⛽ Determination of water content in ethanol as a blending component for petrol by Karl Fischer coulometric titration — a weighed test portion of 1–2 ml is injected with a syringe below the anolyte surface in the titrator vessel, where iodine is generated coulometrically at the anode; the amount of water follows from the charge (Faraday’s law); range (0,039–0,500) % (m/m), result to 0,001 % (m/m), PN-EN 15489

Petrochemistry PN-EN 15489

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of SIST EN 15489:2007 (text of EN 15489:2007, English): from the title page through the contents, foreword and Clauses 1–12 up to and including 13.3 (reproducibility). Outside the sample remain Table 1 (typical precision values), Clause 14 (test report) and the bibliography.

ACCORDING TO THE TEXT OF EN 15489:2007 (foreword, Clauses 1–13). The standard was prepared by CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin” (secretariat NEN), specifically by its Ethanol Task Force, on the basis of the Energy Institute standard IP 539; CEN approved it on 30.06.2007. Scope (1): direct determination of water in ethanol for blending with petrol, at water contents from 0,039 % (m/m) to 0,500 % (m/m). References (2): EN ISO 3170 (manual sampling), EN ISO 3696 (laboratory water). Term (3.1): water content determined by the coulometric Karl Fischer procedure of this standard. Principle (4): a weighed test portion is injected into the vessel of a coulometric Karl Fischer titrator in which iodine for the reaction is generated coulometrically at the anode; after all the water has been titrated, excess iodine is detected by an electrometric end-point detector; one mole of iodine reacts with one mole of water, so the amount of water is proportional to the total charge (Faraday’s law). Reagents (5): grade 3 water according to EN ISO 3696; water-free xylene (approximately 100 g of activated molecular sieve in approximately 2 l of xylene, overnight); pyridine-free Karl Fischer reagent — anolyte and catholyte, or a single reagent for cells with or without a diaphragm; molecular sieve activated at 200–250 °C for 4 h, cooled in a gas-tight bottle or desiccator. Apparatus (6): automatic coulometric Karl Fischer titrator meeting the requirements of Clause 9; glass syringes with needles reaching below the anolyte surface through the septum (according to the note bore 0,5–0,8 mm; a 10 µl syringe with fixed needle for checking the titrator and 1 ml or 2 ml for the ethanol); balance weighing to 0,1 mg. Samples (7): according to EN ISO 3170, minimising uptake of atmospheric moisture (e.g. a glass bottle with a septum). Preparation (8): according to the manufacturer’s instructions; seal the cell connections; with two electrolytes, anolyte in the outer compartment, catholyte in the inner one 2–3 mm below the anolyte level; titrate residual moisture to a constant background current below the maximum recommended by the manufacturer; clean a contaminated vessel with xylene, do not use acetone or other ketones. Verification (9): reagent performance deteriorates with use — check by injecting 10 µl of water initially with fresh reagent and then after every 10 injections; electrolytes are replaced when the result for 10 µl of water is outside 10 000 µg ± 200 µg or persistently high, the background current is unstable, phase separation or electrode coating occurs, the total sample volume exceeds one third of the anolyte volume, or the titrator indicates it. Procedure (10): with a clean, dry syringe withdraw at least three portions and discard them, immediately withdraw a 1–2 ml test portion, wipe the needle and weigh the syringe with contents to the nearest 0,1 mg; insert the needle through the septum, start the titration and, with the needle tip just below the liquid surface, inject the entire portion; wipe the needle and reweigh the syringe; after the end-point read the mass of water from the display. Calculation (11): Cs = m2 / (m1 × 10⁴), where m1 — mass of the test portion in g, m2 — mass of water from the titrator in µg; result in % (m/m). Result (12): to the nearest 0,001 % (m/m). Precision (13): from interlaboratory tests according to EN ISO 4259 on European ethanols from biological raw materials (among them raw wine, molasses, pulp, corn); repeatability r = 0,011 16 (X + 1), reproducibility R = 0,018 80 (X + 1), where X — the average of the results compared.

STATUS (as of 03.10.2026). The PKN search (term “PN-EN 15489”, 03.10.2026) shows PN-EN 15489:2009 (Polish version, “Introduces: EN 15489:2007 [IDT]”) without a withdrawal note and the withdrawn PN-EN 15489:2007 (English version, replaced by PN-EN 15489:2009); the other three items are ISO 15489 standards on records management. In the iTeh catalogue (read on 03.10.2026) EN 15489:2007 has the status “Published” and stage 90.93 “Decision to confirm — Review Enquiry” (23.03.2012), with a reference to Directive 98/70/EC and mandate M/344. Water by the coulometric method in petroleum products is described in a separate entry on PN-EN ISO 12937.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 03.10.2026). The number 15489 appears in 7 records at 5 laboratories: AB 009, AB 098, AB 103, AB 387 (3 records), AB 484. In the current PCA documents (read on 03.10.2026, issues from 18.02.2026 to 30.07.2026) the number appears in 7 rows of the same laboratories (AB 387 — 3, the others 1 each). The form “PN-EN 15489” without year (AB 009, AB 098 — alongside PN-EN ISO 12937 excluding points 6.2.4–6.2.8, AB 387), “PN-EN 15489:2009” (AB 484) and “PN-EN 15489:2009” after PN-A-79521:1999 (AB 103). None of these items is suspended (AB 009, AB 103 and AB 484 have suspensions in other parts of their scopes). The “Laboratories” tab (“PN-EN 15489”) shows 4 laboratories: AB 009, AB 098, AB 387, AB 484; AB 103 is under the term “PN-A-79521” — checked with tab queries on the production server labcoda.pl on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). Liquid biofuels: bioethanol and ethanol fuel E85 (AB 009, flexible scope “E”), bioethanol (AB 484), absolute ethanol and bioethanol (AB 103), liquid fuels in the flexible scope “E” (AB 098, AB 387 — in three places of the scope). Characteristic: water content by coulometric titration. Ranges: (0,039–0,500) % (m/m) (AB 009, AB 103), (0,073–0,500) % (m/m) (AB 484); AB 098 and AB 387 give no range. Ethanol fuel E85 is not in the scope of the standard (Clause 1 speaks of ethanol for blending with petrol).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. With atmospheric moisture: a sealed cell and samples (7.2, 8.2), rinsing the syringe three times with the sample (10.1). With the portion mass: weighing the syringe before and after injection to the nearest 0,1 mg (10.1, 10.2). With the reagent: a 10 µl water check at the start and every 10 injections, limit 10 000 µg ± 200 µg; electrolyte replacement when samples exceed one third of the anolyte volume (9). With cleaning: xylene, never acetone or other ketones (8.6). With the background current: start only at a constant and low background current (8.5). With the range: (0,039–0,500) % (m/m) (1).

WHAT WE DO NOT GIVE. We did not read the table of typical precision values (Table 1) or the content of the test report. Nor do we give requirements for the water content of ethanol from product standards.

Method principle

A weighed portion of ethanol (1–2 ml) is injected into the vessel of a coulometric Karl Fischer titrator, in which iodine is generated electrolytically at the anode and reacts with water in a 1 : 1 ratio; excess iodine after all the water has been titrated is detected by an electrometric detector. The mass of water from the charge (Faraday’s law) is related to the mass of the portion: Cs = m2 / (m1 × 10⁴) in % (m/m).

Applications

• Ethanol as a blending component for petrol — water content (0,039–0,500) % (m/m) (1)
• Bioethanol and absolute ethanol as liquid biofuels — items in the accreditation scopes of 5 laboratories in PCA

Key parameters

Standard

Standard number

PN-EN 15489:2009

Title (PL)

Etanol jako komponent benzyny silnikowej — Oznaczanie zawartości wody — Miareczkowanie kulometryczne metodą Karla Fischera

Title (EN)

Ethanol as a blending component for petrol — Determination of water content — Karl Fischer coulometric titration method

Step-by-step procedure

1. Cell preparation

   Seal the connections, add the electrolytes, titrate residual moisture to a constant background current. PN-EN 15489:2009 without a withdrawal note (03.10.2026).

2. Check

   Inject 10 µl of water — result 10 000 µg ± 200 µg; repeat every 10 injections.

3. Test portion

   Rinse the syringe with three portions of the sample, withdraw 1–2 ml, weigh to the nearest 0,1 mg.

4. Titration

   Inject the entire portion below the anolyte surface, reweigh the syringe, read the mass of water.

5. Result

   Cs = m2 / (m1 × 10⁴), to the nearest 0,001 % (m/m).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Ethanol and xylene — flammable liquids; Karl Fischer reagent — according to the manufacturer’s safety data sheet
• The standard does not address all hazards — the user establishes safety practices (1, warning)

Frequently asked questions