C&N Solids:

δ13C, δ15N, %C, and %N analysis of solid samples

SIBS uses a Costech Elemental Combustion System coupled to a Thermo Scientific Delta V advance stable isotope mass spectrometer in continuous flow (He) mode.

Common sample materials are plant, soil, feather, hair, fecal, cellulose, blood, liver, fish, and insects.

Samples packed in tin capsules are loaded in a Zero-blank Autosampler (Costech). We use 49-position carousel for large samples (soil) and 99-position carousel for small samples (plant and animal tissue). Samples are first combusted in an oxidation tube packed with chrominium oxide and silvered cobaltus oxide (1050C) with injected oxygen gas. Produced gases go through a reduction tube packed with copper (850C) to remove excess of oxygen gas and reduce NOx gas to N2 gas, and then go through a water trap. N2 and CO2 gases are separated by a packed gas chromatograph, go through an open split of Conflo IV, and are analyzed by the Delta V Advantage Isotope Mass Spectrometer for the nitrogen and carbon isotope ratios, respectively. An analysis of eash sample takes 6 min.

 

  • Sample size:  Generally ~2 mg for plants (2%N, 45%C), 1-90 mg for soil (depending on %N), 1mg for animal tissues. If you need only carbon isotope ratios, sample size could be smaller than these.
  • What you will receive:  All δ13C, δ15N, %C, and %N results and Quality Assurance and Quality Control report. It is the same price for only δ13C (or δ15N) analysis.
  • Key:  Very fine, homogeneous samples. Homogenization is very important for a better accuracy and precison of your samples.

 

  • Calcareous samples:  Samples with carbonate require acid treatment prior to analysis of organic δ13C and %C. Our method is acid fumigation (See “Acid treatment”). For the organic δ15N and %N, non-treated samples are used.
  • Isotopically enriched samples:  We often accept 15N or 13C enriched samples. Indicate which samples are not natural abundance (>50 permil) and how much enrichment you expect. We may not accept highly enriched samples (>400 permil). Please contact us.
  • Insect samples:  Depending on the insect size, grinding might not be required. Contact us.
  • Fish samples:  Lipid removal might be required for the carbon isotope analysis.

 

Sample Submission Procedures

1. Make sure samples are completely dry and ground well. Check if your particle size is good for isotope analysis. Grinding service can be provided with fee

2. Download the Sample Submission Form [C&N Solids], and fill it (both Submitter's Info and Sample Info sheets). Send it to Dr. Ayumi Hyodo (ahyodo@tamu.edu).

3.

(a) If you are sending ground samples (not weighed samples):

  • Ask us for the sample size. Send at least 5 times more than the required weight.
  • Avoid plastic centrifuge tube containers or any bags to store ground samples. Glass vials with screw caps are the best. We use 4mL (15x45mm, PN 66010-425 from VWR) or 20mL (28x57mm, PN 66022-081 from VWR) glass vials.
  • Sample IDs should be clearly written on sample labels on vials. Do not write IDs directly on glass vials.
  • Make sure vials are not touching each other in a shipping box. Otherwise they might break during shipment
  • Send your samples to Ayumi Hyodo, 474 Olsen Blvd. Rm 125 Kleberg Center,  2126 TAMU Department of Ecosystem Science & Management Texas A&M University College Station, TX 77843-2126.
  • If you need samples back, please note it.

 

(b). If you are sending pre-weighed samples:

  • First ask us for the sample size.
  • Use 4×6 mm tin capsule (Costech Part #041070) for plant and animal tissue samples. Use 5×9 mm tin capsules (Part #041077) for organic-poor soils (<~0.03%N,<~0.5%C).
  • Make tin capsules a small sphere (not a square). See a photo below. Ensure samples are not leaking from the tin.
  • Put the tin in seat A1, A2…H12 of a sample tray (Costech Part #080016). Record the seat position, sample ID, and weights in the Sample Submission Form [download from Section 2].
  • We recommend to include 10% duplicates of the total number of samples in an analysis (e.g., include duplicates of 3 any samples if you are sending 30 unknown samples).
  • Tape the tray lid to the tray to avoid move or jump of samples.
  • Send your samples to Ayumi Hyodo, 474 Olsen Blvd. Rm 125 Kleberg Center,  2126 TAMU Department of Ecosystem Science & Management Texas A&M University College Station, TX 77843-2126.

 

If your samples contain carbonate, send them without weighing or acid treatment. Samples treated by acid fumigation are highly absorbent and should be analyzed immediately after acid treatment. We do weighing and acid treatment here . See 3-(a) section above.

 

Examples of nice round tin balls (bigger balls are soil. Small balls are plant or chemical standards).

IMG 5844 3