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• 13 •
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www.restek.com2004 vol. 3
Make GC/MS Column Changes in Minutes
Without Venting
EZ No-Vent
™
Connector Allows Fast Re-equilibration with No Loss of Data
A laser machined critical orifice in the EZ No-
Vent
™
connector minimizes the amount of air
admitted into the MS source, eliminating the
need for purge gas and for the lengthy vent and
pump-down cycle otherwise required with a col-
umn change. This can save hours of downtime
with each column change. The EZ No-Vent
™
con-
nector easily attaches to the MS source without
special tools or extra plumbing: Figure 1 shows
the connector installed and ready for use.
We tested the EZ No-Vent
™
connector for dead
volume, using highly volatile gases that are very
susceptible to tailing. For reference, we operat-
ed the system as a purge-and-trap GC/MS sys-
tem, with a split at the injection port and with
the column inserted directly into the MS inter-
face. When we installed the EZ No-Vent
™
connec-
tor in the MS interface, we anticipated that any
dead volume in the connector would be revealed
by tailing and broader peaks, relative to direct
connection. Peak shape was excellent.
After establishing the connector had no effect
on peak shape, we evaluated the ability of the
MS to stabilize after a column change without
venting. Again we used a purge-and-trap sys-
tem, and halogenated volatiles as the analytes.
We acquired Figure 2a, changed the column,
and acquired Figure 2b 76 minutes later. Note
the peak shapes and responses are unchanged.
In the interval between the two analyses we
verified MSD tuning, and the system passed bro-
mofluorobenzene (BFB) criteria. Subsequent
detailed investigations confirmed the EZ No-
Vent
™
connector will allow several column
changes in a single day, with no harm to the MS
or loss of data.
If you're tired of waiting for your MS to stabilize
after column changes, we highly recommend an
EZ No-Vent
™
connector. It will greatly reduce
downtime and increase sample throughput.
by Brad Rightnour, Instrument Innovations Manager,
and Christopher English, Environmental Innovations Chemist
•Cut downtime by 50% or more when changing columns.
•No special tools - no extra plumbing - low cost.
•Gold plated for inertness.
• 100µm ID transfer line keeps analytes focused.
a)
First column, equilibrated system
b) With EZ No-Vent™ connector, acquired 76 min.
after installing new column
Figure 2
Sample acquired within an hour and a half after changing columns, using an EZ No-Vent™ connector.
Figure 1
MS transfer line installed in an
EZ No-Vent™ connector. Connection can be
made quickly, without special tools.
EZ No-Vent
™
GC Column-Mass Spectrometer Connector
Description
qty.
cat.#
price
EZ No-Vent
™
Connector Kit for Agilent 5971/5972 and 5973 GC/MS
Kit includes: EZ No-Vent
™
Connector, two 0.4mm ID ferrules for capillary col-
umn, two 0.4mm ID ferrules for transfer line, 100µm deactivated transfer line
(3 ft.), column plug, column nut.
kit
21323
$175
Replacement ferrules for connecting capillary column to EZ No-Vent
™
:
0.4mm ID
2-pk.
21015
$28
0.5mm ID
2-pk.
21016
$28
Replacement ferrules for connecting transfer line to EZ No-Vent
™
: 0.4mm ID
2-pk.
21043
$25
Replacement 100µm deactivated transfer line
3 ft.
21018
$20
Replacement EZ No-Vent
™
Column Nut
5-pk.
21900
$30
Replacement EZ No-Vent
™
Plug
2-pk.
21915
$36
Open-End Wrenches (
1
/
4
" x
5
/
16
")
2-pk.
20110
$25
5 6
4 3
7 8 9 10 11 12 13 14 15 16 17 18 19
min.
20
Conditions for both chromatograms:
Rtx
®
-624 column, 60m, 0.25mm ID, 1.4µm (cat# 10969) using
Ez-No Vent
™
, column #1, equilibrated system.
Halogenated Volatiles @ 200 ppb in water.
Inj.:
purge & trap
Inj. temp.:
300°C
Carrier gas:
helium, constant flow, 1.0mL/min.
Oven temp.:
60°C (hold 15 min) to 220°C @ 30°C/min. (hold 1 min).
Det:
Agilent 5973 GC/MS
GC_EV00659c
3 4 5 6 7 8 9 10 11 12
20 min.
13 14 15
19 18 17 16
GC_EV00659d
Restek offers supplies
and innovative tools
for your MS. Refer to
our general catalog.
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?
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!