Hello My Agilent HPLC has problem with retention time change every day. We changed MCV and plungers and all. But still same. How to fix this

Hi Tenamyd 

Maybe a bit more detail would help to get you an answer.  Here's a few questions:

• Is the method gradient or isocratic
• Do you prepare the mobile phase freshly each day
• Is the column maintained at a set temperature using a column oven/thermostat
• Is there just variability day-to-day, or is there the same variability across the day
• Provide us more details about the HPLC - what modules does the system contain; I can tell that you have a quaternary pump, since you mention changing the MCGV
• Have you carried out any tests on the pump, either leak rate test or gradient test?

Probably enough questions for now.

/Andy

Hi Tenamyd 

Maybe a bit more detail would help to get you an answer.  Here's a few questions:

• Is the method gradient or isocratic
• Do you prepare the mobile phase freshly each day
• Is the column maintained at a set temperature using a column oven/thermostat
• Is there just variability day-to-day, or is there the same variability across the day
• Provide us more details about the HPLC - what modules does the system contain; I can tell that you have a quaternary pump, since you mention changing the MCGV
• Have you carried out any tests on the pump, either leak rate test or gradient test?

Probably enough questions for now.

/Andy