DIN EN 15488-2007 Ethanol as a blending component for petrol - Determination of copper content - Graphite furnace atomic absorption spectrometric method English version of DIN EN 1.pdf

1、November 2007DEUTSCHE NORM English price group 9No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 75.160.20!$J3-“1391610

2、www.din.deDDIN EN 15488Ethanol as a blending component for petrol Determination of copper content Graphite furnace atomic absorption spectrometric methodEnglish version of DIN EN 15488:2007-11Ethanol zur Verwendung als Blendkomponente in Ottokraftstoff Bestimmung des Kupfergehaltes Graphitrohr-Atoma

3、bsorptionsspektrometrieEnglische Fassung DIN EN 15488:2007-11www.beuth.deDocument comprises 13 pagesDIN EN 15488:2007-11 2 National foreword This standard has been prepared by Technical Committee CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biologi

4、cal origin” (Secretariat: NEN, Netherlands). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Technical Committee NA 062-06-81 AA Gasfrmige und flssige Kraft- und Brennstoffe, Schmierstoffe und verwandte Produkte

5、mit minerallstmmiger, synthetischer oder biologischer Herkunft of the Fachausschuss Minerall- und Brennstoffnormung (FAM). EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15488August 2007ICS 71.080.60English VersionEthanol as a blending component for petrol - Determination ofcopper content - Graph

6、ite furnace atomic absorptionspectrometric methodthanol comme base de mlange lessence -Dtermination de la teneur en cuivre - Mthode parspectromtrie dabsorption atomique avec four en graphiteEthanol zur Verwendung als Blendkomponente inOttokraftstoff - Bestimmung des Kupfergehaltes -Graphitrohr-Atoma

7、bsorptionsspektrometrieThis European Standard was approved by CEN on 30 June 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and b

8、ibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility

9、 of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Irela

10、nd, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B

11、-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15488:2007: EEN 15488:2007 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative reference 4 3 Terms and definitions .4 4 Principle5 5 Reagents and materials 5 6 Appar

12、atus .5 6.1 Atomic absorption spectrometer .5 7 Samples and sampling6 8 Preparation of blank and calibration solutions 6 8.1 Intermediate calibration solution .6 8.2 Calibration solutions .6 9 Procedure .7 9.1 Instrument preparation .7 9.2 Calibration 7 10 Sample analysis.8 11 Calculation8 12 Expres

13、sion of results 8 13 Precision.8 13.1 Repeatability.8 13.2 Reproducibility.9 14 Test report 9 Annex A (informative) Example of thermal program of the graphite furnace.10 Bibliography 11 EN 15488:2007 (E) 3 Foreword This document (EN 15488:2007) has been prepared by Technical Committee CEN/TC 19 “Gas

14、eous 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 Febr

15、uary 2008, and conflicting national standards shall be withdrawn at the latest by February 2008. This document is based on IP 478 1. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austr

16、ia, Belgium, Bulgaria, 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. EN 15488:2007

17、(E) 4 1 Scope This standard specifies a procedure for the determination of copper content in ethanol from 0,07 mg/kg to 0,20 mg/kg using graphite furnace atomic absorption spectrometry. NOTE For the purpose of this document, the terms “% (m/m)” and “% (V/V)“ are used to represent the mass fraction,

18、respectively the volume fraction of a material. WARNING 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 app

19、ropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. 2 Normative reference The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated reference

20、s, the latest edition of the referenced document (including any amendments) applies. EN ISO 3170, Petroleum liquids Manual sampling (ISO 3170:2004) EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696:1987) 3 Terms and definitions For the purposes of this documen

21、t, the following terms and definitions apply. 3.1 radiant power P rate at which energy is transported in a beam of radiant energy 3.2 transmittance T ratio of the radiant power transmitted by a material to the radiant power incident upon it 3.3 absorbance A logarithm to the base 10 of the reciprocal

22、 of the transmittance NOTE Can be derived by the following equation: A = log (1/T) = -log (T) (1) 3.4 integrated absorbance Aiintegrated area under the absorbance peak generated by the atomic absorption spectrometer EN 15488:2007 (E) 5 4 Principle The graphite furnace is aligned in the optical path

23、of the atomic absorption spectrometer. A test portion is pipetted onto the platform or at the wall of the graphite furnace. The furnace is heated in consecutive thermal stages, firstly to dry the test portion completely without spattering, then to eliminate excess sample matrix, and finally to volat

24、ilise the analyte of interest. During this final stage, the amount of light absorbed by the copper atoms is measured over a specified period. The integrated absorbance Ai, produced by the copper in the test portion, is compared to a calibration curve constructed from copper standards in ethanol solu

25、tion. NOTE The second heating stage is used to eliminate as much of the sample matrix as possible before the atomization step, as non-dissociated molecular species are the most common form of interference. Spectrometers are equipped with background correction capabilities to control further possibil

26、ities of erroneous results due to molecular absorption. 5 Reagents and materials 5.1 General All reagents shall be of analytical reagent grade or of higher purity. 5.2 Ethanol, 99,8 % (m/m) minimum purity. 5.3 Copper standard, aqueous solution containing 1 000 mg/l of copper as inorganic salt (e.g.

27、nitrate), or a multi-element aqueous standard containing 1 000 mg/l of copper. 5.4 Water, for analytical laboratory use, conforming to grade 3 of EN ISO 3696. 5.5 Argon, regulated compressed gas of 99,999 % minimum purity for the graphite furnace gas flow system. 5.6 Nitric acid (HNO3), c(HNO3) 0,5

28、mol/l Cautiously add 50 ml 2 ml of nitric acid ( = 1,40 g/ml) to 500 ml 10 ml water (5.4). Mix and allow to cool to room temperature. Make up to 1 000 ml with water (5.4). 6 Apparatus 6.1 Atomic absorption spectrometer 6.1.1 Capable of setting the wavelength at 324,8 nm or 327,4 nm, with the appropr

29、iate slit, e.g. as specified by the manufacturer, and using peak area integration for the signal and background readings. It shall be equipped with the features described in 6.1.2 to 6.1.4. NOTE The wavelength of 327,4 nm can be used for the measurements, however, the precision for results measured

30、at this wavelength was not determined. 6.1.2 Copper hollow cathode lamp 6.1.3 Background correction system, capable to cover the 324,8 nm or 327,4 nm wavelength. 6.1.4 Graphite furnace accessory, which uses pyrolytically coated graphite tubes with or without integrated platforms. 6.2 Autosampler, ca

31、pable of reproducibly delivering 10 l 0,1 l aliquots to the graphite furnace. 6.3 Micropipette, capable of reproducibly delivering volumes in the range 20 l to 100 l with an accuracy of 0,4 l at 50 l. EN 15488:2007 (E) 6 6.4 Polyethylene containers, 25 ml volume. Rinse the containers with water (5.4

32、). 6.5 Analytical balance, capacity of 100 g and capable of weighing to the nearest 0,01 g. 6.6 Ultrasonic bath 7 Samples and sampling Unless otherwise specified, laboratory samples shall be obtained by the procedures described in EN ISO 3170. High density polyethylene containers shall be used. The

33、containers should be carefully cleaned and rinsed with pure water to avoid contamination. Samples should be analysed as soon as possible after removal from bulk supplies, to prevent loss of copper. NOTE High density polyethylene containers are used to prevent losses of copper by wall adsorption. 8 P

34、reparation of blank and calibration solutions 8.1 Intermediate calibration solution Weigh a polyethylene container (6.4) and transfer with a micropipette (6.3) 100 l of copper standard (5.3). Add water (5.4) to the container to bring the mass up to approximately 10,0 g and re-weigh to the nearest 0,

35、01 g. Seal the container, mix well and mark with the copper content calculated as following: wcmVS = (2) where S is the copper content of the intermediate calibration solution in mg/kg; Vcis the volume of copper standard (5.3) in l; mwis the mass of water (5.4) in g. NOTE This procedure leads to int

36、ermediate calibration solution with nominal copper content corresponding to 10 mg/kg. The intermediate solution is stable for up to one week. 8.2 Calibration solutions The calibration solutions shall be prepared daily. Weigh five polyethylene containers (6.4), add about 5 g ethanol (5.2) to each con

37、tainer and then respectively 20 l, 40 l, 60 l, 80 l and 100 l of intermediate calibration solution (8.1). Reserve a sixth container for the preparation of the blank. Add ethanol (5.2) to each of the six containers to bring the mass up to approximately 10,0 g and re-weigh to the nearest 0,01 g. Seal

38、each container, mix well and mark with the copper content (including the blank) calculated as following: EN 15488:2007 (E) 7 eimSVC= (3) where C is the copper content of the calibration solution in g/kg; S is the copper content of the intermediate calibration solution (8.1) in mg/kg; Viis the volume

39、 of intermediate calibration solution (8.1) in l; meis the mass of ethanol (5.2) in g. NOTE This procedure leads to calibration solutions with nominal copper contents corresponding to 0 g/kg, 20 g/kg, 40 g/kg, 60 g/kg, 80 g/kg and 100 g/kg respectively. 9 Procedure 9.1 Instrument preparation 9.1.1 S

40、et the spectrometer (6.1) at a wavelength of 324,8 nm or 327,4 nm, and the appropriate slit width. 9.1.2 Condition new (or re-installed) graphite tube assemblies with the temperature program provided by the spectrometer manufacturer. 9.1.3 Adjust the autosampler (6.2) tip as near as possible to the

41、graphite platform surface but avoid contact between tip and surface. Use the blank solution (8.2) to evaluate the correct delivery of ethanol solutions. The delivered aliquot should distribute evenly onto the platform. Autosampler cups made of polyethylene, polypropylene or polytetra-fluorethylene (

42、PTFE) can be used. Use nitric acid (5.6) as the rinse solution of the autosampler. Due to the high volatility and surface tension of ethanol, the positioning of the tip and the correct delivery of sample aliquots should be checked periodically, as uneven delivery leads to erroneous measurements. Che

43、ck the correct delivery of aliquots when the integrated absorbance of two repeated injections differ by more than 15 %. 9.2 Calibration 9.2.1 Apply the thermal program for copper analysis as given in the instrument manufacturers instructions. Due to the different design of graphite furnace atomizers

44、, the thermal program shall be developed according to the atomizer characteristics. Refer to the instrument manual to set the best temperatures for copper pyrolisis and atomization steps. A thermal program is given as an example in Annex A. 9.2.2 Temperatures, ramp and hold times of drying steps sha

45、ll be optimised so that the sample dries completely without spattering. 9.2.3 The ramp time for the pyrolisis step may be lengthened if it appears that an excess amount of smoke from the sample matrix is generated very quickly as the furnace heats from the second drying step (Drying 2) to the pyroli

46、sis. Also, all smoke shall be evolved at least 5 s before the end of the pyrolisis step. If smoke still evolves at the end of the pyrolisis step, the hold time shall be lengthened. 9.2.4 For the spectrometer trace of absorbance versus atomization hold time, the absorbance at the end of the atomizati

47、on hold time should return to the initial baseline absorbance. If this is not observed, increase the atomization hold time until this is attained. EN 15488:2007 (E) 8 9.2.5 On each day of analysis, or together with each set of samples, prepare a calibration curve from the six calibration solutions (

48、8.2). For each calibration solution, pipette 10 l onto the platform of the graphite tube. Apply the copper thermal program. Perform three runs for each calibration solution and average the recorded integrated absorbances, Ai. 9.2.6 Plot the average of integrated absorbances (on y-axis) against the c

49、opper content in g/kg (on x-axis). Construct the best fit curve from the data. The correlation coefficient should be not lower than 0,990. Otherwise repeat the procedure in Clause 8. NOTE Many spectrometers have the capability of constructing the calibration curve, internally, or via computer software. Experience has shown that the curve is linear up to approximately 100 g/kg. If curve fitting software is unavailable, the calibration solutions may be diluted with ethanol to bring them into the linear calibration region.