Please use the following procedure for shipping samples:
Before shipping please fill out the sample submission form. This should be included with a list of samples or a weigh sheet that identifies samples and any corresponding information.
Samples can be shipped to:
Stable Isotope Geosciences Facility
406 O&M Bldg
College Station, TX 77843 USA
Samples will not be shipped back to you unless you request it and you will need to provide us with shipping information for the return. Also if you request your samples, the cost of shipping the samples back can be added to your final bill or billed separately. We typically hold onto samples for two months after the analysis is complete in case of any necessary reanalysis.
Solid Sample Analysis for EA-IRMS and TC/EA-IRMS analysis
Solid samples and oil based samples for the analysis of C, N, O and H are analyzed using an elemental analyzer (C, N) or pyrolysis (O, H) system interfaced to an IRMS. These measurements include both elemental and isotopic results and require accurate weighing. Minimally the samples should be sent in clearly labeled vials (glass is preferred to reduce any static effect, but plastic vials are also acceptable) and should be dried and homogenized before shipping. We only require a few milligrams of sample (with the exception of soils) so do not send more than 1 gram of an individual sample. There should be enough sample material to run duplicates or a reanalysis. The samples should be packed in such a way as to avoid any breakage during shipping.
If you prefer to weigh them beforehand please contact the facility manager to discuss sample weights. Samples should be prepared into 48 or 96 position well plates and must meet some minimum requirements before analysis. The samples you weigh into tin or silver capsules should be folded/rolled in such a way as not to have any sharp edges that could potentially get stuck in the autosamplers. They should also not have any sample leaking out. There is a sample size requirement for our instrumentation and that is why it is imperative to contact the facility manager before starting any of your own weighing. There are specific steps that need to be taken for the analysis of H from keratin based samples (hair, feathers, etc). Contact the lab for details concerning these samples. Any extraction steps (lipids, collagen, cellulose) need to be done prior to shipping. At some point in the future we will have equipment available for these extractions but we do not currently have it available at this time.
Solid Sample Analysis for Gasbench and Kiel analysis
Solid samples for the analysis of C and O from carbonate are analyzed using the Gasbench II or the Kiel IV. Samples must be clearly labeled and sent in glass vials (10-25 ml scintillation vials work best). Samples should be dried and ground to a fine powder. In most cases we will not need more than 300 micrograms of sample, although if the sample is not 100% carbonate, then send up to 500 micrograms. Include additional sample if you require duplicates. Carbonate samples analyzed via Gasbench-IRMS are weighed into 12-ml exetainer vials. These vials are evacuated and then flushed with ultra high purity helium before the addition of phosphoric acid to react the sample to form CO2. Typically we weigh samples at 100-200μg to get viable results. Samples should not be preweighed and sent in exetainer vials. That work will be completed by staff here in SIGF or by a researcher weighing out their own samples. Kiel samples are weighed between 10 and 80μg. Higher weights will be needed for partial carbonate samples.
Liquid Sample Analysis for Gasbench and TC/EA analysis
Liquid samples are analyzed for O, H, N and C.
Provide any necessary description and safety hazards. Minimally you should test the liquids for pH level. We will not analyze any liquids which are too acidic or basic.
Equilibration method for δ18O and δD - send a minimum of 10 ml of liquid in a sealed glass or plastic vial. The vial should be labeled and have a corresponding sample list. Make sure there is no headspace in the vial to avoid evaporation effects. Do not send more than 100 ml of liquid. Storage time is indefinite.
Dissolved Inorganic Carbon for δ13C - Water samples should be kept in a cooler and then stored in a refrigerator upon arrival. A minimum of 25 ml is required for analysis but not more than 250ml. Samples should be analyzed within 1-3 months after collection. Plastic containers are fine.
Nitrate from water for δ15N and δ18O - samples should be sent in plastic containers and not more than 500ml. Samples are stored in refrigeration units until the samples are ready to be prepared for analysis. Storage time is indefinite before preparation.
Pyrolysis method for δD and/or δ18O - requires only microliters of liquid. Send 1-5ml of sample but no more than 10ml. There are several vial types that would be suitable for shipping.
Gas samples for analysis using Gasbench
Gas samples should be prepared into 12-ml borosilicate exetainer vials available from Labco. These vials attach to 16.5mm screw cap with septa (color of cap does not matter - except to distinguish between various sets of samples). These vials should be air-tight and sent via ground transportation (high altitudes can sometimes cause the vials to overpressurize and you could potentially lose the samples). If necessary to send via air transportation expect to lose some samples.