Surfactant Glossary: CMC, OECD 301, CLP, REACH

Surfactant documentation is dense with abbreviations, and the same term carries different weight in a marketing claim than in a study report. This glossary defines the terminology used across the PureSurf site and in the technical data sheets, names the issuing body behind each standard, and flags the terms that are most often misused.

How to use this glossary

Terms are grouped conceptually rather than alphabetically: molecular structure, performance metrics, biodegradation, ecotoxicity, human health, regulatory frameworks and readiness language. Use the search box to filter, or the group links to jump.

Where a term names a formal standard, the issuing body and number are given so the method can be looked up. Where a term is routinely stretched in marketing, the definition says what it does not mean. Product-specific figures live on the technical data page rather than here, so that a definition never becomes a stale claim.

Filter terms

Molecular structure and chemistry

Amphiphile: A molecule with both a water-attracting (hydrophilic) and a water-repelling (hydrophobic) part. All surfactants are amphiphiles.
Surfactant: Surface active agent. A molecule that accumulates at interfaces and lowers surface or interfacial tension.
Micelle: A spherical cluster of surfactant molecules with hydrophobic tails inward and hydrophilic heads outward, forming above the CMC.
Amine oxide: A non-ionic surfactant class with an oxidised tertiary amine head group. Strong grease removal, good foam and mildness, with cationic character under acidic pH.
Amine-N-oxide: The formal name for the oxidised tertiary amine head group that defines the amine oxide class. Used in chemical nomenclature where "amine oxide" is used commercially.
Non-ionic surfactant: A surfactant with no net charge on the head group. Tolerant of hard water and electrolytes, generally low irritation potential.
Anionic surfactant: A surfactant carrying a negative charge on the head group, such as LAS or SLES. High foam and detergency, sensitive to water hardness.
Cationic surfactant: A surfactant carrying a positive charge, used for softening and antimicrobial effect. Generally more aquatically toxic than non-ionics.
Amphoteric surfactant: A surfactant whose charge depends on pH, such as betaines. Often used as a mild co-surfactant.
Alkyl chain length: The number of carbon atoms in the hydrophobic tail, for example C12 or C14. It drives solubility, foam, CMC and toxicity. Two grades of the same chemistry can behave very differently on chain length alone.
Furan: A five-membered aromatic ring with one oxygen atom, accessible from carbohydrate feedstocks. It forms the renewable core of the NEXOVANT structures.
Lignocellulose: The structural material of plants, made of lignin, cellulose and hemicellulose. A non-food source of renewable aromatic and carbohydrate building blocks.
Gelator: A substance that builds viscosity and structure in a liquid, often at low concentration and without conventional polymeric thickeners.
Bio-based: Describes carbon originating from renewable biomass rather than petroleum. It says nothing about the production route, the toxicity or the biodegradability of the resulting molecule.
Biosurfactant: A surfactant produced biologically, usually by microbial fermentation. Every biosurfactant is bio-based, but not every bio-based surfactant is a biosurfactant.
Drop-in replacement: An ingredient that can substitute an incumbent without changing the production process or the rest of the formulation. Compatibility should still be verified in your own system.

Performance metrics

CMC: Critical micelle concentration: the concentration at which micelles begin to form. A lower CMC means the same effect at a lower dose. For amine oxides the CMC is strongly pH-dependent, so a CMC without a stated test pH is not comparable.
Surface tension: The energy at a liquid / air boundary, in mN/m. Lower values mean better wetting. Commonly measured under EN 14370 at a defined concentration.
Interfacial tension (IFT): The energy at the boundary between two immiscible liquids. Lower values mean easier emulsification. IFT depends on the oil phase used, so a value is only meaningful with the oil named.
HLB: Hydrophilic-lipophilic balance: a numeric scale describing whether a surfactant favours oil-in-water or water-in-oil systems.
Cloud point: The temperature at which a non-ionic surfactant solution turns turbid as the surfactant loses solubility. Measured under EN 1890.
Foaming capacity: The foam volume generated under a defined test, commonly EN 12728 (Ross-Miles). Reported with the concentration and the drainage behaviour.
Viscosity: Resistance to flow, in mPa·s (dynamic) or mm²/s (kinematic). Always shear-rate and temperature dependent, so both belong with the figure.
log Kow: The octanol / water partition coefficient, a measure of how strongly a substance partitions into fat rather than water. High values indicate bioaccumulation potential. Often calculated rather than measured; the method should be stated.
Benchmark: The incumbent product a new material is compared against. A comparison is only meaningful if the benchmark, the method and the conditions are all named.

Biodegradation

Ready biodegradability: The strict OECD category: 60 % oxygen demand or CO2 evolution, or 70 % dissolved organic carbon removal, within 28 days and within a 10-day window after 10 % degradation is reached.
Inherent biodegradability: Evidence that a substance can be degraded under favourable conditions, without meeting the ready criteria. A weaker claim than ready biodegradability.
Ultimate biodegradation: Complete mineralisation to carbon dioxide, water, mineral salts and biomass. The criterion used by the EU Detergents Regulation, at 60 % within 28 days and without the 10-day window.
OECD 301: A series of six ready-biodegradability screening tests, 301A to 301F. The same substance can pass one method and fail another, so the method must always be named with the result.
OECD 301B: The CO2 evolution (modified Sturm) test. Measures carbon dioxide produced by microbial degradation, expressed as a percentage of the theoretical maximum (ThCO2).
OECD 301F: The manometric respirometry test. Measures oxygen consumed during degradation, expressed as a percentage of theoretical oxygen demand (ThOD).
ThOD: Theoretical oxygen demand: the oxygen required for complete oxidation of a substance. For nitrogen-containing substances it can be calculated on an ammonium or a nitrate basis, and the two give different percentages.
ThCO2: Theoretical carbon dioxide: the CO2 that complete mineralisation would release. The reference value in OECD 301B.
10-day window: The requirement that 60 % or 70 % degradation is reached within 10 days of passing 10 %. Applied under OECD ready biodegradability, but not applied by the EU Detergents Regulation.

Ecotoxicity and environmental fate

EC50: The concentration causing a 50 % effect in a defined test population. A higher EC50 means lower toxicity. Never comparable across different species or test durations.
LC50: The concentration lethal to 50 % of a test population, typically used for fish and other animals.
NOEC: No observed effect concentration: the highest tested concentration at which no statistically significant effect is seen.
OECD 201: Freshwater alga and cyanobacteria growth inhibition test, 72 h. Algae are usually the most sensitive trophic level for surfactants, which is why this endpoint often drives classification.
OECD 202: Daphnia sp. acute immobilisation test, 48 h. The crustacean endpoint of the standard aquatic triad.
OECD 203: Fish acute toxicity test, 96 h. The third endpoint of the aquatic triad and part of the higher REACH tonnage bands.
Aquatic Acute / Chronic category: The CLP hazard categories for aquatic toxicity, from Category 1 (most hazardous) downward, derived from the algae, Daphnia and fish endpoints together with degradability and bioaccumulation data.
PBT / vPvB: Persistent, bioaccumulative and toxic; very persistent and very bioaccumulative. REACH assessment categories for substances of concern. A formal PBT assessment is a defined procedure, not an opinion.
Nominal vs measured concentration: Whether a reported test concentration is the amount added or the amount analytically confirmed in the test vessel. Results on a measured basis can be substantially different, and the basis should be stated.

Human health endpoints

OECD 431: In vitro skin corrosion test using a reconstructed human epidermis model. Distinguishes corrosive from non-corrosive, and can assign sub-categories 1A, 1B and 1C.
OECD 439: In vitro skin irritation test using a reconstructed human epidermis model. A substance can be non-corrosive under OECD 431 and still be an irritant under OECD 439.
OECD 442C (DPRA): Direct peptide reactivity assay: the first key event of the skin sensitisation pathway, measuring reactivity towards model peptides.
OECD 442D (KeratinoSens): Keratinocyte activation assay: the second key event of the skin sensitisation pathway, measuring Nrf2 pathway activation.
OECD 471 (Ames): Bacterial reverse mutation test for mutagenic potential, run in several Salmonella strains with and without metabolic activation (S9).
OECD 492 / 492B: In vitro eye hazard tests using reconstructed human cornea-like epithelium, used to identify serious eye damage or irritation.
Skin Corr. / Skin Irrit.: CLP classes for skin corrosion and skin irritation, with the associated hazard statements H314 and H315.
Skin Sens. 1: CLP class for skin sensitisers, hazard statement H317. Relevant for leave-on and frequent-contact applications.
Eye Dam. 1: CLP class for serious eye damage, hazard statement H318. Common for concentrated surfactants and managed through handling controls and dilution.

Regulatory frameworks

GLP: Good Laboratory Practice: a formal quality framework for non-clinical safety studies. Data is only GLP once the report is finalised and signed by the study director and quality assurance. A completed experiment is not yet GLP data.
CLP: Regulation (EC) 1272/2008 on Classification, Labelling and Packaging. Defines the hazard classes, categories and H-statements on a safety data sheet.
REACH: Regulation (EC) 1907/2006 on Registration, Evaluation, Authorisation and Restriction of Chemicals. Tonnage bands determine the data package required before a substance may be placed on the EU market.
Tonnage band: The annual volume brackets under REACH, such as 1 to 10, 10 to 100 and 100 to 1,000 tonnes per year. Each higher band triggers additional study requirements.
Lead registrant: The company that submits the joint registration dossier for a substance on behalf of a group of registrants under REACH.
BPR: Regulation (EU) 528/2012 on biocidal products. An antimicrobial active must be approved for the relevant product type, and its supplier listed under Article 95, before a biocidal product can be placed on the EU market.
Article 95 list: The ECHA list of approved suppliers of biocidal active substances. Being absent from it prevents market access for the relevant product type, regardless of efficacy data.
EU Detergents Regulation: Regulation (EC) 648/2004, which sets surfactant biodegradability requirements and ingredient labelling rules for detergents in the EU. It applies ultimate biodegradation at 60 % in 28 days without the 10-day window.
EN 1276: European quantitative suspension test for bactericidal activity. It is a test for finished disinfectant products, not for active substances in isolation, and results should be attributed to a formulation.
MIC / MBC: Minimum inhibitory and minimum bactericidal concentration. Laboratory measures of antimicrobial activity that are not equivalent to product-level efficacy under standard disinfectant tests.
ESKAPE pathogens: A group of six bacterial species known for antimicrobial resistance, used as a challenge panel in antimicrobial screening.
SDS: Safety data sheet. Versioned and dated: classifications can change between versions, so always work from the current sheet for the grade you have.
EUDR: The EU Deforestation Regulation, which requires deforestation-free due diligence for listed commodities including palm oil, adding traceability obligations to palm-derived supply chains.

Readiness, quality and supply

TRL: Technology Readiness Level, from 1 (basic principles) to 9 (proven in operation). TRL 4 means laboratory validation; TRL 6 means demonstration in a relevant environment.
Data maturity: How far a figure has travelled from experiment to signed report: screening, internal measurement, third-party measurement, GLP in finalisation, or final GLP. It determines how the figure may be used in a dossier.
Third-party measurement: A figure produced by an independent laboratory or industrial partner rather than the supplier. Stronger evidence than an in-house value, even when it is not GLP.
CoA: Certificate of analysis: the batch-specific record of measured purity and specification conformity that accompanies a delivery.
TDS: Technical data sheet: the grade-level document listing typical properties, application guidance and handling recommendations.
FTO: Freedom to operate: an assessment that a technology can be commercialised without infringing third-party patents. It is a search-based opinion with a date, not a permanent guarantee.
Patent family: A set of patent applications and grants covering the same invention across jurisdictions. Counting families rather than filings avoids inflating a portfolio.
Side stream: A material produced alongside a main product, often treated as waste. Renewable European side streams can serve as chemical feedstock.
Scale-up: Moving a synthesis from laboratory to production scale. Batch size, yield stability and impurity profile are the practical measures of progress.