Oliver,

I've had very good luck using an approach similar to your capillary method
to introduce volatile trihalomethanes into a sealed quartz tube to combust
them to CO2.  Seems this should work for your application too.

I used KIMAX-51 capillary tubes made by Kimble (1.5-1.8 mm diameter by 90
mm length).  Flame-seal one end of a capillary tube, then heat and stretch
the glass near that end to get a very thin, fragile section that is still
open to the rest of the capillary.  Practice a bit to find the right
balance between too thin (breaks during handling or closes completely) and
not-thin-enough (takes a lot of effort to break when in your quartz tube).
It's a very fine line.  Fill the capillary with your acid, then flame-seal
the open end carefully.  Insert the capillary tube in the quartz tube and
seal.  Some moderate shaking can snap the capillary at its weak section and
release the acid.

Good luck.

Cheers,
Bryan
--------------------------------------------------
Dr. Bryan E. Bemis
U.S. Geological Survey
345 Middlefield Road, MS 434
Menlo Park, CA 94025
(650) 329-5603  Office
(650) 329-5590  Fax
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We want to streamline a 13C/12C procedure by releasing strong acid into
seawater samples while keeping them sealed  in quartz tubes. ARe there
tested  methods for such an operation?  We're thinking of adding a small
glass capillary in which  conc. sulfuric is sandwiched between two small
air spaces, with the ends sealed with pre-autoclaved, molten paraffin
wax (or other meltable, inert, CO2-free sealant),  then heating /shaking
to release. Maybe the bugs have been worked out of some such schemes?

Thanks in advance for your experiences/advice.

OLIVER C. ZAFIRIOU
MS4, Fye Building
Department of Marine Chemistry & Geochemistry
Woods Hole Oceanographic Institution
Woods Hole, MA  02543-1543
USA

email: [log in to unmask]
Tel:   (508) 289-2342
Fax: (508) 457-2164