BS 7317-2-1990 Methods for analysis of high purity copper cathode Cu-CATH-1 - Method for determination of chromium cobalt iron nickel and zinc by discrete volume nebulization atomi.pdf

1、BRITISH STANDARD BS 7317-2:1990Methods forAnalysis of high purity copper cathodeCu-CATH-1 Part 2: Method for determination of chromium, cobalt, iron, nickel and zinc by discrete volume nebulization atomic absorption spectrophotometryUDC 669.3.015.4:543.422.062:546.47+546.72/.74+546.76BS7317-2:1990Th

2、is BritishStandard having beenprepared under the directionof the Non-ferrous Metals Standards Policy Committee, was published underthe authority of the BoardofBSI and comes intoeffecton31July1990 BSI 01-2000The following BSI references relate to the work on this standard:Committee reference NFM/34Dr

3、aft for Development DD95-2ISBN 0 580 18461 7Committees responsible for this BritishStandardThe preparation of this BritishStandard was entrusted by the Non-ferrous Metals Standards Policy Committee (NFM/-) to Technical Committee NFM/34, upon which the following bodies were represented:British Bathro

4、om CouncilBritish Cable Makers ConfederationBritish Gas plcBritish Malleable Tube Fittings AssociationBritish Non-ferrous Metals FederationBritish Valve and Actuator Manufacturers AssociationCopper Development AssociationLondon Metal ExchangeNon-ferrous Metal StockistsSociety of British Aerospace Co

5、mpanies Ltd.Transmission and Distribution Association (BEAMA Ltd.)Coopted membersThe following bodies were also represented in the drafting of the standard, through subcommittees and panels:BNF Metals Technology CentreBritish Bronze and Brass Ingot Manufacturers AssociationBureau of Analysed Samples

6、 Ltd.Copper Smelters and Refiners AssociationMinistry of DefenceAmendments issued since publicationAmd. No. Date of issue CommentsBS7317-2:1990 BSI 01-2000 iContentsPageCommittees responsible Inside front coverForeword ii1 Scope 12 Principle 13 Reagents 14 Apparatus 15 Procedure 26 Calculation and e

7、xpression of results 37 Repeatability and reproducibility 38 Test report 4Figure 1 Accessory for discrete volume nebulization 1Table 1 Calibration solutions 2Table 2 Test conditions for impurity element determinations 2Table 3 Maximum mean differences for impurity elements 3Table 4 Repeatability of

8、results 4Table 5 Reproducibility of results 4Publications referred to Inside back coverBS7317-2:1990ii BSI 01-2000ForewordBS 7317 has been prepared under the direction of the Non-ferrous Metals Standards Policy Committee. It describes methods for the determination of impurity elements in high purity

9、 copper cathode designated Cu-CATH-1, each method being published as a separate Part. The methods are based on those previously issued in the Draft for Development series DD95-1 to DD95-7. The information and experience gained from the practical application of DD95 have been taken into account in th

10、e methods in BS7317.This Part of BS7317 supersedes DD95-2:1984, which is withdrawn. It is one of a series of methods in BS7317, the others being as follows: Part 1: Method for determination of cadmium, manganese and silver (screening procedure for chromium, cobalt, iron, nickel and zinc) by atomic a

11、bsorption spectrophotometry; Part 3: Method for determination of antimony, arsenic, bismuth, selenium, tellurium and tin by hydride generation and atomic absorption spectrophotometry; Part 4: Method for determination of antimony, arsenic, bismuth, lead, selenium, tellurium and tin by electrothermal

12、atomization atomic absorption spectrophotometry; Part 5: Method for determination of sulphur by hydrogen sulphide evolution and spectrophotometry; Part 6: Method for determination of phosphorus and silicon by spectrophotometry; Part 7: Method for determination of lead by lanthanum hydroxide separati

13、on and atomic absorption spectrophotometry.The atomic absorption spectrophotometric procedures in Parts1 and2 are complementary. A sample solution concentration found to be satisfactory for nebulizers in standard atomic absorptiometers was20g/L. At this concentration the precision obtainable, using

14、the method described in Part1, is only sufficient to allow the determination of cadmium, manganese and silver. Results would be obtained for chromium, cobalt, iron, nickel and zinc that would prove useful in detecting impurities grossly in excess of the requirements for chemical compositions specifi

15、ed in BS6017 for Cu-CATH-1 and would give a guide to the levels to be determined by this Part.The discrete volume nebulization procedure in this Part was developed to enable a high equivalent sample solution concentration of100g/L to be used without nebulizer blockage. The method involves no chemica

16、l separation, which can give rise to contamination problems, and the extra sensitivity obtained enables the impurities to be determined to an adequate accuracy for the requirements for chemical composition specified in BS6017 for Cu-CATH-1.Parts1 and2 essentially cover the same impurities. Part4 cov

17、ers the electrothermal atomization atomic absorption spectrophotometric method and is recommended where the facility is available. Parts1,2,3 and7 are included for use where the electrothermal atomization equipment is not available.A British Standard does not purport to include all the necessary pro

18、visions of a contract. Users of British Standards are responsible for their correct application.Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an insi

19、de back cover and a back cover.This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS7317-2:1990 BSI 01-2000 11 ScopeThis Part of BS7317 describes a method for the determination of the a

20、ctual amounts of the impurity elements chromium, cobalt, iron, nickel and zinc present in high purity copper cathode (designatedCu-CATH-1), by discrete volume nebulization atomic absorption spectrophotometry.NOTE 1This method is intended to be used for analysis samples prepared by the procedures giv

21、en in BS6017. These samples should be significantly oxygen free. If this method is used for other materials, such as copper wire rod produced from high purity cathodes, where oxygen can be introduced during processing, then low results may be obtained for the chromium and iron contents.NOTE 2The tit

22、les of the publications referred to in this Part of BS7317 are listed on the inside back cover.2 PrincipleThe sample of Cu-CATH-1 is dissolved in the minimum of nitric acid and diluted to volume. The impurity elements are then determined using an atomic absorption spectrophotometer, into which a sma

23、ll volume of the concentrated sample solution is injected by means of a discrete volume nebulization (DVN) system.3 Reagents3.1 GeneralDuring the analysis, use only reagents of recognized analytical quality or of higher purity and only distilled water, deionized water or water of equivalent purity,

24、that has no detectable levels of the particular elements to be determined.NOTEUnless otherwise stated, all solutions are aqueous solutions.3.2 Nitric acid, 1.42g/mL,50%V/V solution.3.3 Copper1), a certified reference material of a minimum of99.999% copper, containing less than0.54g/g of each of the

25、impurity elements.3.4 Primary calibration solutions, as given in3.4.1 to3.4.5. For these solutions use one of the following.a) Solutions prepared by the following method. Dissolve1.000g of the pure(99.95% minimum) element in20mL of nitric acid solution(3.2), cool to ambient temperature and transfer

26、to a1L volumetric flask. Dilute to the mark and mix well.b) Commercially prepared solutions, where available.3.4.1 Cobalt nitrate solution with1.0 0.0005g/L of cobalt.3.4.2 Chromium nitrate solution with1.0 0.0005g/L of chromium.2)3.4.3 Iron(III) nitrate solution with1.0 0.0005g/L of iron.3.4.4 Nick

27、el nitrate solution with1.0 0.0005g/L of nickel.3.4.5 Zinc nitrate solution with1.0 0.0005g/L of zinc.3.5 Acetone4 Apparatus4.1 Atomic absorption spectrophotometer, incorporating a 10 scale expansion facility and fitted with a burner for use withacetylene/dinitrogen monoxide, acetylene/air or hydrog

28、en/air gas mixtures, and a hollow cathode lamp for each element to be determined.NOTEA pure zinc hollow cathode lamp, rather than acopper-zinc hollow cathode lamp, is necessary, because there is a line overlap with the zinc213.856nm line and the copper213.851nm line, which leads to a high blank read

29、ing.4.2 Discrete volume nebulization accessory, suitable for transferring from204L to2004L aliquots of solution into the nebulizer, spray chamber and burner of the spectrophotometer(4.1).1) For information on the availability of copper of suitable purity, apply to Enquiry Section, BSI, Linford Wood,

30、 Milton Keynes MK146LE enclosing a stamped addressed envelope for reply.2) In order to avoid the difficulty of dissolving metallic chromium, the following procedure for the preparation of the chromium nitrate primary calibration solution is recommended. Weigh2.828g of dried potassium dichromate into

31、 a1L beaker. Dissolve in500mL of water and add20mL of nitric acid( =1.42g/mL). Whilst stirring, add carefully50mL ofhydrogen peroxide(30g/L H2O2 solution). When the reaction has ceased, bring to the boil and boil gently for15min. Cool and transfer to a1L volumetric flask, dilute to the mark and mix

32、well.Figure 1 Accessory for discrete volumenebulizationBS7317-2:19902 BSI 01-2000Commercial accessories are available, but the accessory can easily be made in the laboratory from a standard micro-pipette tip. In the latter case, cut approximately1mm from the end of the tip so that the internal diame

33、ter of the tip is slightly smaller than the outside diameter of the nebulizer capillary tube. Push the tube into the tip by approximately0.5mm, avoiding the formation of a liquid trap that could cause cross-contamination. Mount the tip plus tube vertically on a suitable clip attached to the spectrop

34、hotometer(4.1).NOTEA typical discrete volume nebulization accessory is illustrated in Figure 1.4.3 Laboratory glasswareNOTEIt is recommended that new glassware, dedicated to this specific purpose, is used.5 Procedure5.1 GeneralScrupulously clean all glassware in nitric acid solution(3.2) for16h, rin

35、se with distilled water and dry, immediately before use. Table 1 Calibration solutions5.2 Preparation of solutions5.2.1 General. Prepare the calibration solutions and the test portions described in5.2.2 and5.2.3 at the same time and from the same batch of reagents.5.2.2 Calibration solutions. Prepar

36、e six calibration solutions (solutions5.2.2.1 to5.2.2.6) by the following method.Take six1.1g solid portions of copper(3.3). Etch each portion with20mL of nitric acid solution(3.2) in a separate100mL beaker. Wash each etched portion with water, followed by acetone, and dry using gentle heat. Weigh e

37、ach etched and dried portion to verify that the mass is not less than0.9g.Transfer each etched and dried portion into a separate10mL volumetric flask and dissolve in nitric acid solution(3.2) by adding2004L increments, up to a maximum of5.6mL, to each flask. Cool the solutions.Throughout the prepara

38、tion of the calibration solutions, exercise extreme care to avoid contamination by tweezers, etc.Add, using a microlitre pipette, the quantities of each of the primary calibration solutions(3.4.1 to3.4.5) shown in Table 1 to each of the six10mL flasks. Dilute to the marks and mix well.5.2.3 Test por

39、tions. Prepare three test portions (solutions5.2.3.1 to5.2.3.3) as follows.Take three1.1g portions of the sample. Etch each portion with10mL of nitric acid solution(3.2) in a100mL beaker. Wash the etched portions with water, followed by acetone, and dry them using gentle heat. Weigh the etched and d

40、ried portions to verify that the mass of each is not less than0.9g.Transfer each of the etched portions into a separate10mL volumetric flask and dissolve in nitric acid solution(3.2) by adding2004L increments, up to a maximum of5.6mL, to each flask. Cool each solution, dilute to the mark and mix wel

41、l.Throughout the preparation of the test solutions, exercise extreme care to avoid contamination by tweezers, etc.5.3 Adjustment of apparatus5.3.1 General. Adjust the atomic absorption spectrophotometer(4.1), in accordance with the recommendations of the instrument supplier, to give the maximum sens

42、itivity for each element to be determined.Use automatic background correction wherever possible. Table 2 Test conditions for impurity element determinationsCalibration solutionAdditions of primary calibration solutions3.4.1 to3.4.5Equivalent concentration for a1g sample of chromium, cobalt, iron, ni

43、ckel, zinc5.2.2.15.2.2.25.2.2.35.2.2.45.2.2.55.2.2.64L0.005.007.5010.0015.0020.004g/g0.005.07.510.015.020.0Impurity element Wavelength Flame type and conditiona Band widthChromiumCobaltIronNickelZincnm357.9240.7248.3232.0213.8Dinitrogen monoxide/acetylene (red.)Acetylene/air (ox.)Acetylene/air (ox.)

44、Acetylene/air (red.)Hydrogen/air (st.)bNarrowNarrowNarrowNarrowNormala The flame conditions are abbreviated as: (ox.): oxidizing, i.e.lean; (st.): stoichiometric and (red.): reducing, i.e.rich.b The use of a hydrogen/air flame reduces interference.BS7317-2:1990 BSI 01-2000 3Choose a scale expansion

45、for each element that gives the best balance between readability and stability over the range of reference solutions.Use a peak height facility if available.5.3.2 Determination of the optimum sample volume. Transfer 1004L of each of the primary calibration solutions(3.4.1 to3.4.5) into a single100mL

46、 volumetric flask. Dilute to the mark and mix well. With the apparatus adjusted in accordance with5.3.1 and using the test conditions given in Table 2, compare the absorbance value for each element obtained by continuous nebulization with that obtained by discrete nebulization from a number of diffe

47、rent sample volumes within the range204L to2004L. Take the optimum sample volume as the minimum sample volume that will give, by discrete volume nebulization, a signal equal to80% of the signal obtained by continuous nebulization.NOTEThe optimum sample volume may differ from one impurity element to

48、another.5.4 DeterminationsUsing the test conditions given in Table 2 and the optimum sample volume determined in accordance with5.3.2, measure the absorbance values of each of the impurity elements three times for each of the calibration solutions(5.2.2.1 to5.2.2.6) and six times for each of the tes

49、t portions (5.2.3.1 to5.2.3.3).Record the absorbance values to0.0001.6 Calculation and expression of results6.1 Calibration calculationsFor each impurity element, calculate the arithmetic means of the three absorbance value measurements for each of the calibration solutions (5.2.2.1 to5.2.2.6).Construct or calculate a straight line calibration (mean absorbance plotted against calibration solution concentration) for each element using a least squares (first order) fit.From the calibration read off or calculate an apparent impurity element concent