Ghost peaks

Possible Cause

Remedial Action

Contamination (typically injector or column)

Flush the system including the column using an appropriate solvent (see Flushing the Pump with Persistent Contamination Only).

Eluents are degraded, dirty or of poor purity/quality

  • Use fresh and appropriate solvents, for example, MS-grade.

  • Replace the solvent reservoirs using fresh and appropriate solvents (MS-grade) (run the script: B01 - Change Liquids / Solvents).

Negative peaks

Possible Cause

Remedial Action

Different composition of sample solvent and mobile phase

Dissolve the sample in the mobile phase.

Air injected/vial empty

Check whether the vial is empty. Replace the vial with a filled one.

Spikes

Possible Cause

Remedial Action

Electrical interferences from other system modules

  • Avoid operation of equipment generating strong electric or magnetic fields in close proximity.

  • Do not connect equipment that may cause power disturbances to the same power network used to supply the system.

Column temperature significantly above boiling point of mobile phase

When developing methods, prevent the column temperature from getting significantly above the boiling point of the mobile phase.

Solvent insufficiently degassed

Degas solvents in an ultrasonic bath.