Abstract: Gasoline, as a common accelerant, requires precise identification of its combustion residues, which is crucial for the investigation of fire-related cases. Due to significant variations in characteristic components caused by different residual-adhering substrates, source identification is rendered considerably challenging. This study employed gas chromatography-mass spectrometry (GC-MS) to analyze the characteristic components of the residues after the combustion of gasoline alone and in combination with cotton, nylon, polyester, and linen fabrics, revealing significant interference effects of substracts on gasoline combustion byproducts. Research findings indicate that the combustion products of various fabrics mixed with gasoline exhibit distinct specificity. After blending cotton fabric with gasoline, the characteristic intermediate products such as esters and phenols originally present in the fabric disappear, leaving polycyclic aromatic hydrocarbons as the predominant residue. The addition of alcohols was observed upon mixing nylon with gasoline, accompanied by a significant increase in both the variety and abundance of aromatic hydrocarbons, naphthalenes, and polycyclic aromatic hy⁃ drocarbons. Polyester, when blended with gasoline, undergoes a transformation wherein acids and esters are con⁃ verted into aromatic compounds, while the combination of their cleavage radicals generates a novel sub-stance (9-fluorenemethanol). The combustion of gasoline in the presence of flax fabric results in the complete elimination of naphthalene compounds that are typically generated during standalone gasoline combustion. This study elucidates the specific interference mechanisms of four common textile materials on gasoline combustion residues, providing critical forensic indicators for practical case investigations. These findings substantially en-hance the scientific validity and reliability of fire debris analysis.

Key words: fire evidence identification, textile fabrics, combustion residues, gasoline identification, characteris-tic compounds