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.
Please note, the content biobased does not in any way define 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 products biobased 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 carbon biobased 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 carbon (petroleum-based).
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 fuels 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 allows them to be clearly distinguished from biobased sources.
By measuring the isotopic ratio between ¹⁴C, ¹³C, and ¹²C, scientists at the CIRAM precisely determine the content of modern (biobased) and fossil (petro-based) carbon in a sample. This approach forms the basis ofradiocarbon analysis, which is used for the characterization of products biobased, 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 products biobased. 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% carbon biobased.
Since 2003, the official reference values used within the framework of standard NF EN 16640 have been published by the University of Groningen, ensuring international consistency in the interpretation of carbon 14 analysis results.
To illustrate the evolution of these references, we can recall that:
- in 2022, the value corresponding to 100% carbon biobased 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.
Starting from the reference value REF, XTCB can be calculated, which is the carbon contentbiobased 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 carbonbiobased content by the AMS radiocarbon technique has an uncertainty of ± 2%. This implies that the carbon content biobased can vary by ± 2%. That is to say, a value of XTCB at 98% could be considered 100% carbon biobased relative to total carbon, within the limits of uncertainty.
The NF EN 16640 standard does not recommend any particular 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 carbon biobased relative to total carbon, unlike the ASTM D6866 standard which may consider the percentage of carbon biobased relative to total organic carbon.
