While potential users interested in cavity ringdown based instruments  
made by Picarro can contact Nabil ([log in to unmask]), those  
interested in instruments made by Los Gatos Research are invited to  
contact me ([log in to unmask]) or visit www.LGRinc.com for more  
information.

All the best,

Doug Baer, Ph.D.
President
Los Gatos Research

On Dec 9, 2008, at 7:36 PM, Nabil Saad wrote:

> Hi Ulrike,
>
> Have you considered using a cavity rind down spectroscopy (CRDS)  
> type of instrument for your water analysis?
>
> I've spent the last 2 years analyzing water samples using a TC/EA- 
> IRMS system but had the extreme luck of getting introduced to CRDS,  
> meanwhile. The system uses no consumables other than the vials and  
> septa as opposed to the TC/EA glassy carbon tube that costs $1000  
> and packing the tube with granules every 400 injections, not to  
> mention the frequent use of bracketing standards, besides the  
> filament change and the ion source clean up. I believe Willi Brand  
> himself (the senior author on Gehre et al. article) is in the  
> process of testing one, now.
>
> In case you're interested, you can check www.picarro.com/isoanalyzers/isotopicliquid.php 
>  for more info.
>
> As for standards, we split them up in 2ml quantities, use polyseal  
> caps with borosilicate vials, wrap Teflon tape on the threads,   
> flush the top of the vial with Argon, seal them and freeze them to  
> avoid any fractionation. We calibrate several working stds against  
> SMOW/SLAP and we do monthly checks with SMOW/SLAP perse. let me know  
> in case you have further questions.
>
> Hope this helps.
>
> Nabil
>
> On Tue, Dec 9, 2008 at 2:20 AM, Ulrike Schulte  
> <[log in to unmask]> wrote:
> Dear listmembers,
>
> from next year on we want to start on-line water analysis (delta18O,  
> deltaD) with a TC/EA (equipped with a liquid autosampler) coupled to  
> a MAT 253.
> We know the publication of Gehre et al. (2004) about continous flow  
> analysis of water sample but we would like to get in contact with  
> people who already use this method successfully.
> At the moment we are discussing intensively how to do the  
> calibration of the system with SMOW, SLAP and GISP and how to store  
> these reference materials after the ampule has been opened: Is it  
> better to store it in a large bottle or vial (25 ml, glas or  
> plastic?) and to reopen this bottle regularly for calibration checks  
> or should we split the water in for example 1 ml portions and store  
> it in very small vials?
> How often do you check your system with these RMs?
> How many secondary standards do you use, what?s the difference in  
> their isotopic composition and how did you produce them?
> Probably a lot of questions will rise during the next months and we  
> will be glad about any information, literature or warnings....
>
> Thanks in advance and have a nice day
>
> Ulrike Schulte
>
>
>
> -- 
> ------------------------------------------------
> Dr. Ulrike Schulte
> Institut für Geologie, Mineralogie und Geophysik
> Lehrstuhl für Sediment- und Isotopengeologie
> Ruhr-Universität Bochum
> Universitätsstr. 150
>
> D-44801 Bochum
>
> Tel.: 0234/32-25454
> Fax.: 0234/32-14571
> ------------------------------------------------
>