Stable Isotope Analysis (Water)

The McDonnell  Lab is equipped with several Los Gatos Research (LGR) liquid and vapor water Off-Axis Integrated-Cavity Output Spectroscopy (Off-Axis ICOS) machines for the analysis of stable isotopes of water. The lab is capable of measuring the ratios of D/H, ¹⁸O/¹⁶O and ¹⁷O/¹⁶O isotopes of fresh water and soil water samples (Laser Spectroscopy & Direct Equilibration).

Please see details and requirements listed above for each analysis method.

Price List - Isotope Analysis

• *All prices are listed in CAD and are per sample.

The McDonnell lab participated in the IAEA’s water isotope inter-comparison (¹⁸O, ²H) for laser spectrometers in 2016 & 2020 our lab received an Acceptable Point Score on Oxygen-18 for all samples and an Excellent Point Score on Deuterium for all samples. The lab’s z Scores for both isotopes was Acceptable. Our results for ¹⁷O were also satisfactory but without two internationally recognized standards some uncertaitnly should be expected.

Laser Spectroscopy: Liquid Water Isotope Analysis

The McDonnell Lab is equipped with several Los Gatos Research (LGR) liquid and vapor water Off-Axis Integrated-Cavity Output Spectroscopy (Off-Axis ICOS) machines for the analysis of stable isotopes of water. The lab is capable of measuring the ratios of D/H, ¹⁸O/¹⁶O and ¹⁷O/¹⁶O isotopes of fresh water and soil water samples.

Requirements

• Volume minimum 2 ml/sample (please contact the lab if you have lower than 2 ml water volumes)
• Freshwater (no saline or samples containing volatile organics)
• Samples must be stored in well-sealed vials (no evaporation!) with little to no headspace
• Samples should be collected and shipped in glass vials with solid deep threaded caps. Please contact Kim if you have questions about sample vials

Our lab utililizes Los Gatos Research liquid water Off-Axis Integrated-Cavity Output Spectroscopy (Off-Axis ICOS) and post processes data using LIMS for Lasers. Our lab’s 2-sigma uncertainties of 2H, 18O and 17O analyses are 2 ‰, 0.8 ‰ and 0.5 ‰ respectively. Our lab’s reproducibilities are ± 1.0 ‰ for 2H, ± 0.2 ‰ for 18O and 17O. All values are reported as parts per thousand (‰) according to the Vienna Standard Mean Ocean Water-Standard Light Antarctic Precipitation (VSMOW-SLAP) scales. All samples will be scanned for volatile organic compound contamination with LGR’s Spectral Contamination software.

*Prices include sample transfer and filtering.

Shipping

Samples must be well packaged to reduce breakage!

Please note that between September and April inclusive samples must be shipped in insulated containers in order to prevent freezing!! If samples freeze the vial shatters and your sample is gone!

Direct Vapour Equilibration: Soil Water

Methodology

• L.I. Wassenaar, M.J. Hendry, V.L. Chostner, and G.P. Lis. 2008. High Resolution Pore Water δ2H and δ18O Measurements by H2O (liquid)−H2O (vapor) Equilibration Laser Spectroscopy. Environmental Science & Technology 42 (24), 9262-9267 DOI: 10.1021/es802065s
• M.J. Hendry, E. Schmeling, L.I. Wassenaar, S.L. Barbour, and D. Pratt. 2015. Determining the stable isotope composition of pore water from saturated and unsaturated zone core: improvements to the direct vapour equilibration laser spectrometry method. Hydrology and Earth System Sciences 19, 4427-4440; DOI: 10.5194/hess-19-4427-2015

 Requirements

• Soil samples that contain at least 8% Gravimetric Water Content (GWC) (lower GWC can be analyzed but accuracy will be reduced.)
• Soils must contain uncontaminated fresh water (no brines, no industrial contamination, or volitile organics)
• Please contact Kim Janzen for sample collection container details.

Our lab’s 2-sigma error 𝛅²H 4.0 ‰; 𝛅¹⁸O 0.70 ‰; 𝛅¹⁷O 0.6 ‰ with a reproducibility of ±2.2 for 𝛅²H; ±0.4 for 𝛅¹⁸O; ±0.4 for 𝛅¹⁷O. All values are reported as parts per thousand (‰) according to the Vienna Standard Mean Ocean Water-Standard Light Antarctic Precipitation (VSMOW-SLAP) scales.

Shipping

Samples must be shipped in a sturdy shipping container such as a plastic bin or cooler, to avoid damage during transport.

• Soil samples collected and shipped from outside of Canada will require an import permit that must be included with the sample shipment. The McDonnell lab will provide importation permits by request. See "Shipping & Contact" tab.

Soil and Plant Water Extraction Services

The McDonnell Lab is equipped with several methods for extracting fresh water from soil and plant material (Centrifugation, High-Pressure Mechanical Squeezing & Cryogenic Vacuum Extraction). The extracted water is suitable for further analyses such as D/H, ¹⁸O/¹⁶O and ¹⁷O/¹⁶O isotopes of fresh water.

*Please Note* that at this time the McDonnell lab is not capable of measuring the stable isotopes of plant extracted water. Plant extracted water needs to be run via mass spectrometry.

Please see details and requirements listed above for each method. 

Price List - Extraction

• All prices are listed in CAD and are per sample.
• A $5.00/sample transfer fee may apply please see Requirements
• * Suitability of extracted water for further analysis

Centrifugation Extraction: Plant & Soil

Methodology

• All samples will be spun at 5,000 rpm for 15 min.
• Test have shown that centrifugation times of <30 min were sufficient, after which no more water could be extracted at a particular speed (see, N. Orlowski, D. Pratt, and J. McDonnell. 2016. Intercomparison of soil pore water extraction methods for stable isotope analysis. Hydrological Processes; DOI: 10.1002/hyp.10870)

Analysis Suitability of Extracted Water

• Stable Isotopes
• Geochemistry

Requirements

• Samples should be collected in either Ziploc freezer bags (samples need to be collected and shipped within 10 days) or collected into Nalgene bottles or multiple scintillation vials. If bottles or vials are used a *$5.00/samples transfer fee will apply.
• The minimum gravimetric water content (GWC) for clay soil is 12% and for sand 8%.
• *Plant samples incur a $5.00 per sample increase in fee due to extra processing and liquid nitrogen requirements.
• The sample size should be decided based on the water amount needed for the desired post-extraction water analysis. For example, laser spectrometry requires 2ml of extracted water, which can be achieved with approximately 20g of a soil sample. If you want to run your extracted water on both laser and IRMS then you would require more like 50g of a sample. Chemistry analysis requires closer to 200g and tritium analysis requires enough sample to extract 1L of water. You should aim for extracting 20% more water than you require for post-extraction analyses.

Shipping

Samples must be shipped in a sturdy shipping container such as a plastic bin or cooler, to avoid having the samples ripped and compromised.

Samples must be collected, shipped and received within 10 days! Most bags will not store samples for longer than this time. *The lab must be contacted before shipping samples in Ziploc bags* to ensure scheduling can be arranged and samples are processed within the short 10-day window. 

• Plant and soil samples collected and shipped from outside of Canada will require an import permit that must be included with the sample shipment. The McDonnell lab will provide importation permits by request. See "Shipping & Contact" tab.

High-Pressure Mechanical Squeezing: Soil & Plant

Methodology

• Böttcher G, Brumsack H-J, Heinrichs H, Pohlmann M. 1997. A new high-pressure squeezing technique for pore fluid extraction from terrestrial soils. Water, Air and Soil Pollution 94(3-4): 289-296. DOI: 10.1007/BF02426064.
• Orlowski N, Pratt D, McDonnell J. 2016. Intercomparison of soil pore water extraction methods for stable isotope analysis. Hydrological Processes 30, 3434-3449. DOI: 10.1002/hyp.10870)

Analysis Suitability of Extracted Water

• Stable Isotopes
• Geochemistry

Requirements

• Samples should be collected in either Ziploc freezer bags (samples need to be collected and shipped within 10 days) or collected into Nalgene bottles or multiple scintillation vials. *If bottles or vials are used a $5.00/samples transfer fee* will apply.
• The soil sample size should be decided based on the water amount needed for the desired post-extraction water analysis (2ml of water for laser analysis, 4ml of water for laser and IRMS and 1L of water for tritium analysis).
• The squeezers can hold approximately 50g of soil per piston. Samples larger than this can be squeezed consecutively and combined.

Shipping

Samples must be shipped in a sturdy shipping container such as a plastic bin or cooler, to avoid having the samples ripped and compromised.

Samples must be collected, shipped and received within 10 days! Most bags will not store samples for longer than this time. *The lab must be contacted before shipping samples in Ziploc bags* to ensure scheduling can be arranged and samples are processed within the short 10-day window.

• Plant and soil samples collected and shipped from outside of Canada will require an import permit that must be included with the sample shipment. The McDonnell lab will provide importation permits by request. See "Shipping & Contact" tab.

Cryogenic Vacuum Extraction: Plant & Soil

Method

• The sample material is heated to ~180°C under vacuum. Thereby, water evaporated from the soil or plant material is subsequently caught in the (cryogenic) liquid nitrogen cold trap. After defrosting, the liquid water sample is transferred into storage vial.
• Koeniger P, Marshall J. D, Link T, Mulch A. 2011. An inexpensive, fast, and reliable method for vacuum extraction of soil and plant water for stable isotope analyses by mass spectrometry. Rapid Commun. Mass Spectrom 25, 3041-3048. DOI: 10.1002/rcm.5198

Analysis Suitability of Extracted Water

• Stable Isotopes

Requirements

• Samples should be collected and shipped in 12ml soda glass exetainer vials, with flat-bottomed – double wadded cap – non evacuated. These can be purchased from Labco Limited (Product No. 737W).
• *Samples that are shipped in any vial other than the one listed above will be subject to a $5.00/sample transfer fee.*
• For soil samples: ensure vials are 1/3 to 1/2 full. For overly wet samples, too much sample in the vial will result in an incomplete extraction. For overly dry samples, you may need to collect multiple replicates of the same sample to extract enough water for your desired analysis.
• For good measure, it may be appropriate to do some water content test by weighing, drying and weighing again your potential samples to find average water content. This will inform you about how much sample is required to be run in the extraction line in order to extract a desired amount of water.
• Laser spectroscopy analysis requires between 100micro liters to 2ml. Mass spectroscopy analysis requires a minimum of 0.7 ml of water. Mass spec water volume requirements are not universal. Clients should consult the lab they will be using for mass spec analysis to confirm required volumes.

Shipping

Samples must be well packaged to reduce breakage!

Please note that between September and April inclusive samples must be shipped in insulated containers in order to prevent freezing!! If samples freeze the vial shatters and your sample is gone!

• Plant and soil samples collected and shipped from outside of Canada will require an import permit that must be included with the sample shipment. The McDonnell lab will provide importation permits by request. See "Shipping & Contact" tab.