Until now the direct injection and on-line SPE-LC analysis of whole blood was not possible due to the presence of corpuscular blood components (e.g.erythrocytes).Current pre-treatment protocols include a preparation of a second specimen, e.g.blood plasma by centrifugation, an addition of hemolysis reagent e.g.saponin followed by centrifugation or an addition of a denaturing agent, e.g.an organic solvent (MeOH, ACN) followed by centrifugation.All these protocols involve manual steps which hardly can be automated or integrated into an on-line analysis procedure.