Abstract #1513

Probing the Relaxation Mechanism that Interferes with Polarization Measurement using the C2 Doublet of 1,2-[13C]2-Pyruvate

Justin Yat Cheong Lau^1,2, Albert P. Chen³, Jianfeng Zhu⁴, Gang Wu⁴, Charles H. Cunningham^1,2

¹Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; ²Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; ³GE Healthcare, Toronto, Ontario, Canada; ⁴Department of Chemistry, Queen's University, Kingston, Ontario, Canada

A current challenge with tracking C₁ polarization by selective small tip angle excitation of C₂ in 1,2-[¹³C]₂-pyruvate is the observed evolution of the C₂ doublet beyond AB asymmetry. We hypothesize that cross coupling between the dipolar field and chemical shift anisotropy (CSA) may, at least in part, be responsible for this behaviour. This study shows that solution pH has an effect on the relaxation mechanism that currently interferes with polarization measurement using C₂ asymmetry of 1,2-[¹³C]₂-pyruvate, suggesting that the C₂ CSA of the protonated form may be less effective at coupling with the dipolar field.