Substance Identification and Characterisation for Complex Bio-Based Materials

Overview

For substances of unknown or variable composition, complex reaction products or biological materials (UVCBs), substance identification forms the foundation of REACH registration.

Unlike conventional single constituent substances, complex natural materials often exhibit variability arising from source material, extraction methods, manufacturing processes and compositional distribution. This creates significant technical and regulatory complexity when establishing substance identity and demonstrating substance sameness under REACH.

A robust identification strategy is essential to support:

• regulatory classification,
• data interpretation,
• joint submission alignment,
• dossier preparation,
• and long-term compliance obligations.

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Core Challenge

The identification of complex bio-based substances presents several interconnected challenges, including:

• variability in composition arising from natural source material and process conditions
• limitations in fully identifying or quantifying all constituents
• defining compositional boundaries suitable for substance sameness assessment
• alignment with existing Substance Identity Profiles (SIPs)
• ensuring consistency between manufacturing process, analytical data and dossier information

For UVCB substances, substance identity cannot rely solely on compositional analysis. The manufacturing process itself becomes a critical component of identification under REACH.

This creates a requirement for alignment across:

• process information,
• analytical characterisation,
• constituent profiling,
• and regulatory interpretation.

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Substance Identification Approach

Manufacturing Process as a Critical Identifier

For UVCB substances, ECHA requires detailed consideration of the manufacturing process as part of substance identification.

This includes:

• starting materials and their ratios
• description of processing or reaction steps
• operating conditions such as temperature and pressure
• purification, extraction or refinement stages

For many complex substances, the process itself becomes a primary identifier and forms a critical component of the regulatory definition of the substance.

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Composition Reporting

REACH requires reporting of:

• constituents present at concentrations of 10% or greater
• constituents relevant for classification
• other constituents, where appropriate, including grouped reporting approaches

Where complete constituent identification is not technically feasible, justification is required to support limitations in characterisation.

For complex natural materials, achieving appropriate balance between compositional understanding and practical analytical limitations is often a significant challenge.

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Boundary Composition and Substance Sameness

To support joint registration and substance sameness assessment, a boundary composition approach is typically required.

This involves defining acceptable compositional ranges within which substances may be considered sufficiently similar for joint submission purposes.

Boundary composition assessment becomes particularly important for:

• variable natural feedstocks,
• process-derived variability,
• and alignment with existing joint registration frameworks.

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Analytical Characterisation

Analytical techniques are required to support both constituent identification and concentration profiling.

Analytical data must demonstrate:

• compositional consistency,
• concentration ranges,
• and alignment with the proposed substance identity definition.

Depending on the nature of the material, multiple analytical approaches may be required to establish an appropriate level of characterisation.

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Outcome

Through structured substance identification strategies, it was possible to:

• establish substance identity in line with REACH requirements
• support alignment with joint registration frameworks
• define boundary compositions for substance sameness assessment
• develop analytical datasets supporting compositional interpretation
• align manufacturing process information with regulatory substance definitions
• support downstream dossier development and registration activities

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Key Consideration

For complex bio-based substances, substance identification extends beyond analytical composition alone. Manufacturing process, compositional variability and analytical interpretation must be considered together to establish robust and defensible regulatory substance definitions under REACH.