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$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 in water, performed according to US EPA
Method 8270D or other GC/MS methods, can
involve 100 or more analytes having widely
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 also must
exhibit excel-
lent efficiency,
to resolve closely eluting compounds with simi-
lar mass spectra, and overcome challenges to
high sensitivity and low detection limits, for reli-
able quantification of all target compounds.
In Advantage2004v2 (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-
plex mixture of EPA Method 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
demanding GC/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 18 min-
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, as well 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 very well,
Fast, Sensitive GC Analyses of Semivolatile
Organics inWater
Using an 0.18mm ID Rtx ® -XLB Column
by Christopher English, Environmental Innovations Chemist
• Extremely low bleed—ideal for GC/MS applications.
• Excellent resolution, high sensitivity for semivolatile compounds in water.
• Stable to 340°C.
!
new
★
Turning Visions into Reality
THE RESTEK ADVANTAGE
2004 vol. 4
Fast, Sensitive Analysis of Semivolatile Organics
with an Rtx® -XLB GC Column. . . . . . . . . . . . . 1-3
Siltek ™ and Silcosteel®-CR Treated Tubing and
Fittings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
GSC Analysis of Permanent Gases and Light
Hydrocarbons using ShinCarbon ST
Micropacked Columns . . . . . . . . . . . . . . . . . . . . . 6
Redesigned Rt-QPLOT™ Columns for
GSC Analyses. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Analytical Reference Materials Introduced
in 2004. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
Pinnacle™ -DB Base-Deactivated HPLC
Columns. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-11
Peak Performers—New HPLC Autosampler
Syringes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Super-Clean ™ Gas Trapping System for LC/MS . . . 13
FID Jets for Agilent GCs . . . . . . . . . . . . . . . . . . . . 14
Cool Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Restek 2005 Catalog Coming 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 effects with pyridine and
N -nitrosodimethylamine we chose to use a
splitless injection liner. (cont. on page 3)
Rtx®-XLB Columns (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
Chromatography on page 3
*Maximum temperatures listed are for 15- and 30-meter lengths. Longer lengths may have a slightly reduced maximum temperature.
12-Meter 20-Meter 25-Meter
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