⛽ Hydrocarbon type content — saturates, olefins and aromatics — in petrols, aviation fuels and petroleum fractions by fluorescent indicator adsorption (FIA) on silica gel; PN-EN 15553

Petrochemistry PN-EN 15553

Overview

WHAT THE STANDARD COVERS. The “Scope” field of the PKN card of PN-EN 15553+A1:2025-05 (English version, scope description in Polish), in full except the final general warning, in our translation: “This document specifies a fluorescent indicator adsorption method for the determination of hydrocarbon types over the concentration ranges from 5 % (V/V) to 99 % (V/V) aromatic hydrocarbons, from 0,3 % (V/V) to 55 % (V/V) olefinic hydrocarbons and from 1 % (V/V) to 95 % (V/V) saturated hydrocarbons in petroleum fractions that distil below 315 °C. This method may apply to concentrations outside these ranges, but the precision has not been determined. When samples containing oxygenate blending components are analysed, the hydrocarbon type results can be reported on an oxygenate-free basis or, when the oxygenate content is known, the results can be corrected to the total sample. This test method is applicable to products of the full boiling range. Data obtained in interlaboratory studies showed that the precision statement is not applicable to narrow-boiling petroleum fractions near the 315 °C limit. Such samples do not elute properly and the results are erratic. It is not applicable to samples containing dark-coloured components that interfere with reading the chromatographic bands, so they cannot be analysed. NOTE 1 The oxygenated blending components methanol, ethanol, methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME) and ethyl tert-butyl ether (ETBE) do not interfere with the determination of hydrocarbon types at concentrations normally found in commercial blends. These oxygenates are not detected, since they elute with the alcohol desorbent. The effect of other oxygenates is verified individually. NOTE 2 For the purposes of this document, the terms »% (m/m)« and »% (V/V)« are used to represent the mass fraction and the volume fraction respectively.” We did not have the text of the standard — the description of the method below comes from the regulation that refers to the standard.

THE METHOD IN LEGISLATION. The Regulation of the Minister of Climate and Environment of 26 June 2024 on test methods for the quality of liquid fuels (Journal of Laws 2024 item 1058; amended by Journal of Laws 2024 item 1966, which does not concern point 10; in force according to ISAP, read on 06.11.2026), in the annex, part I (motor petrols), point 10, gives two methods for determining the content of olefin-type and aromatic-type hydrocarbons: (1) fluorescent indicator adsorption — separation of the hydrocarbons into types according to their adsorption properties (olefins, aromatics and saturates) in an adsorption column packed with activated silica gel; dyes separate selectively with the hydrocarbon types and form coloured zones whose boundaries are visible under ultraviolet light, and the content of each type is calculated from the length of the zone in the column and expressed as a volume fraction in percent (point 10.1); the procedure, apparatus, reagents, calculation and precision are specified by the standard PN-EN 15553 (point 10.2, undated reference); (2) multidimensional gas chromatography with column switching and a flame ionisation detector according to PN-EN ISO 22854 (point 10.3). The regulation of the same date on quality requirements for liquid fuels (Journal of Laws 2024 item 1018; amended by Journal of Laws 2024 item 1980, which concerns the CN code of diesel fuel) allows for motor petrols with oxygen up to 3,7 % (m/m) and up to 2,7 % (m/m) (Annexes 1 and 2, row 11) at most 18,0 % (V/V) olefins and 35,0 % (V/V) aromatics — values drawn up on the basis of PN-EN 228+A1:2017-06. Directive 2009/30/EC, amending Directive 98/70/EC, has the same limits in Annex I (olefins 18,0 % v/v, aromatics 35,0 % v/v) and refers to the test methods of EN 228:2004; the number EN 15553 does not appear in its text.

STATUS (state of the PKN card on 06.11.2026). The card of PN-EN 15553+A1:2025-05 (English version) has no withdrawal note and no “Replaced by” field: published 26-05-2025, 22 pages, Chemistry Sector, KT 222/PK 1 Liquid Fuels, “Adopts: EN 15553:2021+A1:2024 [IDT]”, “Replaces: PN-EN 15553:2022-05 - Polish version, PN-EN 15553:2022-05 - English version”, ICS 75.080; the card has no “Directive” or “Mandate” fields. The previous edition thus had a Polish version; whether a Polish version of the edition with amendment A1 exists — we did not check (the PKN search engine returned a server error on 06.11.2026). The regulation on test methods refers to “PN-EN 15553” without a year, so it covers the current edition.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database refreshed from the production server on 02.11.2026; query over every form of the number 15553 in the reference document fields). 8 records at 7 Polish laboratories: AB 009, AB 079, AB 098, AB 297, AB 474, AB 484 (two — Fuels and Aromatics Laboratory PP1 and Physicochemistry Laboratory), AB 773. Entries: “PN-EN 15553+A1:2025-05” (AB 079, AB 297 — here “z wyłączeniem punktu 7.1”, i.e. excluding point 7.1, AB 474, AB 484) and “PN-EN 15553” without a year (AB 009, AB 098, AB 773). Four laboratories (AB 098, AB 297, AB 474 and AB 484 — in both laboratories, 5 records in total) refer in the same item to ASTM D 1319 (at AB 297, AB 474 and AB 484 — ASTM D 1319-20a; at AB 297 “excluding point 8”) with the same methodology “Content of hydrocarbon groups” — these are two alternative standards for one test. Not included in the set is the only Czech record with the number 15553: “ISO 15553” at laboratory 1206 concerns the protozoa Cryptosporidium and Giardia in water — a different standard. In the current PCA documents we read (AB 079 issue 71 of 15.05.2026, AB 297 issue 32 of 22.01.2026, AB 484 issue 53 of 01.10.2026) the standard appears 4 times (twice at AB 484); we did not read the documents of AB 009, AB 098, AB 474 and AB 773. The “Laboratories” tab (“PN-EN 15553”) shows 7 laboratories — the same 7 Polish ones (tab query on labcoda.pl, 06.11.2026).

WHAT THE LABORATORIES TEST (database copy and PCA documents, whole items). In all 8 records the methodology reads “Content of hydrocarbon groups”, and the technique — “Gel chromatography method (FIA)” or “Gel chromatography method” (AB 474, AB 484 Physicochemistry Laboratory). Unleaded petrol, aviation gasoline, unleaded petrol with bioethanol and petroleum distillates — aromatics (0,5–99,0) % (v/v), olefins (0,3–55,0) % (v/v), saturates (1,0–95,0) % (v/v) (AB 297); unleaded petrol, liquid biohydrocarbons for spark-ignition engines and petroleum fractions with a final boiling point not higher than 315 °C — aromatics (13,0–40,0), olefins (4,0–33,0), saturates (45,0–68,0) % (V/V) (AB 009); unleaded petrol — aromatics (20,0–40,0), olefins (1,0–20,0), saturates (45,0–68,0) % (v/v) (AB 079); unleaded petrol — olefins (0,3–25,0), aromatics (5,0–46,0) % (v/v) (AB 773); unleaded petrol and fuel for aviation turbine engines — aromatics (5,0–70,0), olefins (1,0–55,0) % (v/v) (AB 484 PP1); unleaded petrols, kerosene and fuel for aviation turbine engines — aromatics (5,0–80,0), olefins (0,3–15,0) % (v/v) (AB 474 and AB 484 Physicochemistry Laboratory); liquid fuels without a stated range (AB 098). Only three laboratories (AB 009, AB 079, AB 297) have saturates in their scope.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — the unit: the result is a volume fraction in percent (% (V/V); regulation, point 10.1), and the limits of the regulation on quality requirements are in this unit; a result given in another unit cannot be compared with them directly. Second — the measuring range depends on the laboratory: from (0,3–15,0) % olefins at AB 474 to (0,3–55,0) % at AB 297; a result outside the range in a given laboratory's accreditation scope is not an accredited result, even though the standard might cover it. Third — the saturates type: only three laboratories have it in their scope; the others have only aromatics and olefins. Fourth — two methods in the legislation: the regulation also allows PN-EN ISO 22854 (gas chromatography) for petrols; a result by adsorption and a result by chromatography are two different measurements of the same quantity — the report must state the method. Fifth — edition and exclusions: some laboratories refer to PN-EN 15553 without a year, some with amendment A1:2025-05, and AB 297 excludes point 7.1; what point 7.1 contains and what amendment A1 changed — WE DO NOT STATE. Sixth — the name of the technique: the scopes write “gel chromatography method (FIA)”, and the regulation — “fluorescent indicator adsorption” in a column with activated silica gel; when searching for a laboratory by technique, both names must be known. Seventh — the lower limit: AB 297 declares aromatics from 0,5 % (v/v), whereas according to the PKN card precision was determined from 5 % (V/V); below this value the standard applies, but without determined precision. Eighth — oxygenates: in petrol with ethanol or ethers (AB 297 — petrol with bioethanol) the result can be reported on an oxygenate-free basis of the base fuel or, when the oxygenate content is known, corrected to the total sample (PKN card) — two numbers for the same sample, so the report must say what the result refers to; methanol, ethanol, MTBE, TAME and ETBE are not detected, because they elute with the alcohol desorbent, and the effect of other oxygenates is checked separately. Ninth — unsuitable samples: narrow fractions boiling near 315 °C do not elute properly and give erratic results, and samples with dark-coloured components cannot be analysed (PKN card).

WHAT WE DO NOT STATE. We did not have the text of the standard — neither in full nor an excerpt: the preview of the text of EN 15553 could not be opened (the iTeh catalogue did not respond). We do not state the sample volume, column dimensions, composition of the indicator and desorbent, the way zone boundaries are read, calculation formulae, precision (repeatability and reproducibility), the content of point 7.1 excluded by AB 297, or the changes introduced by amendment A1:2024. We did not read ASTM D 1319, which four laboratories refer to together with PN-EN 15553, and we do not compare the two standards.

Method principle

The sample is introduced into an adsorption column packed with activated silica gel, in which the hydrocarbons separate into types according to their adsorption properties — saturates, olefins and aromatics; the dyes of the fluorescent indicator separate together with them and form zones whose boundaries are visible under ultraviolet light. The content of each type is calculated from the length of its zone in the column and expressed as a volume fraction in percent (Journal of Laws 2024 item 1058, annex, part I, points 10 and 10.1). The procedure, apparatus, reagents, calculation and precision are specified by PN-EN 15553 (ibid., point 10.2) — these details WE DO NOT STATE.

Applications

• Motor petrols — olefin and aromatic content for assessing compliance with quality requirements (Journal of Laws 2024 item 1018: at most 18,0 and 35,0 % (V/V)); method named in Journal of Laws 2024 item 1058, point 10.2
• In accreditation scopes also aviation gasoline, petrol with bioethanol, kerosene, fuel for aviation turbine engines, liquid biohydrocarbons and petroleum fractions with a final boiling point up to 315 °C
• In accreditation scopes: 7 Polish laboratories; four of them in the same item as ASTM D 1319
• Petroleum fractions distilling below 315 °C, products of the full boiling range; not for samples with dark-coloured components or for narrow fractions boiling near 315 °C (PKN card)

Key parameters

Standard

Standard number

PN-EN 15553+A1:2025-05 (English version; adopts EN 15553:2021+A1:2024 [IDT])

Title (PL)

Przetwory naftowe i materiały podobne — Oznaczanie zawartości grup węglowodorów — Metoda adsorpcyjna ze wskaźnikiem fluorescencyjnym

Title (EN)

Petroleum products and related materials — Determination of hydrocarbon types — Fluorescent indicator adsorption method

Step-by-step procedure

1. Sample and column

   Column packed with activated silica gel, sample with the fluorescent indicator added. Sample volume, method of application and elution — NOT STATED.

2. Separation

   The hydrocarbons separate into types according to their adsorption properties: saturates, olefins, aromatics; the dyes form zones with boundaries visible under ultraviolet light (point 10.1).

3. Reading and calculation

   The content of each type is calculated from the length of the zone in the column and expressed as a volume fraction in percent (point 10.1).

4. Result

   Result in % (V/V), stating the method (PN-EN 15553 or PN-EN ISO 22854 / ASTM D 1319) and the edition of the standard. PN-EN 15553+A1:2025-05 — without a withdrawal note (state of the PKN card on 06.11.2026; English version).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Petrols and aviation fuels — flammable liquids, harmful vapours; work under a fume hood, away from ignition sources
• Ultraviolet light when reading the zones — eye protection
• SUBSTANTIVE NOTE: a result by adsorption and a result by gas chromatography (PN-EN ISO 22854) are different measurements — the method is part of the result

Frequently asked questions