ERM® announces new low Sulfur European Reference Materials for Petrol
Every car driver will be aware of the environmental pollution caused by sulfur in fuel, so the implementation of EC Directive 2003/17/EC will come as good news. It requires that petrol (gasoline) with a total sulfur content below 10 mg per kg must be available on forecourts in all EU Member States by 2009. It will be the responsibility of the oil industry to ensure that these new standards are met, and this represents a challenge for analytical chemists in the oil industry and in consumer protection laboratories.
To assist laboratories, the three producers involved in the European Reference Materials (ERM®) collaboration now in its third year - Germany's Bundesanstalt für Materialforschung und -prüfung, the UK's LGC and the European Commission's Joint Research Centre, Institute for Reference Materials and Measurements - have jointly developed and characterised three new certified reference materials (CRMs) which will allow the analysis of the sulfur content in commercially available petrol with a greater certainty than is currently possible.
The reference materials have sulfur present naturally rather than as a spike, so they are as similar as possible to the samples being tested. Two of the materials are made from commercial petrol, while the third is prepared by blending commercial petrols containing different levels of sulfur to give the required concentration.
ERM producers use the most advanced principles currently available, described in ISO Guides 34 and 35 for the production of certified reference materials. The three reference materials, with sulfur nominally at 10, 20 and 50 mg per kg, were characterised independently by all three of the ERM producers using different variants of isotope-dilution mass spectrometry. The producers' technical expertise in these methods was demonstrated by their successful participation in an international interlaboratory comparison study. The results from the three institutes were combined to give the certified values for each material and uncertainties were determined which include contributions for characterisation, stability and between ampoule heterogeneity.