The strategy one should employ is to use all the water in the IAEA ampoules
when one opens them. Calibrate an internal laboratory water reference that
will be analyzed daily and interspersed with unknown waters. Calibrate
enough internal laboratory reference water to last at least three years.
Every three years or so order IAEA reference waters and recalibrate another
internal laboratory water reference. Using this technique one will avoid
any possibility of calibrating with IAEA reference waters that have been
isotopically fractionated by evaporation or by some other process.
Laboratory personnel should prepare internal laboratory reference waters of
two significantly different isotopic compositions--one relatively depleted
in 2H and 18O (we prefer Antarctic snow melt) and one typical of waters
that they will routinely analyze (perhaps near zero per mill). The
container of choice for internal laboratory reference waters is a 10-mL or
so glass ampoule. Several hundred or thousand can be prepared at a time.
Next best for storage are glass bottles with conical plastic insert caps.
Use both internal laboratory calibrated reference waters to normalize
hydrogen and oxygen isotope ratios to the VSMOW-SLAP scale. Manfred
Groening at the IAEA can provide additional information, and Roland Werner
and Willi Brand have prepared an article specifically on referencing
strategies in isotope ratio analysis.
<[log in to unmask] To: [log in to unmask]
Sent by: Stable Subject: Re: storage of IAEA water standards
<[log in to unmask]
01/02/2001 07:17 PM
Please respond to
We are just about to crack open our IAEA water standards and wondered if
anyone has any recommendations as to how to store them once they are
open. I assume that a small glass bottle with screw polyethylene cap
would be fine. If anyone has any experience storing these standards please
let me know.
Thanks in advance,
Paul D. Brooks,
147 Higard Hall MC 3110,
UC Berkeley, Ca. 94720-3110.