Preventive Maintenance

Electron capture detector (ECD)

Packed column:

1.Close the anode purge on/off valve.

2.Remove the column from the detector; install in its place an empty glass column.

3.Establish normal carrier gas flow rate (20 to 30 ml/min); set oven temperature to 250^C.

4.Open the anode purge on/off valve.

5.Heat the ECD to 350^C. Allow thermal cleaning to continue for 3 to 12 hours. If the displayed value does not drop below 60 (600Hz), indicating a high background signal, it is recommended that the detector be returned to Hewlett-Packard for cleaning.

Capillary column:

1.Close the makeup gas and anode purge on/off valve.

2.Remove the column from the makeup gas detector.

3.Install a paper clip or similar gauge wire in the same manner as a capillary column.

4.Open the makeup gas on/off valve and establish a makeup gas flow rate of 50 to 60 ml/min.

5.Open the anode purge on/off valve.

6.Set the oven temperature to 250^C.

7.Heat the ECD to 350^C. Allow thermal cleaning to continue for 3 to 12 hours. If the displayed value does not drop below 60 (600Hz), indicating a high background signal, it is recommended that the detector be returned to Hewlett•Packardfor cleaning.

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