DIN EN ISO 16558-1-2015 Soil quality - Risk-based petroleum hydrocarbons - Part 1 Determination of aliphatic and aromatic fractions of volatile petroleum hydrocarbons using gas chr.pdf

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1、December 2015 English price group 14No part of this translation 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 13.080.10!%Jw 6 to 8 69 to 128

2、Cyclohexane, methylcyclopentane, dimethyl-cyclopentane, methyl- and dimethyl-cyclohexane, branched C7- and C8-alkane 8 to 10 128 to 175 n-nonane, 2-methylnonane, 1,1,3-trimethyl-cyclohexane, 2,3-dimethylheptane, n-decane7EN ISO 16558-1:2015 (E) DIN EN ISO 16558-1:2015-12Structure typeEC number range

3、 Carbon number of n-alkanesBoiling rangeCExample compoundsAromatic compounds 6 to 9 69 to 151 BTEX single compounds, styrene 9 to 10 151 to 184 Allylbenzene, i- and n-propylbenzene, 2- and 3- and 4-ethyltoluene, 1,2- and 1,3-diethylbenzene, 1,2,3- and 1,2,4- and 1,3,5-trimethylbenzene, isopropenylbe

4、nzene4 InterferencesCompounds not related to petroleum hydrocarbon contaminations with boiling point between C5and C10(e.g. halogenated hydrocarbons and ethers as MTBE and TAME) can interfere with the aliphatic fractions.5 PrincipleTest samples are taken from an untreated field moist soil sample. To

5、 prevent losses of the volatiles, samples are taken as undisturbed as possible in the field with a tube corer or by adding methanol immediately in the field (see ISO 22155 for further information).The test sample is extracted with methanol. An aliquot of the methanol extract is transferred into a he

6、adspace vial with a defined amount of water and sealed. The temperature of the vials is stabilized in a thermostatic system to a temperature within the range 50 C to 80 C to achieve specified equilibrium conditions. Gas chromatographic analysis of the volatile compounds in gaseous phase in equilibri

7、um with the water in the vials is carried out by using headspace injection and an appropriate capillary column. The compounds are detected with a mass spectrometric detector (MS).The procedure as described in ISO 22155 is followed for determination of the individual aromatic compounds. Several aroma

8、tic fractions are then determined by summation of individual aromatic compounds.On the basis of the peak pattern of the gas chromatogram and of the boiling points of the individual n-alkanes between C5H12to C10H22(retention time standard), the sub-fractions of the volatile aliphatic hydrocarbons can

9、 be fixed and the peak areas of the sub-fractions can be integrated and hence used for quantification.The total peak areas between the EC range defining standards between n-pentane and n-decane is measured and the content of the volatile aliphatic hydrocarbons in the sample is quantified against an

10、external standard mix consisting of different types of volatile aliphatic compounds which are typical for petroleum hydrocarbons.6 ReagentsAll reagents shall be of recognized analytical grade. Verify whether the reagents are applicable for this specific purpose and free of interfering compounds.6.1

11、Water, free of volatile organic compounds.Water, free from organic contaminants. It shall show negligible interferences in comparison with the smallest concentration to be determined. Sufficient water from the same batch should be available to complete each batch of analyses including all preparatio

12、ns.Water can be heated in a round bottom flask for about 30 min to remove remains of volatile compounds.Table 1 (continued)8 EN ISO 16558-1:2015 (E) DIN EN ISO 16558-1:2015-126.2 Methanol (CAS-RN1)67-56-1).Solvent for the extraction of soil samples and for the preparation of standard solutions.6.3 I

13、nternal standard compounds.For the determination of volatile aromatic hydrocarbons by GC-MS, two or more internal standards shall be selected. They shall not interfere with compounds present in the methanol extract.Examples of suitable internal standards are the following:a) toluene-D8 (CAS-RN 2037-

14、26-5);b) ethylbenzene-D10 (CAS-RN 25837-05-2);c) 1,3,5-trimethylbenzene D3 (CAS-RN 38574-14-0).Example of suitable non-deuterated internal standard: -trifluorotoluene (CAS-RN 98-08-8).6.4 Retention time standard solution.It is the fraction range defining standard solution containing n-pentane, n-hex

15、ane, n-heptane, n-octane, n-nonane, and n-decane.Prepare a mixture of equal amounts, on a mass basis, of the n-alkanes with carbon numbers from C5to C10, dissolved in methanol (6.2), to give concentrations of about 50 mg/l of each n-alkane. Store at room temperature.NOTE This solution is used to giv

16、e information of the retention times of the n-alkanes to define the volatile hydrocarbon fractions in the samples.6.5 Volatile aromatic hydrocarbon standards between EC numbers range 6 to 10 for calibration of headspace GC-MS system.Compound CAS-RN EC number range 6 to 9 benzene 71432 toluene 108883

17、 ethylbenzene 100414 o-xylene 95476 m-xylene 108383 p-xylene 106423 styrene 100425 EC number range 9 to 10 allylbenzene 300572 isoproprenylbenzene 98839 1) CAS-RN: Chemical Abstracts Service Registry Number.9EN ISO 16558-1:2015 (E) DIN EN ISO 16558-1:2015-122-ethyltoluene 611143 3-ethyltoluene 62014

18、4 4-ethyltoluene 622968 1,2,3-trimethylbenzene 526738 1,2,4-trimethylbenzene 95636 1,3,5-trimethylbenzene 108678 isopropylbenzene 98828 sec-butylbenzene 135988 1,2-diethylbenzene 135013 1,3-diethylbenzene 141935 The detector responses of these selected compounds are measured by headspace gas chromat

19、ography with a mass spectrometric detector (electron ionization with selected ion monitoring of mass fragments m/z 78 for benzene and m/z 91 for toluene, ethylbenzene, and xylenes, m/z 104 for styrene, and m/z 91+105+117+118+119+120+134 for di- and tri-alkylated benzene), which are used for quantifi

20、cation.6.6 Volatile aliphatic hydrocarbon standards between EC numbers range 5 to 10 for calibration of headspace GC-MS system.Aliphatic compound CAS-RN n-pentane 109660 n-hexane 110543 n-heptane 142825 n-octane 111659 n-nonane 111842 n-decane 124185 Cyclopentane 287923 2-methylpentane 107835 3-meth

21、ylpentane 96140 methylcyclopentane 96377 2,2-dimethylpentane 590352 2,3-dimethylbutane 79298 Trans-Pentadiene 2004708 Cyclohexane 110827 Methylcyclohexane 108872 1,1-Dimethylcyclohexane 590669 10 EN ISO 16558-1:2015 (E) DIN EN ISO 16558-1:2015-12The detector responses of these selected compounds are

22、 measured by headspace gas chromatography with a mass spectrometric detector (electron ionization with selected ion monitoring of mass fragments m/z 41+43+55+56+57+69+70+71 for olefenic, alicyclic branched, and paraffinic short hydrocarbons), which are used for quantification.6.7 Carrier gases for g

23、as chromatography.Helium or nitrogen gases for headspace gas chromatography shall be used in accordance with the instrument manufacturers instructions.6.8 Standard solutions.6.8.1 Standard stock solutions for the volatile compounds in methanol.Prepare the stock solutions by adding to methanol define

24、d amounts (e.g. 100 l) of each standard compound 6.5 or 6.6 with a microlitre syringe. Immerse the tip of the needle in the solvent methanol and weigh with an accuracy of 0,1 mg.A convenient concentration (4 mg/ml) of the standard stock solution is obtained by weighing 100 mg of the standard substan

25、ce and dissolving it in 25 ml of the solvent. The stock solution is stable for about 6 months when stored at 18 C.For practical reasons, mixed standard stock solutions can also be used.6.8.2 Internal standard for GC-MS and retention time standard stock solutions in methanol.Prepare the internal stan

26、dard stock solutions with the individual internal standard compounds (6.3) and the individual aliphatic retention standard compounds (6.4) in the same procedure as in 6.8.1.The containers containing the solutions shall be weighed so that any evaporation losses of the solvent may be recognized. The s

27、olutions shall be stored at a temperature of (4 2) C in the dark. Prior to use, they shall be brought to ambient temperature.6.8.3 Intermediate mixed standard solutions.Prepare intermediate mixed standard solutions by mixing a defined volume of each individual standard stock solution or a mixed stan

28、dard stock solution and dilute with methanol.NOTE A typical concentration is 40 g/ml.Store the intermediate mixed standard solutions at (4 2) C no longer than 3 months.6.8.4 Working standard solutions.Prepare at least five different concentrations (e.g. from 0,2 g/ml to 3,2 g/ml) by suitable dilutio

29、ns, adding 50 l to 500 l of the intermediate mixed standard solutions (6.8.3) to methanol (10 ml) using a microlitre syringe.6.8.5 Working internal standard for GC-MS and retention time standard solutions.Prepare the internal standard and retention standard solutions of defined concentration (e.g. 0

30、,4 g/ml) as described in 6.8.2.6.8.6 Aqueous calibration standard solutions.Prepare the calibration solutions (see Table 2) by adding a defined amount (e.g. 50 l) of working standard solutions and internal standard solutions to a defined volume (e.g. 10 ml) of water in an appropriate headspace vial.

31、 Use a syringe and immerse the top of the needle in the water. Seal the vial tightly with a crimp cap fitted with polytetrafluoroethylene (PTFE) coated septum. The total volume of 11EN ISO 16558-1:2015 (E) DIN EN ISO 16558-1:2015-12the methanol used for calibration shall be the same which will be ta

32、ken for the methanol extract of the soil sample (see 9.3). Make sure that the content of the organic solvent in the final aqueous calibration standard solution does not exceed 1 % (V/V ).Table 2 Examples for preparation of aqueous calibration standard solutionsCalibration solutionWorking standard so

33、lution (6.8.4)Working internal standard solutions (6.8.5)Concentration in working standard solutionQuantity in calibration solution of 10 ml (sample) waterConcentration in aqueous calibration solutionl l g/ml ng g/l1 50 50 (methanol) 0 0 02 50 50 0,2 10 13 50 50 0,4 20 24 50 50 0,8 40 45 50 50 1,6 8

34、0 86 50 50 3,2 160 166.8.7 Methanol containing internal standards.Prepare methanol containing a suitable concentration of the internal standards (e.g. 0,4 g/ml). The concentration shall be such that the end concentration in the water extract in the headspace vial is of the same level as in the calib

35、ration standards.7 ApparatusUse usual laboratory glassware free of interfering compounds.All glassware shall be cleaned according to the usual procedures for this type of analysis.7.1 Glass vials with suitable septum.Use vials (50 ml to 100 ml) and screw cap fitted with a PTFE-coated septum for fiel

36、d moist soil samples taken in the field. Glass vials (10 ml for 5 ml water and 22 ml for 10 ml water) with a PTFE-coated septum and crimped metallic cap compatible with the headspace system connected to an appropriate gas chromatographic system. The vials shall be capable of being hermetically seale

37、d in the field as well as at elevated temperatures.7.2 Crimping pliers.7.3 Headspace system.This method was developed for using a totally automated equilibrium headspace analyser available from several commercial sources. The system used shall meet the following specifications:a) the system shall be

38、 capable of keeping the vials at a constant temperature (between 50 C and 80 C);b) the system shall be capable of transferring accurately a representative portion of the headspace into a gas chromatograph fitted with capillary columns.7.4 Shaking machine.A shaking machine with 200 to 300 horizontal

39、movements per minute.12 EN ISO 16558-1:2015 (E) DIN EN ISO 16558-1:2015-127.5 Capillary columns.Fused silica capillary columns with a non-polar stationary phase allowing sufficient separation of the compounds of interest shall be used. A thick film of stationary phase increases the efficiency of the

40、 separation of more volatile compounds.NOTE Examples are given in 9.4.7.6 Gas chromatograph equipped with a mass spectrometer (MS).The mass spectrometer should be able of operating over the total mass range of interest and being equipped with a data system capable of quantifying ions using selected

41、m/z values.7.7 Syringe, volume 5 l, 10 l, 50 l, 100 l, 250 l, and 500 l.7.8 Bottle-top dispenser.8 Sampling, preservation, and sample pretreatment8.1 GeneralSampling shall be carried out according to ISO 10381-1 using equipment according to ISO 10381-2 after coordination with the analytical laborato

42、ry.Samples shall be analysed as soon as possible. Samples shall be stored cool according to ISO 18512. Samples are not pretreated. Exposure of samples to air even during sampling shall be avoided as far as possible.Sampling for volatile compounds can be carried out with several techniques. It is str

43、ongly recommended to use one of the procedures described in 8.2 and 8.3 in order to prevent losses by volatilization.Determine the dry matter content of the field moist sample according to ISO 11465. In case sampling method 8.2 is used, a separate sample should be delivered to the laboratory for det

44、ermination of the dry matter.8.2 Sampling using vials pre-filled with methanolTransfer a defined volume of soil using an appropriate device into a pre-weighed vial which is filled with a defined volume of methanol already containing internal standards (6.8.7). Prevent leakages by cleaning the top of

45、 the vessel before sealing.The soil samples should be taken from undisturbed material using an appropriate sample cutter of known volume, e.g. a modified 20 ml disposable plastic syringe with the tip cut off. The soil sample should be collected immediately after exposing a fresh soil surface of the

46、drilling core, e.g. of an open window sampler or the trial pit wall. The incorporation of material like roots or stones should be avoided as far as possible.Make sure that the sample is completely covered with methanol already containing internal standards (6.8.7). Then, close the cap of the PTFE co

47、ated septum. At least one blank sample on every site shall be prepared in the field by opening the prepared vial for the same time period as necessary for the filling with soil sample. Add methanol (6.2) and close the cap of the vial.The sampling vials should be kept dark in a cooler (before and aft

48、er sampling) throughout the whole transportation (for details, see ISO 18512). Weigh the vial with methanol and sample on the laboratory.The procedure described here assumes that methanol containing internal standards is used. It is also acceptable that the internal standards are added to the methan

49、ol in the laboratory at the start of the extraction procedure.13EN ISO 16558-1:2015 (E) DIN EN ISO 16558-1:2015-128.3 Sampling using coring tube methodThis method, by taking an undisturbed sample, greatly reduces or eliminates common losses (e.g. due to evaporation, diffusion, sorption onto plastics). This method involves a stainless steel coring tube of at least 200 ml which is filled in situ, retrieved and capped with a non-permeable material, e.g. stainless steel or aluminium foi