Gasoline Analysis — EN 228 / ASTM D4814

What Is Gasoline?

Gasoline analysis is the measurement of the specification parameters defined in EN 228. Research and motor octane number, distillation curve, vapour pressure, sulfur content, benzene and aromatic content, oxygenate types, oxygen content, lead, manganese, gum formation and copper strip corrosion fall within this scope.

Purpose of Gasoline

The purpose is to verify that the gasoline burns properly in the engine, does not damage emission systems, and meets seasonal volatility requirements.

Which Products Is Gasoline Applied To?

Unleaded automotive gasoline
High-octane gasolines
Ethanol-blended gasolines (E5, E10)
Refinery intermediate products
Filling station and depot samples

In Which Sectors Is Gasoline Used?

Oil & GasPetrokimyaEnergyAutomotive

Standards Related to Gasoline

TS EN 228 (automotive fuels — unleaded petrol specification)
TS EN ISO 5164 / EN ISO 5163 (research and motor octane number)
TS EN ISO 3405 (distillation at atmospheric pressure)
TS EN 13016-1 (vapour pressure)
TS EN ISO 20846 / EN ISO 20884 (sulfur content)
TS EN 12177 / EN 238 (benzene content)
TS EN 13132 / EN 1601 (oxygenates)

Gasoline Conditions

seasonal class: Vapor pressure and volatility class are different for summer and winter
Specimen temperature: The sample is kept cold to prevent loss of volatile components
Octane measurement: In CFR engine, under standard defined conditions

Equipment for Gasoline

CFR octane engine
Automatic distillation apparatus
Vapour pressure measurement apparatus
UV fluorescence or WD-XRF sulfur analyser
GC (oxygenate and benzene analysis)
Copper strip corrosion bath

Sample Requirements for Gasoline

Sampling determines the validity of the result in fuel analysis: ISO 3170 (manual) and ISO 3171 (automatic in-line) define the sampling rules. The sample must be taken into a clean container of a suitable material, filled with no air gap, and kept cold for volatile products.
The sample must be filled with no air gap
The sample must be transported chilled for volatility analyses
The sampling point and date must be recorded
The seasonal class must be stated

Duration of Gasoline

The full specification package takes a few working days due to octane measurements and chromatographic analyses. Individual parameters are completed faster.

Gasoline Procedure

1The sample is taken per the standard and delivered in the cold chain.
2Appearance and density are checked.
3The distillation curve and vapour pressure are determined.
4Octane numbers are measured in the CFR engine.
5Sulfur, benzene, aromatic and oxygenate analyses are performed.
6Results are compared against the EN 228 limits.

Gasoline Acceptance Criteria

The acceptance criterion comes from the relevant product specification and varies by season, market and class. Specification versions are updated; the limit values in force for your product are confirmed from the specification text at the quotation stage.

Evaluation of Results

Volatility parameters are assessed against the seasonal class: winter gasoline may appear non-conforming against the summer specification, and vice versa. Ethanol content affects both the oxygen limit and vapour pressure; re-measurement is needed after blending.

Gasoline Report

Specimen identification, sampling point and date
Applied specification and its version
Method, result and limit of quantification for each parameter
Seasonal class information
Comparison against specification limits

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

98/70/EC Fuel Quality Directive
(EU) 2018/2001 Renewable Energy Directive (blending)

Petroleum, Fuel and Oil Analysis — What Does This Testing Field Cover?

The section below describes the field that the Gasoline test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Petroleum, fuel and oil analysis determines whether a fluid meets its specification and how it behaves in use. Standards in this field consist largely of ASTM and EN publications, with a separate method defined for each parameter.

What distinguishes this family is that product specifications are written as PARAMETER LISTS. Specifications such as EN 590 (diesel), EN 228 (petrol), EN 14214 (biodiesel) and ISO 8217 (marine fuels) state for each parameter both the limit and the method by which that limit is to be measured. If the method changes the result may change too; the specification therefore binds the method as well, and the use of an "equivalent method" is possible only where the specification allows it.

On the fuel side, parameters describe three different properties of the product. Physical properties (density, viscosity, distillation curve, pour point, cloud point) determine pumpability and cold weather behaviour. Combustion properties (cetane number, octane number, calorific value) indicate performance in the engine. Contaminant and stability parameters (sulphur, water, sediment, oxidation stability, copper strip corrosion) affect both emissions and storage life.

Oil analysis is carried out for two different purposes and the two must not be confused. Analysis of NEW oil verifies the conformity of the product to its specification: viscosity index, additive content, flash point. Analysis of USED oil, by contrast, is done to read the condition of the machine — elemental analysis shows wear metals (iron, copper, chromium, aluminium), water and fuel contamination point to leaks, and oxidation and acid number determine the remaining life of the oil.

Used oil analysis is therefore a PREDICTIVE MAINTENANCE tool. The trend of samples taken at regular intervals is followed; it is the trend rather than a single result that is meaningful. Iron levels climbing over the course of months allow intervention before a failure occurs.

Marine fuels are the most active sub-body of the field. The global tightening of sulphur limits has brought new blended fuels onto the market; for these fuels stability, compatibility (whether two fuels form deposits when mixed) and catalytic fines content have become critical parameters.

Sampling is part of the result in this family too. A sample taken from the bottom of a tank shows different water and sediment content from one taken from the upper level; in commercial deliveries the sampling point and method are set by contract.

Method groups in this field

Physical properties
Density (oscillating U-tube and hydrometer), kinematic viscosity, distillation, pour and cloud point, flash point.
Combustion properties
Cetane number and cetane index, research and motor octane number, calorific value.
Sulphur and elements
Sulphur by UV fluorescence and XRF; elemental analysis and additive content by ICP.
Stability and corrosion
Oxidation stability, copper strip corrosion, water and sediment, filter blocking tendency.
Composition analysis
Boiling range distribution by gas chromatography, hydrocarbon types (FIA), benzene and aromatics content, fatty acid methyl ester content.
Used oil
Wear metals, contamination (water, fuel, soot), oxidation, acid and base number, change in viscosity.

Commonly confused in this field

The specification binds the method as well; a result measured by a different method may not be accepted for specification conformity.
A single result on used oil is not meaningful; the decision is made on the trend.
The sampling point determines the result; the tank bottom and the upper level show different water and sediment.
The cetane index is a calculated value and is not the same thing as a measured cetane number.
Fuels blended with biodiesel behave differently in terms of storage life and microbial growth; classical diesel parameters are not sufficient.
Mixing marine fuels from different sources can cause deposits; compatibility is assessed separately.

Which decisions these results support

Conformity of a fuel lot to specification and commercial delivery
Predictive maintenance decisions based on used oil analysis
Determining parameters for customs and tax classification
Quality verification after storage, blending and transport
Compliance with sulphur limits under emissions legislation

Related Tests

Frequently Asked Questions About Gasoline

The octane number came out low — could the fuel have degraded?

Volatile light components in gasoline are lost over time, affecting both octane and vapour pressure. However, low octane is mostly due to blending or mixing; the cause becomes visible when the distillation curve is assessed together with it.

Does E10 gasoline cause problems in older vehicles?

Ethanol content can be incompatible with some older fuel system materials. This is a compatibility question, not an analysis question; the vehicle manufacturer's declaration is consulted. The analysis only verifies ethanol content.