FormNo. 203-821-250 01/05-REV0
LECO is a registered trademark of LECO Corporation
3
To test the accuracy of GCxGC-ECD, dioxin-like PCBs in an Aroclor 1254 dilutionwere quantified
against GCxGC-ECD calibration curves prepared using hexachlorobenzene as an internal standard.
The values producedwere compared against those from a detailed study conducted by Frame
et. al, where numerous GC column sets andmass spectrometry were used to define Aroclor PCB
concentrations (Table 3). The numbers are in good agreement, except for PCB 77, where a large
concentration of PCB 110, a pentachlorobiphenyl, may have thwarted the quantification effort for
PCB 77. This is interesting from the standpoint that these congeners are resolved
chromatographically in the second dimension using Rtx-PCBwhen they exist in approximately
equal concentrations in a sample (Figure 1A). Figure 1B shows the same chromatographic area as
Figure 1A, but for Aroclor 1254. PCB 110, which is at 325 pg/µL as calculated from Frame et. al, is
the dominant PCB, and PCB 77 cannot be detected.
Table3.
Dioxin-like PCB concentrations in Aroclor 1254 (pg/µL) as calculated from the study of
Frame et. al, andwithGCxGC-ECD.
PCB#
Frame et. al
GCxGC-ECD
77
1.05
**
81
ND
ND
105
105
101
114
6.30
7.41
118
257
201
123
5.25
5.41
126
ND
ND
156
28.7
32.6
157
6.65
6.96
167
9.45
11.1
169
ND
ND
189
0.35
1.44
ND= not detected. **possible coelution from PCB 110.
