An on-line system for coupling a normal phase liquid chromatography (LC) column to a reversed-phase LC column is described. The interface consists of an on-line solvent evaporator working on the principles of concurrent eluent evaporation and vapor overflow, and two additional 10 port valves. Optimization of the on-line procedure as well as recoveries, repeatability and linearity characteristics were tested in a simplified system simulating determination of heavy polycyclic aromatic hydrocarbons in edible oils. An application on a real extra virgin olive oil sample is also reported.
