Waters Viridis SFC Columns - Manual (Page 4)

[ Care and Use ManUal ]
4 Viridis SFC Columns
3. If a leak occurs between the stainless steel compression screw
fitting and the column endfitting, a new compression screw
fitting, tubing and ferrule must be assembled.
4. An arrow on the column identification label indicates correct
direction of solvent flow.
Correct connection of 1/16 inch outer diameter stainless steel tub-
ing leading to and from the column is essential for high-quality
chromatographic results. Tubing touches the bottom of the column
endfitting, with no void between them. Extra column peak broadening
can destroy a successful separation. The choice of appropriate column
connectors and system tubing is discussed in detail below.
Figure 1: Waters and Parker Ferrule Types
0.130 inches 0.090 inches
Parker Style Ferrule Settings Waters Ferrule Settings
Various column manufacturers have employed different types of
chromatographic column connectors. The chromatographic performance
of the separation can be negatively affected if the style of the column
endfittings does not match the existing tubing ferrule settings. This
section explains the differences between Waters style and Parker style
ferrules and endfittings (Figure 1). Each endfitting style varies in the
required length of the tubing protruding from the ferrule. The Viridis
SFC column is equipped with Waters style endfittings that require a
0.130 inch ferrule. If a non-Waters style column is presently being
used, it is critical that ferrule depth be reset for optimal performance
prior to installing a Viridis SFC column.
In a proper tubing/column connection (Figure 2), the tubing touches
the bottom of the column endfitting, with no void between them.
Figure 2: Proper Tubing/Column Connection
The presence of a void in the flow stream reduces column performance.
This can occur if a Parker ferrule is connected to a Waters style end-
fitting (Figure 3).
Figure 3: Parker Ferrule in a Waters Style Endfitting
Void
Note: A void appears if tubing with a Parker ferrule is connected to a
Waters style column.
To fix a void, cut the end of the tubing with the ferrule, place a new
ferrule on the tubing and make a new connection. Before tightening
the screw, make sure that the tubing bottoms out in the endfitting of
the column.
Conversely, if tubing with a Waters ferrule is connected to a column
with Parker style endfitting, the end of the tubing will bottom out
before the ferrule reaches its proper sealing position. This will leave a
gap and create a leak (Figure 4).
Figure 4: Waters Ferrule in a Parker Style Endfitting
Gap
Note: The connection leaks if a Waters ferrule is connected to a column
with a Parker style endfitting.
There are two ways to fix a leak:
1. Tighten the screw a bit more. The ferrule moves forward, and
reaches the sealing surface. Do not overtighten since this may
end in breaking the screw.
2. Cut the tubing, replace the ferrule and make a new connection.