RE: Argon
L. Ericsson (ericsson@u.washington.edu)
Sat, 14 Feb 1998 07:13:08 -0800 (PST)
I too use Argon in the Beckman 6300 amino acid analyzer with no apparent
problems. Note that this is not a welder's grade argon but a grade 5
(99.99999% pure). The 6300 analyzer has a built in degasser for each
buffer but not for the ninhydrin where a degasser is not needed since the
ninhydrin is introduced into the stream at low pressure post-column. The
argon provides an excellent non-oxidative protective layer over the
ninhydrin in the bottle since argon is heavier than oxygen.
As mentioned earlier helium is the gas of choice for HPLC buffers, however
if helium is not available degassing the buffers under a vacuum with
stirring or with the bottle of buffer in a sonicator bath for 20 minutes
with aqueous buffers or 5 minutes with buffers containing large amounts of
acetonitrile daily provides a gas free buffer for the day.
-Lowell H. Ericsson, Dept. of Biochemistry, U. of Washington, Seattle