Abstract
The aim with this work is to make untargeted analysis of chromatographic data more
accessible for those working with chromatography on a daily basis. This task has been
fulfilled partly by developing some new tolls, and partly by describing some existing methods
with tutorials in this thesis.
In order to facilitate the choice of method a scheme has been presented which can guide the
reader to select proper methods for their type of data. In this scheme, data is divided into
two main categories; data originating from first-order instruments and from higher-order
instruments. These are then further divided into subcategories depending on the complexity
of the chromatograms.
For low complexity chromatograms from first-order instruments, FastChrom has been
developed. FastChrom is a graphical user interface, running in MATLAB, which removes
baseline contributions and subsequently finds all peaks in the chromatograms and group
those across samples.
For high complexity chromatograms from first-order instruments, an already existing method
is suggested and MATLAB code is provided, so users without MATLAB experience can take
advantage of the method. The principle of the method is to remove artefacts like baseline
and shifts before using multivariate data analysis on the full chromatograms.
For low complexity chromatograms obtained from higher-order instruments, PARAFAC2 is
proposed as the preferred method. In order to make PARAFAC2 more accessible some new
developments have been made, with automation of the evaluation of how many factors to
include as the most important. With this, PARAFAC2 can be used to resolve overlapping
peaks without time consuming manual evaluation which requires considerable chemometric
and chromatographic knowledge. For intervals which are not well modelled with PARAFAC2,
MCR is suggested and carefully described.
For high complexity chromatograms from higher-order instruments it is suggested to use the
approach describe for the complex chromatograms from first-order instruments on e.g. the
total ion chromatograms. A number of other methods are also listed, but not further
described.
accessible for those working with chromatography on a daily basis. This task has been
fulfilled partly by developing some new tolls, and partly by describing some existing methods
with tutorials in this thesis.
In order to facilitate the choice of method a scheme has been presented which can guide the
reader to select proper methods for their type of data. In this scheme, data is divided into
two main categories; data originating from first-order instruments and from higher-order
instruments. These are then further divided into subcategories depending on the complexity
of the chromatograms.
For low complexity chromatograms from first-order instruments, FastChrom has been
developed. FastChrom is a graphical user interface, running in MATLAB, which removes
baseline contributions and subsequently finds all peaks in the chromatograms and group
those across samples.
For high complexity chromatograms from first-order instruments, an already existing method
is suggested and MATLAB code is provided, so users without MATLAB experience can take
advantage of the method. The principle of the method is to remove artefacts like baseline
and shifts before using multivariate data analysis on the full chromatograms.
For low complexity chromatograms obtained from higher-order instruments, PARAFAC2 is
proposed as the preferred method. In order to make PARAFAC2 more accessible some new
developments have been made, with automation of the evaluation of how many factors to
include as the most important. With this, PARAFAC2 can be used to resolve overlapping
peaks without time consuming manual evaluation which requires considerable chemometric
and chromatographic knowledge. For intervals which are not well modelled with PARAFAC2,
MCR is suggested and carefully described.
For high complexity chromatograms from higher-order instruments it is suggested to use the
approach describe for the complex chromatograms from first-order instruments on e.g. the
total ion chromatograms. A number of other methods are also listed, but not further
described.
| Originalsprog | Engelsk |
|---|
| Forlag | Department of Food Science, University of Copenhagen |
|---|---|
| Antal sider | 166 |
| Status | Udgivet - 2012 |