Investigating Soluble Organic Compounds in Aqueously Altered Carbonaceous Chondrites by Ultrahigh Resolution Orbitrap Mass Spectrometry
Date of Final Oral Examination (Defense)
Type of Culminating Activity
Master of Science in Chemistry
Michael P. Callahan, Ph.D.
Adam C. Colson, Ph.D.
Dale D. Russell, Ph.D.
Most meteorites are fragments from main-belt asteroids and contain extremely primitive materials that have preserved a compositional record of the early Solar System. After the formation of their parent bodies, carbonaceous chondrites experienced secondary modification from thermal metamorphism and/or aqueous alteration. Secondary processing likely influenced the synthesis and/or final composition of organic compounds in parent bodies; thus, these effects may be elucidated from the study of different meteorites. Although the role of aqueous alteration has been investigated for a few specific classes of compounds (such as amino acids), the effect of aqueous alteration on the full inventory of organic compounds in carbonaceous chondrites is still poorly understood.
I investigated the nature of soluble organic compounds in a full range of aqueously altered CM chondrites by electrospray ionization ultrahigh resolution orbitrap mass spectrometry. I determined that soluble organic composition was relatively consistent in CM chondrites despite varying degrees of aqueous alteration on the parent body/bodies; however, additional thermal metamorphism did show an extreme depletion in the organics identified. Additionally, I estimated the degree of aqueous alteration for CM chondrites that did not have a numerical degree of aqueous alteration via comparison of identified organics (although these estimates would need further verification). Finally, I observed that the position of the phyllosilicate-bound hydroxyl band in reflectance IR spectra of meteorites is related to the degree of aqueous alteration in meteorites. Organic-rich meteorites exhibited a maximum IR absorbance between 2.70 and 2.85 microns for the phyllosilicate-bound hydroxyl band. This research has the potential to influence asteroid sample return missions, such as the current NASA OSIRIS-REx mission, by providing a more informative and accurate correlation of sample site to organic composition.
Schwartz, Patrick Kyle, "Investigating Soluble Organic Compounds in Aqueously Altered Carbonaceous Chondrites by Ultrahigh Resolution Orbitrap Mass Spectrometry" (2019). Boise State University Theses and Dissertations. 1588.