Preparation of Glass Sampling Containers to Determine Trace Amounts of Accelerants in Fire Samples

Gas chromatography is be used to prove the presence of small amounts of organics trapped on solid samples or in liquid samples from fires and it serves as evidence of the presence of traces of flammable liquids used as substances that support combustion (fire accelerants). Demonstrating the presence of traces of gasoline or diesel fuel can significantly support the hypothesis that a fire was started intentionally. Recently, with the development of gas chromatography instrumentation, the sensitivity of the measurement increases and it is possible to measure lower concentrations. Therefore, it is important to collect the sample correctly, use clean sample containers, collection tools and equipment and prevent contamination of the sample during transport to the laboratory. This places increased demands on the quality of the collected samples and their packaging – sample containers. The contribution deals with the testing of the cleanness of glass sample containers and suggests their cleaning procedures so that their contaminants do not affect the determination of the presence of traces of gasoline or diesel in samples from the fire scene. Gas chromatography with mass spectrometry and solid phase micro extraction (GCMS-SPME) was used to detect contamination in new preserving jar with TWIST OFF caps. By testing different types of lids from different manufacturers it was found that all of them are already contaminated with similar substances to varying degrees. Various methods of cleaning were tried, namely burning, using sorbent materials and cleaning with solvents. Based on these results, a procedure for their cleaning was proposed.