Configuring the Flame Ionization Detector Makeup Gas for Agilent 7890 GC Systems

Created by Carlos Vargas 2 months ago

This Information Applies To: Agilent GC Systems with Flame Ionization Detector (FID)

Issue

This article will describe how an operator can configure the makeup gas on both the instrument keypad and the software driver (Method Editor).

Background:

The Flame Ionization Detector (FID) on an Agilent Gas Chromatograph (GC) use three types of gasses to maintain a stable flame and signal output. The three gasses are: Hydrogen as fuel, Air as oxidizer, and either Helium or Nitrogen as the makeup gas. Selection between Helium or Nitrogen is a user choice.

Resolution

Warning: Hydrogen gas is flammable and explosive.

In the Agilent FID, make-up gas flow from the EPC module and joins the FID hydrogen flow (see Figure 1). The combined gases flow up through the FID jet where they mix with the GC carrier gas flow. This gas mixture then exits the FID jet and then is combined with the FID Air supporting the FID flame at the base of the FID collector.

FID EPC Agilent.png
Figure 1: 7890 GC FID pneumatics diagram. This illustration shows a 7890 GC system, but this configuration is similar to other models of the Agilent GC systems with EPC control of the FID gases.
1. Hydrogen, 2. Makeup gas, 3. Air, 4. Column, 5. Vent, 6. Frit, 7. Valve, 8. Pressure sensor, 9. Restrictor

Using the instrument keypad

Verify or configure the detector makeup gas type using the 7890A GC Keypad by performing the following steps:

Press [Config][device], where [device] is one of the following
1. [Front Det]
2. [Back Det]
3. [Aux Detector 1]
4. [Aux Detector 2]
Scroll to Makeup gas type (or Makeup/reference gas type) and press [Mode/Type].
Scroll to the correct gas and press [Enter].

Note: The selected makeup gas type must match the gas supply.

Using the software driver

From the acquisition software Method Editor, the user can select Helium or Nitrogen as a makeup gas (see Figure 2).

Note: The selected makeup gas type must match the gas supply.

FID Makup Gas Configuration in GC Driver - Agilent.png
Figure 2: Method Editor of a 7890A GC on OpenLab CDS ChemStation C.01.10. Please note that the same GC drivers are used on other Agilent GC acquisition software products.