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Environmental
• 12 •
2008 vol. 2
Characterizing all 136 Tetra- to Octachlorinated
Dioxins and Furans
Using the Rtx®-Dioxin2 Column
By Jack Cochran, Director of New Business and Technology
Successful analyses of dioxins and furans are criti-
cal because of the extremely toxic nature of these
compounds. However, confidently resolving the
most toxic congeners, 2,3,7,8-substituted tetrachlo-
rinated dibenzodioxin (TCDD) and tetrachlorinated
dibenzofuran (TCDF), is often complicated by the
presence of the many other possible congeners.
Even with high resolution GC/high resolution
MS methods, the proper choice of chromato-
graphic column is essential for separating 2,3,7,8-
substituted dioxins and furans from the less toxic
congeners and matrix-related compounds.
Complete Column Characterization
It is rare that a column’s performance is character-
ized against all possible 136 tetra- through
octachlorinated dioxins and furans. These standards
are difficult to obtain, and testing can be time con-
suming. However, here the Rtx®-Dioxin2 column
is characterized against all 136 compounds using
standards from Cambridge Isotope Laboratories,
Inc.When compared to industry standard stationary
phases, a unique selectivity is observed for the
Rtx®-Dioxin2 column, and specific resolutions
and coelutions are noted. Very few coelutions
involving the toxic 2,3,7,8-substituted congeners
are observed, making the Rtx®-Dioxin2 column an
excellent choice for single column analyses of
dioxins and furans (Tables I and II.)
Figure 1 shows fly ash samples, run under the same
chromatographic conditions used to characterize
the column. 2,3,7,8-tetrachlorodibenzofuran is
not resolved under these conditions. However, the
characterization study used simple linear temper-
ature programming, and additional work exploring
nonlinear oven programs and different flow
parameters yielded better resolution between
some congeners, especially 2,3,7,8-TCDF (data
available upon request). The value in this work is
not necessarily to show complete separation of all
the congeners on a single column, but to show
where all of the 136 compounds of interest elute,
making all possible coelutions known.
• Known elution orders for all tetra- through octachlorinated dioxin and furan congeners.
• Resolve 14 of 17 tetra- through octachlorine 2,3,7,8-substituted dioxins and furans.
• TCDD and TCDF specificity, with a column stable up to 340°C.
Figure 1
GC/HR-MS analysis of tetrachlorinated dioxins in fly ash
on an Rtx®-Dioxin2 column.
Figure 2
GC/HR-MS analysis of tetrachlorinated furans in fly ash on
an Rtx®-Dioxin2 column.
Column:
Rtx
®
-Dioxin2, 40m, 0.18mm ID, 0.18µm (cat.# 10759)
Sample:
TCDDs in fly ash
Inj.:
1µL splitless
Inj. temp.:
280°C
Carrier gas:
helium, constant flow
Flow rate:
1mL/min.
Oven temp.:
120°C (hold 1 min.) to 160°C @ 10°C/min. to 320°C @ 4°C/min. (hold 4 min.)
Det.:
Waters AutoSpec Ultima HRMS
Ionization:
EI
Mode:
SIM
Peak List:
TCDDs as labeled
Sample:
TCDFs in fly ash
Peak List:
TCDFs as labeled
See Figure 1 for conditions
GC_EV01027
GC_EV01026