Search the site

The University of Manchester Library

In April 2016 Manchester eScholar was replaced by the University of Manchester’s new Research Information Management System, Pure. In the autumn the University’s research outputs will be available to search and browse via a new Research Portal. Until then the University’s full publication record can be accessed via a temporary portal and the old eScholar content is available to search and browse via this archive.

New NMR methods applied to carbohydrate analysis

Dal Poggetto, Guilherme

[Thesis]. Manchester, UK: The University of Manchester; 2019.

Access to files

Abstract

This thesis concerns the analysis of mixtures by solution state nuclear magnetic resonance (NMR), more specifically the analysis of carbohydrates as these tend to be very challenging samples for NMR. The most common method for the analysis of intact mixtures by NMR is diffusion-ordered spectroscopy (DOSY), which is able to distinguish components based on molecular shape and size (i.e. hydrodynamic radius), through the diffusion coefficient, which derives the rate at which molecules diffuse. For carbohydrates, and many other compounds, it is not unusual for DOSY to fail when some of the solution components have comparable diffusion coefficients, or may not be distinguishable by their NMR signal frequencies due to signal overlap. Therefore, to overcome these difficulties, alternatives to conventional DOSY methods are employed here in the context of carbohydrate analysis. An investigation of the compositions of a few commercial beers was undertaken, in order to evaluate some of the methods presented here. These beverages (Clausthaler Classic premium low alcohol lager and Mackeson stout 2.8% ABV) were chosen because they are known to contain a range of carbohydrates at high concentration, and need no special sample preparation procedure, such as lyophilisation (also known as freeze-drying) or filtration. Similarly, a sample of peppermint oil was analysed. Peppermint (and other mint) oils are dominated by monoterpenoid alcohols named terpineols, which present similar complications to carbohydrates in solution state NMR analysis. Additionally, this thesis contains the publications of two original piece of software, based on Matlab®, for processing and analysing NMR data. These focus on user-friendliness for non-NMR experts, and are very robust. Both software packages are open-source under the GNU General Public License, and are distributed free of charge. They include a calculator to estimate molecular weight or hydrodynamic radius from diffusion coefficient (extracted from DOSY data, for example), and vice-versa, which is also described in this thesis.

Additional content not available electronically

The software (GNAT, MAGNATE and SEGWE), and all AU programs can be downloaded at: https://www.nmr.chemistry.manchester.ac.uk/ free of charge

Bibliographic metadata

Type of resource:
Content type:
Administered thesis
Form of thesis:
Alternative format
Type of submission:
Doctoral level ETD - final
Thesis title:
New NMR methods applied to carbohydrate analysis
Degree type:
Doctor of Philosophy
Degree programme:
PhD Chemistry (CAPES)
Publication date:
2019-02-07T10:17:32
Institution:
The University of Manchester
Location:
Manchester, UK
Total pages:
312
Abstract:
This thesis concerns the analysis of mixtures by solution state nuclear magnetic resonance (NMR), more specifically the analysis of carbohydrates as these tend to be very challenging samples for NMR. The most common method for the analysis of intact mixtures by NMR is diffusion-ordered spectroscopy (DOSY), which is able to distinguish components based on molecular shape and size (i.e. hydrodynamic radius), through the diffusion coefficient, which derives the rate at which molecules diffuse. For carbohydrates, and many other compounds, it is not unusual for DOSY to fail when some of the solution components have comparable diffusion coefficients, or may not be distinguishable by their NMR signal frequencies due to signal overlap. Therefore, to overcome these difficulties, alternatives to conventional DOSY methods are employed here in the context of carbohydrate analysis. An investigation of the compositions of a few commercial beers was undertaken, in order to evaluate some of the methods presented here. These beverages (Clausthaler Classic premium low alcohol lager and Mackeson stout 2.8% ABV) were chosen because they are known to contain a range of carbohydrates at high concentration, and need no special sample preparation procedure, such as lyophilisation (also known as freeze-drying) or filtration. Similarly, a sample of peppermint oil was analysed. Peppermint (and other mint) oils are dominated by monoterpenoid alcohols named terpineols, which present similar complications to carbohydrates in solution state NMR analysis. Additionally, this thesis contains the publications of two original piece of software, based on Matlab®, for processing and analysing NMR data. These focus on user-friendliness for non-NMR experts, and are very robust. Both software packages are open-source under the GNU General Public License, and are distributed free of charge. They include a calculator to estimate molecular weight or hydrodynamic radius from diffusion coefficient (extracted from DOSY data, for example), and vice-versa, which is also described in this thesis.
Additional digital content not deposited electronically:
The software (GNAT, MAGNATE and SEGWE), and all AU programs can be downloaded at: https://www.nmr.chemistry.manchester.ac.uk/ free of charge
Keyword(s):
Thesis main supervisor(s):
Thesis co-supervisor(s):
Funder(s):
Degree grantor:
Language:
en

Institutional metadata

University researcher(s):
Academic department(s):

Record metadata

Manchester eScholar ID:
uk-ac-man-scw:318297
Created by:
Dal Poggetto, Guilherme
Created:
7th February, 2019, 10:17:32
Last modified by:
Dal Poggetto, Guilherme
Last modified:
8th February, 2019, 13:28:14

Can we help?

The library chat service will be available from 11am-3pm Monday to Friday (excluding Bank Holidays). You can also email your enquiry to us.