Retention time varies on ACQUITY UPLC H-Class - WKB241683

SYMPTOMS

• Retention time varies (about 0.2 to 0.5 minutes) within one day of measurement
• User has two H-Class; when bringing the column and sample used in the instrument that has a problem and performing measurement in the other instrument, the retention time does not vary
• The number of peaks is 1. Using isocratic conditions (ammonium acetate in water and acetonitrile) and running a gradient, the peak shows
• The initial pressure is about 6000 psi, the same level as the instrument with no problem, and Δpsi is about 10
• When checking the waste in the cylinder, the flow rate is as per the setting

ENVIRONMENT

• ACQUITY UPLC H-Class

CAUSE

FIX or WORKAROUND

1. Mix solvents in a solvent bottle using the ratio of solvents that are mixed on the instrument, and pump for one time.
   - Check to see if there is a problem with the GPV (valve that adjusts the solvent composition).
2. Perform a leak test.
   - This is the procedure to check whether there are any leaks in the flow path.
   Perform a QSM leak test from the console window.
   The end point is performed at the vent valve. If it passes, perform it at the column.
3. Check APH settings.
   - Check the active preheater settings on the "General" tab of the SM-FTN instrument method.
   If "Use Console Setting" is selected, check the console window settings.
4. Clean or replace the solvent filter.
   - Check if the cause is a blockage in the filter at the end of the tube placed in the solvent bottle.
5. Replace the GPV filter.
   - Check if there is a problem with the GPV filter.

ADDITIONAL INFORMATION