Baseline issue with gas chromatograph:

1、 No peak or very small peak:

1Possible reasons: The detector is turned off or not lit.

Exclusion method: Re ignite.

2Possible cause: Leakage at the injection port.

Exclusion method: Replace the rubber pad.

3Possible reason: The temperature in the gasification chamber is too low, and the sample cannot be gasified.

Exclusion method: Increase the gasification temperature.

4Possible reason: There is no air flow inside the column.

Exclusion method: Check.

5Possible reason: The connection between the chromatographic column and the injection port or detector is incorrect.

Exclusion method: Tighten the joint.

6Possible cause: Recorder malfunction.

Exclusion method: Maintenance.

7Possible cause: Blockage of detector nozzle.

Exclusion method: Cleaning.

2、 During isothermal conditions, the baseline drifts in one direction or irregularly:

1Possible cause: Leakage at the entrance of the column.

Exclusion method: Eliminate air leakage.

2Possible reason: The supplementary air flow rate is too low.

Exclusion method: Increase the tail air flow rate.

3Possible reason: The detector furnace temperature has changed and has not reached equilibrium.

Exclusion method: Allow sufficient time for the baseline to stabilize.

4Possible cause: Fixed liquid loses heat.

Exclusion method: Aging the chromatographic column and adjusting the temperature.

5Possible reasons:FIDThe flow rate of hydrogen gas varies.

Exclusion method: Check the pressure and flow rate control of the gas cylinder.

6Possible cause: Detector leakage.

Exclusion method: Replace the sealing gasket.

3、 Baseline increase during program heating:

1Possible cause: Exceeding the column temperature limit.

Exclusion method: Reduce high temperature.

2Possible cause: The column is contaminated.

Exclusion method: Check the gas filter and aging chromatographic column.

3Possible cause: Detector leakage.

Exclusion method: Replace the sealing gasket.

4Possible cause: Poor chromatographic column.

Exclusion method: Aging chromatographic column.

5Possible cause: Increased loss of column fixed phase.

Exclusion method: This phenomenon is normal within the temperature range of use.

4、 Poor precision and quantitative repeatability:

1Possible cause: Wear of the injection needle.

Exclusion method: Replace the injection needle.

2Possible reason: Poor injection technique.

Exclusion method: Improve the injection technique.

3Possible cause: contamination of the injection port.

Exclusion method: Clean the lining tube and replace the quartz wool.