Decreasing retention times
Possible Cause | Remedial Action |
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Improper solvent composition |
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Increasing retention times
Possible Cause | Remedial Action |
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Improper solvent composition |
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Decreasing flow rate |
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Scattering retention times
Possible Cause | Remedial Action |
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Pressure fluctuations from pump | Run the script: D02 - Test System Tightness (What Should Be Tested = System). |
Air trapped in the autosampler | Run the script: C04 - Purge Sampler with the parameter: Inner Needle Wash Weak Liquid. |
Shifts in retention time for a longer period
Possible Cause | Remedial Action |
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After changing the solvents, the previous solvent has not been removed completely from the pump. | Purge the pump. |
Column temperature, sample temperature or solvent temperature is instable | Wait until the column temperature, sample temperature or solvent temperature is fully equilibrated. |
Retention time outside the expected range
Possible Cause | Remedial Action |
---|---|
The thermal flow sensors may have a small drift or a shift. | Run the script: C01 - Adjust Pump Flow Sensor Offsets. |
Pre-mixed solvents are too old. |
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Pre-heater used in nano LC applications | Remove the pre-heater (see Replacing the Passive Pre-Heater). |
Wrong volume after the column | Check the volume of the capillary connected to the OUT port of the column. |
Sample loop variant does not match the set variant | Check whether the setting for the sample loop matches the installed one and correct it if necessary. |
Solvent in solvent reservoir does not match the solvent setting | Change the solvent in the solvent reservoir or change the solvent setting. |