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SIGF Policy

Instrumentation Policy

Please Read Throughly.

The staff and faculty associated with the Stable Isotope Geosciences Facility understand that graduate students and researchers are interested in the preparation and analysis of their own samples. For preparation of samples please read through the Preparation Facility Policy. Users who are interested in running their own samples will adhere to the following policy:

1. The SIGF has three isotope ratio mass spectrometers available for general use within the College of Geosciences. The instruments include a Thermo Delta Plus XP and associated elemental analyzer, pyrolysis system and Gasbench (Room 406 O&M Bldg); a MAT 252 with an elemental analyzer and GC-C interface (Room 406 O&M Bldg), and a MAT 253 with associated Kiel device (Room 309 O&M Bldg).

2. Depending on the type of analysis being done, users will need to consult with the SIGF Director and Manager about their level of experience and competence working with isotope ratio mass spectrometry instrumentation. We also expect to be informed about the number of samples you are interested in running and the timeframe in which you need them analyzed.

3. Training on equipment may include working alongside or shadowing the SIGF Manager with analysis of samples. Once preparation is complete there may be maintenance steps that are required before analysis can begin. You may be expected to help out during the regular workweek and possibly on weekends if necessary.

4. Analysis of samples will be allowed by the Director and Manager on a case-by-case basis. In many cases it may take several months to a year for users to become adept at running these instruments. That being said, we will only train people who plan on running several samples over the course of a few years. We do not want to waste our time training someone to analyze 100 samples as a one-time project.

5. In the case of smaller projects we will show the user the steps required to analyze the samples and also give a tour of the facility. The user is welcome to help out but will not receive the extensive training on the instrument.

6. The SIGF Executive Committee meets regularly to discuss new projects and as such will determine how much Facility Manager time will go into training new users. This decision will be made on a quarterly basis or as the need arises.

7. Ultimately, SIGF would like for users to feel comfortable asking questions and helping with the analysis portion of their samples as much as they can. Some people would prefer to just turn their samples in and have us analyze them, while other users are more involved with the analysis. Either way is fine with us. We want you, as the client, to gain as much information as you possibly can and to leave satisfied with both the experience and the results.

8. Several risks are associated with running high precision isotope ratio mass spectrometers and associated peripheral devices. These include, but are not limited to, high instrument voltages, explosive gases, and working with volatile chemicals. Please make sure you are up-to-date with your laboratory safety training. Any work performed in SIGF will require that you have the training completed. In addition the laboratory manager will make sure you are specifically aware of safety issues within SIGF.

Preparation Facility Policy

Please Read Thoroughly.

The TAMU Stable Isotope Geosciences Facility has various preparation facilities available for use. The prep labs are located in the following areas: Room 406A (O&M Bldg), Room 309 (O&M Bldg), Room 312 (O&M Bldg), and in special circumstances Ethan Grossman's lab in Halbouty. These preparation labs are structured with the intention of serving a broad community of faculty, staff, and students within the TAMU campus, as well as external users. The facilities contain equipment necessary for preparation of samples for isotope analysis. As such, the facility user policy is outlined below:

1. You must have appropriate safety and instrument training to be approved to use the facility equipment by the manager or director. Under no circumstances should you be using the equipment unless that permission has been given.

2. You must sign-up for the particular piece of equipment you intend to use ahead of time. This is particularly important when there are several users that have needs for the same equipment at the same time. You can sign up in the log-books within the lab or e-mail ahead of time.

3. Advance sign-up should not exceed 10 days prior to using a piece of equipment unless there are special circumstances (i.e. external user coming from out of town on a specific day).

4. It is recommended that you sign-up for continuous blocks of time and not break-up days. With many users hiring part-time assistance it is far easier if they can plan on having one day set aside for them to work. There is flexibility to this rule as schedules become more certain over the course of a semester.

5. In the case of a dispute over a preparation line or piece of equipment, the facility manager shall decide the user schedule.

6. If you need to use the laboratories in 406A, 309, or 312 during off-hours (after 5pm M-F or weekends) you will need facility manager or director approval. The doors to O&M require a TAMU ID approved activation for entrance after 5:00PM during weekdays and all weekend. The doors are also locked on University approved holidays.

7. You are responsible for informing the facility manager of any schedule changes, including cancellations.

8. All users are responsible for keeping the work areas clean and the preparation lines and equipment in full working condition. Please report any breakage or malfunctioning equipment. Any breakage (beyond normal wear and tear) is your responsibility and will be billed to your account.

9. You are responsible for knowing the difference between enriched and natural abundance type samples. Enriched or labeled samples can have a detrimental effect on natural abundance preparation equipment and samples. Please see the SIGF manager if you do not know the difference. If you do make this mistake you are responsible for all clean-up efforts. In some cases a fee may be assessed if clean-up procedures are significant.

10. Absolutely no samples will be admitted into SIGF if they have come in contact with a laboratory that performs tracer radiocarbon work. Personnel within the facility routinely perform measurements on naturally abundant levels of radiocarbon and tracer work would contaminate the work area.

11. All users are required to show proof that they have attended a laboratory safety course in accordance with TAMU Environmental Health and Safety (EH&S). Material safety data sheets are available for users. Laboratory safety is of utmost importance for a suitable working environment. These laboratory policies are subject to change. Please contact the facility manager if you have any questions or concerns.

Shipping Procedure

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
3147 TAMU
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.

Gasbench analysis

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.

TC/EA Analysis

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.

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