Sample Selection and Size Recommendations

For minimum quantities, please contact us.

The following recommendations are not requirements, they are general guidelines. We can analyze extremely small amounts of carbon in our Accelerator Mass Spectrometers (AMS).

Individual sample size requirements vary. We always recommend that you choose the best samples for your research objectives. If you are concerned that your samples are too small then please contact us for advice.

The quantities listed below assume the material is dry and free of adhering/associated matrix.

Pretreatment – It is important to understand the pretreatments that are going to be applied to samples since they directly affect the final result. If your samples are extremely small or fragile, we should discuss your pretreatment options prior to applying them to avoid excessive reduction in sample size. We also welcome your requests to contact you after the pretreatment to discuss your options for AMS dating.

Beta Analytic has removed cancellation and partial analysis fees (except solvent/cellulose extraction) for samples that are too small or do not provide adequate carbon for AMS dating.

Note – Fees are inclusive of d13C measurements using an isotope ratio mass spectrometer (IRMS), quality assurance reports, calendar calibration when applicable, and 24/7 web access to past results and pending analyses. When samples are submitted for radiocarbon dating we also include at no extra charge d15N for non-cremated bones; d18O for carbonates; and d18O and d2H for groundwater.

Click the material name to view additional charges (if any), sample selection, and lab pretreatment procedures. Information about our RadiometricPLUS service is found here.

Additional Charges – Collagen extraction fee applies in addition to the standard price. If the collagen is not suitable for radiocarbon dating, the analysis can be cancelled.

Sample Selection – Chunks, chips, and shavings are best. If your samples are already powderized then please contact us for discussion.

More information on pretreatment and radiocarbon dating antler

Additional Charges – Collagen extraction fee is added to the AMS dating price.

Given the low density of bird bone, the quantity of collagen per unit gram is much lower than in the bones of other animals. Also, often the amount of bird bone available is very small. Attempts to radiocarbon date bird bone samples of as little as 300 milligrams have been successful in cases where preservation is good. Further consideration needs to be given to food source and the possibility of reservoir effects.

More information on radiocarbon dating bones

Bones that have undergone low-temperature heating. They are typically discolored and often fragile.

Additional Charges – A collagen extraction fee is added to the AMS dating fees.

Sample Selection – Low temperature heating damages the collagen, making it less resistant to preservation and more susceptible to contamination that is difficult to remove. If possible it is best to choose the pieces that have undergone the least heating. Choose good cortical bone fragments, preferably from the shafts of femurs or tibiae, as these preserve well. Spongy bones such as ball and sockets, vertebrae etc. do not preserve well and are less likely to yield sufficient collagen following low-temperature heating.

The degree of heating and burial conditions will ultimately determine whether a heated bone can be dated by AMS. There is no way to predict what will be recovered from a heated bone. On occasion good collagen may still be available. On other occasions, organics may be recovered but not identifiable as collagen. Dating these “residual bone organics” can yield reasonable AMS results, but caution should be taken with their interpretation.

No cancellation charges are applied if a heated bone is deemed unsuitable for dating after pretreatments.

More information on pretreatment and radiocarbon dating bones

Bones that have undergone sufficient high-temperature heating to char the collagen without removing it.

Additional Charges – Collagen extraction fees apply in addition to the standard AMS dating price.

Sample Selection – Whether a charred bone will yield carbon for a radiocarbon date depends on the degree of charring. If low, the bone will qualify as burned – see the section above. If high, all the available carbon may have burned away. Generally, if it is black or blue there is a good chance charred collagen is available for AMS dating. If it is white and appears highly calcined, it is unlikely an AMS date on charred carbon will be attainable. However, unidentifiable organics may be recovered. Dates on these residual bone organics can often yield reasonable AMS dates, but caution should be taken with their interpretation.

No cancellation charges are applied if a charred bone sample is deemed unsuitable for dating after pretreatments.

More information on pretreatment and radiocarbon dating bones

Bones that have been exposed to temperatures greater than 600 degrees Celsius for a sufficient time to remove soluble carbonate ions such as calcite and adsorbed carbonates while leaving intact the original structural carbonate primary to the bone.

Additional Charges – Bone carbonate extraction fee applies in addition to the standard price.

Sample Selection – White chips or chunks showing little to no signs of black, blue or grey mottling are best. Carbonate yield from separate sections of bone may be indicative of incomplete cremation. To test this, two portions of the bone are tested for carbonate yield. If they are similar, the lab proceeds with AMS dating. If they are dissimilar, the lab will contact you to discuss whether to proceed or cancel the analysis.

Bone carbonate dating is a special request that incurs additional costs. Please contact us before sending samples for bone carbonate dating.

No cancellation charges are applied if a cremated bone sample is deemed unsuitable for dating after pretreatments.

More information on pretreatment and radiocarbon dating bones

Additional Charges – A collagen extraction fee is added to the Carbon-14 dating price.

Sample Selection – You should choose cortical bones from the larger bones of the body (femur, tibia, upper arm bone, jaw, skull plate and sometimes the ribs). Long, dense bones work best for AMS dating as they have higher collagen mass per unit gram.

Spongy bones such as ball/sockets and vertebra do not tend to preserve well in harsh conditions and may not yield sufficient collagen for the analysis.

More information on ultrafiltration, pretreatment and radiocarbon dating bones

Sample Selection – Water flotation is a common technique used to consolidate or separate charcoal from sediment matrix. There is little chance of actual contamination from the water as long as it is potable. Use of non-organic carbon dispersants is fine. If you float your samples, make sure that all sieves and containers used are completely free of carbon.

Please try to avoid touching the samples with your hands (introducing modern hand oils). If a sample is inadvertently touched then it should still be viable material for dating, however, please make sure that the lab is notified of this exposure. Dry the sample before shipping to avoid any mold or mildew growth.

Details on pretreatment and radiocarbon dating charcoal

Sample Selection – Please inform the laboratory of the burial conditions of the dung and the likelihood of contamination from surrounding organics. If your sample is from a desert environment for example, the alkali steps may be omitted to retain sample mass. If your sample is from a complex soil context or is in limited quantity then AMS with full pretreatments is recommended.

Dung tends to be highly resistant since it is composed of organics that have survived the digestive tract. However, in certain circumstances it may react strongly with the alkali used to remove secondary humic acids. With AMS analysis, this is usually not an issue except in the case of tiny samples.

Please consult the lab before submitting samples to discuss sample suitability.

You are welcome to include specific instructions on pretreatment (e.g. light acid etch or no pretreatment at all) or reporting. For modern studies – Δ14C values reported upon request. For ancient studies – radiocarbon age corrected for marine reservoir effect. d13C and d18O are included in the cost for radiocarbon dating.

Sample Selection – Samples should arrive pre-extracted.

Details on pretreatment and radiocarbon dating forams

Please consult the lab before submitting samples.

Please consult the lab before submitting samples.

Sample Selection – Carbon for accurate AMS dating is quite often irrecoverable due to repeated applications of oils and other preservatives through time. Unadulterated leather from archaeological sites quite often returns very reasonable dates. Leather artifacts such as armor or saddles often yield suspect results.

Please consult the lab before submitting samples to discuss sample suitability and pretreatments (either acid-alkali or acid–solvent extraction).

Sample Selection – Often researchers dating sediment horizons will opt to AMS date macro-fossils or a thin, high-resolution section of the profile rather than obtain a gross average from a large mass. Sometimes a larger volume of sediment (no more than 200 grams) is useful for extraction of soot, macrofossils, or when an alkali-soluble or non-soluble fraction is dated. The laboratory can do these types of extractions.

We recommend that only as much sediment as needed for the analysis be sent. We can help advise as to how much may be required, but in all cases the amount sent should never exceed 200 grams. Please note that most organic sediment samples sent for AMS dating require only 2-4 grams or less depending on the carbon content.

Disposal of Sediment Samples – Please note that sediment samples received from foreign countries as well as many US States must be handled in accordance with the guidelines established by the US Department of Agriculture, Animal and Plant Health Inspection Service (APHIS). These guidelines require that imported sediment samples are treated either chemically or by heat on receipt and that they are eventually disposed of by incineration. As such, the sediment samples received at our laboratory will be disposed of in this manner, and we unfortunately cannot return them.

Details on pretreatment and Macrofossil vs Sediment Dating

Sample Selection – Size requirements for peat vary according to the state of the peat and its contents. For pure sedges send 10-20 milligrams for AMS. For mucky peats send 2-10 grams for AMS. As humification or sediment content increases, the available carbon content decreases, and it becomes more difficult to estimate the sample size required. The presence of plant material within a partially humified peat sample could lead to two fractions: one plant material and one organic sediment.

More information on pretreatment and radiocarbon dating peat

Sample Selection – Phytoliths should arrive already extracted and ready for analysis as the laboratory does not have extraction capabilities at this time. However, we will gladly put you in contact with experts who can guide you through the extraction process. If you do your own extractions please do not evaporate your sample dry in solvents such as acetone or hexane. The final steps should be performed with a final hydrophilic solvent such as acetone followed by multiple rinses in high-grade water (deionized, milli-Q, distilled) prior to drying.

Phytoliths submitted in pre-extracted, isolated, and clean form can be routinely dated using 200-400 milligrams of material.

More information on pretreatment and AMS dating phytoliths

Consult the lab for questions or concerns.

Pretreatment information is found on our AMS dating seeds and grains page.

For small samples, please consult us for discussion.

Pollen samples must be submitted “ready for analysis”. Beta does not presently have facilities to extract and isolate pollen.

Sample Preparation – The extract must be neutral (pH 6-8) for AMS dating to be possible. When enough sample is available, a small portion will be tested to ensure neutrality. If the extract is acidic, it will be rinsed with de-ionized water to achieve a neutral pH level. However, loss of sample mass may occur during this process.

The pollen does not have to be dry. The sample can be dried in the laboratory. However, if you do want to dry the sample, do not use acetone or methanol as a final drying step in your sample preparation because doing so can lead to falsely old results.

NOTE: Occasionally the lab receives samples identified as “pollen” but when viewed under the microscope consists of many components including sediment, fibers, and plant material. In such cases, the lab will contact you to request for instructions to proceed or cancel the analysis. If you proceed, the results report will cite the analyzed material as “organic material” rather than “pollen”.

Laboratory pretreatments are not possible.

More details on radiocarbon dating pollen

Sample Selection – Available material may exist in several forms: charred food residue found on the interior surfaces, fuel carbon on the exterior surfaces, extractable tempering agents; organic carbon within the clay itself. Generally organic residues from the interior surfaces are considered the preferred choice since they represent the time of usage of the pot and constitute short-lived material. However, on occasion they are not in a form capable of surviving alkali pretreatments, if they cannot then we will contact you for discussion.

More details on radiocarbon dating pottery

Sample Selection – If you suspect all the shells from a context are the same age, there is no problem with combining multiple species to make one sample.

Given enough material, the lab typically etches off the outer half of the shell during pretreatments to eliminate any potential secondary carbonate. Please consider this when selecting your samples. Generally, the more material provided the better chance of yielding good results. In the case of very small or tiny samples, we may be limited to a very minor etch or no etch at all.

Since the lab will be analyzing the Carbon-14 in the carbonate, there is no need to worry about handling the samples with bare hands. If the lab were to analyze the organic fraction, the samples must not be handled directly because modern oils present in hands would contaminate the samples.

See radiocarbon dating shells for pretreatment and other details.

Sample Selection – Preferred samples are incisors, canines, and molars with the roots still attached.

More information on pretreatment and radiocarbon dating teeth

Please consult the lab before submitting samples.

Textiles often require either cellulose extraction, solvent extraction or both due to excessive handling. Due to the high cost to the laboratory in time and resources, fees for solvent extraction and cellulose extraction will be charged even if the sample is cancelled.

Sample Selection – If the textile is well preserved, has a good structure, and has not been treated with any conservation materials, the sample is acceptable for AMS dating with standard acid alkali acid pretreatments. Samples may be submitted as a strip, fibers, or a patch.

Policy on Textiles and Artwork – Beta Analytic does not accept materials of commercial value, including materials which are commonly sold in the antiquities markets. The lab does not analyze antiques, books, manuscripts or materials of a religious nature.

Please see details on radiocarbon dating textiles

Please consult the lab before submitting samples.

Important – Please let us know if your samples contain salt or have been in the proximity of any location using labeled 14C (artificial 14C). This includes from ships, laboratories, or sites known to have handled or been contaminated with artificial C14. The collection and/or shipping containers must be new and not previously used for any purpose. Do not add any chemicals to the water upon collection.

We cannot accept seawater samples that have been treated with mercuric chloride (HgCl2) or sodium azide (NaN3) because we do not have the disposal capabilities for these toxic substances.

Sample Collection – Run the tap as long as possible or until you are confident you are collecting the water of choice. Rinse the bottle with the running water prior to collection. Do not add anything to the water. When filling the bottle, please leave a small space at the top (keep the neck of the bottle empty). This should allow for any necessary expansion during shipment. Please put the bottles inside a plastic bag and seal the bag with a zip-tie or duct tape. If any of the bottles leak during shipment, the water will not weaken the cardboard shipping container.

Further water sampling instructions and recommended containers are found in our groundwater dating page.

Please consult the lab before submitting samples.

Sample Selection – Water flotation is a common technique used to consolidate or separate wood from sediment matrix. There is little chance of contamination from the water as long as it is potable. The use of non-organic carbon dispersants is also acceptable. If you float your samples, be sure that all sieves and containers used are completely free of carbon. Please do not touch the samples with uncovered hands as this will introduce modern hand oils. If a sample is touched in error then it should still be a viable sample, however, please make sure that the lab is notified of this exposure.

We recommend you dry the sample before shipping to avoid any mold or mildew growth. However, if drying is not possible (e.g. shipping from the field or very small samples suspended in solution), please send the sample using the fastest possible shipment method.

Conserved wood may need either cellulose extraction, solvent extraction, or both depending on the type of conservation done on the material. If radiocarbon dating is cancelled, fees for solvent extraction and cellulose extraction will still be charged due to the high costs incurred by the lab during pretreatment.

Details on pretreatment and radiocarbon dating wood

Recommended Packaging

Place large samples for radiocarbon analysis directly into ziplock bags. The bags will not contaminate the sample. Small samples or those with fine particles should be wrapped in aluminum foil to contain them in a pouch. Place each foil-wrapped pouch into a labeled ziplock bag.

NOTE: Always handle ONLY one sample at a time. Begin and end the packaging process for each sample prior to beginning the next. This will best ensure mix-ups are avoided during packaging of samples.

We highly recommend sending your samples in small boxes whenever possible (instead of using envelopes) to protect the physical integrity of the samples during shipment. The equipment used by postal services typically run envelopes through rollers during the automated sorting process, and the small amount of pressure exerted during this process is enough to crush small fragments and powder them.

Shipping Recommendations and Addresses

Payment Terms

Sample Handling Advice