SIST EN 13657:2004

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.HQWRYCharakterisierung von Abfällen - Aufschluss zur anschließenden Bestimmung des in Königswasser löslichen Anteils an Elementen in AbfällenCaractérisation des déchets - Digestion en vue de la détermination ultérieure de la part des éléments solubles dans l'eau régale contenus dans les déchetsCharacterization of waste - Digestion for subsequent determination of aqua regia soluble portion of elements13.030.40Naprave in oprema za odstranjevanje in obdelavo odpadkovInstallations and equipment for waste disposal and treatmentICS:Ta slovenski standard je istoveten z:EN 13657:2002SIST EN 13657:2004en01-januar-2004SIST EN 13657:2004SLOVENSKI
STANDARD



SIST EN 13657:2004



EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13657October 2002ICS 13.030.40English versionCharacterization of waste - Digestion for subsequentdetermination of aqua regia soluble portion of elementsCaractérisation des déchets - Digestion en vue de ladétermination ultérieure de la part des éléments solublesdans l'eau régale contenus dans les déchetsCharakterisierung von Abfällen - Aufschluss zuranschließenden Bestimmung des in Königswasserlöslichen Anteils an Elementen in AbfällenThis European Standard was approved by CEN on 19 August 2002.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 bibliographical references concerning such nationalstandards may be obtained on application to the 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 of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2002 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13657:2002 ESIST EN 13657:2004



EN 13657:2002 (E)2ContentspageForeword.3Introduction.41Scope.52Normative references.53Terms and definitions.54Safety remarks.65Sample.65.1Sample pre-treatment.65.2Mass of test portion.76Equipment.76.1Closed vessel system.76.1.1Microwave unit.76.1.2Digestion vessels.76.2Semi-open vessel system.86.2.1Microwave unit.86.2.2Digestion vessels.86.3Apparatus for thermal heating digestion.86.3.1Reaction vessels.86.3.2Reflux condenser.86.3.3Absorption vessel.86.3.4Roughened glass beards.86.3.5Temperature-controlled heating apparatus.86.4General equipment.87Reagents.98Interferences and sources of error.98.1General informations.98.2Closed vessel system.98.3Semi-open vessel system for microwave or thermal heating digestion.109Procedure.109.1Blank test.109.2Procedure for microwave assisted digestion in closed vessels.109.3Procedure for microwave assisted digestion in semi-open vessels.119.3.1Amount of samples.119.3.2Digestion.119.3.3Preparation of the solution for analysis.119.4Procedure for thermal heating digestion in reflux systems.119.4.1Amount of samples.119.4.2Digestion.129.4.3Preparation of the solution for analysis.1210Test report.12Annex A
(normative)
Calibration of the power adjustment.14Annex B
(informative)
Validation.15B.1Inter-laboratory study.15B.2Robustness study.23Bibliography.26SIST EN 13657:2004



EN 13657:2002 (E)3ForewordThis document EN 13657:2002 has been prepared by Technical Committee CEN/TC 292 "Characterization ofwaste", 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 textor by endorsement, at the latest by April 2003, and conflicting national standards shall be withdrawn at the latestby April 2003.In this European Standard the annex A is normative and the annexe B is informative.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark,Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,Spain, Sweden, Switzerland and the United Kingdom.SIST EN 13657:2004



EN 13657:2002 (E)4IntroductionThe aim of this European Standard is to describe suitable methods for the extraction of elements in waste,soluble by digestion with aqua regia, i. e. aqua regia soluble elements.For those types of waste, where the sample material by the described digestion with aqua regia are not broughttotally in solution, the obtained results will not be the total amount of the elements in the waste.The obtained results of aqua regia soluble elements cannot be regarded as available for leaching, as thedigestion with aqua regia is too vigorous to represent natural processes.SIST EN 13657:2004



EN 13657:2002 (E)51 ScopeThis European Standard specifies methods of digestion with aqua regia. Solutions produced by the methods aresuitable for analysis e.g. by atomic absorption spectrometry (FLAAS, HGAAS, CVAAS, GFAAS), inductivelycoupled plasma emission spectrometry (ICP-OES) and inductive coupled plasma mass spectrometry (ICP-MS).The digestion with aqua regia will not necessarily release all elements completely. However for mostenvironmental application and waste characterization the results fit for the purpose.The method is applicable to the digestion of waste for example for the following elements: Al, Sb, As, B, Ba, Be,Ca, Cd, Cr, Co, Cu, Fe, Pb, Mg, Mn, Hg, Mo, Ni, P, K, Se, Ag, S, Na, Sr, Sn, Te, Ti, Tl, V, Zn.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN ISO 3696:1995, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987).3 Terms and definitionsFor the purposes of this European Standard, the following terms and definitions apply.3.1aqua regiadigestion solution obtained by mixing 1 volume of nitric acid (65 % m/m to 70 % m/m) and 3 volumes ofhydrochloric acid (35 % m/m to 37 % m/m)3.2digestionmineralization of the organic matter of a sample and dissolution of its mineral part, more or less completely,when reacted with a reagent mixture3.3sampleportion of material selected from a larger quantity of material[ENV 12506:2001]3.4laboratory samplesample or subsample(s) sent to or received by the laboratory[ENV 12506:2001]3.5test sample; analytical samplesample, prepared from the laboratory sample, from which test portions are removed for testing or analysis[ENV 12506:2001]SIST EN 13657:2004



EN 13657:2002 (E)63.6test portion; analytical portionquantity of material of proper size for measurement of the concentration or other properties of interest, removedfrom the test sample[ENV 12506:2001]NOTE 1The test portion may be taken from the laboratory sample directly if no preparation of sample is required (e. g. withliquids), but usually it is taken from the prepared test sample.NOTE 2A unit or increment of proper homogeneity, size and fineness, needing no further preparation, may be a test portion.3.7dry residuedry matter expressed as a percentage by mass after drying at 105 °C ± 5 °C to the constancy of weight3.8digestion vesselspecial flask where the test portion and the acid mixture are filled in and the digestion is performed3.9microwave unitwhole microwave digestion system (oven and associated equipment)3.10microwave unit cavitythe inner part of the microwave unit in which the digestion vessel is located and the microwave digestion isperformed3.11focused microwave unitmicrowave unit in which a precise control of the electric field is made by using a wave guideNOTEMicrowaves are focused at the bottom part of the digestion vessel.4 Safety remarksAll this work has to be performed by skilled persons.The reagents used within this EN are strongly corrosive and partly very toxic. Safety precautions are absolutelynecessary due to strong corrosive reagents, high temperature and high pressure.All procedures have to be performed in a hood or in closed force-ventilated equipment. By the use of strongoxidising reagents the formation of explosive organic intermediates is possible especially when dealing withsamples with a high organic content. Do not open pressurised vessels before they have cooled down. Avoidcontact with the chemicals and the gaseous reaction products. Samples and solutions have to be disposed ofaccording to regulations.5 Sample5.1 Sample pre-treatmentThe test portion should be transferred into the vessel as it is without any pre-treatment if possible.This isapplicable only if the test portion is representative for the laboratory sample and the effectiveness of thedigestion is proven.SIST EN 13657:2004



EN 13657:2002 (E)7If these conditions are not met a pre-treatment of the laboratory sample is necessary. This procedure shall notchange the concentration of the elements of interest.Pre-treatment should include drying or grain size reduction below a particle size of 250 µm for solid waste orhomogenizing by use of a high speed mixer or sonification for liquid samples.The mass of laboratory samples shall be sufficient for the multiple digestion procedures and determination ofthe dry residue.5.2 Mass of test portionThe mass of test portion for a single digestion has to be selected in a way, that:— it is representative for the laboratory sample;— it complies with the specifications of manufacturer of the digestion unit.NOTEIf the representative test portion exceeds the manufacturers specifications the test portion should be devided intosmaller quantities and digested seperately. The individual digests should be combined prior to analysis.For representativity reason mass above 200 mg is to be preferred. Unless recommended by the manufacturerthe amount of organic carbon shall not exceed 100 mg because of safety reasons in the case of closeddigestion vessel.6 Equipment6.1 Closed vessel system6.1.1 Microwave unitThe microwave unit shall provide programmable power which can be programmed to within ± 10 W of therequired power. Typical units provide a nominal 600 W to 1 200 W of power. If necessary (referring tomanufactures specifications) calibration of the microwave unit has to be performed (see annex A).The microwave unit has to comply to European and national regulations relevant to microwave radiation.The microwave unit cavity has to be well ventilated. It has to have an exhaust air tube which is connected to acorrosion resistant laboratory air outlet system or the instrument is provided for use in a laboratory hood.All electronics are sufficiently protected against corrosion for safe operation. All parts which could have contactwith acids or their vapours have to be corrosion resistant.The microwave unit shall be designed in a way that guarantees homogeneous heating of the samples.The microwave unit cavity has to be built in a way that even in case of leakage or explosion of the vessels thesafety of the operators can be guaranteed. Household instruments are not suitable for laboratory use.NOTEThe microwave unit should include a temperature and/or pressure control system.6.1.2 Digestion vesselsThe vessels used in the microwave unit shall be equiped with a pressure relieve valve or another technicalequipment which avoids the bursting of the vessels at suddenly occuring excess pressure. The material of thevessels has to be inert to the acids used for digestion. The digestion vessel shall withstand the pressure of atleast 8 bar. If the amount of organic carbon exceeds 100 mg it has to be ensured that the digestion vessel iscapable of withstanding higher pressures.SIST EN 13657:2004



EN 13657:2002 (E)86.2 Semi-open vessel system6.2.1 Microwave unitThe microwave unit shall be equiped with power control. Typical unit provides a nominal 200 W or 300 W ofreleased power. If necessary, calibration of the microwave unit has to be performed by the manufacturer.The microwave unit shall comply with European and national regulations relevant to microwave radiation.The microwave unit shall be designed for use in a laboratory hood.Fume extraction equipment, used to extract acid vapours from the reaction vessels during the digestionprogram, shall have sufficient flow rate to prevent the release of dangerous vapours into the laboratory.All electronics shall be sufficiently protected against corrosion for safe operation. All parts which can be incontact with acids or their vapours shall be corrosion resistant.6.2.2 Digestion vesselsThe vessel is working at atmospheric pressure and has to be connected with a reflux system to avoid losses ofanalytes. The vessel shall comply with the manufactures specifications and should have a minimum volume of50 ml.The material of the vessels has to be inert to the reagents used for digestion.6.3 Apparatus for thermal heating digestion6.3.1 Reaction vesselsThe reaction vessel shall have a volume of at least 5 times of the volume of the aqua regia used.6.3.2 Reflux condenserWater-cooled reflux condenser, minimum assembled length 340 mm with conical ground joints.6.3.3 Absorption vesselNon-return type.6.3.4 Roughened glass beardsDiameter 2 mm to 3 mm (or anti bumping granules), acid washed.6.3.5 Temperature-controlled heating apparatusCapable of heating the contents of the reaction vessel to reflux temperature.6.4 General equipmentThe following equipment is used by the systems described in 6.1, 6.2 and 6.3:— volumetric graduated flasks and pipettes of adequate size;— filter equipment of adequate chemical resistance and purity or centrifuge;SIST EN 13657:2004



EN 13657:2002 (E)9— analytical balance, with an error limit of ± 0,1 mg.For the preparation of standards and the treatment and storage of samples for determination of boron the use ofborosilicate glass shall be avoided.7 ReagentsUse reagents of analytical grade quality or better and water of grade 1 according to EN ISO 3696:1995.— Hydrochloric acid (HCl): a mass fraction of 35 % to 37 %;— Nitric acid (HNO3): a mass fraction of 65 % to 70 %;— Diluted nitric acid: c(HNO3) = 0,5 mol/l.8 Interferences and sources of error8.1 General informationsDue to the volatility of some compounds it is of great importance to take care, that the sample is not heatedbefore the digestion and that the volatile reaction products which might be formed during the digestion are notallowed to escape.The container in which the sample is delivered and stored can be a source of errors. Its material shall be chosenaccording to the elements to be determined (e.g. elemental Hg can penetrate polyethylene walls very fast inboth directions. Glass can contaminate samples with elements contained: e.g. B, Na, K, Al).Grinding or milling samples includes a risk of contamination of the sample by the environment (air, dust, wear ofmilling equipment). Due to elevate temperature losses of volatile compounds are possible.For the determination of elements forming volatile compounds (e.g. Hg, As, Pb) special care has to be taken atsample pre-treatment.The use of the described digestion procedures may leave large parts of the sample undissolved. This includesthe risk of bad repeatability.High acid and solute concentrations in the digest may cause interferences at determination.Depending on the concentration of the element of interest and the wanted precision, a particular caution to thecleaning of the vessels shall be taken. It is recommended to clean the vessels with 10 % nitric acid.Care shall be taken to ensure that all of the test portion is brought into contact with the acid mixture in thereaction vessel.Some elements of interest can be lost because of precipitation with some ions of the solution. It is the case forinsoluble chlorides, fluorides and sulphates for example. In this case the precipitate can be analysed separately.In the case of filtration of the digested solution it is necessary to take care that the filtration procedure does notintroduce contaminants.8.2 Closed vessel systemThe upper limits of mass of the test portion referring to the manufacturers specifications have to be taken intoaccount.SIST EN 13657:2004



EN 13657:2002 (E)10Very reactive or volatile materials that may create high pressures when heated may cause a venting of thevessels with potential loss of sample and analytes. The complete decomposition of either carbonates, or carbonbased samples, may cause enough pressure to vent the vessel.After digestion, the vessel shall be cooled to room temperature before opening. If not, losses of certainelements, particulary volatile elements as mercury or arsenic can occur.8.3 Semi-open vessel system for microwave or thermal heating digestionDepending on the volatility of some elements of interest, the reflux system can be inefficient to condense thevapours and losses of some elements of interest can happen.9 Procedure9.1 Blank testTo detect possible contaminations from vessels and/or reagents, blank tests shall be carried out in parallel bythe same digestion procedure and filtration if appropriate, using the same quantities of all reagents but omittingthe test portion.9.2 Procedure for microwave assisted digestion in closed vesselsWeigh between 0,2 g to 0,5 g of the sample, to the nearest 0,1 mg, prepared according to clause 5 and transferit into the vessel. If necessary the sample may be moistened with a minimum amount of water. Then addseperately 6 ml of HCl and 2 ml of HNO3.It is necessary to use only one specific reaction mixture as well as the same kind of matrix in the same quantityof test portion in a single batch in the microwave unit cavity to ensure consistent reaction conditions.If a vigorous reaction occurs, allow the reaction to lie down before capping the vessel. Transfer the digestionvessels into the microwave unit cavity according to the manufactures instructions and start the followingdigestion procedure.Table 1 — Power programmeTimeminPowerW225020525054005500The power programme (see Table 1) is intended to be used for batches of 6 samples. Commercial availablemicrowave units may contain more or less sample positions. In order to ensure consistant reaction conditions inthese cases the power programme has to be adjusted according to the manufactures instructions. For batcheswhere all positions are not occupied either the empty positions shall be filled up with e.g. blanks or duplicates orthe power programme shall be adjusted in accordance with the number of samples.At the end of the programme let the vessels cool down to room temperature. Confirm that no losses of digestionsolution occured during the procedure (e.g. by control of burstmembran referring to the manufacturesspecifications or controll of mass). Otherwise the samples have to be discarded. Carefully uncap and vent eachvessel in a fume hood, then transfer quantitatively the content of the vessels into a suitable sized volumetricflask and fill to the mark.SIST EN 13657:2004



EN 13657:2002 (E)11If the digested sample contains particles which might clog the nebulizers of the measurement apparatus orwhich might interfere with the injection of the sample into the instrument, the sample solution may becentrifuged, allowed to settle or be filtered. In the case of filtration, dilute the content of the vessel beforefiltering, rinse and then fill to the mark of the volumetric flask. The method used has to be reported in the testreport.9.3 Procedure for microwave assisted digestion in semi-open vessels9.3.1 Amount of samplesWeigh between 0,2 g to 1,0 g of the sample, to the nearest 0,1 mg, prepared according to clause 5 and transferit into the vessel. If necessary the sample may be moistened with a minimum amount of water.9.3.2 DigestionTransfer the digestion vessels into the microwave unit cavity according to the manufactures instructions andstart the following digestion procedure.Table 2 — Microwave programmeStepAcidVolumemlPowerWTimemin1HCl9002HNO3340153HCl9004HNO334015NOTEIntroduction of the digestion vessel into the microwave cavity, reagent injection into the digestion vessel,temperature and/or power control can be done automatically or manually depending on the apparatus used.24 ml of aqua regia is sufficient only for the oxidation of about 0,4 g organic carbon. If there is any doubt of the amount ofcarbon present, carry out a determination. If there is more than 0,4 g of organic carbon in the test portion, proceed asfollows.Allow first reaction with the aqua regia to subside. Then add an extra 1 ml of nitric acid only to every 0,1 g of organic carbonabove 0,4 g. Do not add more than 10 ml of nitric acid at any time, and allow any reaction to subside before preceedingfurther.At the end of the programme let the vessels cool down to room temperature.9.3.3 Preparation of the solution for analysisTransfer quantitatively the solution content of each vessel into a suitable sized volumetric flask and dilute to themark.If the digested mixture contains particles which might clog the nebulizers of the measurement apparatus orwhich might interfere with the injection of the sample into the instrument, the sample may be centrifuged,allowed to settle or be filtered. In the case of filtration, dilute the content of the vessel before filtering, rinse andthen dilute to the mark of the volumetric flask. The method used has to be reported in the test report.9.4 Procedure for thermal heating digestion in reflux systems9.4.1 Amount of samplesWeigh 1 g to 10 g, to the nearest 0,1 mg of the prepared sample and transfer to the reaction vessel.SIST EN 13657:2004



EN 13657:2002 (E)129.4.2 DigestionAdd, while mixing, the appropriate amount of hydrochloric acid followed by nitric acid, dropwise if necessary toreduce foaming. The mass: volume ratio between sample and acid mixture shall be 1:10. Connect thecondenser to the reaction vessel, fill the absorption vessel with aqua regia. Connect the absorption vessel to thecondenser and allow to stand at room temperature until effervescence lies down to allow for slow oxidation ofthe organic matter in the test portion.30 ml of aqua regia is sufficient only for the oxidation of about 0,5 g organic carbon. If there is any doubt of theamount of carbon present, carry out a determination. If there is more than 0,5 g of organic carbon in the testportion, proceed as follows.Allow first reaction with the aqua regia to subside. Then add an extra 1 ml of nitric acid only to every 0,1 g oforganic carbon above 0,5 g. Do not add more than 10 ml of nitric acid at any time, and allow any reaction tosubside before preceeding further.Raise the temperature of the reaction mixture slowly to reflux conditions and maintain for 2 h ensuring that thecondensation zone is lower than 1/3 of the height of the condenser, then allow to cool. Add the content of theadsorption vessel to the reaction vessel via the condenser, rinsing both the absorption vessel and condenserwith further 10 ml of diluted nitric acid.9.4.3 Preparation of the solution for analysisIf the digested mixture contains particles which might clog the nebulizers of the measurement apparatus orwhich might interfere with the injection of the sample into the instrument, the sample may be centrifuged,allowed to settle or be filtered. In the case of filtration, dilu
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