Nuclear magnetic resonance (NMR) is a phenomenon similar to MRIin which radio frequency signals are used to excite and manipulate atomicnuclei within a static magnetic field. Following excitation, the nuclei returnto equilibrium, all the while offering valuable molecular level informationpertaining to the sample.

Within the last decade, the development of small and inexpensive NMRspectrometers and permanent magnet NMR sensors has been a significantfocus within the NMR community. More recently, application scientists havesought practical applications for the new technologies.

In this thesis, a prototype NMR apparatus consisting of a spectrometerand 3.2MHz permanent magnet sensor was extended to enable scientificmeasurements. This involved developing radio frequency electronic circuitryfor the spectrometer front-end, and electromagnetic noise shielding and tem-perature regulation for the magnetic sensor. Experimental results confirmedthat repeatable measurements using the modified apparatus were indeedpossible.

The NMR apparatus was thereafter successfully used to study flow,diffusion and kiwifruit using several different experimental techniques. Asignificantly larger effort was then expended upon the study of T2 relaxation inpectin model systems using pH as the adjustable parameter. The fascinatingexperimental results were successfully interpreted and modeled across threepH zones in terms of a proton chemical exchange model and molecularconformational changes. In addition, it was found that pectin carboxylde-protonation was significantly less than expected. Further experimentsperformed upon galacturonic acid monomers, dimers and trimers appearedto further illuminate the pectin results. Future experiments are planned.

Also while studying pectin solutions, an unexpected pH-dependent watertransverse relaxation behavior was observed at both 3.2MHz and 400MHz.

The only references found in the literature were from a small publicationalmost 50 years ago, and a 2011 publication.

Altogether, this thesis contributed to original knowledge in several ways:it showed how a low-field apparatus and single-sided sensor could be im-proved and utilized for a variety of scientific measurements; it showed bothexperimentally and theoretically how T2 for pectin solutions change withpH; it revealed an unexpected de-protonation limit for pectin molecules; itrevealed a T2 pH dependence for water