Separation of Toxic Congeners from PCB Mixtures on Two Series Coupled Narrow-Bore Columns (50 m SIL-8 AND 25 m HT-5)

Publisher Website
Google Scholar
Abstract
The complete separation of the toxic non-ortho-substituted polychlorinated biphenyls (PCBs) PCB-77, PCB-126 and PCB-169 from the technical PCB mixtures Askarel and Aroclors (A1232, A1242, A1248, A1254, A1260 and A1262) was obtained on two series coupled narrow-bore columns: 50 m × 0.25 mm, 0.26 μm 5% diphenyldimethylsiloxane (CP-SIL-8) and 25 m × 0.2 mm, 0.1 μm 5% 1,2-dicarba-closo-dodecarborane dimethylsiloxane (HT-5). The high upper temperature limit for these GC-phases (>300°C) allowed for fast temperature programming and short analysis time (60 min). In addition to the non-ortho-substituted PCBs most of the toxic mono-ortho-substituted PCBs were completely separated from other PCBs (PCB-74, PCB-81, PCB-105, PCB-118, PCB-123, PCB-157 and PCB-189). Only four toxic PCBs were eluted with interference: PCB-60/PCB-56, PCB-114/PCB-134, PCB-167/PCB-128 and PCB-156/PCB-202. These could be analyzed satisfactorily on a CP-SIL-19 column i.e. 50 m × 0.25 mm, 0.20 μm 14% cyanopropylphenyl 1% vinyldimethylsiloxane. The 2,3,7,8-TCDD toxicity equivalents (TEQ) of the technical mixtures, analyzed by GC-ECD and GC-MS (ITS-40), were determined from published toxicity equivalent factors (TEF). Aroclor A1254 was the most toxic PCB formulation (56–216 mg TEQ kg−1 depending on the TEF model used) and A1262 the least toxic formulation (4–11 mg TEQ kg−1). PCB-74, PCB-77, PCB-105, PCB-118, PCB-126 and PCB-156 contributed with 80–99% of the total toxicity in all technical mixtures and it is suggested that future PCB legislation should be based on these six congeners.

This publication has 38 references indexed in Scilit: