$400
42820
$260
42815
30 to 340/360°C
0.33
0.20mm
$360
42802
30 to 340/360°C
0.18
0.18mm
temp. limits
df (µm)
ID
A single analysis of semivolatile organic com-
pounds inwater, performed according toUS EPA
Method 8270D or other GC/MSmethods, can
involve 100 ormore analytes havingwidely
diverse chemical properties and reactivity.This
complexity puts stringent demands on the col-
umn used to perform the analysis. Some ana-
lytes elute at
high tempera-
tures, for
example, so
column bleed
must be low at
high tempera-
ture.The col-
umn alsomust
exhibit excel-
lent efficiency,
to resolve closely eluting compoundswith simi-
larmass spectra, and overcome challenges to
high sensitivity and low detection limits, for reli-
able quantification of all target compounds.
In
Advantage
2004v2 (literature#59037) we
showed how a 20m, 0.18mm ID, 0.18µm df
Rtx
®
-5Sil MS column (cat.# 42702) offers excel-
lent selectivity, improves detection limits, and
increases productivity in an analysis of a com-
plexmixture of EPAMethod 8270 semivolatile
compounds. Here, we show equally notable
results from our ultra-low-bleed Rtx
®
-XLB col-
umn, in equivalent dimensions, under equivalent
conditions.
A 20m, 0.18mm ID, 0.18µm df Rtx
®
-XLB column
(cat.# 42802) is an excellent choice for analyz-
ing semivolatile compounds.The Rtx
®
-XLB sta-
tionary phase is specifically designed for the
demandingGC/MS analysis of semivolatiles, and
these columns exhibit extremely low bleed.
Figure 1 (page 3) is a chromatogram for nearly
90 analytes and surrogates, at 2.5ng each on-
column, showing excellent resolution and negli-
gible baseline rise at 330ºC.The short length
and small internal diameter of these columns
ensure faster runtimes, increasing productivity:
the last compound elutes in less than 18min-
utes.The thin phase film allows satisfactory res-
olution of structural isomers benzo(b)fluoran-
thene and benzo(k)fluoranthene in this very
short analysis time. Peak shape and response
are excellent for active compounds such as pyri-
dine (peak 1), 2,4-dinitrophenol (peak 54), and
pentachlorophenol (peak 66); even at this low
concentration, all compounds can be quantified
with high accuracy.
The temperature program, aswell as the physi-
cal dimensions of the column, contributes to bet-
ter resolution of closely eluting peaks and short-
ens the analysis time.The column accommo-
dates the 330°C final temperature verywell,
Fast,SensitiveGCAnalysesofSemivolatile
Organics inWater
Using an 0.18mm IDRtx
®
-XLB Column
by Christopher English, Environmental Innovations Chemist
•Extremely low bleed—ideal for GC/MS applications.
•Excellent resolution, high sensitivity for semivolatile compounds inwater.
•Stable to 340°C.
!
new
★
Turning Visions into Reality
THE
RESTEK
ADVANTAGE
2004
vol.4
Fast, Sensitive Analysis of SemivolatileOrganics
with an Rtx
®
-XLBGCColumn. . . . . . . . . . . . .
1-3
Siltek
™
and Silcosteel
®
-CRTreatedTubing and
Fittings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-5
GSCAnalysis of Permanent Gases and Light
Hydrocarbons using ShinCarbon ST
MicropackedColumns . . . . . . . . . . . . . . . . . . . . .
6
RedesignedRt-QPLOT
™
Columns for
GSCAnalyses. . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
Analytical ReferenceMaterials Introduced
in 2004. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-9
Pinnacle
™
-DBBase-DeactivatedHPLC
Columns. . . . . . . . . . . . . . . . . . . . . . . . . . . .
10-11
Peak Performers—NewHPLCAutosampler
Syringes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Super-Clean
™
GasTrapping System for LC/MS. . .
13
FIDJets for Agilent GCs. . . . . . . . . . . . . . . . . . . .
14
CoolTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Restek 2005CatalogComing Soon . . . . . . . . . . . .
16
in this issue
because our QA bleed specification for Rtx
®
-XLB
columns, including the new 0.18mm ID, 0.18µm
df column, is less than 6pA at 340ºC.
Optimization of injection conditions also is an
important consideration in this analysis.To
reduce solvent effectswith pyridine and
N
-
nitrosodimethylaminewe chose to use a
splitless injection liner.
(cont. on page 3)
Rtx
®
-XLBColumns
(fused silica)
(proprietary low-polarity phase)
ID
df (µm)
temp. limits*
15-Meter
30-Meter
60-Meter
0.25mm 0.10
30 to 340/360°C
12808
$455
0.25
30 to 340/360°C
12820
$265
12823
$445
12826
$710
0.50
30 to 340/360°C
12838
$445
1.00
30 to 340/360°C
12850
$265
12853
$445
0.32mm 0.10
30 to 340/360°C
12809
$475
0.25
30 to 340/360°C
12821
$285
12824
$470
12827
$770
0.50
30 to 340/360°C
12839
$470
1.00
30 to 340/360°C
12854
$470
0.53mm 0.50
30 to 340/360°C
12840
$525
1.50
30 to 340/360°C
12867
$290
12870
$525
Chromatographyonpage3
*Maximum temperatures listed are for 15- and 30-meter lengths. Longer lengthsmay have a slightly reducedmaximum temperature.
12-Meter
20-Meter
25-Meter
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