Waters

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.

Quantitative - ppmC (dissolved or total C)

Requirements:

  • Mandatory use of 40mL pre-cleaned borosilicate EPA vials with septa caps, purchased from a major laboratory supplier; quality assurance grade is not necessary. Please order your EPA vials early; they are often back-ordered.
EPA vials for TICTOC analysis.
  • Number of replicate vials needed per sample if you want:
    Concentration only (ppm-C) = 1 vial per sample
    Inorganic 13C (DIC/TIC) only,with or without concentration = 2 identical full vials (no headspace) with extra septum
    Organic 13C (DOC/TOC) only, with or without concentration = 2 identical vials (extra septum not necessary; a small amount of head space is ok)
    Inorganic AND organic 13C (DIC/TIC & DOC/TOC) with or without concentration = 3 identical full vials all with the extra septum
  • 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 silcone/teflon septum provided with the EPA vials allow inorganic carbon to diffuse out unless the extra septum is used. The extra septum is not required for DOC or TOC; however if inorganic and organic carbon are required, please submit three identical full vials with extra septum (if re-running for DIC/TIC we must use a fresh vial). 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).
Extra septa for inorganic C analysis.

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 each one is listed in the submission file. This helps us to quickly locate samples. Replicate vials should have the same number on the cap (i.e. the three replicate vials for the first sample in the sub file should all have "1" on the cap, etc.). Only enter this sample once in the submission file. Please include the number of replicate vials per sample that you are sending directly in the submission file in either the comments box or comments column.
    Numeric labelling of vial caps
  • Filtration:
    Samples for DIC or DOC should be carefully and gently filtered to 0.45 µm or less. Samples for TIC or TOC should NOT be filtered.
  • Range of measurement:
    We can analyse water samples ranging from about 0.5 to 100 ppm of carbon. The peripheral allows us to select a variable volume of sample according to the expected concentration (hence the importance of providing all pertinent concentration info). Please note: organic C and inorganic C concentrations can be vastly different. We must regularly re-run samples with varying volumes to target each one.
  • Preservation agents:
    Samples should remain refrigerated after sampling and kept cool but not frozen during shipping. We will transfer the vials to our refrigerator upon arrival. If the samples are refrigerated 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 as well.
  • "Abnormal" water samples
    "Normal" freshwater lake or river samples have organic and inorganic C concentrations of less than 100 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, etc.), please contact us. We will let you know if we can analyse them. Our instrumentation is not adapted to handle extreme samples. Deep ground waters tend to be very 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 (0.5 ppm) there is nothing to be done; no isotopic data will be possible.
  • Submission files
    - Only 1 media code per submission file (DIC-42, DOC-41, DIC-DOC conc.-40; each a separate file).
    - Submit a file for concentration (DIC and DOC ppm-C; media code 40) only if you are not submitting for isotopes (you will receive concentrations along with the isotope results).
    - List each sample only once.
    (& **PLEASE INCLUDE THIS ESSENTIAL INFO directly in the sub file**):
    - Describe the type of waters you are submitting (e.g. lake, river, pond, sea water, brines, groundwater, etc.).
    - Include the number of replicate vials per sample in the Comments box at the top or in the Comments column if variable.
    - Include the pH & salinity data for each sample if you have it; otherwise, give an estimate for the total.
    - Include the DIC and DOC concentrations (ppm-C or mg/L) of each sample if you have the data; otherwise, provide an estimate (helps enormously in estimating sample volume to use in analysis). If submitting for DOC only, please include a DIC concentration estimate as well, as we may need to sparge the samples (acidification and removal of DIC) prior to analysis if the DIC concentrations are high in relation to the DOC.
    - If a preservation agent was used, include the type of agent (e.g. HgCl2, HCl, etc) and amount used in the general comments box.

 

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:

  • OI Analytical (2005). Aurora 1030 Wet Oxidation TOC analyzer Operator's Manual. College Station, Texas.
Quantitative - dissolved N2, O2+Ar, CO, CH4, CO2, C1-C5

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 + Cwhere:

  • 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
Isotopes of Carbon (DIC/DOC or TIC/TOC)

Requirements:

  • Mandatory use of 40mL pre-cleaned borosilicate EPA vials with septa caps, purchased from a major laboratory supplier; quality assurance grade is not necessary. Please order your EPA vials early; they are often back-ordered.
EPA vials for TICTOC analysis.
  • Number of replicate vials needed per sample if you want:
    Concentration only (ppm-C) = 1 vial per sample
    Inorganic 13C (DIC/TIC) only,with or without concentration = 2 identical full vials (no headspace) with extra septum
    Organic 13C (DOC/TOC) only, with or without concentration = 2 identical vials (extra septum not necessary; a small amount of head space is ok)
    Inorganic AND organic 13C (DIC/TIC & DOC/TOC) with or without concentration = 3 identical full vials all with the extra septum
  • 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 silcone/teflon septum provided with the EPA vials allow inorganic carbon to diffuse out unless the extra septum is used. The extra septum is not required for DOC or TOC; however if inorganic and organic carbon are required, please submit three identical full vials with extra septum (if re-running for DIC/TIC we must use a fresh vial). 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).
Extra septa for inorganic C analysis.

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 each one is listed in the submission file. This helps us to quickly locate samples. Replicate vials should have the same number on the cap (i.e. the three replicate vials for the first sample in the sub file should all have "1" on the cap, etc.). Only enter this sample once in the submission file. Please include the number of replicate vials per sample that you are sending directly in the submission file in either the comments box or comments column.
    Numeric labelling of vial caps
  • Filtration:
    Samples for DIC or DOC should be carefully and gently filtered to 0.45 µm or less. Samples for TIC or TOC should NOT be filtered.
  • Range of measurement:
    We can analyse water samples ranging from about 0.5 to 100 ppm of carbon. The peripheral allows us to select a variable volume of sample according to the expected concentration (hence the importance of providing all pertinent concentration info). Please note: organic C and inorganic C concentrations can be vastly different. We must regularly re-run samples with varying volumes to target each one.
  • Preservation agents:
    Samples should remain refrigerated after sampling and kept cool but not frozen during shipping. We will transfer the vials to our refrigerator upon arrival. If the samples are refrigerated 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 as well.
  • "Abnormal" water samples
    "Normal" freshwater lake or river samples have organic and inorganic C concentrations of less than 100 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, etc.), please contact us. We will let you know if we can analyse them. Our instrumentation is not adapted to handle extreme samples. Deep ground waters tend to be very 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 (0.5 ppm) there is nothing to be done; no isotopic data will be possible.
  • Submission files
    - Only 1 media code per submission file (DIC-42, DOC-41, DIC-DOC conc.-40; each a separate file).
    - Submit a file for concentration (DIC and DOC ppm-C; media code 40) only if you are not submitting for isotopes (you will receive concentrations along with the isotope results).
    - List each sample only once.
    (& **PLEASE INCLUDE THIS ESSENTIAL INFO directly in the sub file**):
    - Describe the type of waters you are submitting (e.g. lake, river, pond, sea water, brines, groundwater, etc.).
    - Include the number of replicate vials per sample in the Comments box at the top or in the Comments column if variable.
    - Include the pH & salinity data for each sample if you have it; otherwise, give an estimate for the total.
    - Include the DIC and DOC concentrations (ppm-C or mg/L) of each sample if you have the data; otherwise, provide an estimate (helps enormously in estimating sample volume to use in analysis). If submitting for DOC only, please include a DIC concentration estimate as well, as we may need to sparge the samples (acidification and removal of DIC) prior to analysis if the DIC concentrations are high in relation to the DOC.
    - If a preservation agent was used, include the type of agent (e.g. HgCl2, HCl, etc) and amount used in the general comments box.

 

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. First, 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). Second, 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.

 

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.

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
Hydrogen & Oxygen Isotopes of Water

Requirements:

  • We require a minimum of 2 mL of water, although at least 5 mL is preferable.
  • Either plastic or glass bottles can be used for sampling as long as the bottles are air-tight and have a minimum of head space.
  • 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.

Flush and fill set-up.

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 1.2 µL of water. Up to 20 injections are averaged for better precision.

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. Prepared vials are kept either in the fridge if analysis will happen within a few days, or in the freezer for longer delays. GC vials are not designed for long-term storage. Ideally 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
Isotopes of Dissolved Oxygen

Requirements:

  • 12 mL Exetainer vials with butyl rubber septa should be sufficient in most cases.  If the concentration of oxygen 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 that is 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 oxygen. 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 oxygen is 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 from other gases is used.

The vials are run against a tank of oxygen 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
Isotopes of Dissolved Gases (C-1 to C-3 or other)

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.

 

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