A simple method for performing backflush with gas-phase microfluidic devices using the Agilent 6890 gas chromatograph is described.
This document outlines a technique to reduce cycle times in gas chromatography (GC) analysis by reversing the flow through the column to remove late-eluting compounds. By configuring the Agilent 6890 to use a Post Run program, users can set specific pressure and time parameters to force sample components back out of the inlet end of the column.
The guide details the setup using microfluidic devices, such as the QuickSwap accessory, and explains how to configure the Column Configuration screen to select the microfluidic pressure source as the inlet for Column 2. It provides specific instructions on setting inlet and outlet pressures, determining the necessary backflush duration based on void times, and optimizing conditions for turbopump systems to ensure effective cleaning of the column and MSD source.
| Minimum controlled inlet pressure | 1.0 psig |
|---|---|
| Maximum allowable flow to MSD | 10-* torr ion gauge reading |
| Recommended backflush duration | at least 5 void times |
The document recommends backflushing for at least 5 void times to ensure all components are removed from the column.
Backflushing should only be done with turbopump systems due to the limited pumping capacity of diffusion pumps.