Soil Mineral Analysis by Particle Correlated Raman Spectroscopy (PCRS): Method Optimization
Tuesday, March 09, 2021: 9:10 AM - 9:30 AM
The potential of soil analysis is not being realized in modern forensic laboratories. Soil can associate an unknown specimen from a shoe, tire tread, or shovel with a known, but also can provide investigative leads. Although numerous cases have demonstrated this capability, criticisms of forensic soil analysis (e.g., subjective, labor-intensive, time-consuming) have resulted in a considerable decline in its use in forensic investigations. The failure to collect and analyze soil evidence has created countless missed opportunities, and the criminal justice community is missing out on a valuable and powerful type of physical evidence that has been proven to help in the investigation and adjudication of cases. Consequently, there is a need for a statistically-supported, automated, and objective analytical method for soil analysis. Particle correlated Raman spectroscopy (PCRS), also known as particle driven or morphologically directed Raman spectroscopy (MDRS), is a novel yet reliable analytical technique that can add significant value to the forensic examination of soil evidence. PCRS is capable of delivering particle size distribution and microscopic morphological characteristics for the particles present within a soil sample, and at the same time provides secure mineral identification. The research presented here focuses on the method optimization for soil mineral analysis with PCRS. The parameters for the chemical identification of minerals via Raman spectroscopy (e.g., laser wavelength, laser power, exposure time, magnification, grating), the imaging of particles (e.g., contrast/illumination method, magnification, targeted morphological analysis), and dispersion of the particle mixtures were optimized using response surface modeling of a multi-level experimental design. This research presents the first steps in achieving the overall aim of developing a robust, automated, and objective analytical method for the analysis and comparison of soil minerals using PCRS.
Keywords: Please select up to 4 keywords ONLY:
Environmental - Soils, Hazardous Waste,Method Development,Particle Size and Distribution,Raman/Surface Enhanced Raman Spectroscopy