Chromatography Forum

Hi,

During the last couple of runs, whenever I inject the 6M Urea into the column while doing a IPA gradient clean it seems to build too much pressure causing the line to come out. I'm not sure what is the result of this. I've never had this problem before. Could it just be the IPA's viscosity? I'm already running it at 0.2 ml/min. Whenever it reaches to around 50%IPA/50% MilliQ pressure builds up and the line comes off. Right now I've slowed down the flow rate to 0.1. Will someone please help!

The Urea doesn't seem to have any issues when injecting with my mobile phase. So. I'm not exactly sure.

WE'RE NOT MIND READERS!!!!

It would really, really help if you told us little useful details like what kind of instrument, what kind of column (type of chemistry and dimensions), what kind of pressure you usually see, etc.

Oops sorry about that

This is Zorbax column 300SB-CN 2.1x150mm 5um

I use a 1200 series Agilent HPLC column.

I run an IPA gradient through the column (IPA/MilliQ) up to 90% IPA. I'm assuming this is causing the high pressure (the system is suppose to withstand up to 250 before it shuts off), but I find the line is popping off around 150).

Is IPA even a good cleaning method for columns? Or is using Acetonitrile and MilliQ sufficient enough?

What is good and what is bad for column cleaning, depends on the column itself and even more so, on the contamination you want to remove from it. A good cleaning agent would be something the contaminant will readily dissolve in.

Btw. IPA is quite viscous, so you should expect pressure increase under all circumstances.

Best Regards

A fitting does not hold 150 bars? Tighten it or get a better fitting.