Identification of accelerants, fuels and post-combustion residues using a colorimetric sensor array.

Area of Science:

• Analytical Chemistry
• Sensor Technology
• Forensic Science

Background:

• Accurate identification of fuels and combustion residues is crucial for forensic analysis and environmental monitoring.
• Existing sensor technologies often lack the sensitivity and specificity required for complex fuel mixtures and post-combustion samples.
• A need exists for rapid, reliable, and cost-effective methods for fuel analysis.

Purpose of the Study:

• To develop and validate an integrated pre-oxidation technique with a colorimetric sensor array for enhanced fuel detection.
• To assess the sensitivity, specificity, and reproducibility of the developed system for identifying automotive fuels and fire accelerants.
• To investigate the system's capability in differentiating volatile residues after fuel combustion.

Main Methods:

• A linear (1 × 36) colorimetric sensor array was coupled with a pre-oxidation unit.
• The pre-oxidation unit utilized a packed tube containing chromic acid on an oxide support, optimized for support material and concentration.
• The system was tested with twenty automotive fuels (gasolines, diesel) and common fire accelerants, including analysis of post-combustion residues.

Main Results:

• The pre-oxidation technique substantially increased the sensitivity of the colorimetric sensor array for fuel vapor detection.
• Individual identification of twenty automotive fuels from five retailers was achieved with high accuracy (no misclassifications) over multiple trials.
• Sub-parts-per-million (sub-ppm) limits of detection were established for gasoline and diesel fuels.
• Clear differentiation was demonstrated among various fire accelerants and their respective volatile residues post-combustion.

Conclusions:

• The integration of pre-oxidation with a colorimetric sensor array offers a highly sensitive and specific method for fuel and post-combustion residue analysis.
• The optimized pre-oxidation technique provides excellent reproducibility and enables reliable identification of diverse fuel types.
• This approach holds significant potential for applications in forensic investigations, environmental monitoring, and quality control of fuels.