It is well known that all contemporary organisms contain the same amount of carbon-14, while fossil materials (such as petroleum, coal, etc.) contain no carbon-14 due to their ancient age. The carbon-14 content in the modern biosphere is known, allowing the calculation of the percentage of fossil and biological components in a sample.

ASTM D6866 is based on this principle and is the standard method used industrially to determine biomass content through carbon-14 dating.

Test Method for Determining the Bio-based Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis

It can determine samples in any form, including gaseous ones like CO2 and methane, or liquid ones like bio-alcohol and biodiesel.

The ASTM D6866 testing method is the most rigorous and precise measurement tool for quantifying and verifying carbon credits. This method can determine the renewable carbon content of waste fuels in any state, as well as their CO2 emissions. Therefore, ASTM D6866 monitors the content of biological components used during combustion by measuring the biomass content in combustion exhaust gases.

ASTM D6866 is commonly used to verify the percentage of organic CO2 (carbon dioxide) released into the atmosphere. Organic CO2 is considered an offsettable greenhouse gas (carbon neutral), making it meaningful to determine the organic percentage of gas emissions, allowing companies to report lower greenhouse gas emissions.

The ASTM D6866 testing method is also widely used for raw materials, semi-finished products, and finished products. For example, bio-based products include biopolymers, biodiesel, biopharmaceuticals, biosolvents, biolubricants, bioactive agents, bioadhesives, biocatalysts, biosensors, biodiluents, biopaints, biofertilizers, automotive biofibers, and bioresins.

ASTM D6866 is also widely used to determine the bio-based percentage content in bioplastics. However, this method cannot determine the biodegradability of a product. It is also important to note that bio-based products and product biodegradability are two entirely different concepts. A bioplastic can be 100% bio-based but not biodegradable—for example, high-density polyethylene (HDPE) falls into this category.