1.
Contact the mass spec lab manager, Christine France
(francec@si.edu, 301-238-1261), to discuss your project and sample
preparation. Every project and sample set is unique and may
require subtle variations to the guidelines listed below. We
always strive to obtain the highest quality results for our users, so
we ask that you please communicate directly with the manager before preparing your samples! 2. Fill
out a project submission request form (available from the lab manager)
which includes a brief description of your project and your contact
information. 3.
Discuss the appropriate weights for your samples with the lab
manager. The following are some general guidelines for the most
common types of samples, but please confirm the appropriate weight with the manger before proceeding. Please note there are other types of samples that we can accommodate that are not listed here. Animal tissues for C and N (muscle, hair, feather, nails, extracted protein, etc.) - 0.5-0.7 mg Other organic solids for C and N - 0.4-0.6 mg
Plant tissues for C only - 0.3-0.4 mg Plant tissues for C and N - 3.5-5.0 mg Soils/sediments for C and N (high organic content) - 4.0-6.0 mg Soils/sediments for C and N (low organic contect) - 8.0-10.0 mg Sulfates and sulfides for S - 0.4-0.6 mg Pure organic solids for S - 0.4-0.6 mg Soils, sediments, animal tissue, plant tissue for S - >10 mg Phosphates and nitrates for O - 0.4-0.6 mg Organic solids for O - 0.3-0.5 mg Organic solids for H - 0.3-0.4mg Pure carbonates for C and O - 0.3-0.5 mg Enamel and hydroxyapatite for C and O - 0.8-1.0 mg
4. For EA and TC/EA analyses, weigh
and pack your samples; place them in a 96-well sample tray.
Obtain the sample list template (excel format) from the
lab manager and record your sample names and weights (in mg to at
least 3 decimal places). We can recommend vendors for the tin
cups, silver cups, and sample trays if necessary.
Samples for EA carbon, nitrogen, or sulfur isotopes and elemental abundances
- Samples should be weighed into tin cups (3.5x5mm, 4x6mm, or 5x9mm)
and tightly packed into a ball. Samples for sulfur analysis
should have about 0.3-0.5mg of vanadium pentoxide added to the sample
before packing the tin cup. Samples for TC/EA oxygen isotopes - Samples should be weighed into silver cups (3.5x5mm, 4x6mm, or 5x9mm) and tightly packed into a ball. Samples for TC/EA hydrogen isotopes - Samples
for hydorgen analyses must be brought to the isotope lab at least 3 days
prior to analysis to allow exchangeable hydorgen to equilibrate with
our local atmospheric water vapor. All samples for hydrogen
analyses must therefore be weighed and packed at the isotope lab.
Contact the lab manager to make arrangements. Samples should
be weighed into silver cups (3.5x5mm, 4x6mm, or 5x9mm) and tightly packed into a ball.
5.
For carbonate analyses, samples will have to be delivered in bulk
to the mass spec lab where they will then be transferred into the
appropriate exetainer vials. 6.
We can accommodate some gaseous samples for dual inlet analyses.
Please communicate with the lab manager for details. 7.
Once your samples are prepared, submit your project submission
request form and your sample templates electronically to the lab
manager. Include a paper copy of the sample templates with your
trays. Cover your trays securely and coordinate with the lab
manager to either drop off your samples in person or mail them to the
lab. Please contact the lab manager before you send your samples! Internal SI mail can be sent to MRC 534. Securely packed samples can be mailed to the following address: Christine France Smithsonian Museum Conservation Institute 4210 Silver Hill Rd. Suitland, MD 20746
Contact
For further information regarding the Smithsonian Institution OUSS/MCI Stable Isotope Mass Spectrometry Facility please contact Peter Marra or Christine France.