Service Provided: Simultaneous determination of carbon and nitrogen and/or sulfur content and stable isotope ratios for solid samples by Elemental Analysis - Isotope Ratio Mass Spectrometry (EA-IRMS). Samples can be prepared and delivered to the MSI Analytical Lab for analysis (reach out to MSI Analytical staff to determine proper sample amounts) or can be prepared in-house, including weighing and encapsulation of samples into tin capsules. Additional preparatory services may be available on request, including sample grinding, acidification, and drying.
Technique Used: Automated Organic Elemental Analyzer (Dumas combustion method)
Measurement Range and Precision:
| Analyte | Optimal Range | Detection Limit | Precision |
|---|---|---|---|
| Carbon, δ13C | 100 - 250 µg | 10 µg | +/- 0.1 ‰ |
| Nitrogen, δ15N | 20 - 80 µg | 10 µg | +/- 0.2 ‰ |
| Sulfur, δ34S | 15 - 30 µg | 5 µg | +/- 0.2 ‰ |
Sample Collection and Preparation
Before collecting samples, filters must be pre-combusted at 450°C for 30 minutes. Whatman filters, either GFC or GFF, provide low background contamination and are highly preferred. Filters up to 25mm in diameter are analyzed whole and are considered as 'Regular' on our rate schedule. Larger filters up to 47mm in diameter are too big to analyze whole and must be cut in half for analysis. Both halves are analyzed simultaneously, but these samples fall under the "Double-drop" analysis on our rate schedule.
After collection, filters should be placed in a 60°C drying oven and must be submitted completely dry. They should contain no more than 4mg of dried material. If more than 4mg of material is present, or if you have other concerns, please contact the Analytical Lab. Be sure to include filter blanks along with the samples.
Filters submitted to the Analytical Lab for Organic Carbon analysis (TOC) should be treated with 10% v/v hydrochloric acid (HCl) to remove inorganic carbonates. After acidification, filters should be placed in a 60°C drying oven and must be submitted completely dry. The Analytical Lab can provide the acidification service upon request.
Glass or plastic scintillation-type vials are the preferred containers, but plastic petri dishes with lids or glassine envelopes work well also. Wrapping filters in aluminum foil is not recommended as filters have a tendency to stick to the foil during drying and sample losses may occur.
Biological samples typically require 2-3mg of sample per analysis. For materials with low organic content, a larger amount of material will be analyzed to obtain a signal within the optimal range. We ask that 10-100mg of sample be provided. If less than 10mg of material is available, or if you have other concerns, please contact the Analytical Lab.
Samples must be thoroughly dried and finely ground to a powder. Sample homogeneity is usually the limiting factor for analytical precision.
Biological materials submitted to the Analytical Lab for Organic Carbon analysis (TOC) should be treated with acid (H2SO3) to remove inorganic carbonates. It is best to weigh samples into silver capsules first, then acidify gently with multiple aliquots of H2SO3. After acidification, samples should be placed in a 60°C drying oven to dry completely before closing the sliver capsule. The Analytical Lab can provide the acidification service upon request.
Screw-cap glass vials are the preferred containers.
Geological samples typically require 10-50mg of sample per analysis. For materials with ultra low organic content, two aliquots may be analyzed simultaneously. These samples fall under the "Double-drop" analysis on our rate schedule. We ask that 100-1000mg of sample be provided.
Samples must be thoroughly dried and finely ground to a powder. Sample homogeneity is usually the limiting factor for analytical precision.
Geological materials submitted to the Analytical Lab for Organic Carbon analysis (TOC) should be treated with acid (H2SO3) to remove inorganic carbonates. It is best to weigh samples into silver capsules first, then acidify gently with multiple aliquots of H2SO3. After acidification, samples should be placed in a 60°C drying oven to dry completely before closing the sliver capsule. The Analytical Lab can provide the acidification service upon request.
Screw-cap glass vials are the preferred sample containers.
Synthetic samples typically require 1-2mg of sample per analysis, but sample size requirements vary depending on the theoretical elemental composition. We ask that 10mg of sample be provided. If less than 10mg of material is available, or if you have other concerns, please contact the Analytical Lab.
Samples must be thoroughly dried and finely ground to a powder. Sample homogeneity is usually the limiting factor for analytical precision.
Screw-cap glass vials are the preferred sample containers.
The Analytical Lab does not prepare samples for analysis in a glove box. If you are submitting air sensitive or hazardous materials, please contact the Analytical Lab with details and we'll do our best to work with you.
Rates
| Analytical Service Provided | UC Rate | Non UC Rate | ||
|---|---|---|---|---|
| Isotope Ratio Mass Spectrometry | ||||
| δ15N, δ13C, δ34S | $23.00 | $36.00 | ||
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| Lab Personnel Labor Rates | ||||
| Analytical Lab Group rate (per hour) | $95.00 | $149.00 | ||
Instruments
EA - IRMS
- Manufacturer: Thermo Fisher Scientific, Thermo Finnigan
- Model: Flash EA IsoLink CN with a Thermo Delta plus Advantage IRMS
- Features
- Individual or simultaneous δ15N, δ13C, and δ34S analysis on solid samples
- Ramped GC-oven for improved elemental separation
- Customized for low concentration δ34S analysis
- We can analyze C, N, and S isotopes from a variety of solid substrates, including organics, soils, and sediments. The EA can either be run with a dual reactor for C & N analysis or in single reactor mode for analyses with S. After high temperature combustion, reaction products N2, CO2, and SO2 pass through a ramped GC oven to sharpen peaks. Downstream hardware components are treated with a SulfinertⓇ coating to reduce S carry-over effects.
- Samples should be dry and homogenized before sending to MSI AL. We typically weigh and encapsulate samples in tin in-house; we offer a discount for analysis of pre-encapsulated samples. If submitting prepared samples, please double check with AL staff to ensure the
- Some substrates likely contain both organic and inorganic C—such as marine sediments, rock powders, or soils. In this case, it may be necessary to acidify sample material to remove inorganic C from the analysis. However, acidification can produce a δ15N offset; in this case, individual samples for either d13C (decarbonated) and d15N (regular) analysis may be recommended. Large S samples perform better with interspersed blanks to mitigate carry-over effects.
Please reach out to the analytical lab personnel for in-depth questions on sample preparation, capabilities, and instrument availability.