Indian Council of Agricultural Research
(Agricultural Knowledge Management Information System)

ICAR-Indian Institute of Soil Science, Nabi Bagh, Berasia Road, Bhopal-462038 Madhya Pradesh (
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Instrument Details
Instrument/Facility Name: Gas Chromatograph
Make                                   : M/s Agilent Technologies
Model                                  : 7890A
Specification   :Gas chromatography for greenhouse gas (GHGs) analysis

Click to ViewAgilent 7890A GC systems. This said GC has been specially designed simultaneous analysis of for greenhouse gases (GHGs). Two analytical methods based on the Agilent 7890A GC system are developed for simultaneous analysis of methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O) in air samples. Each system has its own features to meet different requirements of greenhouse gases analyses. Results from both methods demonstrated high sensitivity and excellent repeatability for the required analyses.

  Working Principles
Click to ViewThis system consists of two separate channels with 1/8-in stainless steel packed columns (HayeSep Q 80/100). The first channel employs two valves with TCD and FID. The TCD and methanizer-FID are connected in series to measure CH4 and CO2. This channel provides the flexibility for CO2 in varying levels. Low level CO2 can be converted to CH4 through the methanizer and measured by FID. The system is flexible depending on the requirements. The TCD can be used for high concentrations of CO2. If only higher levels of CO2 (higher than 50 ppm) analysis is required, the methanizer can be removed. This channel can be expanded to include O2 and N2 analysis by adding an additional Molsive column. Another micro-ECD channel with two valves is dedicated to measuring N2O. Precolumns (column 1 and 2) direct heavier components (mainly water) to be backflushed to vent 1 and vent 4. O2 should be excluded from the methanizer and micro-ECD and vented through vent 2 and vent 3. A typical plumbing diagram for this setup is shown in Figure 1.

  User Instructions
Agilent 7890A GC systems have been developed to meet the different requirements for simultaneous analyses of greenhouse gases including CH4, CO2, and N2O in air samples. Method (SP1 7890-0467) has two separate channels with three detectors and can achieve even faster results. The separate channels increase flexibility to make the valve switching time less critical and the method easier to set up. The use of the third TCD allows measurement of a wide concentration range of CO2 (0.2 ppm to 20%). Results obtained on both analyzers are the same for greenhouse gases (N2O, CH4, and CO2). The users are advised to analysis gas samples immediately after collection of samples from the field.

  Contact Us
Contact No. 0755-2730970
Email Id

  Gas Chromatograph Charges
Procedure Name
National LAB/R&D
GHG analysis
Rs 2000*
Rs 1000*
Rs 1000*
*Tentative cost/sample

Additional Rs 100/-towards postal charges if result are to be posted
The Demand Draft should be in favour of "Director, ICAR-IISS, Bhopal"
Letter, DD & Samples send to "Additional Rs 100/-towards postal charges if result are to be posted The Demand Draft should be in favour of "Director, ICAR-IISS, Bhopal" "