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Whitepaper: Analytical Characterisation of UVCBs for REACH Registration

Substances of Unknown or Variable composition, Complex reaction products or Biological

materials (UVCB) are substances in which:

  • The number of constituents is relatively large and/or
  • The composition is, to a significant extent, unknown and/or
  • The variability of composition is relatively large or poorly predictable

By their very nature, UVCB substances can present a difficult analytical challenge and their characterisation may demand a somewhat different approach to that used for well-defined (mono- and multi-constituent) substances. Typical examples of UVCBs include petroleum products, plant- derived essential oils and complex inorganic species such as synthetic minerals.

Formal substance identification involves several elements:

  • The main identifiers including the name, source and most relevant steps of the production process
  • Analytical data appropriate to the substance in question
  • Other relevant parameters such as boiling range or optical activity

Substance identity is often defined by the commercial sector within which each UVCB is produced and marketed. Formal quality standards are usually set that must be fulfilled in order for a substance to be sold for a given application. This usually includes at least some analytical information that could be used as a point of reference.