FormNo. 203-821-250 01/05-REV0
LECO is a registered trademark of LECO Corporation
2
Table1.
World HealthOrganization non- andmono-ortho substituted polychlorinated biphenyls.
PCB#
Cl #
Cl Position
77
4
34-34
81
4
345-4
105
5
234-34
114
5
2345-4
118
5
245-34
123
5
345-24
126
5
345-34
PCB#
Cl #
Cl Position
156
6
2345-34
157
6
234-345
167
6
245-345
169
6
345-345
189
7
2345-345
Results andDiscussion
The second dimension column chosen for this work is highly selective for those PCBs that can form
planar configurations, whichmakes it an ideal column for usewith GCxGC to determine the dioxin-
like PCBs. Table 2 shows how the PCBs with fewer ortho-chlorines (which allows the planar shape
to occur), generally elute later in the second dimension than those withmore ortho-chlorines. It is
important to note that even though the retention time differences shown in this table seem rather
small, the distances are inmost cases adequate for quantification due to the very narrow peaks
produced using GCxGC (in this work they are approximately 200ms at half-height). In addition,
the first dimension separation afforded by the Rtx-1 cannot be ignored for reducing the potential
for interferences while trying to determine dioxin-like PCBs.
Table2.
Second dimension retention times in seconds (RT 2) for dioxin-like PCBs (on left)
compared to thosewith greater degrees of ortho-chlorine substitution (on right).
PCB#
Cl Position
RT2
PCB#
Cl Position
RT2
77
34-34
6.42
49
24-25
5.06
81
345-4
6.28
52
25-25
5.00
105
234-34
6.50
87
234-25
5.82
114
2345-4
6.28
95
236-25
5.80
118
245-34
5.94
99
245-24
5.56
123
345-24
6.04
101
245-25
5.50
126
345-34
6.78
110
236-34
5.90
156
2345-34
6.72
132
234-236
6.14
157
234-345
6.72
138
234-245
6.18
167
245-345
6.12
149
236-245
6.12
169
345-345
7.08
153
245-245
5.88
189
2345-345
6.92
180
2345-245
6.30
