RestekTrademarks:
Crossbond,Rtx, and theRestek logo.
Product Listing
Rtx
fi
-5MSColumns
ID df ( m)
temp. limits
20-Meter 40-Meter
0.10mm
0.10 -60 to 330/350C 58136
0.18mm
0.18 -60 to 330/350C
550590
Because anMS is used for detection,many analystswant a col-
umnwith the lowest bleed possible. Some laboratoriesmay use
silarylene columns (e.g., Rtx
fi
-5SilMS orDB-5MS
fi
columns)
due to their low bleed feature. However, these columns yield a
coelution between 2,3,7,8-TCDD and 1,2,3,9-TCDD; and their
elution orders and retention timeswill differ from the phase for
which thewindow performancemixtureswere designed. The
Rtx
fi
-5MS (5% diphenyl/95% dimethyl polysiloxane) column is
better suited tomeet the performance standards for this analysis.
It separates all of the important compoundswithin 30minutes,
and each one is individually tested to provide low bleed levels
forMS detection.
Chromatographic resolution and analysis time also aredependent
on columndimensions (i.e., length, ID, phase thickness).
Experimentally,wehave found175,000plates are required to
obtain separationof 2,3,7,8-TCDD from its nearest neighbors
(1,2,3,7- and 1,2,3,8-TCDDthe unresolved pair eluting before;
and 1,2,3,9-TCDDthe compound eluting after).
3
A40m, 0.18mm
ID, 0.18mRtx
fi
-5MS columnmeets this criteria, and can com-
plete the analysis in approximatelyhalf asmuch time as a60m
column.A20m, 0.10mm ID, 0.10mRtx
fi
-5MS column is capable
ofmeeting these requirements in about one-quarter the timeof a
60m column; however, there is little tubing length available for
trimming tomaintain columnperformance. Therefore,we suggest
using a40m column.
Tominimize the number of ions thatmust bemonitored simulta-
neously, elute the bulk of PCB compounds prior to eluting dioxin
and furan compounds.Accomplish this by injecting the non-
coplanar PCB fraction into a 20mRtx
fi
-5MS column that is set
up parallel (i.e., two separate injectors) to a 40mRtx
fi
-5MS col-
umn, which is used for the separation of the dioxin/furan/copla-
nar PCB fraction. Both fractions are injected simultaneously. The
*KarenMacPherson andDr. Eric Reiner, OntarioMinistry of the Environment..
References
1.Berg,M. V., L. Birnbaum,A.T.C. Bosveld, B. Brunstrom, P. Cook,
M. Feeley, J.P. Giesy,A. Hanberg, R. Hasegawa, S.W. Kennedy, T.
Kubiak, J.C. Larsen, F.X.R. Leeuwen,A.K.D. Liem, C. Nolt, R.E.
Peterson, L. Poellinger, S. Safe, D. Schrenk, D. Tillitt,M.
Tysklind,M.Younes, F.Waern, andT. Zacharewski,
Environmental Health Perspectives, 106 (1998), p. 775.
2.KolicT.M., K.A.MacPherson, E.J. Reiner, T. Gobran, andA.
Hayton, OrganohalogenCompounds, 46 (2000), p. 562.
3.Reiner E.J., K.A.MacPherson, R. Brunato, T. Chen,M.A. Bogard,
A.R. Boden, andG. Ladwig, OrganohalogenCompounds, 45
(2000), p. 17.
columns are installed into theMS ion source in parallel. The
resulting analysis time is less than that for a single fraction on a
conventional 60m column (Figure 1). Table I summarizes the
high resolutionMS conditions andwhichmasses aremonitored
forwhich compound.
For the analysis of dioxin-like PCBs and dioxins/furans,method
consolidation and throughput increase is possiblewhen using a
parallel, dual-column systemwithGC/HRMS. Thismethod
allows the combination of several different analyticalmethods to
a single system, and results in a total analysis time of less than 30
minutes for elution of octachlorodibenzodioxin.
