Chromatography Forum

im using agilent 1050 hplc and changing reversed hplc to normal hplc.
so purging all line in methanol.
actucally i had hard condition because of vaccine so couldnt check hplc
so pump was working 2 day
when i came to school methanol was empty so i filled it and pump on again
but only one line is working now. please give me some advice

31 views before me, so let me take a try, as I'm old enough to have hands-on experience with 1050 pumps.

If you have a 1050 vacuum degasser, know that EACH CHANNEL has a dead volume of like 40ml. You may need to pump/suck solvent through each channel manually using a big syringe.

I think I'd bypass ANY degasser to get the pump operational. These pumps do NOT pump air well, they are designed to pump liquids. Again, you may need to use a syringe to pull air out of the purge valve or purge valve fitting while the pump is set to 5ml/minute.

Sounds like you lost prime. Try filling all channels with pure IPA (NOT methanol). IPA is a much better solvent to use when transitioning between NP/RP modes. It has high viscosity which helps to reduce cavitation and make priming easier. The HP 1050 pump is VERY easy to prime and will easily suck AIR (yes, air, but not recommended due to excessive seal wear) and of course liquids (unless it is damaged or worn) so OPEN the prime-purge valve fully (fully = ONE TURN to open it, that is it. DO not keep turning the valve!) and prime each line, ONE-AT-A-TIME (100% A, 100% B and so on), not 25/25/25/25.

BTW: IF the HP 1050 degasser is operating correctly (almost no chance of that being true after all these years!), then include it in the flow path for priming and flushing, BUT keep in mind that due to the HUGE channels volumes it has (~ 40 mL each), allow enough time to flush the solvent through each channel 2 or 3 times before moving on to the next one. Suggest flushing at 10 mL/min rate to speed up the process (4 minutes + for just one volume).

Here is a link to free article on how to properly prime and flush most popular types of HPLC pumps.

"Tips and Advice for Priming your HPLC PUMP (or similar pumps, FPLC or UHPLC Pump)"; https://hplctips.blogspot.com/2020/09/t ... -hplc.html