Study on Rapid Screening of Ignitable Liquid by Attenuated Total Reflection Infrared Spectroscopy

As a destructive criminal behavior,arson has brought serious losses to public safety and social stability.Subject to the destruction of fire and fire fighting behavior,most evidence has become beyond recognition.It brings a great difficulty in determining the direction of investigation and a fair trial of criminal suspect.The ignitable liquids at fire scenes are important evidence to judge the case nature.And the types determination is the key point of criminal identification.In this paper,the rapid screening method of common Ignitable Liquid was established by attenuating total reflection infrared(ATR-FTIR)spectroscopy combined with PCA,HCA and DA.The IR spectra of gasoline,diesel oil,vegetable oil and oxygenated organic solvents were significant different and by virtue of this,mutual distinction can be achieved.But there was no significant difference in IR spectra of diesel,kerosene,aviation kerosene,solvent oil and turbine oil and only by direct comparison can not achieve mutual distinction. Next,the IR absorption range(1 136~976cm~(-1))combined with chemometric tools(PCA,PCA-HCA,PCA-DA)was used for separating aviation kerosene from the remaining four types of ILs.Finally,the infrared absorption peaks in the range of 837~ 400cm~(-1) were selected,and the other four kinds of ILs were distinguished by PCA,PCA-HCA and PCA-DA chemometrics methods.Our experimental results showed that ATR-FTIR can provide sufficient information on ignitable liquids.Combined with some chemometrics methods,ATR-FTIR successfully completed the qualitative analysis of common ILs.Once the model is established,this method becomes convenient and accurate,and can be applied to rapid screening of ILs types.