Pressure issue with acetonitrile gradient
Posted: Mon Oct 22, 2012 2:15 pm
Hi everyone. I've experienced an issue when using a gradient elution up to 100 % acetonitrile a few times during the last year now and I thought I'd check with you what the reason for this could be.
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!
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!