Check your local favourite supplier of HPLC and GC/MS vials. You want
an "HPLC insert" that is borosilicate glass about 2-3mm dia and 25-35mm
long. You do NOT want the kind that has plastic "springs" at the
bottom. You also do NOT want any insert that is too narrow at the
bottom, otherwise the acid does not get all the sample.
Now the hard part: These inserts are compatible with a Gilson
autosampler AS LONG AS YOU ALIGN THE NEEDLE to avoid it hitting the
insert as it aspirates the sample into the mass spec. The way you load
the tubes into the autosampler rack will also affect the lifetime of the
needle. Good luck!
M Stocki wrote:
> Hi everyone,
> Our lab is beginning the automated analysis of carbonates using a Finnigan
> Mat Gas Bench coupled to a Delta Plus. Our present difficulty is in getting
> the small amount of acid dispensed into the vacutainers to meet with the
> small amount of carbonate (0.5 mg) located on the flat bottom of the
> vacutainer. I have heard that there is such a thing as miniature
> lightweight disposable "cones" available for this purpose. The carbonates
> are weighed directly into this lightweight cone on a balance. Then this
> cone with carbonate in the bottom of it is fitted inside the flat bottomed
> vacutainer. This supposedly enables the small drop of acid dropped into the
> vacutainer to meet with all of the small amount of carbonate. If you know
> of a supplier of such a thing as this please let me know.
> Thank you,
> Myles Stocki
> University of Saskatchewan
Mass Spectrometry Lab
U.S.D.A. Human Nutrition Research Center at Tufts University
711 Washington St.
Boston, MA 02111
(617)556-3164 (NEW NUMBER)