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By Corby Hilliard and Amanda Rigdon
• Keep your instruments running longer. Fewer particle obstructions mean less maintenance and
more reproducible retention times.
• Water minimally impacts retention, allowing the analysis of water-containing samples without thermal
conditioning between analyses.
• Versatile column is ideal for many applications including hydrocarbons, halogenated compounds, and sulfur gases.
Porous layer open tubular (PLOT) columns are very useful to GC
analysts working on a wide variety of applications, and their unique
selectivity makes them particularly good for separating gaseous
compounds without cryogenic cooling. However, traditional PLOT
columns are hampered by the characteristic instability of the porous
layer that coats the inside of the column. With most PLOT columns,
particles are shed from this layer and create significant problems
because they form obstructions inside the column that alter flow and
cause retention-time instability. In addition, particle buildup makes
frequent maintenance necessary as jets become obstructed, valves
are damaged, and detectors are contaminated.
In contrast, new Rt®-Silica BOND columns from Restek are exception-
ally robust due to optimized manufacturing and deactivation steps
that greatly reduce particle release. These proprietary techniques
result in an extremely stable porous layer. As shown in Figure 1, the
Rt®-Silica BOND column shows no visible shedding of particles or
peeling of the coating layer. In comparison, the non-Restek® PLOT col-
umn in the figure exhibits uneven coating as well as areas where the
particles have completely detached from the column wall. The excep-
tional stability of Rt®-Silica BOND columns—in combination with their
high loadability, inertness, and consistent selectivity—make these
columns the best choice for the analysis of light hydrocarbons, sulfur
gases, and halocarbons.
Minimize Downtime with Virtually Particle-Free
PLOT Column Performance
The nearly particle-free nature of Rt®-Silica BOND columns can be
demonstrated by a particle-generation experiment in which a column
is temperature- and pressure-ramped multiple times. Changes in
temperature cause changes in pressure, which can result in particle
shedding with conventional PLOT columns. The free particles generate
large spikes when they hit the flame ionization detector (FID), which
interferes with quantification. Figure 2 shows that no particle spikes
were generated when this experiment was carried out on a brand
new Rt®-Silica BOND column (Figure 2). The highly stable nature of an
Rt®-Silica BOND column improves lab productivity by greatly reducing
the particle shedding that can interfere with quantification and result
in more frequent maintenance to replace obstructed FID jets and
damaged valves.
Get Reliable PLOT Column Performance with
Less Downtime for Maintenance by Switching to
Virtually Particle-Free Rt®-Silica BOND Columns
Figure 1:
Traditional non-Restek® PLOT columns (middle)
have an uneven coating of particles that can shed, foul-
ing instrument parts. Rt®-Silica BOND columns (top) have
a very fine porous layer with no visible particles and look
very similar to wall-coated open tubular columns (bottom).