Assessment of ionic liquid stationary phases for the determination of polychlorinated biphenyls, organochlorine pesticides and polybrominated diphenyl ethers.
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Resum
Five ionic liquid stationary phases were tested for the gas chromatographic (GC) analysis of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). In comparison with a non-polar DB5MS stationary phase, which is normally used in single-column GC for these compounds, all phases tested provided a different elution pattern. Mono-ortho substituted PCBs showed longer retention times, whereas di-ortho PCB congeners eluted earlier. These different patterns provide a potential for use of these columns for single-column PCB analysis, but in particular for use in comprehensive two-dimensional GC (GC×GC). The SLB-IL111 phase showed the most striking differences in elution of PCBs compared to DB5MS. The analysis of OCPs was hindered by adsorption and on-column degradation with most of the phases tested. Additional experiments with polybrominated diphenylethers (PBDEs) also revealed serious degradation of most of the congeners. Only the SLB-IL60 column showed a better performance for OCPs, in combination with a relatively low bleeding.