ADV06-15_1-412

229 / 413

• 31 •
2008 vol. 1
General Information
Segment coating technology eliminates problematic connections
Both retention gaps and guard columns must be coupled to the analytical col-
umn. While there are several types of effective coupling devices, all can create
dead volume and can be a potential source of leaks and reactivity. Segment
coating technology allows the retention gap or guard column to be built
directly in the same piece of tubing as the analytical column, eliminating the
connector and associated risks. This technology, available from Restek, is
termed Integra-Guard™ or Integra-Gap™ and is based on the static coating
method. In this process the capillary column is filled with a coating solution
of stationary phase in a volatile solvent. The column is sealed on one end and
on the other side a vacuum is applied. The solvent is evaporated and the dis-
solved polymer is deposited on the inside deactivated wall of the fused silica
column. The static coating method allows columns to be coated by segment.
When filling, for example, a 40m capillary with the coating solution, only 30m
are filled. The first 10m remain uncoated, having only the deactivation treat-
ment (Figure 1). This method deposits the stationary phase only in a desig-
nated portion of the capillary, creating the Integra-Guard™ or the Integra-
Gap™. The advantages of this technology are clear: eliminating the connector
removes a potential source of leaks and reduces dead volume. Additionally,
maintenance is faster and simpler since there is no manual connection to make.
Guard columns and retention gaps are useful tools to the practicing chemist,
and it is important to understand the difference between them. While they
help protect analytical columns and focus samples, respectively, they are also
a source of potential problems, such as leaks. Segment coating technology
offers a better solution—integrated columns containing both the guard or gap
section and the analytical column together in a single piece of tubing. These
Integra-Guard™ and Integra-Gap™ columns are a simple, effective solution;
they eliminate the risks of a separate connection and provide stable, accurate data.
Using Guard Columns and Retention
Gaps in GC (Part 2) Continued from page 2.
Figure 1 Static coating allows Integra-Gap™ integrated retention
gaps to be built directly into the analytical column tubing.
Attend a FREE Restek seminar covering basic
fundamentals and practical applications.
Special sections focus on method develop-
ment, transfer, and hands-on tips and tech-
niques.
Course Topics
• HPLC Separation Theory
• The HPLC (and UHPLC) Column
• Developing a UHPLC Method
• Transferring Methods
• Tips and Techniques for UHPLC
Date Location Cat.#
United States
March 17 Columbia, MD 65765
March 18 Bridgewater, NJ 65766
March 20 Malvern, PA 65767
April 23 Atlanta, GA 65768
June 10 St. Louis, MO 65769
June 12 Cincinnati, OH 65770
June 13 Pittsburgh, PA 65771
Canada
April 24 Montreal, PQ 65772
April 21 Toronto, ON 65773
April 22 Toronto, ON 65774
April 23 Burlington, ON 65775
Visit us at for more
information or to register.
Seating is limited—register today and learn
how to improve your analyses with UHPLC!
Interested in Learning
More About UHPLC?
For more information on Integra-Gap™
technology, see “Selecting a GC Column for
Glycerin in Biodiesel” on page 10.