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 - Posts: 60
 - Joined: Fri Jul 01, 2011 6:15 am
 
Today, I washed one of our columns with a gradient washing method going from 5 % acetonitrile to 100 % acetonitril in 60 min (5 % holding for 20 min, ramping up during 20 min, holding 100 % for 20 min). When at ~90% acetonitrile the pressure became unstable and I'm not sure what the reason for this is. The column was a Supelco Ascentis C18, previos run was using 90:10 phosphate buffer:acetonitrile. The 20 min of 5 % acetonitrile should have flushed out all phosphates so that should not have been the issue here. I was running this on a Shimadzu LC-20 system with quartenary pumps.
Any ideas would be very welcome.
Thank you!
