1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Dentistry - Analysis of fluoride concentration in aqueous solutions by use of fluoride ion-selective electrodeBS EN ISO 19448:2018National forewordThis British Standard is the UK implementation of EN ISO 19448:2018. It
2、is identical to ISO 19448:2018. The UK participation in its preparation was entrusted to Technical Committee CH/106/7, Oral hygiene products.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessar
3、y provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2018 Published by BSI Standards Limited 2018ISBN 978 0 580 86047 8ICS 71.100.70; 97.170Compliance with a British Standard cannot confer immunity from legal obligations.This British Standa
4、rd was published under the authority of the Standards Policy and Strategy Committee on 28 February 2018.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 19448:2018EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 19448January 2018ICS 71.100.70EUROPEAN COM
5、MITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2018 CEN Ref. No. EN ISO 19448:2018: EAll rights of exploitation in any form and by any means reserved worldwide for CEN national MembersDentistry -
6、Analysis of Fluoride Concentration in Aqueous Solutions by use of Fluoride-Ion Selective Electrode (ISO 19448:2018)Mdecine bucco-dentaire - Analyse de la concentration en fluorure dans les solutions aqueuses laide dune lectrode slective dions fluorures (ISO 19448:2018)Zahnheilkunde - Analyse der Flu
7、oridkonzentration in wssrigen Lsungen mit einer fluoridionenselektiven Elektrode (ISO 19448:2018)This European Standard was approved by CEN on 23 December 2017.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard t
8、he status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.This European Standard exists in three official versions (English, Fren
9、ch, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria,
10、Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
11、Turkey and United Kingdom.English VersionEN ISO 19448:2018 (E)European ForewordThis document (EN ISO 19448:2018) has been prepared by Technical Committee ISO/TC 106 “Dentistry“ in collaboration with Technical Committee CEN/TC 55 “Dentistry” the secretariat of which is held by DIN.This European Stand
12、ard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2018, and conflicting national standards shall be withdrawn at the latest by July 2018.Attention is drawn to the possibility that some of the elements of this doc
13、ument may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgiu
14、m, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
15、Switzerland, Turkey and the United Kingdom.Endorsement noticeThe text of ISO 19448:2018 has been approved by CEN as EN ISO 19448:2018 without any modification.2BS EN ISO 19448:2018ISO 19448:2018(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 R
16、eagents and materials . 25.2 Chemicals to prepare sodium fluoride standards. . 26 Apparatus . 27 Preparation 37.1 TISAB solution . 37.2 TISAB blank solution . 37.3 Fluoride standard solutions 37.4 Calibration curve . 48 Procedure. 58.1 Direct analysis technique . 58.2 Standard addition technique 68.
17、3 Dilution analysis technique 78.4 Multiple sample addition technique . 78.5 Internal standards technique . 79 Technical notes about the analytical techniques 710 Calculations 810.1 Direct analysis technique . 810.2 Standard additions technique 810.3 Dilution analysis technique 910.4 Multiple sample
18、 addition technique . 910.5 Internal standards technique . 911 Test report . 912 Trouble shooting 9Bibliography .11 ISO 2018 All rights reserved iiiContents PageBS EN ISO 19448:2018ISO 19448:2018(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national
19、 standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. Internationa
20、l organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended fo
21、r its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.or
22、g/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be
23、in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the voluntary nature of standards, the meaning of I
24、SO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.This document was prepared by Technical Commi
25、ttee ISO/TC 106, Dentistry, Subcommittee SC 7, Oral care products.iv ISO 2018 All rights reservedBS EN ISO 19448:2018ISO 19448:2018(E)IntroductionFluoride is used in dentistry primarily for caries prevention. Fluoride is the active ingredient for caries prevention in many dental products such as den
26、tifrices, gels, oral rinses, and fluoride releasing varnishes. The fluoride concentration in these products is an integral part of other standards where the product is intended to be analysed for fluoride content. This document provides methods based on the use of fluoride ion-selective electrode te
27、chnology for the analysis of the total fluoride content in aqueous samples. The methods describe uses for fluoride ion-selective electrode technology and anticipate that the sample-specific preparations such as digestion, distillation, etc. have been described in the standards specific to product ty
28、pes. ISO 2018 All rights reserved vBS EN ISO 19448:2018This page deliberately left blankDentistry - Analysis of fluoride concentration in aqueous solutions by use of fluoride ion-selective electrode1 ScopeThis document specifies test methods for the quantification of fluoride concentrations in denta
29、l products including dentifrices, gels, oral rinses, fluoride releasing varnishes, and other fluoride containing products. The methods are based on fluoride ion-selective electrode technology for the analysis of fluoride in aqueous samples derived from dental products.2 Normative referencesThe follo
30、wing documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 78-
31、2, Chemistry Layouts for standards Part 2: Methods of chemical analysisISO 835, Laboratory glassware Graduated pipettesISO 1942, Dentistry VocabularyISO 3696, Water for analytical laboratory use Specification and test methods3 Terms and definitionsFor the purposes of this document, the terms and def
32、initions given in ISO 78-2 and ISO 1942 apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at https:/www.iso.org/obp4 PrincipleThis test method c
33、overs the determination of fluoride concentration in aqueous solutions derived from dental products. The following test methods are presupposed to use fluoride ion-selective electrodes (F-ISE) .The sensing element of the fluoride ion-selective electrode consists of a single crystal of europium (II)-
34、doped lanthanum fluoride, LaF3. When the sensing element is in contact with a solution containing fluoride ions, an electrode potential develops across the sensing element. This potential, which depends on the activity of free fluoride ion in solution F-, is measured against a constant reference ele
35、ctrode potential with a digital pH/mV meter or ISE (concentration) potentiometer. A potential (E) is developed which is proportional to the logarithm of the activity of the fluoride ion F- in solution following the Nernst Equation.E = E0+ S * log F- (1)INTERNATIONAL STANDARD ISO 19448:2018(E) ISO 20
36、18 All rights reserved 1BS EN ISO 19448:2018ISO 19448:2018(E)whereE is the measured electrode potential;E0is the reference potential (a constant);F- is the fluoride ion activity level in solution;S is the electrode slope (58,2 mV per decade change of F- at 20 C).The level of fluoride ion, F-, is the
37、 activity or “effective concentration” of free fluoride ion in solution. The fluoride ion activity is related to free fluoride ion concentration, F, by the activity coefficient, . The activity coefficient is related to the ionic strength of the solution. For these measurements, the ionic strength of
38、 the samples and standards are held constant by the use of total ionic strength adjusting buffer solution (TISAB), which also chelates fluoride-binding cations and establishes the solution pH at the optimal level for the fluoride ion-selective electrode sensitivity. When using TISAB to set the ionic
39、 strength of the solution, the electric potential is proportional to the concentration of the fluoride ion in solution. TISAB may come in several variations. Which one to use is specific to the sample preparation procedure. One has to be aware that other interferences may exist and it is up to the u
40、ser and sample preparation to properly identify them.A calibration curve is drawn, plotting measured potential versus the log of the fluoride ion concentration of known standard solutions. Then, the potential for the unknown sample is measured and the concentration of F-in the sample can be calculat
41、ed from the calibration curve.The sample will have been pretreated as specified for the particular sample type, and the final composition is an aqueous sample of at least 1 ml volume. Samples that contain more than 0,01 mol/l F (190 mg/l F) shall be diluted to concentrations less than 0,01 mol/l F w
42、ith deionized water.5 Reagents and materials5.1 Chemicals to prepare total ionic strength adjusting buffer (TISAB) solution.5.1.1 Cyclohexylene dinitrilotetraacetic acid (CDTA) or 1,2-diaminocyclohexane-N,N,N,N-tetraacetic acid.5.1.2 Acetic acid (CH3COOH) reagent grade.5.1.3 Sodium chloride (NaCl) s
43、alt.5.1.4 Sodium hydroxide (NaOH), at 5 mol/l.5.1.5 Deionized water, in accordance with ISO 3696, grade 2.5.2 Chemicals to prepare sodium fluoride standards.5.2.1 Sodium fluoride (NaF), previously dried at least 4 h at 150C.5.2.2 Deionized water, in accordance with ISO 3696, grade 2.6 Apparatus6.1 A
44、nalytical balance, accurate to 0,000 1 g.6.2 Magnetic stir bar.2 ISO 2018 All rights reservedBS EN ISO 19448:2018ISO 19448:2018(E)6.3 Magnetic stir plate.6.4 Pipette, of nominal capacity 5,0 ml to smallest scale division: 0,05 ml; 1,0 ml to 0,01 ml; and 0,10 ml to 0,01 ml, in accordance with ISO 835
45、, Class A.6.5 Fluoride ion-selective electrode (F-ISE) with separate reference electrode, or combination F-ISE/reference electrode pair.6.6 Plastic vial (or beaker or small container), 20 or more ml capacity.NOTE Fluoride does not react with plastic but does react with glass.6.7 pH/mV electrometer (
46、pH meter), with a sensitivity of 0,1 mV.7 Preparation7.1 TISAB solution7.1.1 In a 1 l beaker with about 500 ml deionized H2O, dissolve 57 ml CH3COOH, 58 g NaCl, and 4 g CDTA or 1,2-diaminocyclohexane-N,N,N,N-tetraacetic acid.7.1.2 Cool to room temperature and adjust pH to 5,05,5 with 5 mol/l NaOH.7.
47、1.3 Cool to room temperature, transfer to 1 l volumetric flask, and dilute to volume with deionized H2O.NOTE Preparation of TISAB solution is described in ASTM D1179-16 1, 18.1.TISAB is the buffering system that is used to prepare the sample for analysis via the fluoride ion-selective electrode (F-I
48、SE). The F-ISE has several limitations that can limit its use. It is sensitive only to ionic fluoride in solution, and cannot respond to complexes of fluoride such as calcium-fluoride. Multivalent cations such as calcium, magnesium, iron, aluminium, etc., can form fluoride complexes in solution whic
49、h reduces the ionic fluoride concentration. Additionally, the F-ISE is sensitive to variations in sample pH and to the ionic strength of the sample. For accurate analyses, the samples and the standards must have the same pH and ionic strength. The fluoride complexes must be disrupted such that all the fluoride in the sample and standard is in its ionic form. To address these limitations, a total ionic strength adjusting buffering system (TISAB) that adjusts the sample pH and ionic strength, and also contains chelator
