environmental
Applications
note
Restek Corporation • (800)356-1688 • (814)353-1300 •
#59113
environmental
Siltek
™
DeactivationDelivers Inertness toAnalyteBreakdown andReactivity,
andDurability toPhysical andChemical Challenges
1
2
3
4
5
Figure1
Siltek
™
-deactivated liner shows excellent inertness for acidic andbasic probes.
30m, 0.25mm ID, 0.25µmXTI
®
-5 (cat.# 12223) with a Siltek
™
-deactivated 4mm splitless single gooseneck sleeve (cat.# 20798-214.1).
Oven temp.:
40°C
(hold 2min.) to 100°C@ 30°C/min., to 180°C@ 9°C/min., to 330°C@ 30°C/min. (hold 10min.);
Inj. temp.:
250°C;
Det.:
330°C;
Carrier gas:
He.
1. 1,2-hexanediol
2.
N
-nitroso-di-
n
-propylamine
3. benzoic acid
4. C14
5. 2,4-dinitrophenol
6. 4-nitrophenol
7. 4-nitroaniline
8. pentachlorophenol
9. carbazole
10. C20
11. C21
12. C22
13. benzo(b)fluoranthene
14. benzo(k)fluoranthene
A common concern ingas chromatographic (GC) analyses is the
interactionof analyteswith active surfaces in theGCpathway.
The injectionport is the first source of active sites, often leading
to adsorption andbreakdownof analytes.However, not all
analyses are affectedby reactivitywithin the injectionport.
Hydrocarbons, typically, arenot susceptible to adsorptionor
breakdown. In contrast, active compounds such as pesticides,
drugs, phenols, amines, and alcohols,which areoften injected
via splitlessmode, aremore prone to these problems.With a
splitless injection, carrier gas flow rate through the liner is very
slow, increasing the sample residence time in the injector and the
chance for reactivity. Complete and effective liner deactivation is
crucial tominimize available active sites and ensure repeatable
results.
Restekhas designedSiltek
®
deactivation todeliver both en-
hanced inertness anddurability.Gas chromatography accessories
coatedwithSiltek
®
deactivationprovidedurability formatrices
of extremepHor high-temperature applications.
Inertness
Semivolatile analysis places extreme demands on theGC system.
One key to successfully analyzing semivolatiles is having the
capability tohandle basic and acidic compounds in theGC
system. The analytical columnmust provide selectivity for both
classeswithout resulting inpoor peak shape.Additionally, liner
deactivation is critical to analytical success because the vapor-
ized sample comes in contactwith the inlet liner first.
TheRestekXTI testmixwas chosen to evaluate the inertnessof a
Siltek
™
-deactivated liner.Thismixcontainsbothacidicandbasic
probes, someofwhicharepollutantsmonitored inUSEnviron-
mental ProtectionAgency (EPA)Method8270 (4-nitroaniline,
N
-nitroso-di-
n
-propylamine,2,4-dinitrophenol,pentachlorophenol,
benzoicacid, benzo(b)- andbenzo(k)fluoranthene).A splitless
injectionof theXTImixwithanon-columnconcentrationof
4-10ng shows anexcellent response for all of theprobes, including
theactivecompoundsdinitrophenol, 1,2-hexanediol, andbenzoic
acid (Figure1).
6
7
8
9
10 11 12
13
14
