ASTM D6866-24

Overview

ASTM D6866-24 sets forth standardized test methods for determining the biobased content of solid, liquid, and gaseous samples using radiocarbon analysis. Developed by ASTM International, this standard is critical for accurate quantification of biobased or biogenic carbon in a variety of materials, enabling manufacturers, laboratories, and regulatory agencies to differentiate between modern, renewable carbon sources and fossil-derived carbon sources. The standard focuses on materials whose carbon originates from atmospheric CO₂, such as plant-based products, and details appropriate methodologies for various sample types.

Key Topics

• Purpose: Provides reliable methods to experimentally measure the percentage of biobased carbon content in products by radiocarbon analysis.
• Scope: Applicable to solids, liquids, and gases containing carbon, including flue gases from utilities and incinerators, provided the carbon can be combusted to form CO₂.
• Techniques Covered:
  • Accelerator Mass Spectrometry (AMS) and Isotope Ratio Mass Spectrometry (IRMS): Highly sensitive methods for precise quantification (instrumental uncertainty as low as 0.1-0.5% RSD, up to ±3% total inter-laboratory uncertainty).
  • Liquid Scintillation Counting (LSC): Involves conversion of the sample’s carbon to benzene before measurement, offering similarly accurate results (up to ±3% error).
• Measurement Principle: Differentiates contemporary/biogenic carbon from fossil carbon by analyzing ratios of radioactive (¹⁴C) to stable (¹²C or ¹³C) carbon isotopes compared to internationally recognized standards.
• Traceability: Use of certified reference materials (e.g., NIST SRM 4990C, HOxII) ensures method reliability and data comparability.

Applications

• Product Certification: Determining the biobased content of chemicals, polymers, plastics, and fuels for eco-labeling, certification, and compliance with biobased procurement policies.
• Environmental Science: Quantifying renewable versus fossil carbon content in emissions or recovered fuels, supporting greenhouse gas reporting and sustainability metrics.
• Industrial Quality Control: Validating supplier and in-house claims of renewable content as part of supply chain transparency and green product initiatives.
• Research & Development: Investigating carbon cycling in natural and engineered systems by tracing contemporary versus fossil carbon contributions.

Practical Considerations

• Sample Type: Applicable to all combustable carbon-based materials, with protocols ensuring accuracy for diverse matrices.
• Laboratory Requirements: Stringent laboratory separation is mandatory if artificial ¹⁴C is handled anywhere in the facility, due to risks of cross-contamination that could skew radiocarbon measurements.
• Reporting: Results are calculated as percent modern carbon (pMC), adjusted using annual reference values to account for changes in atmospheric ¹⁴C levels, and expressed as percent biobased carbon content with documented uncertainty.
• Limitations: Does not address product performance, environmental impact beyond carbon source, or compliance thresholds for biobased content; does not determine geographic origin.

Related Standards

• ISO 16620-2: Plastics – Biobased content – Part 2: Determination of biobased carbon content (equivalent to ASTM D6866).
• CEN/TS 16640: Biobased products-Determination using radiocarbon methods.
• EN 15440: Solid recovered fuels-Methods for determination of biomass content.
• ISO 13833: Stationary source emissions-Determination of the ratio of biomass and fossil carbon dioxide-Radiocarbon sampling and determination.
• ASTM D883: Terminology relating to plastics.

By following ASTM D6866-24, organizations can reliably identify and quantify biobased content, supporting regulatory compliance, sustainable product claims, and contributions to a circular carbon economy. This standard is recognized internationally and harmonized with equivalent ISO and CEN methodologies, ensuring global interoperability and credibility in biobased product analysis.