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thePerfect
Solution?
Let Restek create theperfect referencemixture—to
your exact specifications. Contact theTechnical Service
Teamor visit us onlineat
Although glass iswidely thought of as an “inert”
material, glass surfaces are, in fact, slightly acidic and
highly adsorptive, due to the presence of silanol
groups (SiOH). These reactive groups interact via
hydrogenbondingwith amine (-NH), carboxylic acid
(-COOH), hydroxyl (-OH), or thiol (-SH) functional
groups, and compounds containing these groups
adsorb tountreated glass surfaces. Tominimize
adsorption in sample preparation glassware and in
theGC sample pathway, andprevent chromatographic
Siltek™/Sulfinert®TreatedElectropolishedStainlessSteelTubing
1
/
8
" OD: 5 ft. to 100 ft. in one continuous coil;
1
/
4
" OD: 5 ft. to 300 ft. in one continuous coil.
Longer lengthswill bemore than one coil.
Price-per-foot
ID
OD
cat.#
5-24 ft.
25-99 ft.
100-299 ft.
>300 ft.
0.085"
1
/
8
"
22538
0.180"
1
/
4
"
22539
Silcosteel®-CRTreatedElectropolishedStainlessSteelTubing
Restek also sets the highest standard in transfer tub-
ing for analytical and process applications. The near-
mirror finish of this electropolished tubing (surface
roughness of only 5-7micro-inches) creates a very
small surface area that, in combinationwith
unequalledRestek surface treatments, ensures supe-
rior inertness (Siltek
™
) or greatly enhanced corro-
sion resistance (Silcosteel
®
-CR). Further, we can
provide continuous coils of
1
/
8
" tubing up to 100 feet
(30.5m) or
1
/
4
" tubing up to 300 feet (91.4m)—a
first for electropolished tubing.
Price-per-foot
ID
OD
cat.#
5-24 ft.
25-99 ft.
100-299 ft.
>300 ft.
0.085"
1
/
8
"
22536
0.180"
1
/
4
"
22537
Siltek
™
andSilcosteel®-CRTreatedElectropolishedStainlessSteelTubing
✔
Exceptional inertness.
✔
Improved reliability and reproducibility; longer lifetime.
✔
Usewith treated fittings for themost inert sample pathway available.
The extremely inert Siltek
™
surface is ideal in sulfurs
or automotive exhaust testing, stack gas sampling,
processmonitoring, or any other application in
which a representative samplemust be transferred
without loss.
In systems used to transfer hydrochloric, nitric, sul-
furic, or other acids, or seawater, Silcosteel
®
-CR
treated electropolished stainless steel tubingwill last
longer and require lessmaintenance. Silcosteel
®
-CR
treated samples were very well protected from pit-
ting and crevice corrosion, compared to bare steel
samples (Table 1 and Figure 1, p. 10).
Formaximum inertness, we recommend a sample
transfer system constructed fromRestek treated
electropolished stainless steel tubing andRestek
treated Swagelok
®
fittings. To find out howRestek
treated components will improve your system’s per-
formance, contact our Technical Service Group (ext.
4), or your Restek representative, and ask to speak
with our coatings experts.
Dimethyldichlorosilane (DMDCS)
Neat, 20mL/ampul
Each
5-pk.
31840
31840-510
DeactivatingGlass Surfaceswith
Dimethyldichlorosilane (DMDCS)
by Jack Crissman, Ph.D., Analytical ReferenceMaterials Product MarketingManager
OH
Si
O
O
O
OH
Si
O
O
O
Si
O
O
O
O
Me
Me
Si
O
O
Si
+HCl
Figure1
Dimethyldichlorosilanedeactivates silanol groupsonaglass surface.
DMDCS
An alternative procedure, polymeric deactivation, providesmaximum coverage of
glass surfaces and should be used to treat inlet liners for critical analyses involving
very low concentrations of highly active compounds (e.g., endrin, DDT, drugs).
All liners supplied by Restek undergo polymeric deactivation.
For ultimate inertness, andmost accurate data for trace levels of reactive analytes,
we recommend Siltek
™
deactivation. Siltek
™
deactivated guard columns, inlet sleeves,
and other glassware are listed in theRestek catalog. For other items, ask our
Technical Service chemists or your Restek representative about deactivation.
tailing or loss of sensitivity at low sample concentra-
tions, it is important to eliminate ormask the reactive
silanol groups.
One popular way to deactivate glass surfaces is to
chemically bond a non-adsorptivemolecule to the
active silanol groups (Figure 1). This typically is
accomplished using dimethyldichlorosilane—
DMDCS. The procedure is suitable formost analyses
that involve concentrated samples and non-active
matrices. It can be followed to clean and deactivate
glass GC inlet liners, derivatization vials, and all
glassware used for preparing analytical reference
materials. Restek now offers DMDCS in 20mL
ampuls, for analysts whowish to deactivate their
glassware themselves.
✔
Convenient 20mL ampuls.
✔
Unopened ampuls have long shelf life.
✔
Detailed deactivation procedure available on request.
Restek
Innovation
!
Alternative
Surface
Treatments
