Fast sample injection for dissolution dynamic nuclear polarisation NMR spectroscopy

Katsikis, Sotirios (2016). Fast sample injection for dissolution dynamic nuclear polarisation NMR spectroscopy. University of Birmingham. Ph.D.

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Abstract

Introduction: One of the most critical problems of NMR is the intrinsic lack of sensitivity owing to the small energy difference between nuclear energy levels. This issue can be addressed in different ways. One possibility is to reduce the spectral noise, which to a large extent is created by the console electronics. Another approach is to actually increase the signal strength of the NMR signal. An experimental approach to achieve this is ex situ dissolution Dynamic Nuclear Polarisation. It increases the population difference of the spin states by transferring the high electron polarization to the NMR detectable nuclei. A theoretical introduction into NMR, quantum mechanical basics of spin physics and DNP are presented in Chapters 1 and 2.

Methods: One of the main drawbacks of D-DNP is the necessity for a post-polarisation sample transfer to an NMR spectrometer. One of the major aims of the work presented in this thesis was to build an autonomous robotic device to transfer the sample under pressure controlled by Arduino microelectronics to overcome problems associated with the sample transfer. Chapter 3 presents how this device was constructed and. In addition applications performed using this device are presented.

Results: The benefits of the application of this device for fast-relaxing nuclei are discussed in chapter 4 with the application on 2-D DNP-NMR acquisition of U-\(^1\)\(^3\)C Glucose. Novel experiments using Dissolution DNP were also performed as part of the work for this thesis. A method for analysing aminoacids of biological fluids using DNP is presented in the Chapter 5 by acetylating which creates long lived tags. An approach for extracting the maximum of information out of a single polarisation experiment is what Chapter 6 covers with an approach to perform Parallel Receiver DNP and the application on ATP and 1-13C TetraMethylPhosphonium. Finally, the future applications of the DNP and the authors’ personal ideas for further development are presented in Chapter 7, the discussion. Briefly, DNP-NMR using a fast sample transfer system can be a capable system for performing different types of analysis, but the maximum outcome is always when the system is combined with \(in-vivo\) MRI scanners.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):