1、ICS 75.100Prfung von Schmierstoffen Bestimmung des Gehaltes an1,2-Ethandiol in Motorenlen Teil 2: GaschromatographischesVerfahrenIn keeping with current practice in standards published by the International Organization for Standardization(ISO), a comma has been used throughout as the decimal marker.
2、Ref. No. DIN 51375-2 : 2001-06English price group 05 Sales No. 010505.03DEUTSCHE NORM June 200151375-2Continued on pages 2 to 5. No part of this translation may be reproduced without the prior permission ofDIN Deutsches Institut fr Normung e.V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has t
3、he exclusive right of sale for German Standards (DIN-Normen).Translation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.Determining the 1,2-ethanediol content ofmotor oils by gas chromatographySupersedes March 1986edition.ForewordTh
4、is standard has been prepared by Technical Committee Prfung von Schmierlen, sonstigen lenund Paraffinen of the Fachausschuss Minerall- und Brennstoffnormung of the NormenausschussMaterialprfung (Materials Testing Standards Committee).AmendmentsThis standard differs from the March 1986 edition as fol
5、lows:a) the specifications for equipment and reagents have been revised;b) details of preparing the standard solution have been changed and the gas chromatographic analysishas been described in greater detail;c) precision data have been updated.Previous editionDIN 51375-2: 1986-03.1 ScopeThe method
6、specified in this standard serves to determine the 1,2-ethanediol content of used and unusedmotor oils, for concentrations of 200 mg/kg or more. 1,2-ethanediol may get into motor oil during production,while in the case of used motor oils, an increased 1,2-ethanediol content may indicate contaminatio
7、n withantifreeze from the cooling water.Additives may be examined by this method, provided that they are diluted with a suitable base oil.2 Normative referencesThis standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the ap
8、propriate places in the text, and the titles of the publications arelisted below. For dated references, subsequent amendments to or revisions of any of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of the pub
9、lication referred to applies.DIN 1333 Presentation of numerical dataDIN 12691 Class AS fast delivery one-mark bulb pipettes, with a waiting time of 15 seconds, for laboratoryuseDIN 51405 Testing of liquid petroleum products, related liquids and solvents for paints and varnishes bygas chromatography
10、GeneralDIN 51574 Sampling of lubricating oils taken from internal combustion enginesPage 2DIN 51375-2 : 2001-06DIN 51750-1 Sampling of petroleum products GeneralDIN 51750-2 Sampling of liquid petroleum productsDIN EN ISO 4259 Petroleum products Determination and application of precision data in rela
11、tion to methodsof test (ISO 4259 : 1992 + Corr 1 : 1993)3 UnitThe unit in which the content is expressed shall be mg/kg.4 PrincipleA sample of the motor oil under test and an internal standard, 1,3-propanediol (C3H8O2), are applied to aprepacked column to separate the 1,2-ethanediol and the internal
12、 standard from the oil matrix by solid-phaseextraction. The diols are then eluted from the adsorption phase with ethanol and the eluate is analysed by gaschromatography.5 DesignationDesignation of the method of determining the 1,2-ethanediol content of motor oils in accordance with thisstandard (02)
13、 by gas chromatography (GC):Test DIN 51375 02 GC6 Apparatus and reagents6.1 ApparatusThe following equipment shall be used.a) Ultrasonic bath.b) Prepacked diol or silica gel column, for preliminary separation, having a volume of 3 ml or 6 ml/500 mgof solid phase.c) Vacuum unit, with Luer connections
14、.d) Gas chromatograph, with flame ionization detector as in DIN 51405.e) Balance, with 0,1 mg scale intervals.f) One-mark bulb pipette, of capacity 1 ml (e.g. DIN 12691-VPAS 1 pipette).g) Micropipettes, of capacities 1 000 l and 2 000 l.h) Microlitre syringe.i) GC sample containers, of capacities 2,
15、5 ml, 10 ml and 100 ml, with septum closures.j) Disposable medical syringes, of capacity 2 ml.k) Gas chromatography column (e.g. capillary column packed with a polar stationary phase), having aresolution for the individual components of at least R = 5. The column shall be checked at regular interval
16、s,at least twice a year, using a mixture of equal parts of 1,2-ethanediol/1,3-propanediol in ethanol and theresult evaluated as specified in subclause 6.2 of DIN 51405, May 1987 edition.NOTE: In preliminary tests, a capillary column containing polyethylene glycol as stationary phase and havinga diam
17、eter of 0,2 mm, a length of 25 m, and a film thickness of 0,2 m was found satisfactory1).6.2 ReagentsThe following reagents shall be used.a) Cyclohexane1), having a purity of at least 99,8 %.b) Synthesis-grade isobutyl methyl ketone, having a purity greater than 99 %1).c) Analytical grade (absolute)
18、 ethanol.d) Analytical grade 1,2-ethanediol.e) 98 % (m/m) 1,3-propanediol.f) Helium or nitrogen (having a purity of not less than 99,5 % (V/V).g) Hydrogen (having a purity of at least 99,5 % (V/V) and hydrocarbon-free synthetic air, as detector gases.7 SamplingSee DIN 51574, DIN 51750-1 and DIN 5175
19、0-2.1) Information on sources of supply is obtainable from Fachausschuss Minerall- und Brennstoffnormung,Kapstadtring 2, 22297 Hamburg, Germany.8 Procedure8.1 Determining the substance-specific factor8.1.1 Preparation of solutionWeigh, to an accuracy of 0,1 mg, 50 mg to 100 mg each of 1,2-ethanediol
20、 and 1,3-propanediol into a sealablecontainer, add about 40 g of isobutyl methyl ketone (MIBK) and mix thoroughly. Dilute one part by volume ofthis solution with nine parts by volume of isobutyl methyl ketone.Apply 2 ml of this solution to the diol column and suck it through the column into a beaker
21、 by applying a vacuum(about 0,1 kPa). Wash the column three times with 2 ml of cyclohexane and then dry for five minutes with air.Place a collection vessel in the vacuum unit and elute the diols with two 1 ml portions of ethanol into the samplecontainer after a residence time of 30 seconds in each c
22、ase. Then elute with two 1 ml portions of ethanol, withouta residence time.To determine a mean value of the substance-specific factor, f, take at least two somewhat different values forthe initial sample mass.NOTE: Since the ratio of the weighed amounts of 1,2-ethanediol and 1,3-propanediol is not t
23、he same as thatof the resultant peak areas, it is advisable to treat the solution prepared for determining the substance-specific factor in the same way as the motor oil to be tested.8.1.2 CalculationCalculate the substance-specific factor, f, using equation (1):(1)where:A (C3H8O2) is the 1,3-propan
24、ediol peak area;A (C2H6O2) is the 1,2-ethanediol peak area;m (C3H8O2) is the mass of 1,3-propanediol, in mg;m (C2H6O2) is the mass of 1,2-ethanediol, in mg.8.2 Standard solution8.2.1 PreparationWeigh, to an accuracy of 0,1 mg, between 50 and 100 mg of 1,3-propanediol into a sealable container and ad
25、dabout 75 g of isobutyl methyl ketone, weighed to an accuracy of 0,1 mg. This solution will be stable for aboutsix months if refrigerated.NOTE: The concentration of the standard in this solution is in the range from 1 mg/ml to 2 mg/ml, i.e. well belowthe solubility limit of propanediol in isobutyl m
26、ethyl ketone (about 10 mg/ml).8.2.2 EvaluationCalculate the 1,3-propanediol content, w(C3H8O2), in mg/kg, using equation (2):(2)wherem (C3H8O2) is the initial sample mass of 1,3-propanediol, in mg;m (MIBK) is the initial sample mass of isobutyl methyl ketone, in mg.8.3 Test solution8.3.1 Sample pret
27、reatmentAfter heating the sample to about 60 C, shake it vigorously for one minute and then homogenize for about fiveminutes in an ultrasonic bath. Then shake the sample well for a further minute.Using the analytical balance, weigh, to an accuracy of 0,1 mg, about 2,5 g of the oil to be analysed and
28、 1,6 gof standard solution into a 10 ml volumetric flask. Make the mixture up to the mark with cyclohexane and shakewell.Page 3DIN 51375-2 : 2001-06)()()()(G32G38G33G32G36G32G32G36G32G32G38G33G4FG48G43G4FG48G43G4FG48G43G4FG48G43mAmAf=()()()(G32G38G33G36G32G38G33G32G38G33G4FG48G43G4DG49G42G4BG31G30G4
29、FG48G43G4FG48G43mmmw+=Page 4DIN 51375-2 : 2001-068.3.2 ExtractionIt is not necessary to precondition the prepacked column. Prepare the vacuum unit for the sample and placea collection vessel (e.g. 50 ml beaker) in it. Apply 2 ml of the test solution prepared as specified in subclause8.3.1 to the col
30、umn. After connecting the column to the vacuum unit, apply a slight vacuum (about 0,1 kPa) tosuck the solution through the column. After washing three times with 2 ml of cyclohexane, wash the packedcolumn until it is oil-free. Remove the collection vessel from the vacuum unit and dry the column for
31、five minuteswith air.Place a collection vessel (e.g. septum flask) in the vacuum unit with the lowest part of the metal tips of thecolumn projecting into it. Then elute the diols with two portions of 1 ml of ethanol into the sample vessel, witha residence time of 30 seconds in each case. Following t
32、hat, elute with two portions of 1 ml without a residencetime.8.4 Gas chromatography8.4.1 GeneralIdentify the diols by comparing the retention times, if necessary also by adding the substance concerned to theanalytical mixture. To obtain a quantitative evaluation, compare the 1,2-ethanediol peaks obt
33、ained with thoseof the internal standard.It is advisable to bake the column after a series of measurements.8.4.2 Analysis of the solutionsThe following equipment parameters have proved satisfactory for analysing the solutions prepared as specifiedin subclauses 8.1.1 and 8.3.2.Temperature of injectio
34、n system: 200 C.Detector temperature: 250 C.Column oven temperature programme:Heat to 60 C, maintain for 5 minutes, then continue heating to 100 C, maintain for 5 minutes, at a rate of5 C/min, or maintain temperature at 140 C to 180 C (isothermal).Split ratio: about 1 : 20.Carrier gas (helium or nit
35、rogen) flow: 1 ml to 2 ml/min.Volume injected: about 1 l.To obtain good separation, inject only small amounts and set the amplification of the gas chromatographysignal to a relatively high level.Always check the substance-specific factor daily.9 EvaluationCalculate the 1,2-ethanediol content, w(C2H6
36、O2), in mg/kg, using equation (3):(3)wherew(C3H8O2) is the proportion by mass of 1,3-propanediol in the internal standard, in mg/kg (see subclause 8.2);A (C3H8O2) is the peak area of 1,3-propanediol internal standard;A (C2H6O2) is the 1,2-ethanediol peak area;m (C3H8O2) is the initial sample mass of
37、 1,3-propanediol internal standard solution, in g;mpis the initial sample mass, in g;f is the substance-specific factor of 1,2-ethanediol (see subclause 8.1).10 Expression of resultRefer to this standard and report the 1,2-ethanediol content in mg/kg. Take due account of DIN 1333 whenrounding to the
38、 last significant place.()()()()pmAwmfAw=G32G38G33G32G38G33G32G38G33G32G36G32G32G36G32G4FG48G43G4FG48G43G4FG48G43G4FG48G43G4FG48G43Page 5DIN 51375-2 : 2001-0611 Precision(cf. DIN EN ISO 4259)Repeatability limit(same operator, same equipment)If two results are obtained under repeatability conditions
39、by the same operator, both results shall be consideredacceptable and in conformity with this standard if they differ by no more than 10 %.Reproducibility limit(different operator, different equipment)If two separate laboratories each obtain a result under reproducibility conditions, both results shall be consid-ered acceptable and in conformity with this standard if they differ by no more than 20 %.
