Isogeochemists:

For those of you who do not have indicating magnesium perchlorate but wish
a visual indicator of water saturation, try mixing in a few grains of
silica gel throughout the magnesium perchlorate.  I use Fisher Scientific
silica gel, 6-16 mesh, part number S160-500, along with the perchlorate in
the water trap of our CE NA 1500.  The grain size is very similar to that
of the magnesium perchlorate and its anhydrous bright blue color stands out
well among the white perchlorate.  When saturated, the silica gel turns a
pale pink color.

A note of caution regarding packing of furnace and trap tubes with
chemicals.  Although it is inviting to leave chromium trioxide, copper
wires, and magnesium perchlorate loosely packed in tubes for easy removal
once the chemicals are exhausted, such loose packing may lead to
considerable dead volume and loss of chromatography, in my experience.

Steve


---------------------------------------------------------------------------
Stephen S. Howe                         Office:  (518) 442-5053
Dept. of Earth & Atmos. Sciences        Stable Isotope Lab:  (518) 442-4471
Earth Science 352B                      FAX:  (518) 442-5825
University at Albany                    E-mail:  [log in to unmask]
1400 Washington Avenue        http://www.albany.edu/geosciences/sshowe.html
Albany, NY  12222-0001
---------------------------------------------------------------------------