Nuclear spin relaxation in NMR spectroscopy
Department
Chemistry
Major
Chemistry
Research Advisor
Woelk, Klaus
Advisor's Department
Chemistry
Funding Source
Materials Research Foundation & CASB FYRE Program
Abstract
Several hyperpolarization techniques are known to enhance the intrinsically low sensitivity of NMR spectroscopy. The enhanced sensitivity allows users to record spectra from very low sample concentrations, or improve the spatial resolution and imaging contrast in medical MRI. The relaxation of hyperpolarization to thermodynamic equilibrium is often viewed as the limiting factor for NMR and MRI enhancements. When hyperpolarization techniques are used, relaxation may not follow a mono-exponential but a multi-exponential decay. To accurately describe relaxation of hyperpolarization, a numerical algorithm is introduced which uses relaxation-matrix calculations that apply to both hyperpolarized and regular spin arrangements. For two-spin systems, the algorithm provides four eigenvectors with their respective eigenvalues, which are then used to model the relaxation of both regular and hyperpolarized spin-state distribution. An extension to three-spin systems leads to six Eigenvectors. Standard inversion-recovery and hyperpolarized spin-state experiments are used to provide evidence for the validity of the new algorithm.
Biography
Kelsey Brakensiek is a junior in Chemistry from O’Fallon, Missouri. She transferred to Missouri University of Science and Technology in the Fall of 2018 after receiving her Associate of Science degree in Chemistry from St Charles Community College, where she combined her passions for chemistry and helping others by tutoring chemistry for two years. She joined Dr. Woelk’s team in the spring of 2019 under the FYRE program, where she plans to continue her undergraduate research until graduation. She also serves as safety officer for the research team on Chem E Car. She hopes to receive her PhD in chemistry, and to work in industry, focusing on renewable energy and green chemistry.
Research Category
Sciences
Presentation Type
Oral Presentation
Document Type
Presentation
Award
Sciences oral presentation, First place
Location
Ozark Room
Presentation Date
16 Apr 2019, 10:30 am - 11:00 am
Nuclear spin relaxation in NMR spectroscopy
Ozark Room
Several hyperpolarization techniques are known to enhance the intrinsically low sensitivity of NMR spectroscopy. The enhanced sensitivity allows users to record spectra from very low sample concentrations, or improve the spatial resolution and imaging contrast in medical MRI. The relaxation of hyperpolarization to thermodynamic equilibrium is often viewed as the limiting factor for NMR and MRI enhancements. When hyperpolarization techniques are used, relaxation may not follow a mono-exponential but a multi-exponential decay. To accurately describe relaxation of hyperpolarization, a numerical algorithm is introduced which uses relaxation-matrix calculations that apply to both hyperpolarized and regular spin arrangements. For two-spin systems, the algorithm provides four eigenvectors with their respective eigenvalues, which are then used to model the relaxation of both regular and hyperpolarized spin-state distribution. An extension to three-spin systems leads to six Eigenvectors. Standard inversion-recovery and hyperpolarized spin-state experiments are used to provide evidence for the validity of the new algorithm.
