Services
Warning
We do not accept samples with enriched 14C (often used as a tracer). Any contamination of any amount of enriched 14C ("hot") material may cause thousands of dollars in clean-up and other costs. If you submit "hot" samples to this lab, you may be liable.
Our services
See below a list of our services.
Requirements
- All material must be dry and powdered.
- Special cases such as small feathers or 1cm lengths of hair for example are not possible to powder.
- Store in air-tight vials or bottles. Glass is usually better (less static), but plastic is ok too.
- Glass fibre filters may be stored and shipped wrapped flat in aluminum foil.
- If the material is too coarse or non-homogenised, an extra charge per sample for grinding with the ball mill or mortar and pestle will be applied (see price list).
- Typically 4-5 mg of organic matter is used, 10-100mg of sediments. Our large capacity elemental analyser can combust up to 500 mg.
- Tungstic oxide (WO3) is added to sediments as a combustion aid.
- Best to group samples with similar properties and matrix.
Methodology
Solids are weighed into tin capsules, with WO3 (for difficult samples with iron, calcium, potassium or sodium oxides). Elemental standards are prepared with every batch of samples for normalization of the data.
The prepared capsules are loaded into the carousel of the autosampler.The sample falls down into the top of a column of solid chemicals at 1150°C and is flash combusted at 1800°C with the addition of oxygen. Ultra-pure helium is used to carry the resulting gases through the column of chemicals to obtain N2 , CO2 , H2O, and SO2 , then through a series of adsorption traps to separate the gases: "purge and trap". A thermo conductivity detector (TCD) measures the gases as they are released.
The analytical precision (2 sigma) is +/- 0.1%.
References
- Pella, E., (1990) Elemental organic analysis, parts 1-2. American Laboratory, Feb. & Aug.
- Instruction Manuals for the elementar Isotope Cube
Requirements
- Most material should be ground to a dry powder. Some types of material such as small feathers or cut strands of hair may not need to be ground; check with the lab.
- If the material is too coarse, an extra charge per sample for grinding with the ball mill or mortar and pestle will be applied (see price list).
- Typically 1-2 mg of material is used.
Methodology
Dry, powdered samples are weighed into silver capsules and placed into a zero blank autosampler which is place under vacuum for a few minutes. The samples are analysed with a Thermo Scientific TC/EA unit. Benzoic Acid standards are prepared with every batch of samples for individual run calibration.
The analytical precision is +/- 0.3%
References
- Instruction Manual for the Thermo TC/EA
- Instruction manual for Flash Ht Plus.
Requirements
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Sample grain size should be less than very fine sand. If the material is too coarse, an extra charge per sample for grinding with a mortar and pestle will be applied (see price list).
- Sample vials must be air tight.
- One submission sheet for one type of mineral only.
- Purity of mineral for each sample must be indicated in comments column. Indicate %S or %C(organic) if more than about 1%.
- If possible, keep the size of vial appropriate to amount of material submitted. We use about 0.5-0.7 mg of calcite equivalent per analysis; please send a few milligrams if possible.
Gasbench Methodology
A spare Exetainer vial is filled with about 10mL of specially prepared anhydrous phosphoric acid (method adapted from: Coplen et al., 1983), capped, heated and evacuated on a vacuum line for at least 1 hour to degas the acid. Meanwhile about 0.5-0.7mg of sample or standard is measured into clean Exetainers. A calibrated internal standard is also loaded with each batch to be run as an unknown.
Once the samples and standards have been weighed, the vials are loaded 8 at a time without caps into an extra rack turned on its side (i.e. Exetainers are kept almost horizontal). A 1mL disposable syringe is used to carefully drop 0.1mL of acid just past the threaded top of each Exetainer. Vials are kept horizontal while being recapped (after every 8). Once all the vials have acid added and caps on, each column of 8 vials is flushed and filled with UHP helium off-line for 4 minutes at a rate of 60-70 mL/min.
Prepared vials are then tipped upright and immediately placed in the heated block of the GasBench (either 25.0°C or 50.0°C), and left to react for 24 hours. Regular analysis of CO2 headspace follows.
The analytical precision is +/- 0.15 permil.
Off-line Extraction Methodology (single mineral)
Sample material is weighed into a glass vessel with a side-arm. 1-3 mL of specially prepared anhydrous phosphoric acid (method adapted from: Coplen et al., 1983) is measured into the side-arm of the vessel. The vessel is capped and evacuated on a glass vacuum line. Vessels are closed, removed from the line, and tipped to add the acid to the sample material. Reaction occurs either at room temperature, or at 50ºC for at least over-night.
The following day, the resulting CO2 gas is extracted on a glass vacuum line using sequential cold traps, and frozen into a glass break seal. Ideally there should be about 25 µM of CO2 in each breakseal.
The break seals are run on a Delta V+ IRMS using the dual inlet.
References
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Coplen, T.B., Kendall, C., and Hopple, J., (1983). Comparison of stable isotope reference samples, Nature, vol. 302, pp. 236-238.
- Revez, K. et al., (2001). Measurement of delta13C and delta18O Isotopic Ratios of CaCO3 using a Thermoquest Finnigan GasBench II Delta Plus XL Continuous Flow Isotope Ratio Mass Spectrometer with Application to Devils Hole Core DH-11 Calcite. USGS Open-File Report 01-257.
- Instruction Manuals for the GasBench and the Thermo Finnigan DeltaPlusXP IRMS.
Requirements
- Most material should be ground to a dry powder. Some types of material such as small feathers or cut strands of hair may not need to be ground; check with the lab.
- If the material is too coarse or not homogeneous, an extra charge per sample for grinding with the ball mill or mortar and pestle will be applied (see price list).
- Organic and inorganic material must be submitted in separate submission files; they have different media codes (one media code per file).
- Purity of mineral or %H for each sample must be indicated in submission file. If the %H is unknown, an elemental analysis run (separate submission) must be done first.
- About 40 ug of H equivalent is required, please send more material though for repeats or duplicates.
- If you weigh the samples yourself, please use 4 x 3.2 mm SILVER capsules.
Methodology (non-exchangeable H)
Dry, powdered samples are analyzed with a Thermo DeltaPlus XP continuous-flow isotope-ratio mass spectrometer coupled with a Thermo Scientific thermal conversion elemental analyzer (TC/EA) via a Confo IV, and having a Costech Zero-blank autosampler that can be sealed and pumped out. The δ2H and δ18O measurements are performed individually because operating parameters of the TC/EA are different for eacheach of the two elements. For δ2H measurements, the method of Qi and Coplen is used: He flow rate = 120 mL/min, reactor temperature = 1450°C, GC temperature = 85°C, and GC length = 1m, 5Å. Powdered minerals are weighed into silver capsules targeting about 40 µg H. Calibrated internal/international standards are prepared with every batch of samples for normalization of the data.
The analytical precision is +/- 3 permil.
Methodology (exchangeable H)
Dry samples of either pieces or powder are analyzed with a Thermo DeltaPlus XP continuous-flow isotope-ratio mass spectrometer coupled with a Thermo Scientific thermal conversion elemental analyzer (TC/EA) (via a Confo IV) having a Costech Zero-blank autosampler that can be sealed and pumped out. Two identical sets of samples are weighed into silver capsules but left open in trays. One set is allowed to exchange with water depleted in 2H and another set with water enriched in 2H in order to perform isotope-mass-balance calculations.
After the exchange process is complete, samples are dried under vacuum for 24 hours. For δ2H measurements, the method of Qi and Coplen is used; operating parameters included the following: mass of each human-hair sample = 460 ± 10 μg, which were weighed into 3.5 × 5 mm silver capsules; He flow rate = 120 mL/min; reactor temperature = 1350°C; GC temperature = 80°C; and GC length = 1m, 5Å.
The analytical precision is +/- 3 permil.
References
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Coplen, Tyler B., and Qi, Haiping (2012) USGS42 and USGS43: Human-hair stable hydrogen and oxygen isotopic reference materials and analytical methods for forensic science and implications for published measurement results, Forensic Science International, Volume 214, Issues 1–3, 10 January 2012, Pages 135–141.
- Instruction Manuals for the Thermo TC/EA and the Thermo Finnigan DeltaPlus XP.
Requirements
- All material must be dry.
- Most material should be powdered. Special cases such as small feathers or 1cm lengths of hair for example are not possible to powder.
- Store in air-tight vials or bottles. Glass is usually better (less static), but plastic is ok too.
- Glass fibre filters may be stored and shipped wrapped flat in aluminum foil.
- If the material is too coarse or non-homogenised, an extra charge per sample for grinding with the ball mill or mortar and pestle will be applied (see price list).
- Organic and inorganic material must be submitted in separate submission files; they have different media codes (one media code per file).
- Quantitative %C for each sample must be indicated in the submission file. If the %C is unknown and cannot be found in a literature search, samples (or a subset) must also be submitted for a preliminary elemental analysis run (separate submission).
Methodology (organic)
NOTE: Carbon (C) and nitrogen (N) are usually analysed together in one run. If both are requested, the target weight is determined by the element with the lower %, almost always nitrogen (N); however, a dual run is not recommended for samples with a C:N ratio larger than 100. In this case, two runs are required.
Organic solids are weighed into tin capsules. Calibrated internal standards are prepared with every batch of samples for normalization of the data. In general, 100 ug of nitrogen (or 300µg of C if running only for C) are required for analysis. The carbon is normally diluted with helium since there is almost always higher %C than %N. If a requested analysis is strictly for the C, with a low %C, the analysis can be done without dilution using a lower sample weight (down to 30 µg of C if necessary).
The isotopic composition of organic carbon (and nitrogen) is determined by the analysis of CO2 (and N2) produced by combustion on an Elementar VarioEL Cube Elemental Analyser followed by "trap and purge" separation and on-line analysis by continuous-flow with a DeltaPlus Advantage isotope ratio mass spectrometer coupled with a ConFlo III interface.
For difficult materials such as soils or filters, up to 250 mg of material can be handled in a single sample with at least double that amount of tungstic oxide (WO3). Inorganic carbon must first be removed before samples can be analysed for organic carbon. There are several ways to accomplish the removal; none is perfect. Do a literature search in your field to see what others have done.
The routine precision of the analyses is 0.20‰.
References
- Pella, E., (1990) Elemental organic analysis, parts 1-2. American Laboratory, Feb. & Aug.
- Instruction Manuals for the elementar VarioEL Cube and the Thermo Finnigan DeltaPlus Advantage.
- Brodie, Chris R., Leng, Melanie J., Casford, James S.L., Kendrick, Christopher P., Lloyd, Jeremy M., Yongqiang, Zong, Bird, Michael I., Evidence for bias in C and N concentrations and d13C composition of terrestrial and aquatic organic materials due to pre-analysis acid preparation methods, Chemical Geology (2011), doi: 10.1016/j.chemgeo.2011.01.007
Methodology (inorganic - graphite)
The analysis of inorganic carbon isotopes is similar to that for organic carbon (above). The main differences are:
- Graphite is very difficult to combust; therefore, the samples must be extremely finely powdered.
- WO3 must be added in great excess (at least 4-5 times the weight of sample) and thoroughly homogenised with the sample material before being closed in a tin capsule.
References
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Instruction Manuals for the elementar VarioEL Cube and the Thermo Finnigan DeltaPlus Advantage.
Requirements
- All material must be dry.
- Most material should be powdered. Special cases such as small feathers or 1cm lengths of hair for example are not possible to powder.
- Store in air-tight vials or bottles. Glass is usually better (less static), but plastic is ok too.
- Glass fibre filters may be stored and shipped wrapped flat in aluminum foil.
- If the material is too coarse or non-homogenised, an extra charge per sample for grinding with the ball mill or mortar and pestle will be applied (see price list).
- Organic and inorganic material must be submitted in separate submission files; they have different media codes (one media code per file).
- The %C and %N of each sample must be indicated in the submission file. If the %C and %N are unknown and cannot be found in a literature search, an elemental analysis run of all samples (or a subset of these) will need to be done first; separate submission. If requesting only N isotopes, the %C is still required so that we can set the dilution properly.
- About 0.1 mg of N equivalent is required, please send more.
Methodology (organic)
NOTE: Carbon (C) and nitrogen (N) are usually analysed together in one run. If both are requested, the target weight is determined by the element with the lower %, almost always the nitrogen (N).
Organic solids are weighed into tin capsules. Calibrated internal standards are prepared with every batch of samples for normalization of the data. In general, 100 µg of N are required for analysis. The carbon is normally diluted with helium since there is almost always higher %C than %N. It is possible to do samples targeting only 30 µg of N if necessary.
Please check with us before weighing your samples either here in the lab or in your own space. In some cases (C:N ratio >50), the quantities might need to be altered . In extreme cases (C:N ratio >100), it is not possible to run both C and N isotopes on a single sample. Weights must be targeted to the %N only for one run and for %C for a second run.
The isotopic composition of organic nitrogen is determined by the analysis of N2 produced by combustion on an Elementar Vario Cube Elemental Analyser followed by "trap and purge" separation and on-line analysis by continuous-flow with a DeltaPlus Advantage isotope ratio mass spectrometer coupled with a ConFlo III.
For difficult materials such as soils or filters, up to 250 mg of material can be handled in a single capsule with at least double that amount of tungstic oxide (WO3). If inorganic carbon must first be removed from soils or sediments for C analysis, some unaltered material must be kept for the N analysis. Any treatment will alter the N isotope signature.
The routine precision of the analyses is 0.2‰.
References
- Pella, E., (1990) Elemental organic analysis, parts 1-2. American Laboratory, Feb. & Aug.
- Instruction Manuals for the elementar VarioEL Cube and the Thermo Finnigan DeltaPlus Advantage.
- Brodie, Chris R., Leng, Melanie J., Casford, James S.L., Kendrick, Christopher P., Lloyd, Jeremy M., Yongqiang, Zong, Bird, Michael I., Evidence for bias in C and N concentrations and d13C composition of terrestrial and aquatic organic materials due to pre-analysis acid preparation methods, Chemical Geology (2011), doi: 10.1016/j.chemgeo.2011.01.007
Methodology (inorganic)
The analysis of inorganic nitrogen isotopes is similar to that for organic nitrogen (above).The main differences are:
- Some material may require the addition of sucrose to help with combustion.
- Some materials (very low concentrations) may require the addition of tungstic oxide and tin powder.
References
-
Instruction Manuals for the elementar Isotope Cube and the Thermo Finnigan DeltaPlus XP.
Requirements
- Most material should be ground to a dry powder. Some types of material such as small feathers or cut strands of hair may not need to be ground; check with lab.
- If the material is too coarse or non-homogenised, an extra charge per sample for grinding with the ball mill or mortar and pestle will be applied (see price list).
- Organic and inorganic material must be submitted in separate submission files; they have different media codes (one media code per file).
- Purity of mineral or %O for each sample must be indicated in submission file. If the %O is unknown and cannot be found in a literature search, an elemental analysis run (separate submission) must be done first.
- About 0.1 mg of O equivalent is required, please send at least double if possible.
Methodology
Dry, powdered samples are analyzed with a Thermo DeltaPlus XP continuous-flow isotope-ratio mass spectrometer coupled with a Thermo Scientific thermal conversion elemental analyzer (TC/EA) via a Conflo IV having a Costech Zero-blank autosampler that can be sealed and pumped out. The δ2H and δ18O measurements are performed individually because operating parameters of the TC/EA are different for δ2H and δ18O measurements. For δ18O measurements, the method of Qi and Coplen is used; He flow rate = 120 mL/min, reactor temperature = 1450°C, GC temperature = 85°C, and GC length = 1m, 5Å. Powdered minerals are weighed into silver capsules targeting about 100 µg O. Calibrated internal/international standards are prepared with every batch of samples for normalization of the data.
The analytical precision is +/- 0.3 permil.
References
-
Coplen, Tyler B., and Qi, Haiping (2012) USGS42 and USGS43: Human-hair stable hydrogen and oxygen isotopic reference materials and analytical methods for forensic science and implications for published measurement results, Forensic Science International, Volume 214, Issues 1–3, 10 January 2012, Pages 135–141.
- Instruction Manuals for the Thermo TC/EA and the Thermo Finnigan DeltaPlus XP.
Requirements for material sent for analysis
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Material must be ground to a powder. If the material is too coarse, an extra charge per sample for grinding with a mortar and pestle will be applied (see price list). Hair, fur & feathers do not need to be ground.
- Sulphide and sulphate minerals must be submitted in separate submission files; they have different media codes (one media code per file). Organic sulphur is also a different media code.
- Mineral type and purity or %S must be included for each sample in the submission file.
- Indicate %C (inorganic) or %C (organic) if more than about 5%.
- About 50 µg of sulfur equivalent is used, please send more for duplicates or replicates.
Methodology (inorganic)
Sulphide and sulphate minerals are weighed into tin capsules with at least double that amount of tungstic oxide (WO3). Calibrated internal standards are prepared with every batch of samples for normalization of the data. The formula "5 ÷ %S" gives the amount of sample material in milligrams (mg) to be weighed (e.g. pyrite contains 50% sulfur: 5 / 50% = 0.1 mg).
When using the Isotope Cube (Elementar, Germany) samples with as little as 0.05% S can be analysed directly.
The prepared capsules are loaded into the carousel of the Isotope Cube autosampler. A sample falls down into the top of a column of solid chemicals at 1150°C, and is flash combusted at 1800°C with the addition of oxygen. Ultra-pure helium is used to carry the resulting gases through the column(s) of oxidizing/reducing chemicals to obtain N2, CO2, H2O, and SO2. Water is cleaned out of the system by sicapent traps. The SO2 is separated for analysis by the chemical adsorption "trap and purge" method. The SO2 gas is carried by helium into the Thermo Finnigan DeltaPlus XP IRMS via a Conflo IV for analysis.
The analytical precision is +/- 0.3 permil.
References
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Grassineau, N. V., et al., (2001). Sulfur Isotope Analysis of Sulfide and Sulfate Minerals by Continuous Flow-Isotope Ratio Mass Spectrometry. Analytical Chemistry, vol. 73, no. 2, pp. 220-225.
- Instruction Manuals for the Elementar Isotope Cube, and the Thermo Finnigan DeltaPlus XP.
Methodology (organic)
Organic solids are weighed into tin capsules. Calibrated internal standards are prepared with every batch of samples for normalization of the data. In general, 50 µg of S are required for analysis. Elemental analysis must be performed first if the concentration of sulphur in a sample is unknown; separate submission.
If the amount of carbon is very high relative to the amount of sulphur (eg. wood), a special configuration of the elemental analyser is needed. Advance notice to the lab is required.
The prepared capsules are loaded into the carousel of the Isotope Cube autosampler. A sample falls down into the top of a column of solid chemicals at 1150°C, and is flash combusted at 1800°C with the addition of oxygen. Ultra-pure helium is used to carry the resulting gases through the column(s) of oxidizing/reducing chemicals to obtain N2, CO2, H2O, and SO2. Water is cleaned out of the system by sicapent traps. The SO2 is separated for analysis by the chemical adsorption "trap and purge" method. The SO2 gas is carried by helium into the Thermo Finnigan DeltaPlus XP IRMS via a Conflo IV for analysis.
The routine precision of the analyses is 0.4‰.
References
- Pella, E., (1990) Elemental organic analysis, parts 1-2. American Laboratory, Feb. & Aug.
- Instruction Manuals for the Elementar Isotope Cube and the Thermo Finnigan DeltaPlus XP.
Fresh water to saline water
Requirements
Mandatory use of 40mL pre-cleaned borosilicate amber EPA vials with septa caps (PTFE-lined silicone), purchased from a major laboratory supplier; quality assurance grade is not necessary (e.g. Fisher # 05-719-102UC; 72/cs). Please order your EPA vials early; they are often back-ordered.
NOTE: Please do not send 60 ml EPA vials. They do not fit into the carousel.
Number of replicate vials needed per sample:
- Concentration (ppmC) only (no isotope analysis):
- DIC/DOC = 1 vial per sample, filtered, full (no bubble or headspace) with extra septum
- TIC/TOC = 1 vial per sample, full (no bubble or headspace) with extra septum
- NOTE: pack correctly to ensure vials survive shipping as there will be no back-ups
- Inorganic C isotope analysis (DIC/TIC) only:
- 13C (DIC) only = 2 identical full vials filtered (no bubble or headspace) with extra septum
- 13C (TIC) only = 2 identical full vials (no bubble or headspace) with extra septum
- NOTE: 2 replicate vials per sample is best for DCI/TIC, as a re-run on a vial with headspace can alter the 13C signal. You will also receive a concentration measurement.
- Organic C isotope analysis (DOC/TOC) only:
- 13C (DOC) only = 1 vial, filtered, no extra septum. A small headspace is ok; none is best.
- 13C (TOC) only = 1 vial, no extra septum. A small head space is ok; none is best.
- NOTE: pack correctly to ensure vials survive shipping as there will be no back-ups. You will also receive a concentration measurement.
- Both Inorganic & Organic C isotope analysis (DIC & DOC or TIC & TOC):
- 13C (DIC&DOC) = 2 identical full vials, filtered (no bubble or head space) with extra septum.
- 13C (TIC&TOC) = 2 identical full vials, (no bubble or head space) with extra septum.
- NOTE: Both vials need to be full and have the extra septum as we may need to use both in order to obtain the inorganic C (DIC/TIC) measurement. The organic C (DOC/TOC) can be run from the previously used vials. The two vials should be identical.
- Both Dissolved & Total, Organic and Inorganic C analysis (DIC & DOC and TIC & TOC):
- Samples for dissolved C (filtered waters) are considered distinct from samples for total C (unfiltered waters).
- For each sample you should provide 2 identical vials of filtered water and 2 identical vials of unfiltered water.
- List the dissolved samples and total samples separately in each submission file. Thus if you have three separate samples (A, B and C) and you are submitting each for dissolved and total C analysis you should have six samples listed: eg. "sample A-dissolved", "sample B-dissolved", "sample C-dissolved", "sample A-total", "sample B-total", "sample C-total".
- As above, only one media code per submission fie (organic vs. inorganic)
- NOTE: when requesting 13C, you get a concentration measurement as a bonus (you needn't submit a separate submission file) however we still ask that you provide us with a concentration estimate (ppm-C) a priori as it guides us as to what sample volume we should use for the 13C analysis in order to fall within the mass spec's range (estimate examples: <1, <5, 5-10, 20-40, >40 ppm). And please keep in mind that when isotopes are requested the instrumentation and standards are geared to isotope analysis; the concentrations provided will thus not be as precise as in the case of a concentration only run.
Extra septum
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Samples for DIC or TIC require an extra septum (PTFE-rubber, see info below) inserted between the top of the vial and the cap. The silicone/Teflon septum provided with the EPA vials allow inorganic carbon to diffuse out unless the extra septum is used.
- We now advise that you put the darker PTFE side against the water. The rubber side of the septum can potentially affect the organic carbon. (A. Parkes (2016) verbal communication).
- The extra septum is not required for DOC or TOC; however if inorganic & organic carbon are requested, please submit 2 identical full vials with extra septum (if re-running for DIC/TIC we must use a fresh vial).
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NOTE: the septa pictured below are being discontinued. Chromatographic Specialties has worked with a supplier to find an alternative. Contact them directly to inquire about testing the new "22mm PTFE/grey butyl septa for 24-400 Screw Cap, pk1000".
Chromatorgraphic Specialties
Part No. C8850522C
PTFE-rubber, 22mm flexseal disc
Labelling
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In addition to your personal label on the vial, please label each sample cap from 1 to xx in the same order as listed in the submission file. This helps us to quickly locate samples and replicates.
- Each set of identical vials should have the same number on the cap. Only enter this sample once in the submission file.
- Please include the number of replicate vials per sample directly in the submission file; either in the General Comments box if all samples have the same number of replicates or in the Comments column if the number varies.
- DO NOT use multiple layers of tape on the vial body - especially not DUCT tape - as the vials will not fit into the carousel. Please remove any excess tape before sending. The sequential number on the cap is sufficient for us if it comes to that.
Filtration
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ONLY samples for DIC or DOC should be carefully and gently filtered to 0.45 µm or less. This can be done using nitrocellulose filters (0.45 um) pre-rinsed with a minimum of 150 ml of DI water to prevent leaching of DOC from the filter. Glass fibre filters do not have the 0.45 um pore size (only 0.070 um) and also need to be pre-rinsed (M. Grinter, MSc Thesis, UOttawa, 2017). Because filtering can cause isotopic shifts due to turbulence and exposure to air, some prefer to analyse strictly TIC in order to avoid these problems.
- Samples for TIC or TOC should NOT be filtered (both dissolved and particulate C are thus analysed).
- NOTE: A filtered and an unfiltered version of the same sample water are considered two separate samples.
Flocculation
If you suspect that some of your dissolved organic matter (DOC) may have precipitated after filtration, it is possible for us to add a stir bar to the vial before analysis; however, this will incur an extra cost of $5 per sample and should be specified in the sub file.
Range of measurement
- We can analyse water samples ranging from about 0.4 to 100 ppm of carbon.
- The wet oxidation instrument (used for fresh waters and inorg. C of saline waters) allows us to select a variable volume of sample (0.5 to 8 ml) according to the expected concentration, in order fall within the mass spectrometer's sweet spot; hence the importance of providing us with all pertinent concentration info.
- Please note: organic C and inorganic C concentrations can be vastly different. Although we can obtain both C-inorg and C-org in one run, we now analyse for inorganic C first and then analyse for organic C in a second run, after sparging the samples offline.
Preservation agents
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Samples should remain refrigerated after sampling and kept cool but not frozen during shipping. Vials will be transferred to our refrigerator upon arrival.
- If the samples are refrigerated and can be shipped and analysed quickly, it is preferable to not poison the waters for preservation. We do understand that in some cases it is necessary.
- If the waters are poisoned, it MUST be clearly stated in the submission file; include the type of poison and amount.
- IF submitting only for DOC/TOC (isotopes and/or conc.) you may add acid (HCl or phosphoric) to preserve the samples, but you MUST keep the pH > 3; aim for a pH of 3-4 so as not to lose the volatile organic matter (VOM).
"Abnormal" water samples
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"Normal" samples are considered to be freshwater lake, river, groundwater, or regular seawater samples that have organic and inorganic C concentrations of less than about 80 ppm.
- If your samples are out of the ordinary in any way (i.e. very high C concentrations, high salinity, organic contamination, very high or low pH, high sulfur content, etc.), please contact us. We will let you know if we can analyse them. Our instrumentation is not adapted to handle extreme samples. Deep groundwaters tend to be problematic. If accepted, your high salinity and/or high concentration samples can be diluted with deionised water for an extra charge.
- If your sample concentrations are below our minimum ( approx. 0.4 ppm) there is nothing to be done; no isotopic data will be possible.
Submission files
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Only 1 media code per submission file: DIC/TIC (media code 42) or DOC/TOC (code 41) or ppmC-only (code 40); each requires a separate file.
- Submit a file for concentration (ppmC; media code 40) only if you are NOT submitting for isotopes.
- List each sample only once in the Sample ID column (do NOT list replicate vials unless you want them analysed too!).
- Include the number of replicate vials per sample in the Comments box at the top if the same for all, or in the Comments column if variable.
- Describe the type of waters you are submitting (e.g. lake, river, pond, ice meltwater, sea water, brines, groundwater, sediment porewater etc.).
- Include the pH & salinity data for each sample if you have it; otherwise, provide an estimate.
- Include the DIC/TIC and/or DOC/TOC concentrations (ppmC or mg/L) of each sample if you have the data; otherwise, provide an estimate (this can be from previous years in the same region or from the literature; it helps enormously in estimating sample volume to use for analysis).
- If submitting for DOC only, please include a DIC concentration estimate as well if you have it, as we may need to sparge the samples (acidification and removal of DIC) prior to analysis.
- If a preservation agent was used, include the type of agent (e.g. HgCl2, HCl, etc) and the amount used in the general comments box.
- PLEASE REPEAT within your email message the number of samples that you are sending (including the number of replicate vials per sample) as well as the type of analysis that you wish done, for verification purposes.
Shipping
- NEVER EVER ship vials glass on glass. They WILL break.
- See sample submission (shipping) for more details.
Methodology
The quantitative determination of total or dissolved, inorganic or organic carbon is performed using a modified OI Analytical model 1030 wet TOC analyser, with a model 1088 autosampler. Quantities determined are parts per million carbon (ppmC).
Waters are sampled in TraceClean pre-cleaned, amber borosilicate 40mL EPA vials.Two internal standard solutions (KHP and sucrose) are used to determine the regression curve for the concentration (ppm) and isotopes (13C). Sample and standard vials are loaded into the carousel. An aliquot of water is drawn up from the vial via a needle, is deposited in the reaction chamber and acidified with 5% H3PO4 to release the inorganic carbon. The gases are purged from the chamber using ultra-pure helium and pass through water traps to remove water. The CO2 is measured by a non-destructive infrared (NDIR) detector. After the inorganic carbon has been completely removed, a persulphate reagent is added to release the organic carbon which is also purged and measured.
The analytical precision (2 sigma) of the analyses is +/- 0.2 ppmC.
References
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OI Analytical (2005). Aurora 1030 Wet Oxidation TOC analyzer Operator's Manual. College Station, Texas.
Requirements
- About 10 ml are used to flush the the 1 ml sample loop of the instrument.
- 500, 750 or 1000mL Wheaton Bottles or other pre-approved containers must have a thick butyl rubber septum for extracting the gas.
- Exact bottle volume must be known. If Isoflasks are used, weight of Isoflask and weight of water should be provided.
- Bottles should be filled full without any air bubble.
- Samples should be stored at 4oC.
- Consult with Paul before sampling to make sure you have the appropriate container, etc.
Methodology
At room temperature, a head space is created by gently displacing the water with high purity Helium, typically 10% of the total bottle volume. The bottle is shaken for 5 minutes and equilibrated for 30 minutes. The head space is analysed for gaseous components on an SRI GC 8610C of N2, O2+Ar, CO2, CO, methane, ethane, propane, butane and pentane percentages, a calibration curve is created with known gas concentrations prior to sample analysis. We cannot analyse for Hydrogen and Helium using this approach.
Corrections are applied for volume, temperature and gas solubility using Henry’s law as per the three references listed below.
Corrections
TC = CAH + CA where:
- TC = total concentration of gas in original aqueous sample
- CAH = aqueous concentration in head space after equilibrium in mg/L = (55.5mol/L)*(pg/H)*MW(g/mol)*103mg/g
where pg= partial pressure of gas in atm from GC analysis, H = Henry’s law constant, MW = molecular weight in g/mol - CA = aqueous concentration in water after equilibrium in mg/L
= [(Vh/(Vb-Vh)]*Cg*(MW(g/mol)/(22.4L/mol))*[273K/(T+273K)]*103mg/g
where Vh = head space volume, Vb = bottle volume, Cg = gas concentration (also equal to pg ), T = temperature in Kelvin
Expected error has not been determined yet, we believe it should be around 10% of the absolute value.
References
-
Analysis of dissolved methane, ethane and ethylene in ground water by standard gas chromatographic technique, Journal of Chromatographic Science, Vol 36, May 1998.
- Sample preparation and calculations for dissolved gas analysis in water samples using a GC head space equilibration technique, RSKSOP-175, revision No 2, May 2004.
- Compilation of Henry’s Law Constants for Inorganic and Organic Species of Potential Importance in Environmental Chemistry. http://www.henrys-law.org/henry-3.0.pdf
- SRI Chromatogragh Operating notes, Peak simple version 4.44
Requirements
Mandatory use of 40mL pre-cleaned borosilicate amber EPA vials with septa caps (PTFE-lined silicone), purchased from a major laboratory supplier; quality assurance grade is not necessary (e.g. Fisher # 05-719-102UC; 72/cs). Please order your EPA vials early; they are often back-ordered.
NOTE: Please do not send 60 ml EPA vials. They do not fit into the carousel.
Number of replicate vials needed per sample
- Concentration (ppmC) only (no isotope analysis):
- DIC/DOC = 1 vial per sample, filtered, full (no bubble or headspace) with extra septum
- TIC/TOC = 1 vial per sample, full (no bubble or headspace) with extra septum
- NOTE: pack correctly to ensure vials survive shipping as there will be no back-ups
- Inorganic C isotope analysis (DIC/TIC) only:
- 13C (DIC) only = 2 identical full vials filtered (no bubble or headspace) with extra septum
- 13C (TIC) only = 2 identical full vials (no bubble or headspace) with extra septum
- NOTE: 2 replicate vials per sample is best for DCI/TIC, as a re-run on a vial with headspace can alter the 13C signal. You will also receive a concentration measurement.
- Organic C isotope analysis (DOC/TOC) only:
- 13C (DOC) only = 1 vial, filtered, no extra septum. A small headspace is ok; none is best.
- 13C (TOC) only = 1 vial, no extra septum. A small head space is ok; none is best.
- NOTE: pack correctly to ensure vials survive shipping as there will be no back-ups. You will also receive a concentration measurement.
- Both Inorganic & Organic C isotope analysis (DIC & DOC or TIC & TOC):
- 13C (DIC&DOC) = 2 identical full vials, filtered (no bubble or head space) with extra septum.
- 13C (TIC&TOC) = 2 identical full vials, (no bubble or head space) with extra septum.
- NOTE: Both vials need to be full and have the extra septum as we may need to use both in order to obtain the inorganic C (DIC/TIC) measurement. The organic C (DOC/TOC) can be run from the previously used vials. The two vials should be identical.
- Both Dissolved & Total, Organic and Inorganic C analysis (DIC & DOC and TIC & TOC):
-
Samples for dissolved C (filtered waters) are considered distinct from samples for total C (unfiltered waters).
- For each sample you should provide 2 identical vials of filtered water and 2 identical vials of unfiltered water.
- List the dissolved samples and total samples separately in each submission file. Thus if you have three separate samples (A, B and C) and you are submitting each for dissolved and total C analysis you should have six samples listed: eg. "sample A-dissolved", "sample B-dissolved", "sample C-dissolved", "sample A-total", "sample B-total", "sample C-total".
- As above, only one media code per submission fie (organic vs. inorganic)
- NOTE: when requesting 13C, you get a concentration measurement as a bonus (you needn't submit a separate submission file) however we still ask that you provide us with a concentration estimate (ppm-C) a priori as it guides us as to what sample volume we should use for the 13C analysis in order to fall within the mass spec's range (estimate examples: <1, <5, 5-10, 20-40, >40 ppm). And please keep in mind that when isotopes are requested the instrumentation and standards are geared to isotope analysis; the concentrations provided will thus not be as precise as in the case of a concentration only run.
-
Extra septum
-
Samples for DIC or TIC require an extra septum (PTFE-rubber, see info below) inserted between the top of the vial and the cap. The silicone/Teflon septum provided with the EPA vials allow inorganic carbon to diffuse out unless the extra septum is used.
- We now advise that you put the darker PTFE side against the water. The rubber side of the septum can potentially affect the organic carbon. (A. Parkes (2016) verbal communication).
- The extra septum is not required for DOC or TOC; however if inorganic & organic carbon are requested, please submit 2 identical full vials with extra septum (if re-running for DIC/TIC we must use a fresh vial).
-
NOTE: the septa pictured below are being discontinued. Chromatographic Specialties has worked with a supplier to find an alternative. Contact them directly to inquire about testing the new "22mm PTFE/grey butyl septa for 24-400 Screw Cap, pk1000".
Chromatorgraphic Specialties
Part No. C8850522C
PTFE-rubber, 22mm flexseal disc
Labelling
-
In addition to your personal label on the vial, please label each sample cap from 1 to xx in the same order as listed in the submission file. This helps us to quickly locate samples and replicates.
- Each set of identical vials should have the same number on the cap. Only enter this sample once in the submission file.
- Please include the number of replicate vials per sample directly in the submission file; either in the General Comments box if all samples have the same number of replicates or in the Comments column if the number varies.
- DO NOT use multiple layers of tape on the vial body - especially not DUCT tape - as the vials will not fit into the carousel. Please remove any excess tape before sending. The sequential number on the cap is sufficient for us if it comes to that.
Filtration
-
ONLY samples for DIC or DOC should be carefully and gently filtered to 0.45 µm or less. This can be done using nitrocellulose filters (0.45 um) pre-rinsed with a minimum of 150 ml of DI water to prevent leaching of DOC from the filter. Glass fibre filters do not have the 0.45 um pore size (only 0.070 um) and also need to be pre-rinsed (M. Grinter, MSc Thesis, UOttawa, 2017). Because filtering can cause isotopic shifts due to turbulence and exposure to air, some prefer to analyse strictly TIC in order to avoid these problems.
- Samples for TIC or TOC should NOT be filtered (both dissolved and particulate C are thus analysed).
- NOTE: A filtered and an unfiltered version of the same sample water are considered two separate samples.
Flocculation
-
If you suspect that some of your dissolved organic matter (DOC) may have precipitated after filtration, it is possible for us to add a stir bar to the vial before analysis; however, this will incur an extra cost of $5 per sample and should be specified in the sub file.
Range of measurement
- We can analyse water samples ranging from about 0.4 to 100 ppm of carbon.
- The wet oxidation instrument (used for fresh waters and inorg. C of saline waters) allows us to select a variable volume of sample (0.5 to 8 ml) according to the expected concentration, in order fall within the mass spectrometer's sweet spot; hence the importance of providing us with all pertinent concentration info.
- Please note: organic C and inorganic C concentrations can be vastly different. Although we can obtain both C-inorg and C-org in one run, we now analyse for inorganic C first and then analyse for organic C in a second run, after sparging the samples offline.
Preservation agents
-
Samples should remain refrigerated after sampling and kept cool but not frozen during shipping. Vials will be transferred to our refrigerator upon arrival.
- If the samples are refrigerated and can be shipped and analysed quickly, it is preferable to not poison the waters for preservation. We do understand that in some cases it is necessary.
- If the waters are poisoned, it MUST be clearly stated in the submission file; include the type of poison and amount.
- IF submitting only for DOC/TOC (isotopes and/or conc.) you may add acid (HCl or phosphoric) to preserve the samples, but you MUST keep the pH > 3; aim for a pH of 3-4 so as not to lose the volatile organic matter (VOM).
"Abnormal" water samples
-
"Normal" samples are considered to be freshwater lake, river, groundwater, or regular seawater samples that have organic and inorganic C concentrations of less than about 80 ppm.
- If your samples are out of the ordinary in any way (i.e. very high C concentrations, high salinity, organic contamination, very high or low pH, high sulfur content, etc.), please contact us. We will let you know if we can analyse them. Our instrumentation is not adapted to handle extreme samples. Deep groundwaters tend to be problematic. If accepted, your high salinity and/or high concentration samples can be diluted with deionised water for an extra charge.
- If your sample concentrations are below our minimum ( approx. 0.4 ppm) there is nothing to be done; no isotopic data will be possible.
Submission files
-
Only 1 media code per submission file: DIC/TIC (media code 42) or DOC/TOC (code 41) or ppmC-only (code 40); each requires a separate file.
- Submit a file for concentration (ppmC; media code 40) only if you are NOT submitting for isotopes.
- List each sample only once in the Sample ID column (do NOT list replicate vials unless you want them analysed too!).
- Include the number of replicate vials per sample in the Comments box at the top if the same for all, or in the Comments column if variable.
- Describe the type of waters you are submitting (e.g. lake, river, pond, ice meltwater, sea water, brines, groundwater, sediment porewater etc.).
- Include the pH & salinity data for each sample if you have it; otherwise, provide an estimate.
- Include the DIC/TIC and/or DOC/TOC concentrations (ppmC or mg/L) of each sample if you have the data; otherwise, provide an estimate (this can be from previous years in the same region or from the literature; it helps enormously in estimating sample volume to use for analysis).
- If submitting for DOC only, please include a DIC concentration estimate as well if you have it, as we may need to sparge the samples (acidification and removal of DIC) prior to analysis.
- If a preservation agent was used, include the type of agent (e.g. HgCl2, HCl, etc) and the amount used in the general comments box.
- PLEASE REPEAT within your email message the number of samples that you are sending (including the number of replicate vials per sample) as well as the type of analysis that you wish done, for verification purposes.
Shipping
- NEVER EVER ship vials glass on glass. They WILL break.
- See sample submission (shipping) for more details.
Methodology - Wet oxidation (media codes 40, 41 & 42)
Freshwater and saline DIC / freshwater and brackish (< 12 PSU) DOC
A modified OI Analytical Aurora model 1030 wet TOC analyser with a model 1088 autosampler are interfaced (interface designed in-house by Paul) to a Thermo Finnigan DeltaPlus XP isotope ratio mass spectrometer (IRMS) for analysis by continuous flow. Data is normalised using two different internal organic standards (KHP and sucrose).
A prescribed aliquot of water (variable according to the expected ppm-C of each sample) is drawn up from the sample vial via a needle and transferred to the reaction chamber. In a first step, the sample is acidified with 5% H3PO4 to release the inorganic carbon for analysis. The gas is purged from the vial using ultra-pure helium and passes through water traps as well as an in-house designed scrubber-conditioning interface. The carbon dioxide concentration is measured by a non-destructive infrared (NDIR) detector and subsequently sent to the IRMS for 13C analysis (via the interface). In a second step, once the inorganic carbon has been completely removed, a persulphate reagent is added to release the organic carbon which is purged and measured once again for concentration and 13C.
The 2sigma analytical precision is 4% of the concentration (in ppm) for the quantitative, and +/- 0.4 permil for the isotopes.
NOTE: What we refer to as DOC or TOC is actually N-POC (non-purgeable organic carbon). Because we initially acidify the water sample in order to remove the inorganic carbon, it is entirely possible that we may at the same time remove any purgeable organic carbon. What remains is the non-purgeable organic carbon (N-POC).
Methodology - High temperature combustion (media codes 67, 68 & 69)
Saline DOC (> 12 PSU)
An OI Analytical Aurora Model 1030W TOC Analyser with a model 1088 autosampler and a combustion unit is interfaced to a Finnigan Mat DeltaPlusXP isotope ratio mass spectrometer (interface designed in-house by Paul) for analysis by continuous flow. Data is normalised using two different internal organic standards.
All vials are pre-acidified and sparged. The vials of samples and standards are placed into the carousel, interspersed with blanks.
A pre-determined quantity of water is drawn up via a needle and deposited in the reaction chamber where hydrochloric acid is added to release the inorganic carbon. The produced gases are flushed from the chamber with ultra pure oxygen in continuous flow. The remaining water is retrieved and injected into a combustion unit to convert the organic carbon into CO2. This gas is carried through a chemical trap and nafion water trap before passing through the detector. The slug of cleaned CO2 gas continues into the mass spectrometer for analysis.
The 2sigma analytical precision is 4% of the concentration (in ppm) for the quantitative, and +/- 0.4 permil for the isotopes.
NOTE: What we refer to as DOC or TOC is actually N-POC (non-purgeable organic carbon). Because we initially acidify the water sample in order to remove the inorganic carbon, it is entirely possible that we may at the same time remove any purgeable organic carbon. What remains is the non-purgeable organic carbon (N-POC).
References
-
OI Analytical (2005). Aurora 1030 Wet Oxidation TOC analyzer Operator's Manual. College Station, Texas.
- Lalonde, K., Middlestead, P., and Gélinas, Y. (2014) Automation of 13C/12C ratio measurement for fresh water and seawater DOC using high temperature combustion. Limnol. Oceangr.: Methods 12, 2014, 816-829
- St-Jean, Gilles (2003). Automated quantitative and isotopic (13C) analysis of dissolved inorganic carbon and dissolved organic carbon in continuous-flow using a total organic carbon analyser. Rapid Communications in Mass Spectrometry, vol. 17, pp. 419-428. Published on-line in Wiley InterScience. DOI: 10.1002/rcm.926
Requirements
- We require a minimum of 2 mL of water, although at least 5 mL is preferable.
- Either good quality plastic or glass bottles can be used for sampling as long as the bottles are air-tight and have a minimum of head space. Do not use paper/foil-lined caps!
- Preservatives are not necessary; water for this type of analysis can be kept at room temperature for years.
- Salinity and pH must be listed in the submission form, as well as whether the samples have been filtered (0.45 micron).
- Enriched or highly depleted waters must be clearly identified in the shipment and in the submission file. Highly enriched samples will need to be diluted before being run by either method below.
- Saline (greater than 3PSU) and fresh waters (less than 3PSU) must be submitted in two separate submission files; they have different media codes.
Methodology (saline/contaminated waters)
This headspace technique is used primarily for waters with greater than 3PSU (salinity), and for waters and other liquids that contain alcohol, oil or other contaminants. Hydrogen and oxygen must be run separately with this method, although a single aliquot is used.
H isotopes of water are determined on a Thermo Delta plus XP + Gasbench. A precise amount of water is pipetted into Exetainer vials; 0.2 mL (fresh & contaminated) or 0.6 mL (saline). A platinum catalyst pellet on a stick is added to each Exetainer; the pellet must be placed above the water. The vials are flushed and filled with a gas mixture of 2% H2 in helium off-line using a set-up designed by Paul.
The flushed vials are left at room temperature for either a minimum of 1.5 hours for fresh water or a minimum of 24 hours for saline water. The H2 gas is analysed automatically in continuous flow. The results are normalized to VSMOW using three calibrated internal standards spanning most of the natural range. A fourth calibrated standard is run as an unknown for long-term monitoring and stats. The routine precision (2 sigma) of the analysis is +/-2.0 permil. A salt effect correction may be required depending on the salt's nature and concentration. This correction is left to the user.
O isotopes of water are determined on a Finnigan MAT Delta plus XP + Gasbench. A precise amount of water is pipetted into Exetainer vials; 0.2 mL (fresh + contaminated) or 0.6 mL (saline). No catalyst is required. The vials are flushed and filled with a gas mixture of 2% CO2 in helium off-line using a set-up designed by Paul (see photo above). The flushed vials are left at room temperature for either a minimum of 24 hours for fresh water or a minimum of 5 days for saline water. The CO2 gas is analysed automatically in continuous flow. The results are normalized to VSMOW using three calibrated internal standards spanning most of the natural range. A fourth calibrated standard is run as an unknown for long-term monitoring and stats. The routine precision (2 sigma) of the analysis is +/-0.15 permil. A salt effect correction may be required depending on salts nature and concentration. This correction is left to the user.
References
-
Friedman, I., and O'Neil, J.R., (1977) Compilation of stable isotope fractionation factors of geochemical interest. In: Data of Geochemistry. U.S. Geol. Surv., Prof. Pap., 440-KK, 6th ed.
- Instruction Manuals for the Gasbench and the Thermo Finnigan DeltaPlus XP
- Horita J., Wesolowski D., Cole D., (1993) The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: I. Vapor-liquid water equilibration of single salt solutions from 50 to 100 C. Geochemica and Cosmochemia Acta, Vol 57, Issue 12, June 1993, pp 2797-2817.
Methodology (pure/fresh waters)
Fresh waters with less than 3 PSU can be analysed using the Los Gatos Research (LGR) Triple Isotope Water Analyzer in the liquid mode. This unit can determine the 2H, 18O and 17O data from a single injection of 0.9 µL of water. Up to 20 injections are averaged for better precision. We also now have a Picarro unit.
1.0mL of 0.45 micron filtered water is precisely pipetted into a 2mL glass GC vial. Caps are tightened fully until just before analysis. GC vials are not designed for long-term storage. Samples are pipetted into the GC vials right before analysis.
The results are normalized to VSMOW using three calibrated internal standards spanning most of the natural range. A fourth calibrated standard is run as an unknown for long-term monitoring and stats. The routine precision (2 sigma) of the O analysis is +/-0.2 permil, and +/-2.0 permil for the H analysis.
References
- Instruction Manual for the LGR - TIWA
Requirements
-
Analysis of dissolved Oxygen and /or Argon and /or Nitrogen on the same water aliquot.
-
12 mL Exetainer vials with butyl rubber septa should be sufficient in most cases. If the concentration of Oxygen or Argon or Nitrogen dissolved in the water is extremely low, please check with the lab before sampling.
-
Each Exetainer should be filled to the top (no air bubbles) in the field. It is very important not to have any head space as the dissolved gas may start releasing into it.
Methodology
Oxgen/Argon/Nitrogen that are dissolved in water can be analysed on the Gasbench + Thermo Finnigan DeltaPlus XP. When ready for analysis, a headspace must be created in the full 12mL Exetainer vials (with butyl rubber septa) in order to equilibrate with the dissolved gases. A few mL's of water (more or less depending on the concentration) are removed as He is simultaneously added to prevent a vacuum. The dissolved gases are allowed to equilibrated into the head space for 24 hours.
The following day, the samples are loaded into the Gasbench block. Regular head space analysis is performed, except that a GC column specifically targeted to separate Oxygen/Argon/Nitrogen from other gases is used.
The vials are run against a tank of Oxygen/Argon/Nitrogen reference gas. Samples are corrected to air.
References
-
Barth, J., Tait, A. and Bolshaw, M., (2004) Automated analyses of 18O/16O ratios in dissolved oxygen from 12-mL water samples. Limnology and Oceanography: Methods 2, pp.35-41.
-
Instruction Manuals for the Gasbench and the Thermo Finnigan DeltaPlus XP
Requirements
-
500, 750 or 1000mL Wheaton Bottles or other pre-approved containers must have a thick butyl rubber septum for extracting the gas.
- Bottles for dissolved gases must be completely full of water, no head space.
- Exact bottle volume must be known.
- Samples should be stored at 4oC.
- Analysis should be done within 2 weeks.
- Consult with Paul before sampling to make sure you have the appropriate container, etc.
Methodology
Samples are warmed up to room temperature then 10% of water volume is removed and simultaneously replace by Helium. Samples are shaken and equilibrated for 30 minutes before the head space is sampled for GC concentration (SRI GC 8610C) and/or isotope analysis (15N, 13C, 2H) of specific component with a GC Isolink.
References
-
Hudson F., RSKSOP-175, Sample Preparation and Calculation for Dissolved Gas Analysis in Water Samples Using GC Headspace Equilibration Technique, EPA document, May 2004, 17 p.
- Kampbell D., Vandegrift S.,Analysis of dissolved methane, ethane and ethylene in ground water by a standard gas chromatographic technique, Journal of chromatographic science, vol 36, May 1998, pp 253-256.
- Thermo Fisher Scientific, GC Isolink Operating Manual, Revision D-1222980, 2011.
- SRI GC Chromatogram, Operating manual for Peak Simple version 4.44.
Single or mixtures; single-phase, dissolved, breath
Requirements
- About 10 ml are used to flush the the 1 ml sample loop of the instrument.
- 500, 750 or 1000mL Wheaton Bottles or other pre-approved containers must have a thick butyl rubber septum for extracting the gas.
- Exact bottle volume must be known. If Isoflasks are used, weight of Isoflask and weight of water should be provided.
- Bottles should be filled full without any air bubble.
- Samples should be stored at 4oC.
- Consult with Lab Manager before sampling to make sure you have the appropriate container, etc.
Methodology
All bottles are brought to room temperature. Dissolved gas requires additional preparation: a head space is created for dissolved gases by gently displacing the water with high purity Helium, typically 10% of the total bottle volume. The bottle is shaken for 5 minutes and equilibrated for 30 minutes. Either the created head space, or the bottle of gas is sampled by gas-tight syringe and injected into the SRI. The sample is analysed for gaseous components on an SRI GC 8610C of N2, O2+Ar, CO2, CO, methane, ethane, propane, butane and pentane percentages, a calibration curve is created with known gas concentrations prior to sample analysis. We cannot analyse for Hydrogen and Helium using this approach.
Corrections are applied for volume, temperature and gas solubility using Henry’s law as per the three references listed below.
Corrections
TC = CAH + CA where:
- TC = total concentration of gas in original aqueous sample
- CAH = aqueous concentration in head space after equilibrium in mg/L = (55.5mol/L)*(pg/H)*MW(g/mol)*103mg/g
where pg= partial pressure of gas in atm from GC analysis, H = Henry’s law constant, MW = molecular weight in g/mol - CA = aqueous concentration in water after equilibrium in mg/L
= [(Vh/(Vb-Vh)]*Cg*(MW(g/mol)/(22.4L/mol))*[273K/(T+273K)]*103mg/g
where Vh = head space volume, Vb = bottle volume, Cg = gas concentration (also equal to pg ), T = temperature in Kelvin
Expected error has not been determined yet, we believe it should be around 10% of the absolute value.
References
-
Analysis of dissolved methane, ethane and ethylene in ground water by standard gas chromatographic technique, Journal of Chromatographic Science, Vol 36, May 1998.
- Sample preparation and calculations for dissolved gas analysis in water samples using a GC head space equilibration technique, RSKSOP-175, revision No 2, May 2004.
- Compilation of Henry’s Law Constants for Inorganic and Organic Species of Potential Importance in Environmental Chemistry.
- SRI Chromatogragh Operating notes, Peak simple version 4.44
Requirements
-
500, 750 or 1000mL Wheaton Bottles or other pre-approved containers must have a thick butyl rubber septum for extracting the gas.
- Bottles for gases should be slightly pressurized to avoid the creation of a vacuum when the sample is drawn out.
- Samples should be stored at 4oC.
- Analysis should be done within 2 weeks.
- Consult with Lab Manager before sampling to make sure you have the appropriate container, etc.
Methodology
All bottles are brought to room temperature. Dissolved gas requires additional preparation: a head space is created for dissolved gases by gently displacing the water with high purity Helium, typically 10% of the total bottle volume. The bottle is shaken for 5 minutes and equilibrated for 30 minutes. Either the created head space, or the bottle of (dry) gas is sampled by gas-tight syringe and injected into the GC Isolink. The gas of interest (C1-C3 or other) is isolated and converted to CO2,H2 or N2.
References
- Hudson F., RSKSOP-175, Sample Preparation and Calculation for Dissolved Gas Analysis in Water Samples Using GC Headspace Equilibration Technique, EPA document, May 2004, 17 p.
- Kampbell D., Vandegrift S.,Analysis of dissolved methane, ethane and ethylene in ground water by a standard gas chromatographic technique, Journal of chromatographic science, vol 36, May 1998, pp 253-256.
- Thermo Fisher Scientific, GC Isolink Operating Manual, Revision D-1222980, 2011.
- SRI GC Chromatogram, Operating manual for Peak Simple version 4.44.
Requirements
- Container should have a septum, butyl is best.
- Exetainers with about 0.2 to 2% of CO2 are used for Gasbench. Do not use vacutainers.
- Wheaton bottles or other with butyl septa are used for GCIsolink.
- Extra fee may be applied to transfer proper concentration into another vial.
Methodology
Exetainers are analysed on the Gasbench at room temperature, where CO2 is separated from air and sent to IRMS, as per normal CO2 analysis. Carbonate standards are used for 13C and 18O calibration.
Samples in Wheaton or other bottles are sampled using a gas-tight syringe and injected into the CGIsolink. Carbonate standards are used for 13C and 18O calibration.
Reference
- Instruction Manuals for the GasBench and the Thermo Finnigan DeltaPlusXP IRMS.
- Thermo Fisher Scientific, GC Isolink Operating Manual, Revision D-1222980, 2011.
Requirements
- Pyrex tubes should be 6mm or 1/4" in outer diameter, and about 14 cm in length.
- Sealed tips should be smooth; no thin, sharp bits!
- Sealed tips should be relatively small, and stay within the width of the Pyrex tube.
Methodology
Break seals are loaded into the cracker tubes of the 10-port manifold on the Thermo Finnigan DeltaV+, and pumped for 15 minutes. The break seals are snapped to release the contained gas. The gas is run in dual-inlet against a calibrated reference gas. If there is less than about 20 µM of gas, then the microvolume (cold finger) must also be used to pull the gas into a smaller volume before analysis.
Dual Inlet precision
The analytical precision (2 sigma) for carbon isotopes is +/- 0.05 permil.
The analytical precision (2 sigma) for oxygen isotopes is +/- 0.10 permil.
The analytical precision (2 sigma) for hydrogen isotopes is +/- 2.0 permil.
The analytical precision (2 sigma) for sulphur isotopes is +/- 0.2 permil.
NOTE: Dual Inlet analysis offers the best precision. But it is also possible to transfer CO2 or H2 gas from a break seal into an Exetainer flushed with helium. It is then run as a regular headspace sample on the GasBench + Thermo Finnigan DeltaPlusXP IRMS. Aliquots of the calibrated reference gas used in dual-inlet are run with the samples to enable normalization of the data. This analysis is less precise but easier.
References
- Instruction Manual for GasBench and DeltaPlus XP IRMS
Wine, urine, oil residue, etc.
Requirements
- Typically 0.1 mL of liquid is used (about 0.1 g). Please send at least 1 mL.
- Liquids (other than water) must be clearly identified as to type in the submission form.
- Vials should be air-tight, especially when %H is required in order to avoid water loss or absorption.
Methodology
Elemental analysis is the determination of the elemental composition of organic or inorganic compounds.The Elementar Isotope Cube is used to determine %N, %C, %H, and %S.
In general, 0.1mL of liquid is measured into special smooth wall tin capsules, flushed with Helium and sealed with a cold weld, created using our liquid sealing device. The closed capsules are re-weighed on the microbalance. Calibrated standards are prepared in a range of weights and run with the samples. A "blind" standard is also run as a check for the calibration.
The prepared capsules are loaded into the carousel of the autosampler. A sample falls down into the top of a column of solid chemicals at 1150°C, and is flash combusted at 1800°C with the addition of oxygen. Ultra-pure helium is used to carry the resulting gases through the column of chemicals to obtain N2 , CO2 , H2O, and SO2, then through a series of adsorption traps to separate the gases according to the "trap and purge" method. A thermoconductivity detector (TCD) measures the gases as they are released. Elementar's own software, which controls the EA in stand-alone mode, is used to process the results.
The analytical precision (2 sigma) is +/- 0.1%.
References
- Elementar Americas, Inc.
- Instruction Manuals for the Isotope Cube and the VarioEL Cube.
Requirements
-
Organic and inorganic material must be submitted in separate submission files; they have different media codes (one media code per file).
- Purity or %H for each sample must be indicated in the submission file. If the %H is unknown, an elemental analysis run (separate submission) must be done first.
- About 0.1mg of H equivalent is required, please send more material though for repeats or duplicates.
- Liquids (other than water) must be clearly identified as to type in the submission form.
- Vials should be air-tight, especially when %H is required in order to avoid water loss or absorption.
Methodology
In general, enough liquid to obtain 0.1 mg of H2 is measured into special smooth wall silver capsules, flushed with Helium and sealed with a cold weld, created using our liquid sealing device. The closed capsules are re-weighed on the microbalance.
The encapsulated samples are analyzed with a Thermo DeltaPlus XP continuous-flow isotope-ratio mass spectrometer coupled with a Thermo Scientific thermal conversion elemental analyzer (TC/EA) using a zero blank autosampler, via a Confo IV. The method of Qi and Coplen is used: He flow rate = 120 mL/min, reactor temperature = 1450°C, GC temperature = 85°C, and GC length = 1m, 5Å. Calibrated internal/international standards are prepared with every batch of samples for normalization of the data.
The analytical precision is +/- 3 permil.
References
-
Coplen, Tyler B., and Qi, Haiping (2012) USGS42 and USGS43: Human-hair stable hydrogen and oxygen isotopic reference materials and analytical methods for forensic science and implications for published measurement results, Forensic Science International, Volume 214, Issues 1–3, 10 January 2012, Pages 135–141.
- Instruction Manuals for the Thermo TC/EA and the Thermo Finnigan DeltaPlus XP.
Requirements
-
Organic and inorganic material must be submitted in separate submission files; they have different media codes (one media code per file).
- Purity or %C for each sample must be indicated in the submission file. If the %C is unknown, an elemental analysis run (separate submission) must be done first.
- About 0.3mg of C equivalent is required, please send more material though for repeats or duplicates. We can also use less, down to 0.020mg of C
- Liquids (other than water) must be clearly identified as to type in the submission form.
- Vials should be air-tight in order to avoid water loss or absorption.
Methodology
Organic liquids are weighed into smooth-walled tin capsules. These capsules are cold-weld sealed using our liquid sealing device. Calibrated internal standards are prepared with every batch of samples for normalization of the data. In general, 300µg of C are required for analysis, although 20µg can also be easily done. Elemental analysis must be performed first if the quantities of carbon and/or nitrogen in a sample are unknown.
The isotopic composition of organic carbon is determined by the analysis of CO2 produced by combustion on an Elementar Isotope Cube Elemental Analyser followed by "trap and purge" separation and on-line analysis by continuous-flow with a DeltaPlus Advantage isotope ratio mass spectrometer coupled with a ConFlo III.
The routine precision of the analyses is 0.20‰.
References
- Pella, E., (1990) Elemental organic analysis, parts 1-2. American Laboratory, Feb. & Aug.
- Instruction Manuals for the elementar Vario Isotope Cube
- Instruction manual Thermo Finnigan DeltaPlus Advantage.
- Instruction manual Thermo Finnigan Conflo III.
Requirements
-
Organic and inorganic material must be submitted in separate submission files; they have different media codes (one media code per file).
- Purity or %N for each sample must be indicated in the submission file. If the %N is unknown, an elemental analysis run (separate submission) must be done first.
- About 0.1mg of N equivalent is required, please send more material though for repeats or duplicates.
- Liquids (other than water) must be clearly identified as to type in the submission form.
- Vials should be air-tight in order to avoid water loss or absorption.
Methodology
The liquids are weighed into smooth-walled tin capsules. These capsules are cold-weld sealed using our liquid sealing device. Calibrated internal standards are prepared with every batch of samples for normalization of the data. In general, 100µg of N are required for analysis. Elemental analysis must be performed first if the quantities of carbon and/or nitrogen in a sample are unknown.
The isotopic composition is determined by the analysis of N2 produced by combustion on an Elementar Isotope Cube Elemental Analyser followed by "trap and purge" separation and on-line analysis by continuous-flow with a DeltaPlus Advantage isotope ratio mass spectrometer coupled with a ConFlo III.
The routine precision of the analyses is 0.20‰.
References
- Pella, E., (1990) Elemental organic analysis, parts 1-2. American Laboratory, Feb. & Aug.
- Instruction Manuals for the elementar Vario Isotope Cube
- Manual for Thermo Finnigan DeltaPlus Advantage.
Requirements
-
Organic and inorganic material must be submitted in separate submission files; they have different media codes (one media code per file).
- Purity or %O for each sample must be indicated in the submission file. If the %O is unknown, an elemental analysis run (separate submission) must be done first.
- About 0.1mg of O equivalent is required, please send more material though for repeats or duplicates.
- Liquids (other than water) must be clearly identified as to type in the submission form.
- Vials should be air-tight, especially when %O is required in order to avoid water loss or absorption.
Methodology
In general, enough liquid to obtain 0.1 mg of O2 is measured into special smooth wall silver capsules, flushed with Helium and sealed with a cold weld, created using our liquid sealing device. The closed capsules are re-weighed on the microbalance.
The encapsulated samples are analyzed with a Thermo DeltaPlus XP continuous-flow isotope-ratio mass spectrometer coupled with a Thermo Scientific thermal conversion elemental analyzer (TC/EA) using a zero blank autosampler, via a Confo IV. The method of Qi and Coplen is used: He flow rate = 120 mL/min, reactor temperature = 1450°C, GC temperature = 85°C, and GC length = 1m, 5Å. Calibrated internal/international standards are prepared with every batch of samples for normalization of the data.
The analytical precision is +/- 0.4 permil.
References
-
Coplen, Tyler B., and Qi, Haiping (2012) USGS42 and USGS43: Human-hair stable hydrogen and oxygen isotopic reference materials and analytical methods for forensic science and implications for published measurement results, Forensic Science International, Volume 214, Issues 1–3, 10 January 2012, Pages 135–141.
- Instruction Manuals for the Thermo TC/EA and the Thermo Finnigan DeltaPlus XP.
Milling, filtering, precipitation, cleaning, etc.
Use of our Microbalances
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We have 3 of the best microbalances on campus that are certified yearly. Usage is free for samples that will be analysed in the Ján Veizer Stable Isotope Lab; otherwise, usage will be charged hourly as per our price list.
Use of the Micromill
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The Micromill is a high-precision drill for specialized work such as drilling samples of growth rings in a whale's tooth, or a shell. Surfaces must be fairly flat, especially the bottom surface. You should still be able to see where you want to drill with the naked eye.
- 3-4 holes of 300 x 300 microns yield about 0.5mg of material.
- We will provide training, tools, and Kimwipes. You are responsible for providing vials for your ground material.
- Most drilling work can be done using a Dremmel or regular drill with 1/16" to 1/8" bits. Check with us if you are not sure.
Use of the Ball Mill
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Our Retsch ball mill has grinding containers designed for organic material. They are not designed for rocks or minerals.
- We will provide training, tools, Kimwipes and ethanol. You are responsible for providing vials for your ground material.
Grinding of inorganics
- We can grind small grains of carbonate, sulphide or sulphate minerals in a mortar and pestle.
- We also have access to departmental grinding machines for small chunks of rock. In this case two rounds of grinding (coarse and fine) are required; therefore, price x2.
Acidification of sediments or soils
-
There is no one perfect way to remove inorganic carbon from sediments or soils. You must do a literature search to determine which method is best for your field and your samples.
- We can do a simple dilute hydrochloric acid acidification for samples with calcite or dolomite. More resilient minerals (siderite, magnesite) are more difficult to get rid of and may require heating and testing; an extra fee may be added. Please contact us if this is the case.
Dilution of waters for TIC/DIC or TOC/DOC
- Dilution of higher concentrations of waters is done using a pipette and a balance. We provide the extra EPA vial.
Precipitation of sulphides/sulphates in waters
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Zinc acetate solution or powder is added to sample waters by the client to precipitate zinc sulphide directly in the field, which is then converted to silver sulphide. Precipitation is not done in the lab after the fact; the dissolved sulphide will be gone.
- Precipitation of barium sulphate is done by carefully controlled pH precipitation using barium chloride.
- Filtration or centrifugation of acidified sediments or soils, or precipitates is a separate step (and charge). We use glass fibre filters.
Pre-cleaning of hair, feathers, etc.
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A mixture of chloroform and methanol is used to remove oils and dirt.
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Clients are required to sub-sample the material they want cleaned for analysis.
Pre-treatment of carbonates to remove organics
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When a significant quantity of organic material is present in a carbonate sample, a hydrogen peroxide solution is used to remove most organics from carbonates.
Certificate of analysis
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We can provide upon special request a more formal Certificate of Analysis which includes the data, the methodology, any control stats and the signature of the Lab Manager on lab letterhead.
- A pdf of the certificate will be e-mailed to you. There is a charge to have this CoA prepared in addition to the regular final results Excel file.
EPA vials
40mL pre-cleaned borosilicate amber EPA vials with septa caps (PTFE-lined silicone).
PTFE-rubber, 22mm flexseal disc
The septa pictured are being discontinued. Chromatographic Specialties has worked with a supplier to find an alternative. Contact them directly to inquire about testing the new "22mm PTFE/grey butyl septa for 24-400 Screw Cap, pk1000".
Vial caps
Numeric labelling of vial caps.