⛽ Benzene content in gasoline
In short
Determination of the benzene content of unleaded petrol with a final boiling point not greater than 220 °C by column-switching gas chromatography with an internal standard. The test is performed according to PN-EN 12177:2023-04; Range: 0.05 % (V/V) to 6 % (V/V) benzene. The procedure comprises 7 steps; it is used for: Checking the compliance of motor petrol with the requirement of at most 1.00 % (V/V) benzene (Journal of Laws 2024 item 1018), Unleaded petrol with a final boiling point up to 220 °C, including petrol with oxygenates (2022 edition: up to E10), One of the three methods for benzene listed in the regulation on test methods for liquid fuels.
At a glance
- Standard: PN-EN 12177:2023-04
- Category: Petrochemistry
- Procedure steps: 7
- Range: 0.05 % (V/V) to 6 % (V/V) benzene
- Samples: unleaded petrol with a final boiling point not greater than 220 °C, including petrol with oxygenates (2022 edition: up to E10, up to 3.7 % (m/m) oxygen)
- Technique: gas chromatography with switching of two capillary columns of different polarity, two flame ionization detectors (FID)
Overview
STATUS (as of 06.11.2026). According to the PKN catalogue card (read on 06.11.2026) the current standard is PN-EN 12177:2023-04 — a Polish version published on 22.02.2024 (18 pages; an English version is also in the catalogue), implementing EN 12177:2022 [IDT] and replacing PN-EN 12177:2003 (Polish version); there was also PN-EN 12177:2002 (English version). EN 12177:2022 (approved by CEN on 16.10.2022) superseded EN 12177:1998; according to the foreword, the revision extended the scope from petrol containing up to 5 % (V/V) ethanol to petrol containing up to 10 % (V/V) ethanol, i.e. up to 3.7 % (m/m) oxygen. The designation "PN-EN 12177:2010", given in this description until now, does not exist in the PKN catalogue. Of the 2022 edition we had the preview of the Slovak STN EN 12177:2023 (foreword, contents, scope, references); the procedure is described according to the text of EN 12177:1998 (preview of SIST EN 12177:1999, Clauses 1–8.1), and clause numbers are given according to that edition — in the 2022 edition they are shifted by one (e.g. the calculation is Clause 9).
SCOPE. The standard specifies a column-switching gas chromatographic method for the quantitative determination of benzene in the range 0.05 % (V/V) to 6 % (V/V) in unleaded petrol having a final boiling point not greater than 220 °C, including petrol with oxygenates (2022 edition: up to E10, i.e. up to 3.7 % (m/m) oxygen). According to a note to the principle, some oxygenates are known to interfere with the determination of benzene by a single-column method — hence two columns of different polarity.
REGULATIONS. The Regulation of the Minister of Climate and Environment of 26 June 2024 on quality requirements for liquid fuels (Journal of Laws 2024 item 1018) allows at most 1.00 % (V/V) of benzene in motor petrol (Annexes 1 and 2, item 12). The regulation on test methods for liquid fuels (Journal of Laws 2024 item 1058, Annex Part I point 11) lists three methods for benzene: infrared spectrometry (standard implementing EN 238), gas chromatography with isolation of the benzene fraction on a first capillary column and separation of benzene on a second one with a flame ionization detector (PN-EN 12177), and multidimensional gas chromatography with column switching (PN-EN ISO 22854).
WHAT WE DO NOT GIVE HERE. The standard does not give stationary phases, column dimensions, temperatures or flows — the columns only have to be of different polarity and give a resolution of at least 1, and the conditions are set according to the manufacturer's instructions; guidance on column switching is in informative Annex A. We did not have the clauses on the calculation of the volume, expression of results and precision. We have removed figures and names without a source: chromatograph settings, gas flows, temperature programme, concentrations of standard solutions, fluorobenzene as internal standard and isooctane as solvent, step times, brands and prices of apparatus, and names of institutions and companies.
Method principle
The fraction containing benzene is isolated from the sample on a first capillary column, and on a second capillary column (of different polarity) benzene is separated and detected with a flame ionization detector. Benzene is quantified by the internal standard method: a weighed internal standard (isobutyl methyl ketone is preferred) is added to the weighed sample, and the calibration factor is determined from a calibration sample with known masses of benzene and internal standard. The mass of benzene in the sample is calculated from the calibration factor, the peak areas and the mass of the internal standard, and then — according to the calculation clauses of the standard — the volume of benzene, the volume of the sample (from the density at 15 °C) and the benzene content in percent by volume.
Applications
- Checking the compliance of motor petrol with the requirement of at most 1.00 % (V/V) benzene (Journal of Laws 2024 item 1018)
- Unleaded petrol with a final boiling point up to 220 °C, including petrol with oxygenates (2022 edition: up to E10)
- One of the three methods for benzene listed in the regulation on test methods for liquid fuels
Key parameters
| Parameter | Value |
|---|---|
| Range | 0.05 % (V/V) to 6 % (V/V) benzene |
| Samples | unleaded petrol with a final boiling point not greater than 220 °C, including petrol with oxygenates (2022 edition: up to E10, up to 3.7 % (m/m) oxygen) |
| Technique | gas chromatography with switching of two capillary columns of different polarity, two flame ionization detectors (FID) |
| Resolution | benzene peak from the matrix after elution from the second column — at least 1 (R = 1.18 (t′B − t′A)/(wA + wB)) |
| Internal standard | a substance not present in the sample, isobutyl methyl ketone preferred; 2–5 % (m/m) of the sample, not less than 0.050 g |
| Density for conversions | at 15 °C according to EN ISO 3675, EN ISO 3838 or EN ISO 12185, to the nearest 0.1 kg/m³ |
| Requirement for petrol (Journal of Laws 2024 item 1018) | at most 1.00 % (V/V) benzene |
Standard
- Standard number
- PN-EN 12177:2023-04
- Title (PL)
- Ciekłe przetwory naftowe — Benzyna bezołowiowa — Oznaczanie zawartości benzenu metodą chromatografii gazowej
- Title (EN)
- Liquid petroleum products — Unleaded petrol — Determination of benzene content by gas chromatography
Step-by-step procedure
-
Sampling
Take the sample according to ISO 3170 or ISO 3171 or national requirements for sampling petrol (Clause 6).
-
Setting up the apparatus
Prepare the apparatus and set the conditions according to the manufacturer's instructions; adjust the carrier gas pressure and flow so that the resolution meets the requirement of 5.1.2 (Clause 7.1).
-
Calibration
Prepare a calibration sample from known masses of benzene and internal standard in a suitable solvent, inject a quantity that does not exceed the capacity of the columns or the linearity of the detector, record the retention times and calculate the calibration factor f = (m₁ × A₂) / (A₁ × m₂), where m₁, m₂ are the masses of benzene and internal standard and A₁, A₂ their peak areas (Clause 7.2).
-
Density
Determine the density of the sample at 15 °C according to EN ISO 3675, EN ISO 3838 or EN ISO 12185 to the nearest 0.1 kg/m³ (Clause 7.3).
-
Preparation of the test sample
Cool the sample to 5–10 °C. Weigh the container with septum (0.1 mg), add the internal standard (2–5 % (m/m) of the sample, at least 0.050 g) and weigh, then add normally 5–100 ml of the cooled sample, seal immediately with the septum, weigh and mix by shaking (Clause 7.4).
-
Analysis
Inject a suitable quantity of the prepared sample (without exceeding the column capacity or detector linearity) and identify benzene and the internal standard by their retention times (Clauses 7.5–7.6).
-
Calculation
Calculate the mass of benzene m₃ using the formula of 8.1 (calibration factor f, benzene peak area A₃ and internal standard data), then the volume of benzene, the volume of the sample and the benzene content in % (V/V) according to the further calculation clauses of the standard (details are not given here).
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Gas chromatograph with column switching | Programmable oven temperature controller (or controllers for a dual-oven chromatograph) and two flame ionization detectors; a system made entirely of glass from the injection port to the detectors is recommended, since oxygenates in petrol can cause corrosion and changes of retention times in partly metal systems | — |
| Two capillary columns | Of appropriate dimensions, coated with phases of different polarity; resolution of benzene from the matrix after the second column at least 1 | — |
| Carrier gas flow control, recorder or integrator, injection device | Integrator or data processing system giving peak areas | — |
| Test sample container | Normally 10–100 ml, with a self-sealing rubber septum coated with PTFE | — |
| Balance | Weighing to the nearest 0.1 mg | — |
| Density measuring instrument | Hydrometer (EN ISO 3675), pyknometer (EN ISO 3838) or oscillating U-tube density meter (EN ISO 12185) | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Carrier gas | — | Hydrogen, helium or nitrogen, free of hydrocarbons |
| Benzene | 71-43-2 | Purity not less than 99.0 % (m/m) — for calibration samples |
| Solvent | 142-82-5 | Containing no benzene or internal standard, e.g. heptane |
| Internal standard | 108-10-1 | A reagent established not to be present in the sample; isobutyl methyl ketone (4-methylpentan-2-one) is preferred |
Health and safety (OHS)
- The standard warns that its use may involve hazardous materials, operations and equipment, and establishing safety practices is the responsibility of the user
- Hydrogen as carrier gas forms explosive mixtures with air at concentrations from about 4 % to 75 % (V/V) — joints and lines carrying hydrogen must be gas-tight (warning in the standard)
- Benzene (harmonised CLP classification): highly flammable (H225), may be fatal if swallowed and enters airways (H304), causes skin and serious eye irritation (H315, H319), may cause genetic defects (H340), may cause cancer (H350), causes damage to organs through prolonged or repeated exposure (H372)
- Heptane (CLP): highly flammable (H225), H304, H315, H336, H400, H410
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-EN 12177:2023-04 — “Liquid petroleum products — Unleaded petrol — Determination of benzene content by gas chromatography”.
How does this method work?
The fraction containing benzene is isolated from the sample on a first capillary column, and on a second capillary column (of different polarity) benzene is separated and detected with a flame ionization detector. Benzene is quantified by the internal standard method: a weighed internal standard (isobutyl methyl ketone is preferred) is added to the weighed sample, and the calibration factor is determined from a calibration sample with known masses of benzene and internal standard.
What is the measuring range and accuracy?
Range: 0.05 % (V/V) to 6 % (V/V) benzene; Samples: unleaded petrol with a final boiling point not greater than 220 °C, including petrol with oxygenates (2022 edition: up to E10, up to 3.7 % (m/m) oxygen); Technique: gas chromatography with switching of two capillary columns of different polarity, two flame ionization detectors (FID); Resolution: benzene peak from the matrix after elution from the second column — at least 1 (R = 1.18 (t′B − t′A)/(wA + wB)).
How long does the test take?
The procedure comprises 7 steps. The standard does not give a duration for every stage — the laboratory's own procedure decides.
What equipment is required?
Gas chromatograph with column switching, Two capillary columns, Carrier gas flow control, recorder or integrator, injection device, Test sample container, Balance, Density measuring instrument.
Where is this test used?
Checking the compliance of motor petrol with the requirement of at most 1.00 % (V/V) benzene (Journal of Laws 2024 item 1018); Unleaded petrol with a final boiling point up to 220 °C, including petrol with oxygenates (2022 edition: up to E10); One of the three methods for benzene listed in the regulation on test methods for liquid fuels.
What safety precautions apply?
The standard warns that its use may involve hazardous materials, operations and equipment, and establishing safety practices is the responsibility of the user; Hydrogen as carrier gas forms explosive mixtures with air at concentrations from about 4 % to 75 % (V/V) — joints and lines carrying hydrogen must be gas-tight (warning in the standard); Benzene (harmonised CLP classification): highly flammable (H225), may be fatal if swallowed and enters airways (H304), causes skin and serious eye irritation (H315, H319), may cause genetic defects (H340), may cause cancer (H350), causes damage to organs through prolonged or repeated exposure (H372); Heptane (CLP): highly flammable (H225), H304, H315, H336, H400, H410.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-EN 12177.