⛽ FAME content in diesel fuel

Petrochemistry PN-EN 14078

Overview

STATUS (as of 30.10.2026). PN-EN 14078:2014-06 — Polish version, published 12.10.2015, implements EN 14078:2014 [IDT]; it replaced PN-EN 14078:2011. The standard was WITHDRAWN on 25.05.2026 — replaced by PN-EN 14078:2026-05 (English version, published 25.05.2026), which implements EN 14078:2025 [IDT]. Of the 2025 edition only the first pages are publicly available (foreword, contents, scope and normative references — in the preview of the Slovak STN EN 14078:2026). According to the foreword, EN 14078:2025 introduces three significant technical changes: a correction of the result when the average molecular mass of the FAME in the sample differs from that of the FAME used for calibration (9.3, example in informative Annex B), cells with ZnSe windows permitted, and volumetric instead of gravimetric dilution in the sample preparation (8.5). The scope (clause 1) covers the same ranges A, B and C as the 2014 edition; it adds that the measurement uses a transmission sample cell. The rest of the description is based on the text of EN 14078:2014 and uses the clause numbering of that edition (in the 2025 edition the procedure is in clause 8).

SCOPE (clause 1). Determination of FAME in diesel fuel or domestic heating fuel by mid-infrared spectrometry, in three ranges: A — from about 0.05 % to about 3 % (V/V), B — from about 3 % to about 20 % (V/V), C — from about 20 % to about 50 % (V/V). Higher contents can be analysed after dilution, but without precision data. The method was verified for FAME conforming to EN 14214; reliable quantitative results are obtained only if the sample does not contain significant amounts of other esters and carbonyl compounds absorbing in the region used — in their presence the result is too high. To convert g/l to % (V/V), a fixed FAME density of 883.0 kg/m³ (at 15 °C) is adopted.

PRINCIPLE (clause 3, 7.1–7.4). The mid-infrared spectrum of a test portion of the sample is recorded — diluted if necessary with FAME-free middle distillate — and the absorbance at the peak maximum of the ester band at about (1745 ± 5) cm⁻¹ is measured. Calibration and calculations are carried out in grams of FAME per litre. In range A the measurement is preferably made without dilution, in a cell with a long path length (about 0.5 mm, not less than about 0.2 mm); in range B — a cell of about 0.1 mm and a dilution of 1 : 5; in range C — about 0.05 mm with a dilution of 1 : 5 or about 0.1 mm with a dilution of 1 : 10. Each cell is calibrated separately, and calibration and measurement are carried out in the same cell with an exactly determined path length.

LEGAL REQUIREMENTS. Diesel fuel: FAME content at most 7.0 % (V/V) (Journal of Laws 2024, item 1018, Annex 3 item 13).

WHAT WE DO NOT GIVE HERE. The publicly available text of the 2014 edition ends with the calculation of the calibration function (7.4.3). We do not give the sample preparation (7.5), recording of spectra (7.6), calculation formulae (clause 8), expression of results (clause 9), precision (clause 10) or Table A.1 with the calibration and dilution settings. Nor do we give the correction procedure of 9.3 or the example in Annex B of the 2025 edition — these parts are not in the preview; the 2025 edition also cites EN 14103:2020 (determination of ester and linolenic acid methyl ester contents of FAME) and EN 14331 (separation and characterisation of FAME from middle distillates by LC/GC) as normative references.

Method principle

The mid-infrared spectrum of a test portion of the sample — diluted if necessary with FAME-free middle distillate — is recorded in a cell of known path length, and the absorbance at the peak maximum of the ester band at about (1745 ± 5) cm⁻¹ is measured. The FAME content is calculated from a linear calibration function determined with solutions of known FAME content (in g/l), and the result is converted to % (V/V) using a fixed FAME density of 883.0 kg/m³ (clause 3, 7.4).

Applications

• Diesel fuel — FAME content at most 7.0 % (V/V) (Journal of Laws 2024, item 1018, Annex 3 item 13)
• Domestic heating fuel — range A, B or C depending on the FAME content (clause 1)
• Blends of diesel fuel with FAME up to about 50 % (V/V) — range C (clause 1)

Key parameters

Standard

Standard number

PN-EN 14078:2014-06

Title (PL)

Ciekłe przetwory naftowe — Oznaczanie zawartości estrów metylowych kwasów tłuszczowych (FAME) w średnich destylatach — Metoda spektrometrii w podczerwieni

Title (EN)

Liquid petroleum products — Determination of fatty acid methyl ester (FAME) content in middle distillates — Infrared spectrometry method

Step-by-step procedure

1. Sampling and storage

   According to EN ISO 3170 or EN ISO 3171 and national regulations; samples not tested immediately are stored tightly sealed in a cool, dark place (clause 6).

2. Choice of cell and range

   The path length is chosen so that the net signal has at least two decimal places and lies within the linear range of the detector: A — a cell as long as possible, preferably without dilution; B — shorter path length and dilution; C — shorter path length and higher dilution (7.1, 7.3).

3. Calibration

   For the chosen range at least five calibration solutions (preferably more) are prepared, each separately by weighing FAME into a volumetric flask and filling up with FAME-free middle distillate, and the FAME-free distillate itself serves as the “zero” sample; the solutions are not prepared by dilution. The calibration function is obtained by linear regression of the corrected absorbance against the FAME content in g/l — separately for each cell (7.1, 7.4).

4. Cleaning the cell

   After every measurement the cell is carefully cleaned with a solvent or rinsed repeatedly with FAME-free distillate; in persistent cases — twice with 5 ml of n-pentane, once with 5 ml of absolute ethanol, once with 5 ml of n-pentane and dried. If in doubt, a spectrum of a FAME-free sample is recorded — it must show no signals near 1745 cm⁻¹ (7.2).

5. Measurement and result

   The sample spectrum is recorded under the same conditions as the calibration, the FAME content is calculated from the calibration function in g/l and converted to % (V/V) at a density of 883.0 kg/m³. Details of the sample preparation, recording of spectra and calculations are in parts of the standard outside the publicly available text (clause 3, 7.5–8.2). In the 2025 edition the dilution in the sample preparation is volumetric, not gravimetric (8.5), and the result is corrected when the FAME in the sample has a different average molecular mass from the calibration FAME (9.3).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The standard warns that its use may involve hazardous materials, operations and equipment, and that the user establishes the safety and health practices (warning in clause 1)
• n-Pentane, ethanol and cyclohexane are flammable — according to their safety data sheets
• KBr and NaCl cells are sensitive to water — their path length is checked more frequently (7.1)

Frequently asked questions