Petroleum Products Gasoline Diesel and Jet fuel and Analysis

Petroleum products, including gasoline, diesel, and jet fuel, have numerous specifications and test methods due to commercial, safety, environmental, quality, and processing considerations. This document provides an overview of the primary standard test methods for these fuels, as well as typical specification limitations and ranges. Please note that specifications can vary over time, between countries, and for different product classes, so the provided numbers are only examples of this variation.

Gasoline and diesel specifications can range from strict limits, typically found in markets with advanced emission control and fuel efficiency requirements, to weaker limits, often seen in markets with minimal or no emission control requirements. The stricter limits enable the use of advanced technologies that improve vehicle and engine efficiency, as well as sophisticated emissions control systems. The weaker limits focus on basic vehicle and engine performance and protection of emissions control systems.

For up-to-date and detailed versions of these test methods, please refer to ASTM and other vendors. Additionally, standard test methods for crude oil properties are also available.

Acidity, Total Acid Number (TAN)

-Measures the total amount of acid compounds present in petrochemical samples, expressed in mg of KOH per g of sample.

Total Acid Number TAN of Gasoline

- Acidic constituents in petroleum products and biodiesel can corrode metals, impair water separation, and indicate degradation. TAN is crucial for quality control, lubricant formulation, and monitoring degradation.

- How:

    - ASTM D3242: Titration with alcoholic potassium hydroxide, using a color indicator, to determine acidity in aviation turbine fuel.

    - ASTM D664: Potentiometric titration using a glass electrode and reference electrode to determine acid number in petroleum products.


The sample is dissolved in a mixture of toluene and isopropyl alcohol containing a small amount of water. The resulting single phase solution is blanketed by a stream of nitrogen bubbling through it and is titrated with standard alcoholic potassium hydroxide to the end point indicated by the color change (orange in acid and green in base) of the added p-naphtholbenzein solution.

Other Methods

- Alternative test methods: IP 354, ISO 6618, ASTM D974

Typical specifications

    - Jet Kerosine: 0.015-0.10 mg KOH/g (by D3242)

    - Diesel: 0.08 mg KOH/g (by D664)

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