DIN ISO 13165-1-2015 Water quality - Radium-226 - Part 1 Test method using liquid scintillation counting (ISO 13165-1 2013)《水质 镭-226 第1部分 使用液体闪烁计数的试验方法(ISO 13165-1-2013)》.pdf

1、November 2015English price group 11No 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 13.060.60; 17.240!%GD“2365733www

2、.din.deDIN ISO 13165-1Water quality Radium-226 Part 1: Test method using liquid scintillation counting (ISO 13165-1:2013),English translation of DIN ISO 13165-1:2015-11Wasserbeschaffenheit Radium-226 Teil 1: Verfahren mit dem Flssigszintillationszhler (ISO 13165-1:2013),Englische bersetzung von DIN

3、ISO 13165-1:2015-11Qualit de leau Radium 226 Partie 1: Mthode dessai par comptage des scintillations en milieu liquide (ISO 13165-1:2013),Traduction anglaise de DIN ISO 13165-1:2015-11www.beuth.deDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered au

4、thoritative.Document comprises 19 pages11.15 A comma is used as the decimal marker. Contents Page National foreword . 3 National Annex NA (informative) Bibliography . 4 Introduction 5 1 Scope . 6 2 Normative references 6 3 Symbols, definitions and units 6 4 Principle 7 5 Reagents and equipment . 7 5

5、.1 Reagents . 7 5.2 Equipment . 8 6 Sampling . 8 7 Instrument set-up and calibration . 9 7.1 Preparation of calibration sources . 9 7.2 Optimization of counting conditions 9 7.3 Detection efficiency . 9 7.4 Blank sample preparation and measurement . 10 8 Procedure 10 8.1 Direct counting . 10 8.2 The

6、rmal preconcentration 10 8.3 Sample preparation 11 8.4 Sample measurement 11 9 Quality control 11 10 Expression of results . 11 10.1 Calculation of massic activity . 11 10.2 Standard uncertainty . 11 10.3 Decision threshold 12 10.4 Detection limit 12 10.5 Confidence limits . 13 10.6 Calculations usi

7、ng the activity concentration . 13 11 Interference control 13 12 Test report . 14 Annex A (informative) Set-up parameters and validation data 15 Bibliography . 19 2DIN ISO 13165-1:2015-113DIN ISO 13165-1:2015-11National foreword This document (ISO 13165-1:2015) has been prepared by Technical Committ

8、ee ISO/TC 147 “Water quality” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was DIN-Normenausschuss Wasserwesen (DIN Standards Committee Water Practice), Working Committee NA 119-01-03 AA Wasserunter-suchung. Attention is drawn to the possibility that some of t

9、he elements of this document may be the subject of patent rights. DIN shall not be held responsible for identifying any or all such patent rights. ISO 13165, Water quality Radium-226, consists of the following parts: Part 1: Test method using liquid scintillation counting Part 2: Test method using e

10、manometry The following part is under preparation: Part 3: Test method using coprecipitation and gamma-spectrometry Designation of the method: Radium-226 - Test method using liquid scintillation counting (C 25): Method DIN EN ISO 13165-1 C 25 The DIN Standards corresponding to the International Stan

11、dards referred to in this document are as follows: ISO 3696 DIN ISO 3696 ISO 5667-1 DIN EN ISO 5667-1 ISO 5667-3 DIN EN ISO 5667-3 ISO 11929 DIN ISO 11929 ISO 80000-10 DIN EN ISO 80000-10 ISO/IEC 17025 DIN EN ISO/IEC 17025 + Cor 2 ISO 8258 referred to in the Bibliography under 5 has been withdrawn a

12、nd replaced by ISO 7870-2, Control charts Part 2: Shewhart control charts. Expert assistance and specialized laboratories will be required to perform the analyses described in this standard. Existing safety requirements are to be observed. Depending on the objective of the analysis, a check shall be

13、 made on a case-by-case basis as to whether and to what extent additional conditions will have to be specified. This standard has been prepared by the DIN-Normenausschuss Wasserwesen (Water Practice Standards Committee) in collaboration with the Wasserchemische Gesellschaft - Fachgruppe in der Gesel

14、lschaft Deutscher Chemiker (Water Chemistry Society - Division of the German Chemical Society). It is part of the series Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung (German standard methods for the examination of water, waste water and sludge): Radium-226 - Test method

15、using liquid scintillation counting (C 25). Standard methods published as DIN Standards are obtainable from Beuth Verlag GmbH, either individually or grouped in volumes. The standard methods included in the loose-leaf publication entitled Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlamm

16、untersuchung will continue to be published by Beuth Verlag GmbH and Wiley-VCH Verlag GmbH the guidance level for radium-226 in drinking water as recommended by WHO is 1 Bq l1(Reference 7).NOTE The guidance level is the activity concentration with an intake of 2 l day1of drinking water for 1 year tha

17、t results in an effective dose of 0,1 mSv year1for members of the public, an effective dose that represents a very low level of risk that is not expected to give rise to any detectable adverse health effect.This International Standard is one of a series on determination of the activity concentration

18、 of radionuclides in water samples.5DIN ISO 13165-1:2015-11WARNING Persons using this part of ISO 13165 should be familiar with normal laboratory practice. This part of ISO 13165 does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the

19、user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.IMPORTANT It is absolutely essential that tests conducted in accordance with this part of ISO 13165 be carried out by suitably qualified staff.1 ScopeThis part of ISO 13165 spec

20、ifies the determination of radium-226 (226Ra) activity concentration in non-saline water samples by extraction of its daughter radon-222 (222Rn) and its measurement using liquid scintillation counting.Radium-226 activity concentrations which can be measured by this test method utilizing currently av

21、ailable liquid scintillation counters goes down to 50 mBq l1. This method is not applicable to the measurement of other radium isotopes.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated

22、 references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3696, Water for analytical laboratory use Specification and test methodsISO 5667-1, Water quality Sampling Part 1: Guidance on the design of sampl

23、ing programmes and sampling techniquesISO 5667-3, Water quality Sampling Part 3: Preservation and handling of water samplesISO/IEC 17025, General requirements for the competence of testing and calibration laboratoriesISO 80000-10, Quantities and units Part 10: Atomic and nuclear physicsISO/IEC Guide

24、 98-3:2008, Uncertainty of measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)3 Symbols, definitions and unitsFor the purposes of this document, the definitions, symbols and abbreviations given in ISO 80000-10, ISO/IEC Guide 98-3, and the following apply.a massic act

25、ivity of the sample at the measuring time, in becquerels per gramaSmassic activity of the 226Ra standard solution at the measuring time, in becquerels per grama* decision threshold for the massic alpha-activity, in becquerels per gram6DIN ISO 13165-1:2015-11a#detection limit for the massic alpha-act

26、ivity, in becquerels per grama, alower and upper limits of the confidence interval, in becquerels per gramcAactivity concentration, in becquerels per litrem mass of the test sample, in gramsm1mass of initial sample subject to heating or possibly concentration, in gramsm2mass of heated or concentrate

27、d sample, in gramsm3mass of heated or concentrated sample transferred in the vial, in gramsmSmass of 226Ra standard solution used for the preparation of the calibration sample, in gramsr0blank sample count rate in the alpha-window, in reciprocal secondsrgsample gross count rate in the alpha-window,

28、in reciprocal secondsrScount rate of the calibration sample in the alpha-window, in reciprocal secondst0blank sample counting time, in secondstgsample counting time, in secondstScalibration sample counting time, in secondsu(a) standard uncertainty associated with the measurement result; in becquerel

29、s per gramU expanded uncertainty, calculated using U = ku(a), with k = 1, 2, in becquerels per gramw factor equal to 1/m alpha-efficiency density, in grams per litre4 Principle226Ra massic activity is determined by liquid scintillation counting of daughter 222Rn at isotopic equilibrium (99,56 %) rea

30、ched 30 d after the preparation of the sample. The 222Rn is extracted from aqueous solution by means of a scintillation cocktail immiscible with water inside the scintillation vial (References 14).The aqueous sample is acidified, heated and, if possible, concentrated by slow evaporation in order to

31、desorb 222Rn and to achieve a better detection limit. The concentrated aqueous sample is transferred into a radon-tight scintillation vial and a water-immiscible scintillation cocktail is added.After 30 d, the sample is measured by liquid scintillation counting (LSC) applying alpha and beta discrimi

32、nation: only alpha-emission of 222Rn and that of its short lived progeny (218Po, 214Po) are considered, as this counting condition ensures a better detection limit.5 Reagents and equipment5.1 ReagentsAll reagents shall be of recognized analytical grade and, except for 5.1.3 and 5.1.4, shall not cont

33、ain any detectable alpha- and beta-activity.7DIN ISO 13165-1:2015-115.1.1 Laboratory water, distilled or deionized, complying with ISO 3696, grade 3.Deionized water can contain detectable amounts of 222Rn and short-lived daughters. It is therefore strongly recommended that water be boiled under vigo

34、rous stirring and allowed to stand for 1 day before use. Otherwise, flux it with nitrogen for about 1 h for 2 l.5.1.2 Nitric acid, c(HNO3) = 15,8 mol l1, = 1,42 g ml1, mass fraction w(HNO3) = 70 %.5.1.3 Scintillation cocktail, commercially available scintillation cocktails, water immiscible and suit

35、able for alpha and beta discrimination (e.g. diisopropylnaphthalene-based cocktails).5.1.4 226Ra standard solution226Ra standard solutions shall be provided with calibration certificates containing at least the activity concentration, measurement uncertainty and/or statement of compliance with an id

36、entified metrological specification.5.2 Equipment5.2.1 Balance.5.2.2 Hotplate with magnetic stirrer and stirring bar.5.2.3 pH-meter.5.2.4 Wide-mouth HDPE sample bottles, volumes between 100 ml and 500 ml.5.2.5 Liquid scintillation counter, with alpha and beta discrimination option, with thermostated

37、 counting chamber and preferably an ultra-low level counter to achieve better detection limits.5.2.6 Polyethylene scintillation vials, PTFE coated, 20 ml.PTFE-coated polyethylene vials are the best choice, since they prevent both the diffusion of the cocktail into the wall of the vial and the absorp

38、tion of radon from the environment. Glass vials exhibit a considerably higher background and generally degrade the achievable alpha and beta discrimination.6 SamplingIt is the responsibility of the laboratory to ensure the suitability of this test method for the water samples tested.Collect the samp

39、le in accordance with ISO 5667-1. Store the water sample (from 0,1 l to 1 l) in a plastic bottle (5.2.4) according to ISO 5667-3. When preconcentration is desired, acidify the sample to pH 1 to pH 3 with HNO3(5.1.2). If necessary, carry out filtration immediately on collection and before acidificati

40、on.Acidification of the water sample minimizes the loss of radioactive material from solution by plating on the wall of the sample container. If filtration of the sample is required, the acidification is performed afterwards, otherwise radioactive material already adsorbed on the particulate materia

41、l can be desorbed.If the sample is not acidified, the sample preparation should start as soon as possible and always less than 1 month after the sampling date (ISO 5667-3).8DIN ISO 13165-1:2015-117 Instrument set-up and calibration7.1 Preparation of calibration sourcesTransfer an accurately known ma

42、ss, mS, of the 226Ra standard solution (5.1.4) into a scintillation vial (5.2.6). Let the massic activity at the measuring time be a. Dilute with water (5.1.1) to the previously chosen volume, e.g. 10 ml. Add the scintillation cocktail (5.1.3), e.g. 10 ml.Store the sample for at least 30 d to allow

43、the achievement of secular equilibrium.Ensure that the diluted standard solutions are between pH 0 and pH 2.Store samples so as to ensure optimum preservation. Storage in the dark is recommended. Select a single generally applicable temperature in order not to affect distribution coefficients. This

44、temperature shall be consistent with the characteristics of the scintillation cocktail (5.1.3, see manufacturers instructions). Generally, if possible, storage in the scintillation chamber at around 15 C is suitable.7.2 Optimization of counting conditionsSet the alpha-counting window so that the ene

45、rgies of all the three alpha-emitters present in the cocktail phase: 222Rn (5,49 MeV); 218Po (6,00 MeV); and 214Po (7,69 MeV); are covered.Count the 226Ra calibration sample in alpha and beta-discrimination mode (see manufacturer instructions) for an appropriate period, under different discriminator

46、 settings.The best discriminator setting (working point) is chosen by visual inspection of the spectra in order to obtain an alpha-spectrum free of beta counts (see Annex A).NOTE Since no water is present in the scintillation cocktail phase, the quenching is low and constant, while the alpha and bet

47、a discrimination is quite sharp.7.3 Detection efficiencyLet the counting rate be rSfor the counts of the 226Ra calibration sample in the alpha-window, as measured with the previously defined best discriminator setting.Determine the alpha-efficiency: =rramS0S(1)Acceptance limits for efficiency should

48、 be defined.NOTE The alpha-efficiency includes both counting and extraction efficiency. Usual values are in the range 200 % to 300 % (222Rn, 218Po, 214Po alpha-emissions).It is advisable to check the linearity of the method. Assess the efficiency using calibration samples whose activities cover the

49、whole working range.A more accurate estimate of efficiency can be obtained by preparing and measuring a sufficient number of calibration samples.Verify efficiencies at a periodicity established by the laboratory and whenever changes in materials (e.g. scintillation cocktail) or when maintenance operations are performed on the scintillation counter (5.2.5). A verification or a recalibration is necessary when instrument quality control require