Re: HPLC impurities
David A. Schooley (schooley@unr.edu)
Mon, 28 Sep 1998 13:28:40 -0700
Ben-
TEA is a good first guess, as like all trialkylamines it is subject
to air oxidation to a variety of impurities. It should be stored under Ar
or N2 after opening. However, the single most common cause of "ghost"
peaks in RPLC is WATER- have you recently opened a new bottle of LC-grade
water?? Microbes can grow even in LC grade water. Have you compared water
from another manufacturer, or from a Milli-Q apparatus that is maintained
properly with at least twice yearly cartridge changes? The fact that
buffer A is higher in water than B certainly suggests this all too common
problem.
>We are having problems with 'ghost' -peaks that are appearing in are RPC
>runs. We are using a spheri-5 rp-18 column with a precolumn ( rp-8)
>The buffers are:
>A: 0.1M Triethylamine (TEA, >99%) in HPLC-grade water brought to pH7 with
>acetic acid (>99.8%)
>B: 80% acetonitrile in water
David
David A. Schooley
Dept. of Biochemistry/330
Univ. of Nevada
Reno, NV 89557
schooley@med.unr.edu
tel: (702) 784-4136; fax (702) 784-1419