Chromatography Forum

Posted: **Thu Aug 16, 2007 4:06 am**

I am Using Kromasil Column With the Mobile Phase of ACN and 0.1% H3PO4 at 1.5ml Flow on Gradient Condition[/quote]
My Problem is after Few Injection The Column Head Pressure is Increased up to 5000psi and My Shimadzu System couldnot access it.
is there any reason for this.

Posted: **Thu Aug 16, 2007 4:55 am**

There could be several.

Possible ones include :_sample junk depositing on front of column, poorly filtered mobile phases, sample or wash solvents are immiscible with mobile phase, injector valve filling up junk etc etc..

Bruce Hamilton

Posted: **Thu Aug 16, 2007 12:57 pm**

Another possibility - lots of THF in the B phase.

We're going to need more details.