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Installation
12
Column Connection
To prevent detector contamination, we strongly recom-
mend disconnecting the column from the detector during
column bakeout procedures.
Referenced mode
In the referenced mode, the column is connected to the Channel A inlet, and
the carrier gas stream is split and used as a reference in channel B. The gas
flow rate from both channels must be the same (flow balanced). This mode
of operation provides the best baseline stability and the least background
noise.
Unreferenced mode
In the unreferenced mode, Channels A and B are used independently. One
column connects to the Channel A inlet, and the other to Channel B. The
carrier gas must be the same for both channels.
It is also possible to use only one channel with the other capped off, as long
as the filament temperature control knob of the unused channel is set to
zero.
The unreferenced mode has certain limitations: there is a possibility of
detector cross-talk (interference) if compound concentrations exceed 1%,
and baseline drift and background noise are greater than with the referenced
mode.
To make column connection as convenient as possible, each TCD is
shipped with two Valco 1/16" unions (Product No. ZU1C) complete with
nuts and ferrules (Product Nos. ZN1 and ZF1). Also included are two fused
silica adapters (FSR1.8) for use with .53 mm ID wide bore capillary columns
(.8 mm OD). Refer to the information below to determine the correct Valco
fitting for use with other columns.
Column Connection Fittings
Packed Columns
A 1/16" packed column requires only the ZU1C which comes with the TCD.
For 1/8" columns, order a ZRU21.
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