Theses in English

Christian Janfelt
Adjunkt
E-mail: cja(at)farma.ku.dk
Telephone: 35 33 62 57
Office: 13/625

 Direct analysis of compounds on TLC plates
Thin layer chromatography (TLC) is still a widely used analytical technique in organic synthesis as well as in natural product chemistry. Principally, it provides information about the number of components in a mixture, and identification can – if needed – be performed by comparison of the retention factors as in other kinds of chromatography. Using a relatively new technique in mass spectrometry, Desorption Electrospray Ionization, it is possible to analyze compounds directly on surfaces by spraying the surface with a narrow beam of solvent, thereby obtaining an unambiguous identification of the compound on the surface. In this project DESI-MS will be further developed and used for analysis of TLC plates, possibly in collaboration with synthesis chemists or natural product chemists.
Supervisors: Christian Janfelt and Steen Honoré Hansen
Maximum number of students: 1
 
 
Imaging of lipids in tissue sections from mice and rats
Using a new technique with mass spectrometry, Desorption Electrospray Ionization Imaging, it is possible to image the distribution of compounds on a surface. The sample is scanned line by line while mass spectra are recorded in every single point on the surface. Subsequently, for every point on the surface information about the signal intensity from a specific compound may be retrieved and used to generate a map showing where on the surface the compound is present.
In this project the technique will be used on thin slices of tissue from mice and rats, e.g. brain tissue, and the distribution of in particular phosphor lipids will be investigated. The new knowledge thus obtained about the spatial distribution of the compounds will be compared with results of analyses performed by traditional extraction on similar samples.
Supervisors: Christian Janfelt and Steen Honoré Hansen
Maximum number of students: 1
 
 
Imaging of compounds in plant tissue
 Using a new technique with mass spectrometry, Desorption Electrospray Ionization Imaging, it is possible to image the distribution of compounds on a surface. The sample is scanned line by line while mass spectra are recorded in every single point on the surface. Subsequently, for every point on the surface information about the signal intensity from a specific compound may be retrieved and used to generate a map showing where on the surface the compound is present.
In this project the technique will be used to analyze the distribution of compounds in plants. The project will be planned in collaboration with natural product chemists and focused on one or two plants which will be characterized further.
Supervisors: Christian Janfelt and Steen Honoré Hansen
Maximum number of students: 1

Development of new ambient ionization techniques for mass spectrometry
Extractive electrospray ionization is a new ionization technique for mass spectrometry which has been used to analyze compounds in creams and ointments directly, e.g. skin products, sun blockers, tooth paste etc.
The aim of the project is to construct an ion source for extractive electrospray ionization (by inspiration from the literature and possibly a visit abroad) and demonstrate its capabilities for rapid analysis of active ingredients in a pharmaceutical formulation.
Supervisor: Christian Janfelt
Maximum number of students: 2

Fast analysis of plant extracts using combined microextraction on packed syringes (MEPS) and capillary sprayer cell ESI-MS/MS
This project explores the combination of two new methods for fast analysis. In microextraction on packed syringes a complete solid phase extraction system is built into a Hamilton syringe and has the advantages of requiring very little sample (20-100 L) and reuse of the sorbent. The capillary sprayer cell is a very simple ESI-MS interface that makes it possible to analyse crude, unfiltered extracts directly. 20-40 L of the extract is simply dumped into the sprayer cell and an immediate electrospray ionization of the sample is created lasting for 10-20 minutes leaving plenty of time for MS/MS analysis. This project combines for the first time the two methods with cleaner and stronger signals as the goal.
Supervisors: Christian Janfelt and Frants R. Lauritsen