HPLC analysis of PCBs on porous graphitic carbon: Retention behavior and gradient elution

The fractionation of PCB congeners into classes according to their planarity (i.e. amount of ortho substitution) by HPLC on porous graphitic carbon (PGC) as stationary phase has been investigated as a preliminary step before GC analysis, indispensable for a complete separation of PCB congeners. A systematic study of retention behavior on PGC eluted with different n-hexane-dichloromethane mixtures made it possible to design a linear binary gradient which separated PCB congeners in a reasonable time and with good performance. Relationships were obtained between retention behavior and the molecular structure of the PCB congeners. The beneficial effects of elevated temperature on separation efficiency were also investigated. The analysis conditions selected, i.e. continuous gradient separation at 40 degreesC, were successfully used for fractionation of technical PCB formulations, e.g. Aroclor 1242.