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Are Your Volatiles Methods Slowing You Down?
Minimize Downtime with an Rxi®-624Sil MS and
Our Synchronized GC Conditions
By Michelle Misselwitz, Innovations Chemist, Gary Stidsen, Product Manager, and Chris English, Innovations Manager
Maximizing sample throughput while maintaining adequate res-
olution can be a delicate balancing act when analyzing volatile
organic compounds (VOCs). Conditions optimized for resolution
can result in long analysis times, but using faster run times can
result in problematic coelutions. Often, “624” type columns are
chosen for their selectivity, but thermal stability is usually poor,
resulting in phase bleed that decreases detector sensitivity. New
Rxi®-624Sil MS columns offer reliable resolution of VOCs and also
provide lower bleed and greater inertness than other 624
columns. Labs interested in optimizing sample throughput and
resolution can adopt the synchronized conditions established here on Rxi®-624Sil MS
columns to maximize productivity and assure accurate, reliable results.
Reduce Downtime and Resolve Critical Pairs
In order to minimize downtime between injections while ensuring good resolution, we
established parameters that synchronized the purge and trap and instrument cycles while
maintaining desired separations. Several critical pairs were chosen for computational mod-
eling using Pro ezGC software. The initial temperature program determined by the soft-
ware provided the best resolution, but resulted in an analysis time of 19 minutes. Since the
purge and trap cycle time was 16.5 minutes, we tested other conditions to see if adequate
resolution could be maintained using a faster instrument cycle. The program shown in
Figure 1 reduced instrument downtime by better synchronizing injection and analysis, and
also provided excellent resolution. Using a highly inert, low bleed Rxi®-624Sil MS column
under the conditions established here, optimizes sample throughput while assuring good
resolution of volatile organic compounds.
For the complete version of this condensed article, visit
• Optimized analysis allows for 36 runs per 12-hour shift,
increasing instrument productivity.
• Rxi®-624Sil MS column selectivity and inertness resolve
critical pairs.
• High temperature stability reduces bleed profile,
resulting in lower detection limits.
Want lower detection
limits for active
compounds?
See page 2 to learn why Rxi®-624Sil MS
columns improve sensitivity, accuracy,
and MS performance for active analytes.
environmental
ID(mm) df (µm) temp. limits length* cat. #
0.18 1.00 -20 to 300/320°C 20 13865
0.25 1.40 -20 to 300/320°C 30 13868
0.32 1.80 -20 to 300/320°C 30 13870
*Length in meters
Rxi®-624Sil MS Columns (fused silica)
(mid polarity Crossbond® silarylene phase; equivalent to
6% cyanopropylphenyl/94% dimethyl polysiloxane) complete environmental solutions
columns • standards • accessories
technical resources
Get it at
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Website : E-mail : TelNo : 03 9762 2034 . . . in AUSTRALIA