In compliance with this standard, we use radiocarbon dating (also called carbon-14) through analytical testing techniques used to determine the age of carbon-containing objects.
Attention, the bio-based content in no way defines the environmental impact or sustainability of a product. It is possible to measure this impact through a life cycle analysis according to defined sustainability criteria.
Radiocarbon analysis of biobased products
Radiocarbon analysis of bio-based products must comply with the NF EN 16640 standard by using one of the three regulatory methods.
CIRAM laboratories explain AMS carbon-14 analysis in detail.
What is a biobased product?
The term biosourced means "derived from biomass". A biobased product can be entirely or partially derived from biomass. Thanks to our laboratory analyses, we can characterize the quantity of biomass contained in a product (paint, solvent polymers, etc.).
It will be interesting to measure the amount of bio-based carbon during an R&D phase, but also on a finished product (biogenic carbon in biofuels, biogas, fumes, but also in cosmetic and agri-food products) or to evaluate a supplier's raw materials. The measurement of carbon 14 quantifies the content of biogenic carbon and synthetic (petroleum-based) carbon.
Carbon-14, an element present in all living organisms
Carbon-14 (¹⁴C) is a radioactive isotope of carbon produced by the interaction between nitrogen-14 atoms present in the atmosphere and cosmic radiation. Naturally unstable, it gradually decays to become nitrogen-14 again. Its half-life, estimated at 5,568 years, means its concentration halves over this period, and it almost completely disappears after about 60,000 years.
Due to its continuous regeneration by solar activity, the concentration of carbon 14 is considered almost constant in the atmosphere. It is thus present in all living organisms, where it is assimilated by photosynthesis and respiration. The current biomass (cereals, algae, wood, residues, and organic waste) therefore possesses a reservoir of carbon 14 said to be "modern" and fully active.
In contrast, fossil resources such as oil, gas, or coal, resulting from the transformation of organic matter over millions of years, no longer contain carbon 14. They are composed exclusively of ancient carbon or petroleum-based carbon, which clearly distinguishes them from bio-based sources.
By measuring the isotopic ratio between ¹⁴C, ¹³C, and ¹²C, scientists at the CIRAM supports precisely determine the content of modern (bio-based) and fossil (petro-based) carbon in a sample. This approach forms the basis ofradiocarbon analysis, which is used for the characterization of bio-based products, the control of raw materials and verification of environmental claims.
AMS radiocarbon analysis
The NF EN 16640 standard provides three methods for measuring the carbon 14 content of bio-based products. CIRAM laboratories exclusively use accelerator mass spectrometry (AMS), a recognized reference technique for its high precision and sensitivity in radiocarbon analysis.
Before measurement by AMS, the sample is prepared by conversion into pure carbon, in the form of graphite, then compacted into a sample holder cathode. This preparation step is essential to ensure the reliability of the results and the reproducibility of measurements.
The carbon 14 content is then expressed either as a fraction of the sample's mass or as a fraction of the total carbon content. The percentage of modern carbon, called pMC (percent Modern Carbon), corresponds to a normalized and standardized value of the measured carbon 14. This value is compared to that of a reference material (REF), representing 100% bio-based carbon.
Since 2003dating, official reference values used in the context of the NF EN 16640 standard are published by theUniversity of Groningen, ensuring international consistency in the interpretation of resultscarbon-14 analysis.
To illustrate the evolution of these references, we can recall that:
- in 2022, the value corresponding to 100% bio-based carbon was set at 100 pMC;
- in 2010, the reference value for certifying 100% content was 104 pMC;
- In 1964, this value reached 190 pMC, due to the effects of atmospheric nuclear testing on carbon-14 concentrations.
The calculation method for biobased products
The NF EN 16640 standard indicates that in addition to measuring the pMC, we must indicate:
- XTC the total carbon content of the sample,
- Xb the biobased carbon content as a fraction of the sample mass.
From the reference value REF, XTCB can be calculated, which is the bio-based carbon content as a fraction of the total carbon content. It is this value that is decisive.
Attention, the standard NF EN 16640 indicates that the measurement of the bio-based carbon content by the AMS radiocarbon technique has an uncertainty of ± 2%. This implies that the bio-based carbon content can vary by ± 2%. That is to say, a value of XTCB of 98% could be considered 100% bio-based carbon relative to total carbon, within the limits of uncertainty.
The NF EN 16640 standard does not recommend any specific treatment for materials containing inorganic carbonates. However, calcium carbonates contain "old carbon" and risk artificially lowering the XTCB value. This clarification is important because it indicates that the NF 16640 standard defines the percentage of bio-based carbon relative to total carbon, unlike the ASTM D6866 standard which may consider the percentage of bio-based carbon relative to total organic carbon.
