes associated with self-heating in stored corn. Gas chromatography with headspace sampling coupled to mass spectrometry (HS-GC-MS) was used to characterize the VOCs in samples from real fire scenarios and from simulation experiments under controlled conditions. The results suggested a progressive transition from biological deterioration to thermochemical degradation. The mapping of these chemical markers provided supportive evidence for the establishment of a timeline of thermal evolution, culminating in the signatures associated with smoldering combustion. These results highlight the potential of HS-GC-MS as a valuable analytical tool for the chemical reconstruction of fires involving stored grains, providing evidence that assists in the identification of self-heating processes and strengthens the scientific determination of the cause in agricultural storage incidents.