Radiocarbon Determination of Dissolved Organic Carbon (DOC) in Freshwater (salinity≤ 0.5 ppt/psu)

Note – Fees are inclusive of δ¹³C measurements, quality assurance reports, and 24/7 web access to past results and pending analyses. DOC extraction fee applies in addition to the standard price. 

Results – Reports are available in English only.

Sampling Limitations

We are a NATURAL Level carbon-14 testing laboratory and cannot accept water samples that have been collected from any area that is near nuclear power plants, commercial or medical reactors, or industrial/medical waste disposal sites, or from within their drainage areas. The water samples must not be stored or handled in any laboratory or area that uses OR has ever been used in a biomedical facility with artificially labeled carbon-14 at any time.

Should you suspect that your samples may in any way have elevated carbon-14 activities above peak Bomb Carbon levels (~200 pMC / 2.0 F14C), please DO NOT send the samples for testing. Water samples that produce activities above 200 pMC will incur extensive costs related to any cleanup necessary, equipment replacement, and duplicate analyses required for other samples. These costs could easily run into the tens of thousands of dollars, which you will be responsible for as the submitter.

Collecting Samples

1. Be sure to collect water samples at the depth you would like to study.
   
   
2. Nalgene-type bottles may be used for sample collection, but glass is preferable and highly recommended for long-term storage. Regardless of material type, the bottle should be opaque to prevent light exposure of the sample. Chemical reactions that occur with oxygen in the presence of light may alter the DOC signature of the sample. Nalgene and glass bottles must be pre-cleaned in a 10% hydrochloric acid (HCl) bath and rinsed with deionized (DI) water to a neutral pH to remove any possible contaminants. Glass bottles may also be heated at 450˚C for 6 hours to further ensure that there are no contaminants present.
   
   

3. Thoroughly flush the bottle with the sample water at least 3 times before collecting the final sample with the aid of a water filter. Use a filter with pore sizes at 0.7 μm or below. If samples are not filtered, the 14DOC signature is at risk of changing while the samples are in transit.

4. Fill the bottle with little to no headspace.

5. If samples are to be stored for any length of time, they must be refrigerated between 3-5 ˚C (37-41˚F). Beware that glass bottles containing the water sample may crack if they are frozen.

6. Seal the space between the bottle and the cap with parafilm or electrical/duct tape to prevent carbon dioxide (CO₂) exchange with the atmosphere during shipment.

Other Recommendations

• Please clearly mark the outside of the bottle and the outer plastic bag with the same sample ID that is listed on the sample in indelible ink or tamper-proof label.
• It is helpful to measure the pH, salinity, UV Absorbance at λ254 nm, and DOC concentration of your sample prior to shipment, but this is not required.
• Do not add any chemicals to the water samples upon collection, including acids or common sample-preservation compounds, such as mercury (II) chloride (HgCl₂) or sodium azide (NaN₃). If samples are pre-acidified, please contact the laboratory prior to submission.