Standards Development

Scope

This document specifies a wavelength-dispersive X-ray fluorescence (WDXRF) test method for the determination of the sulfur content of liquid, homogeneous automotive fuels from 5 mg/kg to 500 mg/kg, which have a maximum oxygen content of 3,7 % (m/m).

This product range covers:

— diesel fuels containing up to about 30 % (V/V) fatty acid methyl esters (FAME),

— motor gasolines containing up to about 10 % (V/V) ethanol,

— synthetic fuels such as hydrotreated vegetable oil (HVO) and gas to liquid (GTL) having sulfur contents in the range of 5 mg/kg to 45 mg/kg.

Products with higher oxygen content show significant matrix effects, e.g. pure FAME used as biodiesel, nevertheless, pure FAME can be analysed when the corresponding procedures are followed (see 5.3 and 8.1).

Other products can be analysed with this test method, though precision data for products other than those mentioned have not been established for this document.

Sulfur contents higher than 500 mg/kg can be determined after sample dilution, however, the precision was not established for diluted samples.

Purpose

This revision has the intention of adding Palladium as a new anode material in ISO 20884, Sulfur determination by WD-XRF

The aim of this preliminary work item (PWI) is to design an interlaboratory study (ILS) to validate the expectation that a wavelength dispersive X-ray fluorescence (WDXRF) spectrometer with a palladium (Pd) anode can meet the performance criteria of ISO 20884:2019 (determination of sulfur content of automotive fuels, WDXRF). Currently, Pd is not included in the list of anode materials and its inclusion has been requested by laboratories using such a spectrometer.

Within the PWI (2 years), phase one will be defining the parameters for a statistically sound ILS (e.g., sample matrix, number of laboratories). In phase two, the test samples will be prepared and participating laboratories organized. The goal is to subsequently promote the PWI to a work item (WI) to carry out the actual ILS.