Baseline drift

Cause and solution

Column temperature fluctuations: Control the temperature of the column and mobile phase, and check whether there are open windows or air conditioners facing the column oven.

Contaminated or gassed flow cell: flush the flow cell with methanol or other strong polar solvent (preferably disconnect the column). Use 1N nitric acid (do not use hydrochloric acid) if desired.

Insufficient energy of the UV lamp: Replace with a new UV lamp.

Mobile phase contamination, deterioration, or low-quality solvents: Check the composition of the mobile phase and use high-quality chemical reagents and HPLC-grade solvents.

The pH value of the mobile phase is not adjusted well: add an appropriate amount of acid or base to adjust to the optimal pH value.

Retention time change

Cause and solution

Column temperature variation: Allow sufficient time to equilibrate the column before each run.

Column not equilibrated well: Allow sufficient time to equilibrate the column before each run.

Column contamination: Flush the column daily.

Changes in column conditions: stabilize the injection conditions and adjust the mobile phase.

Column lifetime expired: replace the column.

Tailing peak

Cause and solution

Column overloading: reduce sample volume, increase column diameter and use higher capacity stationary phase.

Column interference: clean the sample, adjust the mobile phase.

Decreased column efficiency: Use lower corrosion conditions, replace the column, and use a guard column.

The sintered stainless steel in the column fails: replace the sintered stainless steel, add an in-line filter, and filter the sample.

Column collapsed or short channels formed: Replace the column, using less aggressive conditions.

Excessive dead volume or extra-column volume: Minimize connection points, make appropriate adjustments for all connection points, and use thinner ID connecting tubing whenever possible.

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