1、BRITISH STANDARD BS EN 12441-7:2004 Zinc and zinc alloys Chemical analysis Part 7: Determination of tin Flame atomic absorption spectrometric method after extraction The European Standard EN 12441-7:2004 has the status of a British Standard ICS 77.040.30; 77.120.60 BS EN 12441-7:2004 This British St
2、andard was published under the authority of the Standards Policy and Strategy Committee on 20 January 2005 BSI 20 January 2005 ISBN 0 580 45288 3 National foreword This British Standard is the official English language version of EN 12441-7:2004. The UK participation in its preparation was entrusted
3、 to Technical Committee NFE/8, Zinc, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be f
4、ound in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are re
5、sponsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and kee
6、p the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 11 and a back cover. The BSI copyright notice displayed in this document in
7、dicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN124417 December2004 ICS77.040.30;77.120.60 Englishversion ZincandzincalloysChemicalanalysisPart7:Determination oftinFlameatomicabsorptionspectrometric
8、methodafter extraction ZincetalliagesdezincAnalysechimiquePartie7: DosagedeltainMthodeparspectromtriedabsorption atomiquedanslaflammeaprsextraction ZinkundZinklegierungenChemischeAnalyseTeil7: BestimmungvonZinnFAASVerfahrennachExtraktion ThisEuropeanStandardwasapprovedbyCENon4November2004. CENmember
9、sareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheCentralSecretariatortoanyCENmember
10、. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions. CENmembersarethenationalstandardsbodiesofAustria,Belg
11、ium,Cyprus,CzechRepublic,Denmark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUR
12、OPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN124417:2004:EEN 12441-7:2004 (E) 2 Contents Page Foreword3 1 Scope4 2 Normative references4 3 Terms and definitions .4 4 Prin
13、ciple4 5 Reagents.4 6 Apparatus.6 7 Sampling.6 8 Procedure.6 9 Calculation and expression of results.7 10 Test report8 Annex A (informative) Additional information on international co-operative tests .9 Annex B (informative) Graphical representation of precision data .10 Bibliography 11 EN 12441-7:2
14、004 (E) 3 Foreword This document (EN 12441-7:2004) has been prepared by Technical Committee CEN/TC 209 “Zinc and zinc alloys”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsem
15、ent, at the latest by June 2005, and conflicting national standards shall be withdrawn at the latest by June 2005. Within its programme of work, Technical Committee CEN/TC 209 entrusted CEN/TC 209/WG6 “Methods of analysis and testing“ to prepare the following document: EN 12441-7, Zinc and zinc allo
16、ys Chemical analysis Part 7: Determination of tin Flame atomic absorption spectrometric method after extraction. This standard is a part of a series of eleven standards. The other standards are: Part 1: Determination of aluminium in zinc alloys Titrimetric method Part 2: Determination of magnesium i
17、n zinc alloys Flame atomic absorption spectrometric method Part 3: Determination of lead, cadmium and copper Flame atomic absorption spectrometric method Part 4: Determination of iron in zinc alloys Spectrophotometric method Part 5: Determination of iron in primary zinc Spectrophotometric method Par
18、t 6: Determination of aluminium and iron Flame atomic absorption spectrometric method Part 8: Determination of tin in secondary zinc Flame atomic absorption spectrometric method Part 9: Determination of nickel in zinc alloys Flame atomic absorption spectrometric method Part 10: Determination of chro
19、mium and titanium in zinc alloys Spectrophotometric method Part 11: Determination of silicon in zinc alloys Spectrophotometric method According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Aust
20、ria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 12441-7:2004 (E) 4 1 Scope Th
21、is document specifies a flame atomic absorption spectrometric method after extraction for the determination of tin in zinc and zinc alloys. It is applicable to the products specified in EN 988, EN 1179, EN 1774 and EN 12844. It is suitable for the determination of tin contents (mass fractions) betwe
22、en 0,000 5 % and 0,005 %. 2 Normative references The following referenced documents are indispensable for the application 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.
23、EN 988, Zinc and zinc alloys Specifications for rolled flat products for building EN 1179, Zinc and zinc alloys Primary zinc EN 1774, Zinc and zinc alloys Alloys for foundry purposes Ingot and liquid EN 12060:1997, Zinc and zinc alloys Method of sampling Specifications EN 12844, Zinc and zinc alloys
24、 Castings Specifications 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12060:1997 and the following apply. 3.1 atomic absorption spectrometry measurement of the absorption of an electromagnetic radiation, emitted by an element at a determined wavele
25、ngth, by an absorbent medium (flame) formed by atoms of the same element that are in the ground state. Each element absorbs radiation of specific wavelengths and the intensity of the absorbed radiation is proportional to the concentration of said element 4 Principle A sample of the metal or alloy is
26、 dissolved in hydrochloric acid. Tin is extracted in organic phase using an iso- butyl acetate solution of trioctylphosphine oxyde (T.O.P.O.). The content of tin is determined by atomic absorption spectrometry at the wavelength of 286,3 nm, after direct nebulization of the organic phase. 5 Reagents
27、5.1 General During the test, use only reagents of known analytical grade and distilled or demineralised water. 5.2 Hydrochloric acid, = 1,19 g/ml EN 12441-7:2004 (E) 5 5.3 Hydrogen peroxide, 30 % (mass fraction) Hydrogen peroxide solutions are liable to be stabilised with products containing tin. Th
28、erefore exactly the same volume of hydrogen peroxide shall be used both when dissolving samples and when preparing the calibration solutions. 5.4 Iso-butyl acetate 5.5 Tri-n-octylphosphinoxide (T.O.P.O.), 10 g/l solution In a 200 ml volumetric flask, dissolve 2 g of tri-n-octylphosphinoxide in iso-b
29、utyl acetate (5.4). Dilute to the mark with iso-butyl acetate (5.4) and mix. 5.6 Pure zinc 99,995 %, tin free 5.7 Zinc solution, 200 g/l solution Introduce 200 g of zinc (5.6) into a 2 litre beaker. Add 700 ml of hydrochloric acid (5.2) carefully in small amounts to control the rate of reaction. Whe
30、n the almost part of the metal is dissolved, add about 100 ml of water and heat gently until zinc is completely dissolved. Do not allow any concentration of the solution by heating. After cooling, transfer into a 1 l volumetric flask, dilute to the mark with water and mix. Store in a polyethylene bo
31、ttle. 1 ml of this solution contains approximately 200 mg of zinc. NOTE If dissolution is very difficult, 2 ml of nickel chloride solution (5.10) may be added to expedite the attack. 5.8 Tin, 1 g/l standard solution Weigh 1,000 g of tin with a purity of no less than 99,9 % (mass fraction) to the nea
32、rest 0,001 g. Carefully add 100 ml of hydrochloric acid (5.2). When dissolution is complete, cool to room temperature and transfer quantitatively to a 1 000 ml volumetric flask. Dilute to the mark with water and mix. 1 ml of this solution contains 1 mg of tin. 5.9 Tin, 0,05 g/l standard solution Tra
33、nsfer 10 ml of tin solution (5.8) into a 200 ml volumetric flask. Add 20 ml of hydrochloric acid (5.2), dilute to the mark with water and mix. 1 ml of this solution contains 0,05 mg of tin. 5.10 Nickel chloride solution Dissolve 2 g of nickel chloride hexahydrate (NiCl 2 .6H 2 O) in 500 ml of water.
34、 Make up to 1 litre with water and mix. 5.11 Nitric acid, = 1,4 g/ml 5.12 Aqua regia Mix 3 part volumes of hydrochloric acid (5.2) with 1 part volume of nitric acid (5.11). EN 12441-7:2004 (E) 6 6 Apparatus 6.1 General All glassware used for the preparation of the solutions and for the implementatio
35、n of the method shall be cleaned with boiling aqua regia (5.12) prior to use. 6.2 Specific equipment In addition to standard laboratory apparatus, an atomic absorption spectrometer, equipped with a premix burner, with facilities for using the oxidizer-fuel combination of nitrous oxide-acetylene shal
36、l be used. NOTE 1 Excitation sources should be operated in accordance with the manufacturers recommendations. The optical path length within the flame should be between 5 cm to 10 cm. NOTE 2 Organic solutions should be operated in accordance with the manufacturers recommendations. 7 Sampling The tes
37、t sample shall be selected and prepared in accordance with the procedure given in EN 12060. 8 Procedure 8.1 Test portion Weigh 10 g of the test sample to the nearest 0,001 g. 8.2 Preparation of the test solution 8.2.1 Introduce the test portion (8.1) in a 250 ml beaker fitted with a watch-glass, add
38、 20 ml of water and dissolve by carefully adding 65 ml of hydrochloric acid (5.2). After cooling, oxidize and complete the dissolution by adding 2 ml of hydrogen peroxide (5.3), drop by drop. Do not heat to avoid the loss of SnCl 4 . 8.2.2 Transfer quantitatively to a 250 ml separatory funnel, rinsi
39、ng with about 15 ml of water. Add 80 ml of water. Mix well and allow to cool to room temperature. 8.2.3 Add 20 ml of T.O.P.O.-solution (5.5) and shake for 1 minute. 8.2.4 After clear separation of the phases, discard the aqueous phase completely. 8.2.5 Collect the organic phase quantitatively in 25
40、ml volumetric flask, rinsing with exactly 5 ml of iso-butyl acetate (5.4) and mix. 8.3 Preparation of the calibration solutions 8.3.1 Into each of six 250 ml separatory funnels, introduce 50 ml of zinc solution (5.7), 30 ml of hydrochloric acid (5.2), 2 ml of hydrogen peroxide (5.3) and 100 ml of wa
41、ter. Mix and allow to cool to room temperature. 8.3.2 Than introduce 0,00 ml, 1,00 ml, 2,00 ml, 4,00 ml, 6,00 ml and 10,00 ml of tin standard solution (5.9), corresponding to tin contents (mass fractions) in the test portion of 0,000 0 %; 0,000 5 %; 0,001 0 %; 0,002 %; 0,003 0 % and 0,005 0 %. 8.3.3
42、 Continue as described in 8.2.3 to 8.2.5. EN 12441-7:2004 (E) 7 8.4 Spectrometric measurements Measure the absorbances of the calibration solutions and the test solution(s) by taking alternate readings to ensure that the settings of the burner and of the apparatus do not change during the readings.
43、The wavelength of the line used shall be 286,3 nm. To comply with the concentration ranges recommended by the manufacturer of the apparatus, the same dilutions for the calibration solutions and the test solution(s) shall be made if necessary. NOTE Between each passage of organic solution, nebulize s
44、ome iso-butyl acetate (5.4) for a few seconds, in order to clean the burner head. 9 Calculation and expression of results 9.1 Method of calculation Establish a calibration graph by plotting the measured absorbances of the calibration solutions against their respective contents (mass fractions). Dete
45、rmine from the measured absorbances of the test solutions the associated amount of tin from the calibration graph. If a number of determinations are carried out then a mean of all results shall be determined by adding the individual results together and by dividing by the number of individual result
46、s. The results shall be expressed as specified in EN 988, EN 1179, EN 1774 and EN 12844. 9.2 Precision A planned trial of this method was carried out by 10 laboratories, using 3 samples with 3 levels of tin contents, each laboratory making three determinations of tin content in each sample (see Note
47、s 1 and 2) NOTE 1 Two of the three determinations were carried out under repeatability conditions as defined in ISO 5725-1; i.e. one operator, same apparatus, identical operating conditions, same calibration and a minimum period of time. NOTE 2 The third determination was carried out at a different
48、time (on a different day) by the same operator as in Note 1, using the same apparatus and a different calibration. The details of the samples used and the mean results obtained are given in the Tables A.1 and A.2. The results obtained were treated statistically in accordance with ISO 5725. The data obtained showed a logarithmic relationship between the tin content and the repeatability limit (r) and reproducibility limits (R wand R) of the test results (see Note 3), as su
