In accordance with this standard, we use radiocarbon (also known as carbon-14) analysis, which involves analytical testing techniques used to determine the age of objects containing carbon.
Please note that bio-based content does not in any way define a product's environmental impact or sustainability. This impact can be measured using a life cycle analysis based on defined sustainability criteria.
Radiocarbon analysis of biobased products
Radiocarbon analysis of bio-based products must comply with standard EN 16640 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 in an R&D phase, but also in a finished product (biogenic carbon in biofuels, biogas, smoke, but also in cosmetics and agri-food products) or to evaluate a supplier's raw materials. Carbon-14 measurement quantifies the biogenic and synthetic (petro-based) carbon content.
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 in the atmosphere and cosmic radiation. Naturally unstable, it gradually decays back into nitrogen-14. Its half-life, estimated at 5,568 years, means that its concentration decreases by half over this period and that it disappears almost completely after about 60,000 years.
Due to its continuous regeneration by solar activity, the concentration of carbon-14 is considered to be virtually constant in the atmosphere. It is therefore present in all living organisms, where it is assimilated through photosynthesis and respiration. Current biomass (cereals, algae, wood, residues, and organic waste) therefore has a fully active reservoir of "modern" carbon-14.
Conversely, fossil fuels such as oil, gas, and coal, which are formed from the transformation of organic matter over millions of years, no longer contain carbon-14. They are composed exclusively of ancient or petroleum-based carbon, which clearly distinguishes them from bio-based sources.
By measuring the isotopic ratio between ¹⁴C, ¹³C, and ¹²C, scientists at CIRAM laboratories can accurately determine the modern (bio-based) and fossil (petro-based) carbon content of a sample. This approach forms the basis ofradiocarbon analysis, which is used to characterize bio-based products, monitor raw materials, and verify environmental claims.
AMS radiocarbon analysis
The 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 reference technique recognized for its high precision and sensitivity inradiocarbon analysis.
Before measurement by AMS, the sample is prepared by transforming it into pure carbon in the form of graphite, then compacted into a sample-holding cathode. This preparation step is essential to ensure the reliability of the results and the reproducibility of the measurements.
The carbon-14 content is then expressed either as a mass fraction of the sample or as a fraction of the total carbon content. The percentage of modern carbon, known as 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 2003, the official reference values used in EN 16640 have been published bythe University of Groningen, ensuring international consistency in the interpretation ofcarbon-14 analysis results.
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 EN 16640 standard specifies 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.
Based on the REF reference value, we can calculate XTCB, which is the bio-based carbon content as a fraction of the total carbon content. This value is decisive.
Please note that standard EN 16640 states that measuring bio-based carbon content using the AMS radiocarbon technique has an uncertainty of ± 2%. This means that bio-based carbon content may vary by ± 2%. In other words, an XTCB value of 98% can be considered as 100% bio-based carbon in relation to total carbon, within the margin of uncertainty.
The EN 16640 standard does not recommend any specific treatment for materials containing inorganic carbonates. However, calcium carbonates contain "old carbon" and may artificially reduce the XTCB value. This clarification is important because it indicates that the 16640 standard defines the percentage of bio-based carbon in relation to total carbon, unlike the ASTM D6866 standard , which may consider the percentage of bio-based carbon relative to total organic carbon.
