Best way to start up a UPLC system each week?

I use a Waters Binary UPLC for a related impurities method and the way the testing falls, I could be using it for about 2 weeks in a row, not running every day but spending one day prepping, the next running samples and the next the flush down procedure and leaving the system idle. 

What is the best way to store lines when the UPLC could be idle for up to three weeks before being used again? Its used almost 100% of the time for the same method- column of 1.7 micron particle size, 10 microliter loop, 100x 2.1 internal diameter column. Line A = 100% Acetonitrile B - 20mM potassium phosphate buffer pH 2.8, seal wash 90% Water 10% Acetonitrile and then strong/weak injector. 

I usually flush down system post run with the seal wash to wash out buffer(2 hours) followed by 2 hours of 0.3 ml per min of 100% Acetonitrile then switch off. When starting up after a week or so, I first pump seal wash in fresh solution for 10 minutes, then place Lines A/B into seal wash and prime for 10 mins to wet seals and check valves then set up with fresh buffer and washes, start up system for 20 mins per line and its usually good to go. I store lines in 100% Methanol between using system. 

Can anyone suggest improvements to this or do you think this is sufficient?

Best Answer

  • Pflan
    Answer ✓
    Hi Empower2018, I checked in with the Waters lab and it seems as though your method gets a big seal of approval.  The only thing they said you may want to consider is just flushing it with only Methanol instead of ACN and then Methanol.  But there are some risks with impurities in some Methanol vendors- so keep that in mind.  


  • Thanks very much pflan, I hear so many things in work about the "best" way to use the UPLC, its good to hear some clarity from Waters.