Micro-Spectrochemical Analysis of Complex Samples Utilizing Combined Optical-Photothermal Infrared and Raman Spectroscopy
Abstract
Understanding the fate and transport of contaminants in the environment lies at the forefront of understanding water quality. Interfacial chemistry between water and soil plays an important role in the transformation of contaminants in the environment. However, it is well known that this chemistry can be complex, as these transformations depend on a number of factors. Limiting our understanding of these transformations are the tools needed to investigate these complex environmental systems. Motivated by this lack of knowledge, this research focuses on purchasing and utilizing a relatively new technique to investigate the nature of soil surfaces and other materials relevant to the Army Research Office and the Department of Defense. In particular, micro-spectroscopic techniques, such as optical photothermal infrared (O-PTIR) spectroscopy coupled to Raman spectroscopy, has been developed to provide high spatial resolution that are beyond the limits of conventional techniques. The instrument called a ÒmIRage+RamanÓ is able to achieve submicron spatial resolution, as low as 0.5 micron, which allows for the mapping of chemicals in complex environmental systems to gain information about the nature of coatings found on soil surfaces in the environment. This will allow for the better understanding of how these surfaces interact with chemical contaminants. Currently the instrument has been mainly limited in its application to life sciences and polymer research. The goal of the proposed plan is to further develop this instrument into studying the multiple phases and chemicals that are simultaneously present in environmental systems. By taking advantage of the high spatial resolution chemical mapping capabilities of the mIRage+Raman instrument, we will be able to bridge the chemical data from the spectral analysis and the physical data from the optical images to clearly investigate environmental interfaces that play a role in contaminant transformation. Furthermore, this instrument allows for the study of environmental films that contain soft materials such as biological components and organic matter. The instrument also allows for rough samples to be analyzed and can be used to investigate in detail the heterogeneity of the sample. Thus, the mIRage-Raman instrument will provide a wide range of valuable information about the heterogeneous nature of complex environment samples. These include geochemical (soil) interfaces, urban films, surface films in indoor environments and new materials currently being developed for chemical warfare agent decontamination, thereby opening up its potential in environmental research focused on remediation and decontamination. This research aligns well with the ARO Environmental Chemistry Program as the development of new tools and techniques is key to studying environmental complexity to better understand chemical fate and transport as well as environmental forensics. Since the interfacial region is of most importance, this technique can play an important role in determining the spatial heterogeneity and molecular species on these interfaces. The instrument can also be applied to other areas of interest to the DoD including the development of new materials for decontamination.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 03, 2022
- Source ID
- W911NF2210033
Entities
People
- Vicki Grassian
Organizations
- Army Contracting Command
- United States Army
- University of California, San Diego