Shimadzu GC-2014 Instruction Manual

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 carriergas + 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 N2
ԛ Carrier gas Ar

Shimadzu GC-2014 Specifications

General

Type	Gas Chromatograph
Display	LCD
Maximum Heating Rate	120°C/min
Data Acquisition	Digital
Maximum Number of Detectors	4
Weight	Approx. 45 kg
Carrier Gas	Helium, Nitrogen, Hydrogen
Detector Options	FID, TCD, ECD, FPD
Injection Port	Split/Splitless, On-column
Gas Control	Electronic Flow Control (EFC)
Temperature Programming Rate	0.1 to 120 °C/min
Power Requirements	230 V AC, 50/60 Hz
Detector Temperature Range	Up to 400°C (depending on detector type)