We have analyzed honey for 18O.  Since separate aliquots for 13C analysis 
worked well we assumed that the homogeneity is suitable for 1-1.5 mg of 
material.  So we then pipetted this much (undiluted) into capsules and put 
them in a freeze drier for a week, then quickly collapsed them in a  lab 
air and stored them for another week in a desiccator, then transferred them 
quickly to a Costech zero blank auto sampler.  This keeps the samples in a 
He atmosphere, se we let them sit in this another 3 hours before starting 
the analysis.  This at least keeps the honey as dry as possible and 
pipetting the samples into the capsules is relatively easy to do.  There 
were differences between samples, but without a honey standard it was not 
possible to determine how accurate the results were, or how affected by 
exchangeable O.

Hope this helps, Paul Brooks.



At 01:36 AM 4/11/2006, you wrote:
>Dear All,
>we measure dD and dO in honey-samples.
>We fear, that there is an influence to the values of dD and dO comming from
>1. the water we use to dilute the honey before pipetting it into the Ag-
>capsules for TCEA-measurement
>2. the lab air humidity, which may influence the dD- and the dO-values of
>the dries samples (70°C over night).
>
>Does anyone know, what range of values for dD and dO we can expect (20°C,
>20-50% Humidity, 1000 hPa). Can we calculate it from temperature, relative
>humidity and pressure?
>
>To which extent will the dD- and the dO-values be influenced by exchance-
>reactions with H and O in the sugar-molecules. And what time does it need?
>Is the role of the deliquescence of the dried sugar greater or lower than
>that of the exchange-reactions?
>
>Thank you, Klaus Meylahn
>
>-------------------------------------
>Dr. Klaus Meylahn
>LAVES Lebensmittelinstitut Oldenburg
>http://www.laves.niedersachsen.de/master/C4259035_N4270905_L20_D0_I826.html

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