METHODOLOGY FOR DETECTING THE CONSTITUENTS OF PETROCHEMICAL PRODUCTS IN FRAGMENTS OF BURNT MATERIALS
Purpose. Development and metrological certification of the methodology for detecting alkanes (saturated hydrocarbons) for identification of residues of the highly inflammable liquids in the fragments extracted from a place of fire. Methods. Investigations of the vapor-air mixtures with the application of accumulative, gas-adsorption and gas-liquid chromatography. Mathematical treatment of the experimental data and evaluation of values of the measurement accuracy indices. Results. The highly sensitive method for detecting the alkanes (10<sup>-10</sup> g/cm<sup>3</sup>), i.e. the key constituents of the highly inflammable liquids of oil nature in the form of trace quantities on various career objects, has been created. The migration times of the alkanes from pentane to octane and their isomers have been determined on sorbents of various polarities. The methodology has been developed and certified to detect the alkanes by the gas chromatography method in the samples extracted from the place of fire. The evaluation of the values of the accuracy measurement indices has been provided, the expanded uncertainty and the limits of the permissible relative error of measurements have been calculated. Scientific novelty. The methodology with the low thresholds of detecting the normal and isomeric alkanes, i.e. at the levels of nanoconcentrations of 10<sup>-10 </sup>g/cm<sup>3</sup>, has been developed for the first time where the extraction and concentration of the samples traditionally used in world practice are not required. For the first time the alkanes are considered as the test hydrocarbons for presence of the petrochemical processing products in the fragments of the highly inflammable liquids extracted from the place of fire. Practical value. The methodology is intended for detection and identification of the residues of the highly inflammable petrochemical products in the fragments extracted from the place of fire by the method of gas chromatography. The low thresholds of detection of the methodology have enabled eliminating the extraction and concentration of the samples. The combination of the high sensitivity with rapidity and implementation simplicity makes it possible to conduct the analysis and to identify the combustion initiator promptly increasing the reliability of the fire-technical investigations.