By Anonymous on Wednesday, May 30, 2001 - 01:18 pm:
I was told that acetonitrile can be polymwrized on the HPLV system and causes problems. To removed the polymerized ACN one has to purge the lines with warm water at 10 ml per minute for about 30 minutes. Anyone heard about the polymerization of ACN? Is it a normal practice to purge the lines regurally with warm water at 10 ml/min?
By Anonymous on Wednesday, May 30, 2001 - 01:23 pm:
Sorry, it should be HPLC not HPLV.
By Tom M. on Thursday, May 31, 2001 - 11:54 am:
I do not know if acetonitrile can undergo some type of free radical polymerization. However, I have been told the same thing by Agilent representatives. I know that that Agilent field service engineers here in the Bay area like you to flush the system with hot water before performing the OQ/PV.
We have had 10 HP1100s with quaternary pumps for 4 years. In those four years we have had three instances of the multi-channel gradient valve "sticking". Each time it was an acetonitrile channel sticking open, and each time the problem was fixed by flushing the channel with hot water. I don't know if it is polymerization or a little buffer leaking into the acetonitrile channel and precipating. If anyone has an applicable reference I would greatly appreciate it.
By maris on Thursday, May 31, 2001 - 11:56 am:
Probably, somebody used acrylonitrile instead acetonitrile in HPLV instead HPLC?
Dr.A.Weisman
By B.Buglio on Thursday, May 31, 2001 - 03:19 pm:
Nitriles generally need 2 conditions for
polymerization - an acid or base for catalysis and
the absence of an alpha hydrogen. This doesnt mean
polymerization is impossible just unlike
By Anonymous on Friday, June 1, 2001 - 10:24 am:
Another explaination is that the plymers were produced during the manufacture of acetonitrile. The polymer particals then coated on the HPLC system. In any case warm water flush seems taking care the problem.
By Anonymous on Tuesday, June 19, 2001 - 11:43 pm:
We´ve had problems with pumping 100% ACN; after some time the valves in the pumps didn´t work any more. The representive asked us to filter our ACN using 0,22 µm-Filters. This made no sense to us, because the solvent was already prefiltered in the same way by Merck (ACN gradient grade quality).
We now use a mixture of 10% water and 90 % ACN to clean the columns. Its works perfectly.
There´s also no problem using gradient elution.
Or try to use methanol for column cleaning.
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