 
| Received: |
from taurus.cus.cam.ac.uk (taurus.cus.cam.ac.uk [131.111.8.48]) by list.uvm.edu (AIX4.2/UCB 8.7/8.7) with SMTP id FAA17710 for < [log in to unmask]>; Fri, 8 Nov 1996 05:18:23 -0500 (EST)
from ir200 by taurus.cus.cam.ac.uk with smtp (Exim 0.571 #1)
id 0vLo5T-0003Ex-00; Fri, 8 Nov 1996 10:22:59 +0000 |
| Content-Type: |
TEXT/PLAIN; charset=US-ASCII |
| TO: |
|
| Date: |
Fri, 8 Nov 1996 10:22:59 +0000 (GMT) |
| Reply-To: |
|
| Subject: |
|
| From: |
|
| In-Reply-To: |
|
| MIME-Version: |
1.0 |
| Message-ID: |
|
| Parts/Attachments: |
|
|
Frank
As far as I'm aware the IAEA C3 standard is holocellulose rather
than alpha-cellulose. Therefore there will be some hemicelluloses present
and it will not be truly homogeneous. However, these differences in
structure may not be significant. We measured the 13C/12C values from a
nitrated sample of it:
Mean -24.78
n 14
s.d.(n-1) 0.11
However, 13C/12C values from nitrated samples would appear to be depleted
by 0.30 per mille (Palaoklimaforschung 15, 141-155).
We decided to use a commercial alpha-cellulose as a standard
(Sigma Cellulose ref 92F 0243) and typically have a precision of 0.05 per
mille on 13C/12C measurements... Let me know if you want some. Best
wishes.
Iain
*************************************************************************
Iain Robertson +
Godwin Institute for Quaternary Research, +
University of Cambridge, Free School Lane, + Tel. ++ 44 (0)1223 334881
Cambridge, UNITED KINGDOM CB2 3RS + Fax. ++ 44 (0)1223 334871
-------------------------------------------------------------------------
Godwin Institute homepage http://www.esc.cam.ac.uk/GIQR.html
*************************************************************************
|
|
|
