Optimized Splitless Injection of Hydroxylated PCBs by Pressure Pulse Programming

Hydroxylated polychlorobiphenyls (polyhydroxy-PCBs) are subjected to severe discrimination effect when they are introduced into a capillary gas chromatograph by splitless injection. This effect can be considerably reduced by using a pulsed pressure injection to favor sample transfer and by further programming the eluent gas pressure during the GC run. By multistep gas pressure programming, splitless injection provides analytical performances and chromatograms for (poly)hydroxy-PCBs closely resembling those obtained by on-column injection, whose use is generally discouraged with real environmental samples. Among the six model compounds studies, the dihydroxy congeners exhibit the best results.