Thanks, that might work for us. Our larger  tubes are nearly full of water, so  it'll take a super-shake to break it.
Let me be clear - your sample is in the full-diameter capillary section, or the thin drawn-down section?

O.

Bryan Bemis wrote:

> 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
> [log in to unmask]
>
> |---------+--------------------------->
> |         |           Oliver Zafiriou |
> |         |           <[log in to unmask]
> |         |           EDU>            |
> |         |           Sent by: Stable |
> |         |           Isotope         |
> |         |           Geochemistry    |
> |         |           <ISOGEOCHEM@LIST|
> |         |           .UVM.EDU>       |
> |         |                           |
> |         |                           |
> |         |           08/13/02 12:23  |
> |         |           PM              |
> |         |           Please respond  |
> |         |           to Stable       |
> |         |           Isotope         |
> |         |           Geochemistry    |
> |         |                           |
> |---------+--------------------------->
>   >---------------------------------------------------------------------------------------------------------------|
>   |                                                                                                               |
>   |        To:      [log in to unmask]                                                                       |
>   |        cc:                                                                                                    |
>   |        Subject: [ISOGEOCHEM] How to releasing reagents into pre-sealed tubes?                                 |
>   >---------------------------------------------------------------------------------------------------------------|
>
> 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