Fully automatic headspace samplerIt is a key supporting equipment for gas chromatography detection of VOCs, and its operational stability directly affects the quality of detection data. In daily use, problems such as poor injection accuracy, abnormal peak shape, and equipment alarms are prone to occur. The following are the core issues and corresponding solutions.
1、 Poor injection accuracy (RSD>1.5%). This is often caused by poor sealing of the headspace bottle, fluctuations in carrier gas pressure, or insufficient sample balance. Countermeasure: Replace the aging sealing gasket and tighten the bottle cap according to the specified torque; Check the carrier gas system to ensure stable pressure ≤ 0.01MPa; Extend the equilibrium time or increase the temperature appropriately to ensure that the sample evaporates fully.
2、 Abnormal chromatographic peak shape (peak broadening, tailing, ghost peak). Mainly caused by low pipeline temperature, pipeline contamination, or improper injection speed. Countermeasure: Raise the pipeline temperature to 10-20 ℃ above the boiling point of the sample; Clean the pipeline with organic solvents or blow it with high temperature, and replace the injection port gasket; Adjust the injection speed and adopt the pressure balanced injection mode.
3、 Equipment alarm (temperature/pressure/leakage). Temperature alarm requires checking the sensor or heating module, re fixing or replacing damaged components; Pressure alarm should investigate the pressure of the carrier gas cylinder and pipeline leaks, tighten the joints or replace the pipelines; Leakage alarm requires replacement of damaged sealing gasket and inspection of pipeline joint sealing.
4、 The injection needle is blocked/stuck. Mostly caused by residual impurities in the sample or insufficient lubrication of the driving mechanism. Countermeasure: Rinse the injection needle with organic solvent, and if necessary, use fine steel wire to clear it; Regularly clean and add specialized lubricants to the drive mechanism, and replace the injection needle in a timely manner when damaged.
Strict adherence to operating standards in daily life, regular maintenance of equipment, and optimization of sample pre-treatment can effectively reduce the occurrence of failures and ensure efficient and accurate testing.