Semi-automated scanning electron microscopy energy dispersive X-ray spectrometry forensic analysis of soil samples

Soil is commonly analyzed to provide evidence because soil particles adhere to almost everything that may be of forensic interest. Particles derived from soil can be quantitatively analyzed by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS). We developed a semi-automated SEM-EDS method for analyzing soil minerals. Soil was analyzed using the SEM-EDS automated particle analysis program, then the mineral species were identified from their chemical components. Chi-squared tests were used to discriminate between different minerals, and these tests were also applied to soil samples. The method put samples with the same parent population into the same group and discriminated between samples with different parent populations even when 26 particles were analyzed. The method successfully identified most soil samples with different parent populations as different. The results proved that the method could be used in forensic cases and provide new insights into the forensic analysis of soil samples.