TC Description
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2.25 Theory of Operation
The fundamental requirement for a thermal compartment intended for
chromatography applications is the ability to maintain the preset temperature as
precisely as possible. The TC contains advanced electronic circuitry that
maintains the selected temperature with a precision of ±0.1 °C.
The TC can be heated from 5 to 85 °C in 0.1 °C increments. An increase in
temperature from 20 to 50 °C (or a decrease from 50 to 20 °C) is typically realized
in less than 20 minutes. Columns can be warmed up to 85 °C. If the ambient
temperature changes during the analysis, increased heating or cooling ensures that
the column temperature remains constant.
The thermo-optimized design of the TC reduces the time required to equilibrate
the temperature between the column and the eluent. Peltier elements in the TC
heat up and cool down the columns. They also help to bring the air and all of the
installed components (including the injection valves) to the desired temperature.
If necessary, a temperature stabilizer (standard bore, P/N 064548; microbore,
P/N 064650) can be installed in the TC. Installation of a temperature stabilizer
ensures that:
• The stationary phase temperature remains constant over the total column
length.
• The column and the eluent have the same temperature during the analysis.
Under these conditions, the separation is performed at the nominal temperature.
This minimizes fronting and tailing of peaks, as well as retention time variations.
The temperature achieved may vary from the control range, depending on the
ambient temperature (see the table below).
For example, if the ambient air temperature in the lab is 30 °C and you set the
temperature to 5 °C, the actual temperature achieved will be about 12 °C.
Operating IC columns at temperatures above 70 °C (158 °F) may affect
column performance. Before selecting the TC temperature, refer to the
column manual for the recommended operating conditions. Column
manuals are provided on the Dionex Reference Library CD-ROM
(P/N 053891).
Control Range Achieved Temperatures (Based on Ambient)
5 to 85 °C Minimum temperature 18 °C below ambient
Maximum temperature 70 °C above ambient
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