Dear list members,

I would be interested in hearing from anyone who is or has been using
guanadine hydrochloride as a reagent for determining oxygen isotopes in
water.

Starting off with an internal lab standard of milli-Q water, we have found
that our 45/44 ratios are huge - giving delta 13C of well over +150 when
run against TS limestone (but no doubt contaminating the reference gas so
these values are probably too low).  These ratios could be real and a
consequence of the manufacturing process of GuHCl (the batch of GuHCl I
have was purchased from Aldrich), or there is an (hydrocarbon?) isobaric
interference on mass 45.

Have other people found something similar, and if these high 45/44 ratios
are real, what sort of reference gas was used to get decent analyses?

thanks in advance,

Linda Godfrey

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 Linda Godfrey

Department of Geological Sciences                       tel (607) 255 0058
Cornell University                                      fax (607) 254 4780
Ithaca, NY 14853                               [log in to unmask]
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