ISO/TC 28/WG 24 - Elemental analysis

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. NOTE 1 Sulfur contents higher than 500 mg/kg can be determined after sample dilution, however, the precision was not established for diluted samples. NOTE 2 For the purposes of this document, "% (m/m)" and "% (V/V)" are used to represent the mass fraction, w, and the volume fraction, φ, of a material respectively.

This document specifies an ultraviolet (UV) fluorescence test method for the determination of the sulfur content of the following products: — having sulfur contents in the range 3 mg/kg to 500 mg/kg, — motor gasolines containing up to 3,7 % (m/m) oxygen [including those blended with ethanol up to about 10 % (V/V)], — diesel fuels, including those containing up to about 30 % (V/V) fatty acid methyl ester (FAME), — having sulfur contents in the range of 3 mg/kg to 45 mg/kg, — synthetic fuels, such as hydrotreated vegetable oil (HVO) and gas to liquid (GTL). Other products can be analysed and other sulfur contents can be determined according to this test method, however, no precision data for products other than automotive fuels and for results outside the specified range have been established for this document. Halogens interfere with this detection technique at concentrations above approximately 3 500 mg/kg. NOTE 1 Some process catalysts used in petroleum and chemical refining can be poisoned when trace amounts of sulfur-bearing materials are contained in the feedstocks. NOTE 2 This test method can be used to determine sulfur in process feeds and can also be used to control sulfur in effluents. NOTE 3 For the purposes of this document, "% (m/m)" and "% (V/V)" are used to represent the mass fraction, w, and the volume fraction, φ, of a material respectively. NOTE 4 Sulfate species in ethanol do not have the same conversion factor of organic sulfur in ethanol. Nevertheless, sulfates have a conversion factor close to that of organic sulfur. NOTE 5 Nitrogen interference can occur, see 6.5 for further guidance.

ISO 16591:2010 specifies a method for the determination of the sulfur content by oxidative microcoulometry of petroleum light and middle distillates with a final boiling point not higher than 400 °C. It is applicable to materials with sulfur contents in the range of 1 mg/kg to 100 mg/kg.

ISO 14596:2007 specifies a method for the determination of the sulfur content of liquid petroleum products, additives for petroleum products, and semi-solid and solid petroleum products that are either liquefied by moderate heating or soluble in organic solvents of negligible or accurately known sulfur content. The method is applicable to products or additives having sulfur contents in the range 0,001 % (m/m) to 2,50 % (m/m); higher contents can be determined by appropriate dilution. Other elements do not interfere at concentrations anticipated in the materials subject to this analysis.

ISO 20847:2004 specifies an energy dispersive X-ray fluorescence (EDXRF) test method for the determination of the sulfur content of motor gasolines, including those containing up to 2,7 % (m/m) oxygen, and of diesel fuels, including those containing up to 5 % (V/V) fatty acid methylester (FAME), having sulfur contents in the range 30 mg/kg to 500 mg/kg. Other products may be analysed and other sulfur contents may be determined according to this test method, however, no precision data for products other than automotive fuels and for results outside the specified range have been established for ISO 20847:2004. For reasons of spectral overlap, ISO 20847:2004 is not applicable to leaded motor gasolines, lead-replacement gasolines containing 8 mg/kg potassium to 20 mg/kg potassium, or to products and feedstocks containing lead, silicon, phosporus, calcium, potassium or halides at concentrations greater than one-tenth of the concentration of sulfur measured.

ISO 8754:2003 specifies a method for the determination of the sulfur content of petroleum products, such as naphthas, unleaded motor gasolines, middle distillates, residual fuel oils, base lubricating oils and components. The method is applicable to products having sulfur contents in the range 0,03 % (by mass) to 5,00 % (by mass).

ISO 5275: 2003 specifies a procedure (Doctor test) for the detection of thiols (mercaptans), hydrogen sulfide and elemental sulfur in hydrocarbon solvents and distillate petroleum feedstocks and products.

This International Standard specifies a method for the determination of the chlorine and bromine content of liquid petroleum products, synthetic oils and fluids, and additives for petroleum products (including used oils) that are soluble in organic solvents of negligible or accurately known chlorine/bromine content. The method is applicable to products or additives having chlorine contents in the range 0,0005 % (m/m) to 0,1000% (m/m), and bromine contents in the range 0,0010 % (m/m) to 0,1000% (m/m). Other elements do not generally interfere, although lead may interfere at contents above 0,1500 % (m/m) (see note 2). NOTE 1 For the purposes of this International Standard, the term "% (m/m)" is used to represent the mass fraction of a material. NOTE 2 Used lubricants may pose particular problems due to the range of potentially interfering elements at relatively high concentrations. For used lubricants generally, the lower limit of sensitivity may be 0,0050 % (m/m) even when the provisions of the last paragraph of 9.3 are applied.

This International Standard specifies a method for the determination of vanadium and nickel in liquid petroleum products. It may also be applied to semi-solid and solid petroleum products that are either liquefied by moderate heating or completely soluble in the specified organic solvent mixture. The method is applicable to products having vanadium contents in the range 5 mg/kg to 1 000 mg/kg, and nickel contents in the range 5 mg/kg to 100 mg/kg, although precision data have only been determined up to 100 mg/kg for vanadium and 60 mg/kg for nickel; higher contents may be determined by appropriate dilution. Barium at concentrations above approximately 300 mg/kg interferes with the determination of vanadium, and iron at concentrations above approximately 500 mg/kg interferes with the determination of nickel. Other elements at concentrations above approximately 500 mg/kg may affect precision and accuracy due to spectral line overlap or absorption.

Specifies a procedure for the determination of alkyl nitrate in diesel fuel in the concentration range 0,03 % bis 0,30 % (volume fraction 0,03 % bis 0,30 %). The presence of nitrate esters, inorganic nitrate ions and nitrogen oxides will interfere with this determination.

Specifies a method for determining the vanadium content in the range of 0,4 mg/kg to 4,0 mg/kg in gas turbine fuels and domestic fuel oils by means of flameless atomic absorption spectrometry.

The principle of the method specified is heating a weighed quantity of homogenized sample in a clean platinum basin, removing the combustible material by burning, finally removing the carbon by heating, fusing the residue with a dilithium tetraborate/lithium fluoride flux, digesting the fused mixture in a solution of tartaric acid and hydrochloric acid, dilution to volume with water, measuring the solution by ICPES or AAS. The method is applicable for concentrations between 5 mg/kg and 150 mg/kg for aluminium and 10 mg/kg and 250 mg/kg for silicon.

Specifies a procedure for total lead as lead alkyls at concentrations between 0,026 g and 1,300 g of lead per litre. The method is not apllicable to gasoline containing manganese anti-knock additives.