EN 13506:2001

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Water quality - Determination of mercury by atomic fluorescence spectrometryVSHNWURPHWULMRQualité de l'eau - Dosage du mercure par spectrométrie de fluorescence atomiqueWasserbeschaffenheit - Bestimmung von Quecksilber mittels Atomfluoreszenzspektrometrie13.060.50VQRYLExamination of water for chemical substancesICS:SIST EN 13506:2003enTa slovenski standard je istoveten z:EN 13506:200101-maj-2003SIST EN 13506:2003SLOVENSKI
STANDARDSIST EN ISO 17852:20081DGRPHãþD







EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13506November 2001ICS 13.060.50English versionWater quality - Determination of mercury by atomic fluorescencespectrometryQualité de l'eau - Dosage du mercure par spectrométrie defluorescence atomiqueWasserbeschaffenheit - Bestimmung von Quecksilbermittels AtomfluoreszenzspektrometrieThis European Standard was approved by CEN on 4 October 2001.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, 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© 2001 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13506:2001 E



EN 13506:2001 (E)2Contentspage1Scope.42Normative references.43Principle.54Interferences.55Reagents and Standards.56Apparatus and instrumentation.77Sample collection, preservation and storage.88Sample preparation procedure.99Instrumental set up.910Procedure.911Data analysis and calculations.1012Test report.1113Precision data.12Annex A (informative)
Additional Information.13Annex B (informative)
Schematic Block Diagram.14Annex C (informative)
Availability of Reagents etc.15Bibliography.16



EN 13506:2001 (E)3ForewordThis European Standard has been prepared by Technical Committee CEN/TC 230 "Water analysis", the secretariatof which is held by DIN.This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by May 2002, and conflicting national standards shall be withdrawn at the latest byMay 2002.Annexes designated "informative" are only given for information. In this standard, annexes A, B and C areinformative.WARNING — Persons using this standard should be familiar with normal laboratory practice. This standarddoes not purport to address all of the safety problems, if any, associated with its use. It is theresponsibility of the user to establish appropriate safety and health practices and to ensure compliancewith any national regulatory conditions.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, Netherlands, Norway, Portugal, Spain, Sweden,Switzerland and the United Kingdom.



EN 13506:2001 (E)4IntroductionIt is absolutely essential that tests conducted to this standard are carried out by suitably qualified staff.In natural water sources, mercury compounds generally occur in very small concentrations of less than 0,1 µg/l.Higher concentrations may be found, for example, in industrial waste water.Both inorganic and organic compounds of mercury may be present. Mercury can also accumulate in sediment andsludge.In order to fully decompose all of the mercury compounds, a digestion procedure is necessary. Digestion can beomitted only if it is certain that the mercury concentration can be measured without this pre-treatment.1 ScopeThis European Standard specifies a method for the determination of mercury in drinking, surface, ground and rainwater.NOTEIt is permissible, that this standard is also applied to industrial and municipal waste water after an additionaldigestion step under appropriate conditions.The potential linear dynamic range is approximately 1 ng/l to 100 µg/l. In practice, the working range is often from10 ng/l to 10 µg/l.Samples containing mercury at concentrations higher than the working range can be analysed followingappropriate dilution of the sample.The method detection limit (MDL) will be dependent on the selected operating conditions and calibration range.With high purity reagents a MDL of less than 1 ng/l is obtainable.The relative standard deviation is typically less than 5 % for concentrations greater than twenty times the methoddetection limit.The sensitivity of this method is dependent on the selected operating conditions.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 25667-1, Water quality - Sampling - Part 1: Guidance on the design of sampling programmes (ISO 5667-1:1980).EN 25667-2, Water quality - Sampling - Part 2: Guidance on sampling techniques (ISO 5667-2:1991).EN ISO 5667-3, Water quality - Sampling - Part 3: Guidance on the preservation and handling of samples (ISO5667-3:1994).EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987).



EN 13506:2001 (E)53 PrincipleAn aliquot of sample is digested using chemically generated bromine [1] [2]. This is known to breakdown all of thecommonly occurring organomercury species to mercury(II). Immediately prior to analysis, the excess bromine isremoved by ascorbic acid (see A.2).Elemental mercury vapour is generated from the digested sample by reduction with tin(II) chloride, and is purgedfrom solution by an argon gas carrier stream. Moisture is continually removed from the gas stream and the mercuryvapour is detected by atomic fluorescence spectrometry (AFS). The procedure is usually automated by means ofan auto sampler and control software.4 InterferencesWith mercury there is a risk that exchange reactions, that is adsorption and desorption, will occur on the walls ofsampling and reaction vessels.Mercury vapour can diffuse through various plastics; this phenomenon needs to be taken into consideration in thechoice of tubing material. Glass or special plastics tubing, e.g. FEP tubes, may be used (FEP = perfluoro(ethylene-propylene)). Silicone tubing, for example, is unsuitable.Suppression effects resulting from quenching of the atomic fluorescence signal can be encountered. Dissolvedgaseous species are usually removed during the digestion stage.The presence of water vapour or aerosol in the fluorescence cell may cause suppression due to quenching. Watervapour should be removed from the carrier gas stream using a hygroscopic membrane before entering thedetector[3].Anions which complex strongly with mercury can cause suppression. These include sulfide, iodide and bromide.The potassium bromide - potassium bromate reagent (5.5) causes no suppression if it is applied as required.The noble metals, such as gold, silver and platinum, amalgamate with mercury vapour and, therefore, may causesuppression.Volatile organics do not cause interference with the AFS method [4].5 Reagents and Standards5.1 GeneralReagents and water can contain mercury as an impurity. For high sensitivity use ultra-pure reagents or those withparticularly low mercury content compared to the lowest analyte concentration.5.2 WaterUse water with a purity fulfilling the requirements for grade 1 water according to EN ISO 3696 for all samplepreparations and dilutions.5.3 Potassium bromate solution, c(KBrO3) = 0,0333 mol/lDissolve 1,39 g of potassium bromate in 250 ml of water (5.2). Potassium bromate can be purified, if necessary, byheating in a muffle furnace overnight at 250 °C ± 20 °C. Prepare weekly.5.4 Potassium bromide solution, c(KBr) = 0,2 mol/lDissolve 5,95 g of potassium bromide in 250 ml of water (5.2). Potassium bromide can be purified, if necessary, byheating in a muffle furnace overnight at 300 °C ± 20 °C. Prepare monthly.



EN 13506:2001 (E)65.5 Potassium bromide - potassium bromate reagentMix equal volumes of potassium bromate (5.3) and potassium bromide solution (5.4). A total volume of 200 ml willallow digestion for 100 samples. Prepare daily.NOTEPre-mixed ampoules for potassium bromate-bromide stock solution are commercially available (see C.1). Thisreagent has been found to contain negligible mercury concentrations.5.6 L -ascorbic acid solution, (C6H8O6) = 100 g/lDissolve 10 g of L-ascorbic acid in water (5.2) in a 100 ml volumetric flask and make up to volume. Prepare weekly.5.7 Nitric acid, (HNO3) = 1,4 g/mlSee C.2.5.8 Potassium dichromate solution,
(K2Cr2O7) = 0,05 g/lDissolve 50 mg of K2Cr2O7 in 50 ml nitric acid (5.7) and dilute to 1 000 ml with water (5.2).5.9 Hydrochloric acid (HCl), w(HCl) = 120 g/kgDilute 167 ml of high purity hydrochloric acid w(HCl) = 360 g/kg ( (HCl) = 1,19 g/ml) to 500 ml with water (5.2).5.10 Tin(II)chloride solution,
(SnCl2
2 H2O) = 20 g/lAdd 10,0 g of tin(II)chloride dihydrate to 150 ml of hydrochloric acid (5.9). Heat to dissolve. Dilute to 500 ml withwater (5.2). To remove any traces of mercury, bubble the solution with argon, nitrogen or air e.g. at a flow rate of2 l/min for 15 min.NOTEThe hydrochloric acid used to prepare this solution can be analytical grade since any mercury present will beremoved on bubbling.5.11 Reagent blankFor each 100 ml, prepare a solution containing 15 ml of hydrochloric acid (5.9) and 2 ml of potassium bromide -potassium bromate reagent (5.5). Add 100 µl of ascorbic acid solution (5.6) for each 10 ml prepared [5]. It isessential that the same reagents used for sample and standard preparation are used for preparation of the reagentblank. Treat the reagent blank like a sample.NOTEOn the continuous flow system, the reagent blank solution is run as background for automatic blank subtraction.This solution can contain trace levels of detectable amounts of mercury.5.12 Mercury standard solutions5.12.1 Mercury stock solution A,
(Hg) = 1 000 mg/lUse a commercially available quantitative standard solution. This solution is stable for at least six months.Alternatively use a stock solution prepared from ultra high purity grade chemicals (99,99 / 99,999 % (mass fraction)pure). Dissolve 0,1354 g of mercury(II)chloride HgCl2 in 20 ml water (5.2). Add 5 ml of nitric acid (5.7) and dilute to100 ml.WARNING — Do not dry the inorganic salt, it is highly toxic.5.12.2 Mercury stock solution B, (Hg) = 10 mg/lDilute 1 ml of stock solution A (5.12.1) with water (5.2) to approximately 20 ml. Add 2 ml of potassium bromide -potassium bromate reagent (5.5) and 15 ml of hydrochloric acid (5.9) and dilute to 100 ml in a borosilicatevolumetric flask with water. Prepare weekly.



EN 13506:2001 (E)75.12.3 Mercury stock solution C,
(Hg) = 100 µg/lDilute 1 ml of stock solution B (5.12.2) to 100 ml with reagent blank (5.11) in a borosilicate flask.Prepare the solution on the day of use.5.12.4 Mercury stock solution D,
(Hg) = 1 µg/lDilute 1 ml of stock solution C (5.12.3) to 100 ml with reagent blank (5.11) in a borosilicate flask.Prepare the solution freshly before each series of measurements.5.12.5 Calibration standardsPrepare a minimum of five mercury calibration standards spanning the concentration range of interest by serialdilution of the stock solution D (5.12.4). Each calibration standard shall contain 15 ml of hydrochloric acid (5.9) and2 ml of potassium bromide - potassium bromate reagent (5.5) per 100 ml in borosilicate volumetric flasks. Plasticflasks should not be used if they are permeable to mercury(0) vapour. Prepare daily.The matrix of the reagent blank solution shall be identical to that of the standard solutions.For the concentration range from 10 ng/l to 100 ng/l, for example, proceed as follows: Prepare 5 calibration standards of concentrations 10 ng/l, 30 ng/l, 50 ng/l, 70 ng/l and 100 ng/l by taking 1 ml,3 ml, 5 ml, 7 ml and 10 ml respectively of mercury stock solution D (5.12.4) and diluting accurately to 100 mlwith reagent blank (5.11).For the concentration range from 2 ng/l to 20 ng/l, for example, proceed as follows: Prepare a working stock solution of 100 ng/l by taking 10 ml of mercury stock solution D (5.12.4) and diluting itaccurately to 100 ml with reagent blank (5.11). Prepare daily. From
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