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Hello Karen,

We are using a MultiPrep for carbonats here in Lyon.
When you are in MassLynx if you look in the window called "Inlet Params"
in your inlet editor you will find a parameter  called "Min inlet press
(mBar)" which you can modify. This is the limit used by the system to
decide how to run the sample. After the sample has been reacted, the CO2
is trapped in the external cold finger. Then the external cold finger is
heated and the CO2 is released. The transducer reads the pressure from
the sample CO2 and compares it with this parameter. If it is lower, it
will use the inlet cold finger, if it is above, it will run the sample
through the bellow.
Ours is set to 20 mbars.

The best way to optimise the preparation parameters is to start from the
default ones, modify them one by one and see how it affects your results.
Our experience is that the default pumping times and transfer times seem
to be a bit short and we have doubled most of them as a safety.

The reaction time may have to be adjusted depending on the type of
sample you run. The default one has been calculated for pure calcite.

The quality of your phosphoric acid will be an important parameter and
the acid delivery line is a critical part of the system.

We have been happily running mostly big samples 100ug and above.

Hope it helps,

--
François FOUREL

UMR CNRS 5125 PEPS
Université Claude Bernard Lyon 1
2 rue Raphaël Dubois - Bât. Géode
F-69622 VILLEURBANNE Cedex - FRANCE

Tél : +33 (0) 4 72 44 62 42
FAX : +33 (0) 4 72 43 16 88
Email : [log in to unmask]
Karen Leslie a écrit :
> Hi everyone,
>
> Does anyone have any experience running carbonates using MassLynx Multiprep
> system. Ours is running a Gilson Autosampler connected to an IsoPrime-DI.
>
> I was particularly interested in the way the system decides when to freeze
> down samples into the internal coldfinger and how to decide what are the
> optimum preparation parameters and inlet parameters to use. What sort of
> sample sizes do people run? Any other relevant info would be greatly
> appreciated.
>
> Many thanks,
> Karen
>
>
> Dr Karen Leslie
>
> Earth Sciences
> University of Queensland
> St. Lucia, Qld, 4072
> Australia
> E-mail: [log in to unmask]
> www.earth.uq.edu.au
> Tel:    +61 7 336 51132 / 53281
>
>