Folks,

We're trying to separate siderite from soil/clay samples so that we may
analyze the organic components of the soil for d13C, d15N and CN ratios.
The refs I've come across focus on 'carbonate' removal and indicate that
siderite is less soluble. I found I can dissolve siderite in 6 molar HCl at
50°C overnite, or soaking in 6 molar HCl at 25°C for several days. To
remove excess HCl I plan to freeze dry the samples and not pour out any of
the acid in case some of the organics have also gone into solution (I think
this is the same idea as vapour removal).

Any comments or suggestions regarding possible effects others have observed
using this method, or better methods before I follow the tedious path of
sample preparation testing? The first line of testing I was going to do was
to dose IAEA-C5 (wood) with siderite and see if THIS pretreatment affected
its d13C values.

Thanks in advance for saving me time,

Toti.


Toti Larson Ph.D.
Los Alamos National Laboratory
Earth and Environmental Sciences                505.667.9894 (lab)
Los Alamos, New Mexico 87545            550.667.8006 (office)