General description of SPE

principle:

1. phase transfer of analyte from aqueous sample W (large volume) to sorbent P;
    pre-concentration of analyte in P according to partition equilibrium:

2. Elution of analyte from sorbent P in small volume of organic solvent S

advantages:

• high sample throughput
• small volumes of organic solvent
• polar analytes are also extractable

disadvantages:

• clogging of the cartridge
• potential breakthrough of the analyte trough the cartridge