Chemometric Study on the Forensic Discrimination

13 Abstract 14 Soil has been utilized in criminal investigations for some time because of its prevalence and 15 transferability. It is usually the physical characteristics that are studied, however the research 16 carried out here aims to make use of the chemical profile of soil samples. The research we are 17 presenting in this work used sieved (2mm) soil samples taken from the top soil layer (about 18 10cm) that were then analysed using mid infrared spectroscopy. The spectra obtained were pre19 treated and then input into two chemometric classification tools: Nonlinear iterative partial least 20 squares followed by linear discriminant analysis (NIPALS-LDA) and partial least squares 21 discriminant analysis (PLS-DA). The models produced show that it is possible to discriminate 22 between soil samples from different land use types and both approaches are comparable in 23 performance. NIPALS-LDA performs much better than PLS-DA in classifying samples to location 24