Separation of non-ortho polychlorinated biphenyl congeners on pre-packed carbon tubes. Application to analysis in sewage sludge and soil samples

The analysis of planar (non-ortho) polychlorinated biphenyls (PCB) by HRGC- ECD or HRGC-HRMS requires a fractionation step to avoid the interferences o f the bulk of PCB, usually in much higher concentration than the planar one s. In this paper, a new method, based on the fractionation of PCB on SPE co mmercial tubes pre-packed with Carbopack B, has been developed. After the e xtract has been applied on the stationary phase, the bulk of PCD are eluted with 15 ml of hexane (fraction I), mono-ortho PCB with 20 mi of hexane/tol uene 99:1 (fraction II) and planar PCB with 20 ml of toluene (fraction III) in a station under vacuum. The method has been validated: accuracy (expres sed as recovery in %) is >70% and precision (expressed as % RSD) is <20% co nsidering changes of day, analyst and batch of tubes. The method is linear in the range studied. Other advantages are that the method is simple, rapid and it can be easily automated. The application of this separation to the determination of planar PCB in fly-ash extracts from an intercalibration ex ercise and to sewage sludge, sediment and soil samples has been successful. In addition, this method removes hydrocarbons from the planar PCB fraction and allows its concentration to very small volumes. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.