13 Detector
13.2 Thermal Conductivity Detector (TCD)
166
GC-2014
SIGNAL POLARITY
Selection: +/-, Default: +
When analyzing compounds with a thermal conductivity higher than the carrier gas,
baseline peaks are inverted (negative). When this occurs, switch to a polarity of “-” to
produce positeve peaks.
CURRENT
Range: 0
−
200 mA, Default: 0 mA
The TCD sensitivity is approximately proportional to the cube of the current.
If the sensitivity is insufficient, increase the current within the range shown in
Fig. 13.2.3. The maximum operating current is determined by the detector temperature
and the carrier gas type. Keeping the current highre than necessary shortens the fila-
ments life and can cause baseline drift.
Fig. 13.2.3
Maximum operating current
CAUTION
If the current is turned on before the carr make up gas has
completely replaced the air, the filament can be blown.
Ensure that the current is set to “0” at first. Press the [SYSTEM] key
main screen, allow carrier gas to flow for approximately 10 minutes,
then set the current.
CAUTION
To avoid broken filaments and poor performance, set the current
below the valves indicated by the curves below.
Ԙ
Ԛ
ԙ
ԛ
Current
(mA)
200
100
0
100
200
300
400
TCD temperature(
͠
)
Ԙ
Carrier gas He
ԙ
Carrier gas H
2
Ԛ
Carrier gas N
2
ԛ
Carrier gas Ar
Содержание GC-2014
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Страница 12: ...Contents viii GC 2014 This page is intentionally left blank ...
Страница 28: ...1 Installation 1 3 Gas Supply Plumbing 16 GC 2014 This page is intentionally left blank ...
Страница 42: ...2 Before Use 2 6 Connecting the Relay Terminals 30 GC 2014 This page is intentionally left blank ...
Страница 78: ...5 Analysis 5 2 Notes for Analysis 66 GC 2014 This page is intentionally left blank ...
Страница 90: ...6 Basic Key Operation 6 4 Getting Help 78 GC 2014 This page is intentionally left blank ...
Страница 130: ...11 Creating an Oven Temperature Program 11 2 Temperature Programs 118 GC 2014 This page is intentionally left blank ...
Страница 164: ...12 Injection Port 12 5 Setting the Flow Rate Parameters 152 GC 2014 This page is intentionally left blank ...
Страница 282: ...16 Special Functions 16 10 ROM Version No 270 GC 2014 This page is intentionally left blank ...
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