17
Rtx
®
-5MS
FusedSilica (
Crossbond
®
5% diphenyl - 95%
dimethyl polysiloxane) Stable to 360°C
Rtx
®
-5MSandRtx
®
-5SilMSColumns
Conventional capillarygas chromatography (GC) columns use liquid stationaryphases,many
ofwhich are crossbonded toyield ahigherworking temperature. Evenwith crossbonding,
however, the liquid stationaryphasewill slowly elute.This elutionof the stationaryphase,
also termed columnbleed, ismoredetectable at higher temperatures and is typicallyobserved
as an increasingbaseline that follows theoven temperatureprogram.Dependingon the
methodof detection, columnbleedmaynot be an issue for certain separations. If the capillary
column is connected to a sensitive detector like amass spectrometer (MS), then columnbleed
can cause anumber of problems—specificallymisidentificationof analytes, loss of sensitiv-
ity, and inaccuratequantitation.
The level of columnbleedwill affect the senstivityof anyMS, especially ion trap instru-
ments,whichuse automatic gain control.As the level of columnbleed increases, sodoes the
signal frombleed ions in themass spectra of analytes andunknowns.Also, sensitivity (or
detection limit) severelydegrades. The contributionof bleed ions to themass spectra can
result inmisidentificationof compounds, requiring laboratorypersonnel to subtract these ions
beforeperforming library searches.Doing so can add considerable time to their analyses.
Finally, if bleed ions contribute to the signal of the quantitationmass, quantitationof analytes
andunknownswill bemiscalculated. For these reasons, it is critical that analysts choose the
lowest-bleed columndesigned forGC/MS applications.
Manymanufacturers offer “MS” phases for applications requiring lowbleed. Inmany cases,
these represent nothingmore than the reportingof the bleed signalwhen the columnwas
tested for a single analysis at themanufacturer. Restekhas developed true low-bleedMS
phases. These columns exhibit amuch lower columnbleed thanwas previously available. The
Rtx
®
-5MS column is a low-bleed, dimethyl/diphenyl polysiloxane phase. TheRtx
®
-5SilMS is
a low-bleed silarylenemethyl/phenyl phase. The combinationofRestek’s polymer chemistry
and rigorousQA testing ensures that eachMS column exceeds requirements of themost
sensitivemass spectrometers.
Rtx
®
-5SilMS
FusedSilica (
equivalent selectivity of Crossbond
®
5% diphenyl/95% dimethyl polysiloxane)
Stable to 360°C
ID
df (µm)
temp. limits
15-Meter
30-Meter
60-Meter
0.25mm
0.10
-60 to330/350°C
12605
12608
12611
0.25
-60 to330/350°C
12620
12623
12626
0.50
-60 to330/350°C
12635
12638
12641
1.00
-60 to325/350°C
12650
12653
0.32mm
0.10
-60 to330/350°C
12606
12609
12612
0.25
-60 to330/350°C
12621
12624
12627
0.50
-60 to330/350°C
12636
12639
12642
1.00
-60 to325/350°C
12651
12654
0.53mm
0.50
-60 to320/340°C
12637
12640
1.00
-60 to320/340°C
12652
12655
1.50
-60 to310/330°C
12667
12670
ID
df (µm)
temp. limits
15-Meter
30-Meter
0.25mm
0.10
-60 to330/350°C
12705
12708
0.25
-60 to330/350°C
12720
12723
0.50
-60 to330/350°C
12735
12738
1.00
-60 to325/350°C
12750
12753
0.28mm
0.25
-60 to330/350°C
12790
12793
0.50
-60 to330/350°C
12791
12794
1.00
-60 to325/350°C
12792
12795
0.32mm
0.10
-60 to330/350°C
12706
12709
0.25
-60 to330/350°C
12721
12724
0.50
-60 to330/350°C
12736
12739
1.00
-60 to325/350°C
12751
12754
0.53mm
0.50
-60 to320/340°C
12737
12740
1.00
-60 to320/340°C
12752
12755
1.50
-60 to310/330°C
12767
12770
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ordering
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for U.S. customers only
Website :
E-mail :
TelNo : 03 9762 2034 . . . inAUSTRALIA
