1、Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIBRITISH STANDARD BS EN 12177:2000 BS 2000-425:2002 Methods of test for petroleum and its products BS 2000-425: Liquid petroleum products Unleaded petroleum Determination of benzene c
2、ontent by gas chromatography (Identical with IP 425:2001) The European Standard EN 12177:2000 has the status of a British Standard ICS 75.160.20 Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIBS EN 12177:2000 This British Standar
3、d, having been prepared under the direction of the Materials and Chemicals Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 13 August 2002 Institute of Petroleum present to the responsible international/European committee any e
4、nquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 11 and a ba
5、ck cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIEUROPEAN STANDARD
6、EN 12177 NORME EUROPiENNE It . EUROPAISCHE NORM November 2000 KS 75160.20 Descriptors: petroleum products, gasoline, chemical lanalysis, determination of content, benzene, chromatographic analysis, gas chromatography Englis#h version Liquid petroleum products - Unleaded petrol - Determination of ben
7、zene content by gas chromatography Produits p7:2000 E 425.1 Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIBENZENE BY GAS CHROMATOGRAPHY, IP 425 Foreword This European Standard has been prepared by Technical Committee CEN/TC 19 “
8、Petroleum products, lubricants and Irelated products”, the secretariat of which is held by NNI. This European Standard shall be Igiven the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 1998, and conflicting national standards sh
9、all be withdrawn at the latest by October 1998. According tlo thie CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finlanjd, France, Germany, Greece, Iceland, I
10、reland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. In this standard annex A is informative. Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIBENZENE BY GAS CHROMATOGRAPHY, I
11、P 425 I Scope EN IS0 12185, Crude petrolleum and petroleum This European standard specifies a column1 switching gas chromatographic method for the quantitative determination of benzene content i tlhe ranlge 0,05 % (V/V) to 6 % (V/v) in unleaded petrol having a final boiling point not greater than 22
12、0 “c. products - Determination of density - Oscillating U-tube method (IS0 12185:1996) IS0 3170, Petroleum liquids - Manual sampling The method described1 in this standard is suitable for determining benzene in petrol, including petrol contahng oxygenates, in line with the relevant EC Directives? IS
13、0 3171, Petroleum liquids - Automatic pipeline sampling NOTE For the purposes of this European Standard, the terms ” % ( WV) and ” % (m/m)” are used to represent respectively the volume firaction anld the masIs fraction, 3 Principle The benzene-containing fraction is isolated from the sample using a
14、 capillary column antd, in a second capillary column, the benzene is separated and detected using a flame ionizaltion detector. 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 associat
15、ed with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. NOTE 1 Some oxygenates are known to interfere with the determination of benzene using a single column ga
16、s chromatographic method. NOTE 2 Guidance on the column switching technique is given in annex A. 2 INormative references 4 Reagents and materials Use only reagents of recognized analytical grade. This European Standard incorporates by dated or Iundated reference, provisions from other publications.
17、These normative references are cited at thle appropriate pIlaces in the text and the publiciations are listed herreafter. For dated referenc(es, subsequent arnendments to or revisions of any of these publications appbly to this standard only when incorporated in it by amendment or revision. For unjd
18、ated references the latest edition of the publicatioln referred to applies. 4.1 Carrier gas Hydrogen, helium, or nitrogen, *free of hydrocarbons. WARNING : Hydrogen iis explosive in mixtures with air at concentrations of hydrogen ranging approximately from 4 % (V/V) to 75 % (WV). All joints and line
19、s carrying hydrogen shall be made gas tight to prevent leakage of hydrogen into a confined space. EN ISO :3675 Crude petroleum and liquid petroleum products - Laboratory determination of density or relative density - Hydrometer method (IS0 :3675: 1993) 4.2 Reagents for the preparation of calibration
20、 samples EN IS0 .:3838, Crude petroleum and liquid or solid petroleum products - DIetermination of density or relative density - Capillary- stoppered pyknometer and graduated bicapillary pyknometer methocls (IS0 3838: 198:3) NOTE Calibration samples will normally be combinations of benzene, solvent
21、and an internal standard. 4.2. I Benzene Not less than 99,0 % (m/m) pure. WARNING : Benzene is toxic and carcinogenic. 1) EC Directive 85/21 O/EIEX, Council Directive on the approximation of the laws of the Member States concerning the lead (content of petrol. EC Directive 85,536/EEC, Council Direct
22、ive on crude-oil savings through the use of substitute fuel components in petrol. 4,2!5.3 Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIBENZENE BY GAS CHROMATOGRAPHY, IP 425 4.2.2 Solvent Not containting benzene or internal stan
23、dard, e.g. heptane. 4.3 Internal1 standard Reaqent for which it has been established that it is nit present in the sample. NOTE lsobutyl methyl ketone is preferred as the internal standard. 5 Apparatus Usual laboratory apparaltus and glassware, together witlh thie following: 51 q Gas chromatographic
24、 assembly 5.1 .I Gas chromatograph, provided with a means foIr column switchting, equipped with a programmable oven temperature controller, or controllers in the case of dual oven gas chromatographs, and two flame ionization detectors (FIID). NOTE It is recommendled that a system constructed entirel
25、y of glams from the sample injection port up to the detector system is used since petrol may contain oxygenates which can give rise to corrosion and changes of retention times in systems constructed partly using metals. 51.2 Two capillary columns, of appropriate dimensions, each internally coated wi
26、th a substance of different polarity, such that the resolution between the benzene peak and the matrix is at least 1 after elution from the second column. The resolution, R, between peaks A and B (see figure 1) is calculated using the equation: + - + R= I, 18 ?i!-?!- wA + wB where : t, t, WA wB is t
27、he reduced retention time of component A; is the reduced retention time of component B; is the peak width at half-height of component A; is the peak width at half-height of component B. Start NOTE t, is the hold-up time zero of the column, i.e. the tilme taken for an inert component, such as methane
28、, to travel through the column without chromatography taking place. iFigure 1 - Calculation of the resolution between peaks A and B 425.4 Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIBENZENE BY GAS CHROMATOGRAPHY, IP 425 5.1.3
29、Device for the lcontrol of the flow of carrier the calibration factor, f, for benzene using the gas. following equation: 5.1 A Recorder and/m integrator An amplifier and potentiometric recording device, or an integrator or data processor systeim, giving area values corresponding to the peak area in
30、square millimetres. f= m, x A2 A, x m; where : ml is the mass of benzene in the calibration sample, in grams; 5.2 Injection deviice 5.3 Test sample container, normally with a capacitld of between IO ml and 100 ml, fitted with a sellf sealing rubber septum coat:ed with polytetrafluoroethylent3 (PTFE)
31、. is the peak area of the internal standard, in square millimetres; Al is the peak area of benzene, in square millimetres; 6 Sampling Unless otherwise specified in the commodity specificat:ion, samples shall be taken as Idescribed in IS0 3170 or IS0 3171, and/or in accordance, with thte requirements
32、 of natiional standards or regulations for the sampling of petrol. m2 is the mass elf the internal standard in the calibration sample, in grams,. 7.3 Determination of density 7 Procedure 71 . Setting up the apparatus 7.1. I General Determine the density at 15 “C, FS, of the sample in accordance with
33、 either EN IS0 3675, EN IS0 3838 or EN IS0 12185 and record the result to the nearest 0,l kg/m3. 7.4 Preparation of test sample Prepare the equipmenit and set the test condit- ions iin accordance with thle manufacturers instructions. Cool the sample to between 5 “C ancl 10 C. Weigh, to the nearest 0
34、,l mg, the test sample container (5.3) and its rubber septum without sealing it. 7. I .2 Carrier gas Adjust the pressure and flow rate of the carrier gas to levels such sthat the resolution is in aiccordance with 5.1 .2. 7.2 Clalibration Prepare the calibration sarnple by combining known masses of b
35、enzene (4.2.1) and internal standarid (4.3) in a suitable solvent (4.2,2). Transfer a quantity of the internal standard (4.3) to the test sample container and weigh, to the nearest 0,l mg, the tesIt sample container with contents and septum, without sealing the sample container. The mass, m, in gram
36、s, of the internal standard shall amount to between 2 % (m/m) and 5 % (m/m) of the sample, m, but shall not be less than 0,050 g. Inject a suitable quantity of the prepared calibrat.ion sample intlo the gas chromatograph such that the capacity of the columns and other clomponents is nIot exoeeded an
37、d the linearity of the detector is not impaired. Transfer a quantity, normally between 5 ml and 100 ml, of the cooled sample to the test sample container and seal immediately with the septum. Weigh, to the nearest 0,l mg, the test sample container and contents. Record the mass, m, in grams, of the t
38、est sample taken, to the nearest 0, 1 mg. Determime and record the retention times for bIenze?ne and for the internal standard. Calculate Record the amount of internal standard in the prepared test sample as a percentage by mass. Mix the contents of the test sample container by shaking untit homogen
39、eous. 42!5”5 Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIBENZENE BY GAS CHROMATOGRAPHY, IP 425 7.5 introduction of test portion inject a suitable quantity of the prepared test sample (7,43 ilnto the gas chromatograph. Ensure t
40、hat the test portion size is such that the capacity of the columns and other clomponents of the gas chromatograph is not exceeded and that the linearity of the detector is not impaired. 7.6 Examination of the gas chromatogram Examine the qas chromatoIgram and identify the benzene and the internal st
41、andard by means of their retention times (see 7 ,2), 8 Calculation 81 Calculation of mass of benzene in the test sample Calculate the m ass, /n3, in grams the test sample using th e followin where : f mg = f x A, r: m4 A4 is the benzene , is the square 9 calibration peak. area millimetres of benzen
42、equation: factor e in for of benzene, in is the mass of the internal standard in the test sample (see 7.4), in grams; is the peak: area of the internal standard, in! square millimetres. 8.2 Calculation of volume of benzene in the test sample Calculate the volume, V, ini millilitres, of benzene in th
43、e test sample using the following equation: m3 x 1000 “/, = _- - ._ pb where : is the mass of benzene in the test sample (see 8. I), in grams; pb is the density of lbenzene at 15 “C, i.e. 884,3 kg/m3. 8.3 Calculation of volume of test sample Calculate the volume, V2, in millilitres, of the test samp
44、le using the following equation: where : rns x 1000 v2 = _- P S m5 is the mass of the test sarnlple (see 7.4), in grams; P S is the density at 15 “C of the sample, in kilograms per culbic metre. 8.4 Calculation of benzene content as 96 (V/v) Calculate the benzene content, , of the sample as a percen
45、tage by volume using the following equation: Iwhere : CP v, x 100 = _-._-_- _ 4 VP is the volume of benzene in the test sample (see 8.2), in millilitres; is the volume of the test sample (see 8.3), in millilitres. 9 Expression of results IReport the benzene content to the nearest 0,Ol % (V/l/). 10 P
46、recision 10.1 Repeatability, r The difference between two test results, obtained by the same operator with the same apparatus under constant operating conlditions on ident:ical test material, would in the long run, in #the normal and correct operation of the test method, exceed the values given in t
47、able 1 only in one case in twenty. 10.2 Reproducibility, R The difference between two siingle and independent results, obtained by different Licensed Copy: Wang Bin, ISO/Exchange China Standards Information Centre, 11 November 2002, Uncontrolled Copy, (c) BSIBENZENE BY GAS CHROMATOGRAPHY, IP 425 ope
48、rators working in differlent laboratories on iidentkal test material, would in the Iontg run, in the normal and correct operation of the test mnethodl, exceed the values given in tablie 1 only in one case in twenty. b) a reference to thiis European Standard; b) the sampling procedure used (see 6); d
49、 the density of the sample (see 7.3); II Test report d) the result of the test (see 9); The report shall include at least the following informat:ion: e) any deviation from the procedure described; a 1 the type and identification of the product under tIest ; f) the date of test. Table 1 - Repeatabillity and reproducibility Benzene content ?h w/w Repeatiabilityl r % (V/v) Reproducibility, R % w/w I 0,05 t0 0,15 I 0,005 I 0,Ol I I O,l5 to 1,510 I OF03 I O,l
