SIST EN 18204:2026

• Abstract:

  This document specifies the extraction and determination procedures for the phycobiliproteins C-phycocyanin (C-PC) and the complementary pigment allophycocyanin (APC) from dry samples of species belonging to the genus Arthrospira (Cyanobacteria, Cyanoprokaryota or blue-green algae)(nowadays referred to Limnospira, [1]), and commercially known as Spirulina. This document enables laboratories analysing Arthrospira samples to report accurate C-PC and APC concentrations and yields.

• Status: Published
• Public Enquiry End Date: 09-Sep-2025
• Publication Date: 15-Jun-2026
• ICS: 13.020.55 - Biobased products
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 02-Jun-2026
• Due Date: 07-Aug-2026
• Completion Date: 16-Jun-2026
• Mandate: M/547 - [C(2016)1582] Standardisation request to CEN on Algae and their products
• Ref Project: EN 18204:2026 - Algae and algae products - Determination of the phycocyanin content in Arthrospira (Spirulina)

• Refers: SIST EN 17605:2022 - Algae and algae products - Methods of sampling and analysis - Sample treatment
• Effective Date: 08-Jul-2026
• Refers: SIST EN 17399:2024 - Algae and algae products - Terms and definitions
• Effective Date: 08-Jul-2026

SIST EN 18204:2026 is the Slovenian adoption of EN 18204:2026 from CEN for measuring phycocyanin in Arthrospira (Spirulina). It specifies how laboratories extract and spectrophotometrically determine C-phycocyanin (C-PC) and the complementary pigment allophycocyanin (APC) from dry samples, so they can report concentrations and yields in a consistent way.

What does SIST EN 18204:2026 specify?

SIST EN 18204:2026 specifies a laboratory method for dry samples of Arthrospira, commercially known as Spirulina. The method covers extraction, measurement, calculation and reporting for C-PC and APC.

The document is organized into scope, normative references, terms and definitions, principle, apparatus, reagents and materials, procedures, calculations, and report. Annex A provides informative interlaboratory results that support the method.

What are the key requirements of SIST EN 18204:2026?

SIST EN 18204:2026 is built around controlled sample preparation, buffered extraction, spectrophotometric reading, and calculation against dry biomass. In practice, the method is intended to give comparable results between laboratories when they follow the same handling steps.

Sample handling

Clause 7.1 says dry matter treatment follows EN 17605, and samples should be kept in the dark before analysis. If sample homogeneity is doubtful, the additional preparation steps in EN 17605 are to be applied. This matters because uneven or light-exposed material can distort pigment results.

Extraction and measurement

Clause 7.2 prepares a saline phosphate buffer at pH 6,8 from stock solutions and stores the buffer cold for a limited period. Clause 7.3 recommends triplicate extraction and low-light working conditions, with temperatures kept below the level that can damage C-PC. Clause 7.4 then uses a weighed portion of sample, repeated vortexing, one freeze-thaw cycle, stirring, and centrifugation to obtain the supernatant for analysis.

Spectrophotometric reading and purity

Clause 7.5 measures the supernatant in a UV-VIS spectrophotometer, using a buffer blank and the wavelengths needed to quantify both pigments. The result is expressed as C-PC and APC concentrations in the extract. Clause 7.6 then uses absorbance ratios to judge pigment purity, which helps users decide whether a sample behaves like food grade, reagent grade, or analytical grade material.

Calculations, precision and report

Clause 8 converts pigment concentration and supernatant volume into C-PC and APC content relative to dry biomass. Clause 8.2 also gives the reproducibility check for repeat analysis and summarizes interlaboratory study performance for both pigments. Clause 9 requires the report to identify the lab, the sample, the standard used, the results for C-PC and APC, and any unusual features that could affect the outcome.

What terms does SIST EN 18204:2026 define?

• Phycobiliproteins (PBP) are water-soluble pigments in cyanobacteria and some other algal groups that capture light and transfer energy during photosynthesis.
• C-phycocyanin (C-PC) is the blue phycobilin pigment from cyanobacteria, and it is the main target analyte in this method.
• Allophycocyanin (APC) is the complementary phycobilin accessory pigment measured together with C-PC.
• Arthrospira / Spirulina is the genus and commercial name used in the document for the biomass being analysed.
• Dry matter (DM) is the dry portion of the sample, determined according to EN 17605 before pigment analysis.
• Interlaboratory study (ILS) refers to the collaborative precision study used in Clause 8.2 and Annex A to check method performance across laboratories.

Who uses SIST EN 18204:2026?

SIST EN 18204:2026 is for laboratories that analyse Arthrospira samples and need reported C-PC and APC values they can defend technically. It is relevant for analytical and quality control work on Spirulina biomass, especially where pigment content is used to characterize a product or compare batches.

It also supports method validation teams and technical staff in the algae and algae products sector who need a common extraction and measurement procedure.

Which standards are used with SIST EN 18204:2026?

• EN 17399 - provides the vocabulary for algae and algae products.
• EN 17605 - provides the sample treatment steps and dry matter determination used before the pigment test.

What does the SIST EN 18204:2026 document contain?

The document contains the apparatus list, reagent preparation, step-by-step extraction procedure, spectrophotometric determination, calculation rules, and the required test report content. It also includes a buffer-preparation table in Clause 7.2 and calculation formulae in Clause 8.

Annex A is informative and summarizes the interlaboratory trial and interlaboratory study for C-PC and APC in Spirulina. It includes figures showing participant results and the statistical basis used to support the method’s performance.

SLOVENSKI STANDARD
01-julij-2026
Alge in izdelki iz alg - Ugotavljanje vsebnosti fikocianina v Arthrospira (Spirulina)
Algae and algae products - Determination of the phycocyanin content in Arthrospira
(Spirulina)
Algen und Algenprodukte - Bestimmung des Phycocyaningehalts in Arthrospira
(Spirulina)
Algues et produits à base d’algues - Détermination de la teneur en phycocyanine
d’Arthrospira (Spiruline)
Ta slovenski standard je istoveten z: EN 18204:2026
ICS:
13.020.55 Biološki izdelki Biobased products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 18204
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2026
EUROPÄISCHE NORM
ICS 13.020.55
English Version
Algae and algae products - Determination of the
phycocyanin content in Arthrospira (Spirulina)
Algues et produits d'algues - Détermination de la Algen und Algenprodukte - Bestimmung des
teneur en phycocyanine dans Arthrospira (spiruline) Phycocyaningehalts in Arthrospira (Spirulina)
This European Standard was approved by CEN on 13 April 2026.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N

EUROPÄISCHES KOMITEE FÜR NORMUN G

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 18204:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 6
5 Apparatus . 6
6 Reagents and materials . 6
7 Procedures . 6
7.1 Handling of samples . 6
7.2 Preparation and storage of the phosphate buffer . 6
7.3 Extraction protocol . 7
7.4 Procedure for obtaining the supernatant . 7
7.5 C-PC and APC spectrophotometric determination and quantification . 7
7.6 Purity criteria . 8
8 Calculations . 8
8.1 General. 8
8.2 Interlaboratory reproducibility . 9
9 Report . 9
Annex A (informative) Results of interlaboratory trial and interlaboratory study for
phycobiliproteins . 10
Bibliography . 13

European foreword
This document (EN 18204:2026) has been prepared by Technical Committee CEN/TC 454 “Algae and
algae products”, the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by November 2026, and conflicting national standards shall
be withdrawn at the latest by November 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
This document has been prepared by the experts of CEN/TC 454 'Algae and algae products'.
The European Committee for Standardization (CEN) was requested by the European Commission (EC) to
draft European standards or European standardization deliverables to support the implementation of
Article 3 of Directive 2009/28/EC for algae and algae products.
This request, presented as Mandate M/547, also contributes to the Communication on “Innovating for
Sustainable Growth: A Bio economy for Europe”.
The former working group CEN Technical Board Working Group 218 “Algae”, was created in 2016 to
develop a work programme as part of this Mandate. The technical committee CEN/TC 454 'Algae and
algae products' was established to carry out the work programme that will prepare a series of standards.
The interest in algae and algae products has increased significantly in Europe as a valuable source
including but not limited to carbohydrates, proteins, lipids, and several pigments. These materials are
suitable for use in a wide range of applications from food and feed purposes to other sectors, such as
textile, cosmetics, biopolymers, biofuel and fertilizer/biostimulants. Standardization was identified as
having an important role in order to promote the use of algae and algae products.
The work of CEN/TC 454 should improve the reliability of the supply chain, thereby improving the
confidence of industry and consumers in algae and algae products and will promote and support
commercialisation of the European algae industry.

1 Scope
This document specifies the extraction and determination procedures for the phycobiliproteins C-
phycocyanin (C-PC) and the complementary pigment allophycocyanin (APC) from dry samples of species
belonging to the genus Arthrospira (Cyanobacteria, Cyanoprokaryota or blue-green algae) (nowadays
referred to Limnospira, [1]), and commercially known as Spirulina. This document enables laboratories
analysing Arthrospira samples to report accurate C-PC and APC concentrations and yields.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 17399, Algae and algae products — Vocabulary
EN 17605, Algae and algae products — Methods of sampling and analysis — Sample treatment
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 17399 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
phycobiliproteins
PBP
water soluble pigments present in cyanobacteria and certain algae groups such as glaucophytes,
cryptomonads, and red algae (Rhodophytes) used for capturing light
Note 1 to entry: Phycobiliproteins capture light energy, which is then passed on to chlorophylls during
photosynthesis. Phycobiliproteins are formed of a complex between proteins and covalently bound phycobilins that
act as chromophores (the light-capturing part). They are most important constituents of the phycobilisomes.
3.2
phycocyanin
C-PC
blue-green phycobilin pigment found in cyanobacteria, glaucophytes, cryptomonads, and red algae
Note 1 to entry: Nomenclature for phycocyanin specifically obtained from cyanobacteria is identified as C-PC.
3.3
allophycocyanin
APC
type of phycobilin photosynthetic accessory pigment found in cyanobacteria, glaucophytes,
cryptomonads, and red algae
4 Principle
Phycobiliproteins (PBP) like C-PC and APC can be extracted from dried biomass by vortexing this with a
phosphate buffer solution. The C-PC and APC concentration can be spectrophotometrically determined
and calculated in the resulting supernatant.
5 Apparatus
5.1 Analytical balance, with an accuracy of 0,1 mg
5.2 Vortex
5.3 Magnetic stirrer
5.4 Centrifuge, over 5 000 × g, preferably with temperature operation mode at 4 °C
5.5 UV-VIS Spectrophotometer, for 1 cm cuvettes
6 Reagents and materials
6.1 Phosphate buffer (0,1 M) plus NaCl (0,15 M) at a pH of 6,8
6.2 Stock solutions
6.2.1 0,2 M solution of monobasic sodium phosphate (24,0 g of NaH PO in 1 000 ml distilled water)
2 4
6.2.2 0,2 M solution o
...