In addition to replacing solvents, consider the inlet filter a likely source. The reservoir itself should be cleaned once in a long while.
Bad Buffers:
Not only do many buffers go bad, but many catalyze their own degradation-- if you pour good solvent into an existing supply, the old may help degrade the new that much quicker.
There is a difference between solvents. JTBaker began testing under HPLC gradient conditions (Vs isocratic) when they discovered that material that appeared clean would deliver a ghost peak while running a gradient. They found that with AcN, a characteristic peak appeared that was the result of the manufacturing process, but only showed up when concentrated on column and eluted with the gradient.
The Separations Group (VYDAC) recently included an article on ghost peaks in their quarterly newsletter which is quite informative. I am sure they still have copies available on request.
Christopher
www.WesternAnalytical.com
christopher@WesternAnalitical.com
800-241-5145 / 415-333-5988
fax 415-333-5989
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From: Stephen.A.Bobin@Dartmouth.EDU (Stephen A. Bobin)
Sent: Monday, September 28, 1998 4:53 PM
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Subject: Ghost peaks
Ben,
I believe you are right about the ghost being in buffer A. Try using some water from another source to make your buffer. I keep HPLC grade water from Fisher or B&J around in the lab just for such occasions. I worry about triethylamine, I usually assume it has gone bad the moment I open the bottle. A new bottle would be a good idea. Also, how long has that bottle of acetic acid been around? Jeez, I just looked at mine it has an opened date of May 10, 1995. I don't think it "goes bad" but I do think about all the plastic that has been dipped in it over three years.
Hope this helps.
Steve
Stephen A. Bobin
Manager
Molecular Biology Core Facility
Dartmouth College
Hanover, NH 03755