BS EN 15944:2010 BS 2000-587:2010 BSI Standards Publication Liquid petroleum products — Determination of nickel and vanadium content — Inductively coupled plasma optical emission spectrometry method (ICP OES) BS EN 15944:2010 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 15944:2010 The UK participation in its preparation was entrusted to Technical Committee PTI/13, Petroleum Testing and Terminology A list of organizations represented on this committee can be obtained on request to its secretary Energy Institute, under the brand of IP, publishes and sells all Parts of BS 2000, and all BS EN petroleum test methods that would be Part of BS 2000, both in its annual publication “Standard methods for analysis and testing of petroleum and related products and British Standard 2000 Parts” and individually Further information is available from: Energy Institute, 61 New Cavendish Street, London W1G 7AR Tel: 020 7467 7100 Fax: 020 7255 1472 This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application © BSI 2010 ISBN 978 580 67374 ICS 75.100 Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2010 Amendments issued since publication Date Text affected BS EN 15944:2010 EN 15944 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM November 2010 ICS 75.100 English Version Liquid petroleum products - Determination of nickel and vanadium content - Inductively coupled plasma optical emission spectrometry method (ICP OES) Produits pétroliers liquides - Détermination de la teneur en nickel et vanadium - Méthode directement par spectrométrie d'émission atomique couplage inductif par plasma (SOD-PCI) Flüssige Mineralölerzeugnisse - Bestimmung des Gehaltes an Nickel und Vanadium - Optische Emissionsspektralanalyse mit induktiv gekopppeltem Plasma (ICP OES) This European Standard was approved by CEN on October 2010 CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 15944:2010: E BS EN 15944:2010 EN 15944:2010 (E) Contents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Principle 4 4 Reagents 4 5 Apparatus .5 6 Sampling 6 7 7.1 7.2 7.3 7.4 Preparation of calibration solutions 6 General 6 Calibration solutions .6 Internal standard solution .7 Working solutions 7 8 8.1 8.2 8.3 8.4 8.5 Calibration 7 General 7 Calibration of the ICP OES spectrometer 7 Procedure A 7 Procedure B 8 Check of calibration 8 9 9.1 9.2 Sample analysis .8 Sample preparation .8 Sample measurement 9 10 10.1 10.2 Calculation 9 Procedure A 9 Procedure B 9 11 Expression of results 10 12 12.1 12.2 12.3 Precision 10 General 10 Repeatability, r 10 Reproducibility, R 10 13 Test report 10 Bibliography 11 BS EN 15944:2010 EN 15944:2010 (E) Foreword This document (EN 15944:2010) has been prepared by Technical Committee CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin”, the secretariat of which is held by NEN This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2011, and conflicting national standards shall be withdrawn at the latest by May 2011 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights The method described in this document is based on DIN 51790-6 [1] It has been developed originally as an alternative to (second part of) EN 13131 [2], but as the method enables the use of an instrumental technique more and more employed in analytical laboratories, it was decided to have it as a stand-alone method According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom BS EN 15944:2010 EN 15944:2010 (E) Scope This European Standard specifies an inductively coupled plasma optical emission spectrometry (ICP OES) method for the determination of nickel content in the range mg/kg to 55 mg/kg and of vanadium content in the range mg/kg to 150 mg/kg in fuel oils and residual fuel oils NOTE Nickel content can be determined from mg/kg to mg/kg and vanadium content can be determined from mg/kg to mg/kg However, the precision was not established as no samples with nickel and vanadium contents in these ranges were included in the interlaboratory test Nickel and vanadium contents higher than those reported can be determined after sample dilution However, the precision was not established for diluted samples NOTE For the purposes of this European Standard, the term “% (V/V)” is used to represent the volume fraction (φ) WARNING — The use of this standard may involve hazardous materials, operations and equipment This standard does not purport to address all of the safety problems associated with its use It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use Normative references The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies EN ISO 1042, Laboratory glassware ― One-mark volumetric flasks (ISO 1042:1998) EN ISO 3170, Petroleum liquids ― Manual sampling (ISO 3170:2004) EN ISO 3171, Petroleum liquids ― Automatic pipeline sampling (ISO 3171:1988) Principle The sample is diluted with an organic solvent The solution is then introduced directly into the ICP OES spectrometer Vanadium and nickel contents are determined by comparison with calibration solutions An internal standard is employed to correct viscosity effects Reagents 2 4.1 Paraffin oil, with viscosity between 1,5 mm /s and 6,0 mm /s, Pharmacopeia (EUPHARM EP5), e.g Merck 107174 1) 4.2 Kerosene, boiling range included between 150 °C and 325 °C, e.g Aldrich 32.946-0 1) 4.3 Xylene, analytical reagent grade 4.4 2-Ethyl hexanoic acid, analytical reagent grade or other suitable stabilizer for element standard solution 1) This information is given for the convenience of the users of this European Standard and does not constitute an endorsement by CEN of these products Equivalent products may be used if they can be shown to lead to the same results BS EN 15944:2010 EN 15944:2010 (E) 4.5 Element standard solutions, dissolved in oil, for example with 500 mg/kg per element, available as single element standards, or at least partially as multi-element standards NOTE Some commercial element standard solutions on the market are furnished with higher content Those solutions may be used instead of the required solutions, but an initial mass to mass dilution should be done according to recommendations given in 7.1 4.6 Argon, with minimum purity φ(Ar) = 99,996 % (V/V) NOTE Small amounts of oxygen (minimum purity φ(O2) ≥ 99,995 % (V/V)) may be added to the argon gas stream using a metering valve (30 ml/min to 100 ml/min) to prevent carbon deposits in the area of the plasma torch Apparatus 5.1 Laboratory equipment All glassware shall be cleaned carefully before use to remove soluble constituents Fill new glass vessels with xylene (4.3) and allow to stand for at least two days 5.1.1 Glassware 5.1.1.1 Beakers, tall type, 150 ml 5.1.1.2 Erlenmeyer flasks with wide neck and plug, 50 ml 5.1.1.3 Volumetric flasks, 500 ml, according to EN ISO 1042, with narrow neck and plug 5.1.2 Sample containers, storage bottles with screw cap, brown glass 5.1.3 tips Graduated pipettes or variable volume automatic pipettes, fitted with disposable polypropylene 5.2 Balance, capable of weighing to the nearest 0,001 g 5.3 ICP OES spectrometer, equipped with organic sample introduction system 5.3.1 General Simultaneous and equally suitable sequential ICP OES spectrometer equipped for the analysis of organic liquids, with a high-frequency generator and a nebulizer suitable for organic solvents The use of a feed pump for sample introduction into the nebulizer is required Both setup and operation of the ICP OES spectrometer shall be done in accordance with operating instructions of the manufacturer 5.3.2 Recommended wavelengths The recommended wavelengths for nickel, vanadium and internal standard element are reported in Table Organometallic yttrium has performed well as an internal standard for this test method and is recommended BS EN 15944:2010 EN 15944:2010 (E) Table — Recommended wavelengths Wavelength nm Element Nickel 216,555 – 231,604 – 221,647 Vanadium 292,401 – 309,310 Cobalt Scandium Yttrium 238,892 361,383 224,306 – 371,029 – 360,073 NOTE The line at 227,021 nm may be used for nickel, but this line suffers from interference with tungsten Lines at 268,796 nm and 311,070 nm may be used for vanadium, but these lines suffer from interference with molybdenum and manganese respectively Sampling Samples shall be taken as described in EN ISO 3170 or EN ISO 3171 and/or in accordance with the requirements of national standards or regulations for the sampling of the product under consideration The samples shall be filled into clean containers The containers shall be rinsed with xylene (4.3) at least twice and then dried before use 7.1 Preparation of calibration solutions General In order to avoid inhomogeneity, the standard solutions (4.5) shall be shaken vigorously before use The masses given correspond to a nominal element content of 500 mg/kg per element in the multi-element solutions (4.5) If solutions with other element contents or single element standards are used, these masses shall be adjusted accordingly in order to establish the given nominal concentrations as closely as possible Calculate the exact concentrations of the calibration solutions, taking into account the exact masses 7.2 Calibration solutions For each calibration solution, weigh stock standard solution (4.5), stabiliser (4.4), and paraffin oil (4.1) to the nearest 0,001 g in 50 ml Erlenmeyer flasks (5.1.1.2) as indicated in Table All solutions shall be homogenized by vigorous shaking Table — Calibration solutions Calibration solution Element content mg/kg Standard solution g Stabilizer g Paraffin oil g (blank) - 0,15 24,85 0,25 0,15 24,60 10 0,50 0,15 24,35 20 1,00 0,15 23,85 100 5,00 0,15 19,85 200 10,00 0,15 14,85 BS EN 15944:2010 EN 15944:2010 (E) 7.3 Internal standard solution Weigh g of cobalt, scandium or yttrium stock solution (4.5) with a precision of 0,001 g in a 500 ml volumetric flask (5.1.1.3) Add g of stabilizer (4.4) and fill up to 500 ml with a mixture of kerosene/xylene solvent having a volume ratio of 2:1 (4.2 and 4.3) The solution shall be homogenized before use by vigorous shaking NOTE The use of a mixture of xylene and kerosene is necessary to avoid precipitation of asphaltene fractions occurring when kerosene only is employed, and to reduce the build-up of carbon on the tip of the torch NOTE Experience from daily practice with yttrium used as internal standard has shown that internal standard solutions can be used for about two weeks 7.4 Working solutions For each calibration solution (7.2), weigh (1,0 ± 0,001) g in a 50 ml Erlenmeyer flask (5.1.1.2) Add 10 ml of internal standard solution (7.3) All prepared solutions shall be homogenized by vigorous shaking 8.1 Calibration General The ICP OES spectrometer setup with organic solutions and the instrument check are performed according to the instructions of the manufacturer The choice of the instrumental parameters is made to obtain the best signal/background ratio for all elements Net intensity of analytical lines shall be calculated by subtracting the intensity measured at appropriate background wavelengths Some instruments are equipped with software which allows the automatic correction of the background A separate calibration function for each element under investigation shall be established 8.2 Calibration of the ICP OES spectrometer The calibration of the ICP OES spectrometer shall be done by the measurement of the blank solution and of the working solutions (7.4) using three replicates For the determination of the elements, the wavelengths recommended in Table shall be used The background subtraction shall be performed at wavelengths not affected by other lines IMPORTANT — Ensure that the wavelengths used in calibration also match exactly the ones used in the sample measurement Depending on the spectrometer software, follow either procedure A or B 8.3 Procedure A For each element under investigation, conduct the aspiration of the working solutions (7.4) For each working solution, measure the net emission intensity of nickel, INi, and of vanadium, IV, and the net emission intensity of the internal standard, IIS, at the chosen wavelengths Calculate the intensity ratio of nickel, RNi, and of vanadium, RV, of each working solution using the following: BS EN 15944:2010 EN 15944:2010 (E) RNi = I I Ni and RV = V I IS I IS (1) A calibration curve for nickel and a calibration curve for vanadium are constructed using linear regression with concentration of the element in the calibration solutions (7.2) as independent variable (XA) and the corresponding mean intensity ratio R of nickel or of vanadium as dependent variable (YB) according to the equation: Y A = m A × X A + bA (2) This regression may be performed with built in software of the spectrometer 8.4 Procedure B Conduct the aspiration of working solution (blank solution) to measure the net emission intensity of the internal standard (IBlank) Conduct the aspiration of the each following working solution to measure the net emission intensity of nickel INi, of vanadium IV and of internal standard IIS Calculate the correction factor R of each working solution using the equation: R= I Blank I IS (3) Calculate the corrected intensity of nickel INiCor and of vanadium IVCor of each working solution using: I NiCor = R × I Ni and I VCor = R × I V (4) A calibration curve for nickel and a calibration curve for vanadium are constructed using linear regression with concentration of the element in the calibration solutions (7.2) as independent variable ( XB) and the corrected intensity of nickel or of vanadium as dependent variable (YB) according to the equation: YB = m B × X B + b B (5) This regression may be performed with built in software of the spectrometer 8.5 Check of calibration The calibration curves shall be checked in regular intervals A Quality Control (QC) sample shall be prepared from certified reference materials or from certified stock solutions to verify sensitivity and accuracy of the calibration curve If nickel and vanadium contents of the QC sample differ from the reference values by more than R/1,41 (reproducibility divided by 1,41), prepare a new QC sample If nickel and vanadium contents of the new QC sample still differ from the reference values, a new calibration shall be established 9.1 Sample analysis Sample preparation The sample shall be heated to 60 °C and shall be homogenized by vigorous shaking Weigh (2,0 ± 0,001) g of sample and add 20 ml of internal standard solution (7.3) in a 50 ml flask (5.1.1.2) The mixture is thoroughly homogenised by shaking BS EN 15944:2010 EN 15944:2010 (E) NOTE The dilution factors for the blank solution, the calibration solutions and sample solution should be selected such that the viscosities are as close to one another as possible This can often be achieved by using a somewhat higher dilution factor The prepared sample shall be measured within h from the preparation Shortly before the measurement, the sample shall be homogenised again by shaking NOTE 9.2 If required, the sample may be gently heated in the flask to obtain complete dissolution Sample measurement The analysis of nickel and vanadium is performed with the same instrumental parameters and wavelengths used for the calibration of the spectrometer (8.2) Net intensity of analytical lines shall be calculated by subtracting the intensity measured at appropriate background wavelengths The background subtraction shall be performed at wavelengths not affected by other lines Perform three measurements of the net emission intensity of nickel, INi, of vanadium, IV, and of internal standard, IIS, at the chosen wavelengths and calculate the mean values The RSD of IIS shall be lower than %, otherwise that might indicate nebulizer problems NOTE A maximum variation of 20 % of the intensity of the internal standard from the first calibration blank is accepted In the case this variation is bigger, it might indicate problems with the instrument (blocked nebulizer) or with the sample solution For procedure A (8.3), calculate the intensity ratio R of each element using the corresponding Equation (1) For procedure B (8.4), calculate the corrected intensity of each element using Equation (3) and the corresponding Equation (4) Allow sufficient rinsing time after each sample analysis The drift of the spectrometric system has to be checked before and at the end of the sample series or at least between every ten samples using the QC sample (8.5) If nickel and vanadium contents of the QC sample differ from the reference values by more than R/1,41, proceed as indicated in 8.2 10 Calculation 10.1 Procedure A The content of nickel and of vanadium is calculated from the intensity ratio of each element (9.2) using Equation (2) This may be done either manually, or with use of the appropriate software functions of the ICP OES spectrometer 10.2 Procedure B The content of nickel and of vanadium is calculated from the corrected intensity of each element using Equation (5) This may be done either manually, or with use of the appropriate software functions of the ICP OES spectrometer BS EN 15944:2010 EN 15944:2010 (E) 11 Expression of results Report the content of nickel and the content of vanadium content rounded to the nearest 0,1 mg/kg 12 Precision 12.1 General The precision given in 12.2 and 12.3 was determined by statistical examination of interlaboratory test results in accordance with EN ISO 4259 [3] 12.2 Repeatability, r The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values calculated from the following equations only in one case in twenty: nickel r = 0,051 X + 0,341; vanadium r = 0,046 X + 0,154, where X represents the mean of the two results expressed in milligrams per kilogram 12.3 Reproducibility, R The difference between two single and independent test results, obtained by different operators working in different laboratories on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the values calculated from the following equations only in one case in twenty: nickel R = 0,119 X + 0,794; vanadium R = 0,100 X + 0,339, where X represents the mean of the two results expressed in milligrams per kilogram 13 Test report The test report shall specify: a) the type and identification of the product under test; b) a reference to this European Standard, i.e EN 15944; c) the applied sampling procedure (see Clause 6) and calibration procedure (A or B, see Clause 8); d) the result of the test obtained (see Clause 11); e) all operation details not specified in this European Standard, or regarded as optional, together with details of any incidents which may have influenced the test results; f) the date of the test 10 BS EN 15944:2010 EN 15944:2010 (E) Bibliography [1] DIN 51790-6:2007/-11, Testing of liquid fuels — Determination of the vanadium and nickel content — Part 6: Direct determination by optical emission spectral analysis with inductively coupled plasma (ICP OES) [2] EN 13131:2000, Liquid petroleum products — Determination of nickel and vanadium content ― Atomic absorption spectrometric method [3] EN ISO 4259:2006, Petroleum products — Determination and application of precision data in relation to methods of test (ISO 4259:2006) 11 BS 2000 Series Energy Institute Buying 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