Sample preparation

Sample preparation - context
Sample preparation - motivation
Purpose of sample preparation
Overview of preparation methods
     Liquid liquid extraction (LLE)
           General description of LLE
           Illustration of LLE
           Detailed description of LLE
     Solid phase extraction (SPE)
     Solid phase microextraction (SPME)
     Purge and trap (PT)
     (Accelerated) Solvent extraction ((A)SE)
     Supercritical fluid extraction (SFE)
      Filter Techniques (FT)
Box 10 Filtration
Box 11 Sorbents
Box 12 Preconcentration
Self test
Problems
End of chapter

General description of LLE

principle:

phase transfer of analyte from aqueous sample W (large volume) to organic solvent S (small volume);
pre- concentration of analyte in phase S according to partition equilibrium:

 

 

disadvantages:

  • the formation of emulsions which impair separation of phases S and W
  • the use of large amounts of (toxic) organic solvents S
  • very labor intensive