Bsi bs en 16761 2 2015

BS EN 16761-2:2015 BSI Standards Publication Automotive fuels — Determination of methanol in automotive ethanol (E85) fuel by gas chromatography Part 2: Method using heart cut technique BS EN 16761-2:2015 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 16761-2:2015 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 This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application © The British Standards Institution 2015 Published by BSI Standards Limited 2015 ISBN 978 580 86561 ICS 75.160.20 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 31 December 2015 Amendments/corrigenda issued since publication Date Text affected BS EN 16761-2:2015 EN 16761-2 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM December 2015 ICS 75.160.20 English Version Automotive fuels - Determination of methanol in automotive ethanol (E85) fuel by gas chromatography Part 2: Method using heart cut technique Carburants pour automobiles - Détermination de la teneur en méthanol dans le carburant éthanol (E85) pour automobiles par chromatographie en phase gazeuse - Partie 2: Méthode ''heart-cutting'' Kraftstoffe für Kraftfahrzeuge - Bestimmung des Methanolgehalts in Ethanolkraftstoff (E85) mittels Gaschromatographie - Teil 2: Verfahren mittels HeartCut-Technik This European Standard was approved by CEN on 10 October 2015 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels © 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 16761-2:2015 E BS EN 16761-2:2015 EN 16761-2:2015 (E) Contents Page European foreword Scope Normative references Terms and definitions 4 Principle 5 Reagents and materials 6 Apparatus Sampling Preparation of the apparatus Density determination 10 Calibration 11 Linearity check 10 12 Procedure 10 13 Calculation 11 14 Expression of results 12 15 15.1 15.2 15.3 Precision 12 General 12 Repeatability, r 12 Reproducibility, R 12 16 Test report 12 Bibliography 13 BS EN 16761-2:2015 EN 16761-2:2015 (E) European foreword This document (EN 16761-2:2015) 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 June 2016, and conflicting national standards shall be withdrawn at the latest by June 2016 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 determination of a significant amount of methanol in ethanol (E85) automotive fuels was deemed to be necessary to check the product for compliance against EU emission regulations The CEN/TC 19 Ethanol Fuels Task Force requested the development of such a determination technique In EN 16761, Automotive fuels — Determination of methanol in automotive ethanol (E85) fuel by gas chromatography, two test methods were developed that comply with this scope: — Part 1: Method using single column technique; — Part 2: Method using heart cut technique [the present document] 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom BS EN 16761-2:2015 EN 16761-2:2015 (E) Scope This European Standard specifies a determination method of methanol in automotive ethanol (E85) fuel (also designated as ethanol (E85) automotive fuel or shortly "E85") by capillary gas chromatography using heart cutting technique Fuel quality specifications for this product exist, see Bibliography Entry [1] This standard is applicable to fuels having a methanol content from about 0,5 % (V/V) to about 1,5 % (V/V) Other methanol contents can also be determined, however no precision data for results outside the specified range is available NOTE For the purposes of this European Standard, the terms “% (m/m)” and “% (V/V)” are used to represent respectively the mass fraction, µ, and the volume fraction, φ WARNING — The use of this standard can 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 users of this standard to take appropriate measures to ensure the safety and health of personnel prior to application of the standard, and fulfil statutory and regulatory requirements for this purpose Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies EN 228, Automotive fuels — Unleaded petrol — Requirements and test methods EN ISO 3170, Petroleum liquids — Manual sampling (ISO 3170) EN ISO 3171, Petroleum liquids — Automatic pipeline sampling (ISO 3171) EN ISO 3675, Crude petroleum and liquid petroleum products — Laboratory determination of density — Hydrometer method (ISO 3675) EN ISO 3838, Crude petroleum and liquid or solid petroleum products — Determination of density or relative density — Capillary-stoppered pyknometer and graduated bicapillary pyknometer methods (ISO 3838) EN ISO 12185, Crude petroleum and petroleum products — Determination of density — Oscillating U-tube method (ISO 12185) Terms and definitions For the purposes of this document, the following terms and definitions apply 3.1 methanol calibration area area of the methanol peak in the calibration chromatogram Note to entry: Figure shows an example of a calibration chromatogram 3.2 methanol sample area As area of methanol peak in the sample chromatogram BS EN 16761-2:2015 EN 16761-2:2015 (E) Note to entry: Figure shows an example of a sample chromatogram Principle This standard describes the analysis of methanol content in automotive ethanol (E85) fuels using the heart cut technique The analyser is based upon the principle described by D.R Deans [3] This technique controls the pressure between two columns and directs the effluent of a (pre) column to usually two columns, an analytical column and a monitor column By using columns of a very different nature as pre column and analytical column (e.g a non-polar and a polar column) separations can be achieved that are difficult to obtain using a single column This allows the analysis of methanol to be independent of any impurities or high boiling material that may be present in the sample The method uses external standard calibration The sample is injected onto a methyl silicone pre column which elutes the methanol and part of the ethanol plus any light hydrocarbons to the analytical column (Figure 1) After methanol has fully eluted onto the analytical column, the valve and thus a Pressure Control Module (PCM) pressure is switched and the components coming from the pre column are directed to the monitor column (Figure 2) The methanol is now separated from the ethanol and hydrocarbons on the analysis column and detected by the Flame Ionization Detector The detector response, which is proportional to the component concentration, is recorded The peak areas are measured and the concentration of methanol is calculated using the response factor from the external standard calibration Key split/splitless inlet pre column Pressure Control Module analytical column monitor column Flame Ionization Detector Figure — Valve in ON-position BS EN 16761-2:2015 EN 16761-2:2015 (E) Key split/splitless inlet pre column Pressure Control Module analytical column monitor column Flame Ionization Detector Figure — Valve in OFF-position Reagents and materials Unless otherwise stated, only chemicals of recognized analytical quality shall be used 5.1 Carrier gases, helium or nitrogen, of at least 99,995 % (V/V) purity, any oxygen present should be removed, e.g by a chemical resin filter Follow the safety instructions from the filter supplier 5.2 5.3 Hydrogen, grade suitable for flame ionization detectors Compressed air, regulated for flame ionization detectors 5.4 Calibration components, methanol (anhydrous, ≥ 99,8 % (m/m)) and ethanol (proanalysis ≥ 99,8 % (m/m) by GC) It should be ensured that the ethanol contains no methanol detectable by this test method in a mixture (85/15 % (V/V)) of ethanol and petrol (5.5) 5.5 5.6 Oxygenate-free petrol (EN 228-compliant) Calibration solution: Prepare an E85 stock solution by (S1) by mixing 15 % (V/V) of an oxygenates free petrol (5.5) with 85 % (V/V) ethanol (5.4) Prepare a calibration solution (C1) of methanol (5.4) in E85 by accurately weighing 0,1 g of methanol with 9,9 g of stock solution S1 with an accuracy of 0,1 mg Apparatus 6.1 Gas chromatograph, with the following performance characteristics: 6.1.1 Flame ionization detector, FID, capable of operating at a temperature at least equivalent to the maximum column temperature employed in the method 6.1.2 Column temperature programmer, capable of linear programmed temperature operation over a range from ambient temperature to 250 °C BS EN 16761-2:2015 EN 16761-2:2015 (E) 6.1.3 Sample inlet system, consisting of an injector with variable split flow or similar device 6.2 Columns, the following set of columns are recommended, other columns may be used as long as a similar separation efficiency is achieved: — pre-column: 30 m (length) × 0,53 mm (diameter) × 0,88 µm (film thickness) Polydimethylsiloxane (PDMS); — analytical column: Polar column, typically a 10 m x 0,53 mm x 10 µm OxyPlot or Lowox column has been proven to work satisfactorily; — monitor column: empty fused silica, typically 0,7 m x 0,25 mm Length shall be tuned for each system 6.3 Carrier gas control: the chromatograph shall be able to deliver a constant carrier gas pressure over the whole temperature range of the analysis 6.4 Micro-syringe, of appropriate volume, e.g µl, for introduction of 0,5 μl of the calibration solution and test portions The micro-syringe may be operated either manually or automatically Plunger in needle syringes are not recommended due to excessive carry-over of heavy ends to the following analysis 6.5 6.6 Refrigerator, It is recommended that the refrigerator be of an explosion-protected design Analytical balance, able to weigh with a precision of 0,1 mg 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 petroleum products Store samples in either glass or metal containers Plastic containers for sample storage shall not be used as evaporation of parts of the sample can occur and prolonged contact with the sample can cause contamination of the sample due to possible leaching of the plasticizer Preparation of the apparatus 8.1 Set up and operate the gas chromatograph in accordance with the manufacturer’s instructions Advised operating conditions are shown below: — Oven Temp Program: 100 °C for then 25 °C/min to 250 °C for — Injector temperature: 200 °C — — — — 1) Run Time: Inlet pressure: Injection volume: Split ratio: 15 38 kPa 0,5 μL 100:1 Both column types are examples of suitable commercially available products This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of these products BS EN 16761-2:2015 EN 16761-2:2015 (E) — — Detector temperature: Switching Valve: 250 °C Off After 1,8 the valve shall be switched on, whereas after 2,02 the valve shall be switched off The valve switching time shall be fine-tuned 8.2 Chromatographic resolution: the column resolution as measured for methanol and ethanol eluting from the analytical column shall be at least 3,0 Determine the column resolution, CR, with the calibration solution (5.6) using the following Formula (1): CR = where × ( t2 − t1 ) (1) 1, 699 × (W1 + W2 ) t1 is the retention time, in seconds, for the methanol peak; W1 is the width, in seconds, at half-height of methanol peak; t2 W2 is the retention time, in seconds, for the ethanol peak; is the width, in seconds, at half-height of ethanol peak 8.3 Skewness, determine the skew of the methanol peak by measuring the width of the leading part of the peak at % peak height (A) and the width of the following part of the peak at % peak height (B), see Figure The ratio (B)/(A) shall be not less than or more than Figure — Calculation of peak skewness Density determination Determine the density at 15 °C of the calibration solution and sample solution in accordance with EN ISO 3675, EN ISO 3838, or EN ISO 12185, and record the result to the nearest 0,1 kg/m³ The methanol density is 795,8 kg/m³ BS EN 16761-2:2015 EN 16761-2:2015 (E) 10 Calibration 10.1 The application uses an external single point calibration Quantitative results are based on calibration analyses obtained by injecting a fixed volume of a reference blend With the reference blend, the relation between peak area and component concentration is determined If there is doubt about the system’s linearity, a linearity check can be performed as described in Clause 11 It is strongly advised to perform the calibration procedure in duplicate and use an average response factor in the calculations An example of a calibration chromatogram is given in Figure When not in use, store calibration standards capped in a refrigerator (6.5) at a temperature below 5°C 10.2 Run the calibration solution C1 (5.6) using the specified procedure in Clause 12 Take care to ensure the test portion volume chosen does not allow any peak to exceed the linear range of the detector, or overload the column A skew of > indicates the sample is too concentrated and a skew of < indicates an old column or dirty liner As a guide, 0,5 μl of the calibration solution has been found to be suitable 10.3 Determine the methanol calibration area (3.1), See Figure for an example Key X methanol time (min) Y ethanol FID signal Figure — Example of a calibration chromatogram 10.4 The response factor is calculated according to Formula (2): F m = C c / Ac where Fm is the response factor of methanol Ac is the methanol calibration area Cc (2) is concentration of methanol in calibration solution (% (m/m)) BS EN 16761-2:2015 EN 16761-2:2015 (E) 11 Linearity check 11.1 The linearity check is only needed in case there is doubt about the system’s linearity For day-to-day analysis a single point calibration can be used 11.2 Prepare a stock solution (S2) of methanol (10 % (m/m)) in E85 by mixing 10 % (m/m) methanol (5.4) and 90 % (m/m) E85 stock solution S1 (5.6) 11.3 Dilute stock solution of Methanol in E85 (S2) to concentrations in mass percentage of 0,10 %; 0,50 %; 1,00 %; 1,50 % and 2,00 % with E85 solution S1 as diluent 11.4 Set up the system as described in 8.1 and run an analysis sequence with these solutions Start with a solvent blank sample as first sample in the sequence The linearity shall be regarded as correct only if the correlation coefficient is equal or greater than 0,999 (see Figure for an example) Key X concentration (% (m/m)) Y peak area Figure —Example of a Linearity Check Graph 12 Procedure 12.1 Verify that the programmed valve switching times are valid It is recommended to check the correct timing when the system was shut down or has not been used for some time 12.2 Run a solvent (blank) baseline analysis before the first sample analysis, and then after every five samples 12.3 Cool the column to the starting temperature, and inject the selected sample volume 12.4 Start programming the column temperature 12.5 Continue the analysis until all components have eluted, this will be after approx 15 10 BS EN 16761-2:2015 EN 16761-2:2015 (E) 13 Calculation After the methanol peak has been identified, determine the area As (3.2) See Figure for an example of an E85 sample chromatogram after heart cutting methanol and part of ethanol from pre column Since a fixed amount of sample is injected and the density of the samples may vary, a density correction factor needs to be applied when making the final calculations Key X methanol time (min) Y ethanol FID signal Figure — Example of an E85 sample chromatogram The concentration of methanol in a sample, CS, in % (m/m) is calculated as per Formula (3): = C s d cal / d sample × As × F m where Fm is the response factor of methanol dcal is the density of the calibration solution at 15 °C in kg/m3 (see Clause 9) As dsample is the methanol sample area is the density of the sample at 15 °C in kg/m3 (see Clause 9) The methanol in % (m/m) shall be converted to % (V/V) by using Formula (4): = C m d sample / d m × C s where Cm is the concentration of methanol in sample in % (V/V) dm is the density of methanol at 15°C in kg/m3 (see Clause 9) Cs dsample (3) (4) is the concentration of methanol in sample in % (m/m) is the density of the sample at 15°C in kg/m3 (see Clause 9) 11 BS EN 16761-2:2015 EN 16761-2:2015 (E) 14 Expression of results Report the methanol concentration, Cm, to the nearest 0,1 % (V/V) 15 Precision 15.1 General The precision was determined by statistical examination of inter-laboratory test results using EN ISO 4259 [2] 15.2 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 given in the following Formula only in one case in 20: r = 0,001 + 0,143 × X where X (5) represents the mean of the two results expressed in % (V/V) 15.3 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 value given by the following formula only in one case in 20: R = 0,069 + 0,257 × X where X represents the mean of the two results expressed in % (V/V) 16 Test report The test report shall specify: a) reference to this European Standard, i.e EN 16761-2; b) type and complete identification of the material tested; c) method of sampling (see Clause 7) d) result of the test (see Clause 14); e) any deviation, by agreement or otherwise, from the standard procedures specified; f) 12 date of the test (6) BS EN 16761-2:2015 EN 16761-2:2015 (E) Bibliography [1] [2] [3] CEN/TS 15293, Automotive fuels — Ethanol (E85) automotive fuel — Requirements and test methods EN ISO 4259, Petroleum products — Determination and application of precision data in relation to methods of test (ISO 4259) DEANS D.R Chromatographia 1968, (1-2) pp 18–22 13 This page deliberately left blank This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT 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