SIST EN 238:1998

• Abstract:

  This European Standard specifies an infrared spectrometric method for the determination of benzene in petrol with a benzene content of 0,1 % V/V to 20 % V/V. The presence of cyclopentadiene in the sample will interfere with the benzene determination when it exceeds 5 % V/V. Contents of ethanol less than 10 % V/V and toluene less than 25 % V/V do not interfere with the benzene determination.

• Status: Published
• Publication Date: 30-Apr-1998
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: NAD - Petroleum products, lubricants and related products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-May-1998
• Due Date: 01-May-1998
• Completion Date: 01-May-1998
• Ref Project: EN 238:1996 - Liquid petroleum products - Petrol - Determination of the benzene content by infrared spectrometry

• Referred By: SIST EN 228:2012+A1:2017 - Automotive fuels - Unleaded petrol - Requirements and test methods
• Effective Date: 28-Jan-2026
• Amended By: SIST EN 238:1998/A1:2004 - Liquid petroleum products - Petrol - Determination of the benzene content by infrared spectrometry
• Effective Date: 22-Dec-2008

SIST EN 238:1998 is the Slovenian standard from SIST for determining benzene in petrol by infrared spectrometry. It specifies a laboratory test method for petrol with benzene content from 0,1 % V/V to 20 % V/V, so testing labs, fuel suppliers, and quality teams can measure benzene content in a consistent way.

What does SIST EN 238:1998 specify?

SIST EN 238:1998 specifies an infrared spectrometric method for benzene determination in petrol. The method is intended for petrol samples in the stated benzene range and gives users a way to quantify benzene from an infrared measurement rather than by a wet-chemical procedure.

The scope also sets practical limits for interferences. Cyclopentadiene affects the result when it is present above 5 % V/V, while ethanol below 10 % V/V and toluene below 25 % V/V do not interfere with the benzene determination. In practice, that tells the analyst which fuel blends can be tested directly and when the sample composition may distort the result.

What are the key requirements of SIST EN 238:1998?

The core requirement is to determine benzene in petrol by infrared spectrometry. That matters because the result depends on measuring the infrared response of the sample, so the laboratory needs suitable spectrometric equipment and a controlled measurement procedure.

The standard applies only to petrol and only within the specified benzene range, 0,1 % V/V to 20 % V/V. For the user, that means the method is aimed at routine fuel analysis rather than very low-level trace work or highly benzene-rich materials outside the stated range.

A key technical condition is the interference behaviour of other components in the sample. Cyclopentadiene becomes a problem above 5 % V/V, so a lab working with unusual or heavily cracked petrol streams needs to consider sample composition before reporting a result.

The scope also identifies two common fuel components that do not interfere within given limits:

• ethanol below 10 % V/V
• toluene below 25 % V/V

This is important in practice because petrol blends often contain oxygenates and aromatics. The stated limits help the analyst decide whether the method can be used directly on the blend or whether the sample needs additional attention.

The standard is a measurement method standard, so its value is in providing a repeatable way to obtain a benzene content result. For quality control, that supports incoming fuel checks, batch release testing, and compliance monitoring where benzene content has to be measured consistently.

The document is also specific about the analyte and matrix. It is not a general infrared method for hydrocarbons; it is focused on benzene in petrol. That focus matters because it ties the measurement setup and interpretation to one named compound in one named product.

What terms does SIST EN 238:1998 define?

Benzene is the analyte the standard measures in petrol; the reported result is the benzene content of the sample.

Petrol is the liquid petroleum product to which the method applies, so the procedure is meant for gasoline-type fuel samples.

Infrared spectrometry is the analytical technique used to measure the sample, using infrared absorption to determine the benzene content.

% V/V means percent by volume, the concentration expression used in the scope for both benzene content and interfering components.

Cyclopentadiene is a sample component that can interfere with the measurement when its level is above the stated limit.

Ethanol is a common petrol blend component that the scope says does not interfere below 10 % V/V.

Toluene is another common petrol component that does not interfere below 25 % V/V.

Who uses SIST EN 238:1998?

SIST EN 238:1998 is used by fuel-testing laboratories, refinery and terminal quality control teams, and suppliers of petrol who need a standard way to measure benzene content. It is also relevant for buyers and inspectors who specify or verify test methods for petrol quality.

In practice, these users apply the standard for routine laboratory analysis, product release checks, and verification of fuel composition. It is useful wherever benzene in petrol has to be measured with a recognized infrared spectrometric method.

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