1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58absorption spectrometry Part 5: Determination of iron contentICS 83.060Rubber Determination of meta
2、l content by atomic BRITISH STANDARDBS ISO 6101-5:2006BS ISO 6101-5:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2006 BSI 2006ISBN 0 580 49634 1Amendments issued since publicationAmd. No. Date Commentscontract. Users are re
3、sponsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard was published by BSI. It is the UK implementation of ISO 6101-5:2006. It supersedes BS 7164-27.1:1991 which is withdrawn.The UK participation
4、 in its preparation was entrusted to Technical Committee PRI/23, Test methods for rubber and non-black compounding ingredients.A list of organizations represented on PRI/23 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a INTE
5、RNATIONALSTANDARDISO6101-5Second edition2006-10-01Reference numberISO 6101-5:2006(E)Rubber Determination of metal content by atomic absorption spectrometry Part 5:Determination of iron contentCaoutchouc Dosage du mtal par spectromtrie dabsorption atomique Partie 5: Dosage du ferBS ISO 6101-5:2006iii
6、iiContents Page1 Scope 12 Normative references 13 Principle 14 Reagents . 15 Apparatus . 26 Sampling . 37 Procedure . 37.1 Preparation of test portion . 37.2 Preparation of test solution 37.3 Preparation of the calibration curves 47.4 Determination 58 Expression of results 59 Test report 6BS ISO 610
7、1-5:2006ivForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies(ISO member bodies). The work of preparing International Standards is normally carried out through ISOtechnical committees. Each member body interested in a subject for wh
8、ich a technical committee has beenestablished has the right to be represented on that committee. International organizations, governmental andnon-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the InternationalElectrotechnical Commission (IEC) on all mat
9、ters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standardsadopted by the technical committees are circulat
10、ed to the member bodies for voting. Publication as anInternational Standard requires approval by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patentrights. ISO shall not be held responsible fo
11、r identifying any or all such patent rights.ISO 6101-5 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, SubcommitteeSC 2, Testing and analysis.This second edition cancels and replaces the first edition (ISO 6101-5:1990), which has been revised to updatethe normative referen
12、ces.ISO 6101 consists of the following parts, under the general title Rubber Determination of metal content byatomic absorption spectrometry: Part 1: Determination of zinc content Part 2: Determination of lead content Part 3: Determination of copper content Part 4: Determination of manganese content
13、 Part 5: Determination of iron contentBS ISO 6101-5:20061Rubber Determination of metal content by atomic absorption spectrometry Part 5:Determination of iron content1ScopeThis part of ISO 6101 specifies an atomic absorption spectrometric method for the determination of the ironcontent of rubbers.It
14、is applicable to raw rubber, rubber products and latex having iron contents of to .Higher concentrations may be determined, provided that suitable adjustments are made to the mass of the testportion and/or the concentrations of the solution used.2 Normative referencesThe following referenced documen
15、ts are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenced document(including any amendments) applies.ISO 123, Rubber latex SamplingISO 247:2006, Rubber Determination of ashISO 648:1977,
16、 Laboratory glassware One-mark pipettesISO 1042:1998, Laboratory glassware One-mark volumetric flasksISO 1795, Rubber, raw natural and raw synthetic Sampling and further preparative procedures3 PrincipleA test portion is ashed at in accordance with ISO 247:2006, method A or B. The ash isdissolved in
17、 hydrochloric acid and if any silicates are present they are decomposed with a mixture of sulfuricacid and hydrofluoric acid to remove them.The solution obtained is aspirated into an atomic absorption spectrometer and the absorption is measured at awavelength of for concentrations up to or (by mass)
18、, or for concentrationsof to or (by mass) to (by mass).NOTE ISO 6955, Analytical spectroscopic methods Flame emission, atomic absorption, and atomic fluorescence Vocabulary, defines the spectrometric terms used in this part of ISO 6101.4ReagentsDuring the analysis, unless otherwise stated, use only
19、reagents of recognized analytical grade, and onlydistilled water or water of equivalent purity.5,0 mg/kg 1 000 mg/kg550C 25C248,3 nm 10 mg/kg 0,001 % 372,0 nm10 mg/kg 1 000 mg/kg 0,001 % 0,1 %BS ISO 6101-5:200624.1 Sulfuric acid, .4.2 Hydrochloric acid, .4.3 Hydrochloric acid, dilute, (by volume).Di
20、lute 1 volume of concentrated hydrochloric acid (4.2) with 3 volumes of water.4.4 Hydrofluoric acid, to (by mass).4.5 Nitric acid, .4.6 Iron, standard solution corresponding to of Fe per cubic decimetre.Use either commercially available standard iron solutions, or prepare as follows:Grind metallic i
21、ron, purity greater than (by mass). Weigh to the nearest in a conicalflask (5.11) and dissolve it in a mixture of of hydrochloric acid (4.3) and of nitric acid (4.5).Transfer it to a one-mark volumetric flask (5.4), dilute to the mark with hydrochloric acid (4.3)and mix thoroughly.of this standard s
22、olution contains of Fe.5 ApparatusUse ordinary laboratory apparatus and the following, ensuring that all apparatus and laboratory implements arenon-ferrous:5.1 Balance, accurate to .5.2 Muffle furnace, capable of being maintained at .5.3 Beaker, of capacity .5.4 One-mark volumetric flasks, glass-sto
23、ppered, of capacity , , , and, complying with the requirements of ISO 1042:1998, class A.5.5 Filter funnel.5.6 Crucible, of silica or porcelain, of capacity .5.7 Crucible, of platinum, of capacity to .5.8 Platinum rod, as stirrer.5.9 Filter paper, ashless, of diameter .5.10 Electrical heating plate
24、or gas burner with sand bath.5.11 Conical flask, of capacity .5.12 Atomic absorption spectrometer, fitted with a hollow-cathode lamp capable of emitting radiation of therequired wavelengths and a burner fed with acetylene and compressed air. A high-brightness lamp is advisable.The instrument shall b
25、e operated in accordance with the manufacturers instructions for optimum performance.Alternatively, an electrothermal atomization device (graphite furnace) may be used. It shall be operated by acompetent person in accordance with the manufacturers instructions for optimum performance. = 1,84 Mg/m3 =
26、 1,19 Mg/m31 + 3 = 1,13 Mg/m338 % 40 % = 1,42 Mg/m31g99 % 1g 0,01 mg 250 cm3100 ml 1 + 3 10 ml1 000 cm31 + 31cm31 000g0,01 mg550C 25C250 cm350 cm3100 cm3200 cm3500 cm31 000 cm3150 cm350 cm3150 cm3150 mm250 cm3BS ISO 6101-5:200635.13 Volumetric pipettes, of capacity , , , and , complying with therequ
27、irements of ISO 648:1977, class A.5.14 Watch glasses, for covering the crucibles (5.6 and 5.7).5.15 Heated water bath.6 SamplingCarry out sampling as follows: raw rubber, in accordance with ISO 1795; latex, in accordance with ISO 123; products, to be representative of the whole sample.7 ProcedureWAR
28、NING All recognized health and safety precautions shall be observed when carrylng out theprocedures specified in this part of ISO 6101.7.1 Preparation of test portion7.1.1 Wash the test portion with hydrochloric acid (4.3) to remove surface contamination, wash withwater and allow to dry in a desicca
29、tor.7.1.2 Weigh, to the nearest , of milled or cut rubber into a crucible (5.6 or 5.7), using a non-ferrous cutting implement. If the iron content is about , it may be necessary to increase the mass of thetest portion to maximum to obtain more reliable absorbances.7.1.3 If the rubber contains silica
30、tes, proceed in accordance with 7.1.2 but use the platinum crucible (5.7).7.2 Preparation of test solution7.2.1 Destruction of organic matterAsh in accordance with method A or B of ISO 247:2006 in the muffle furnace (5.2) maintained at. lf the ash is black, caused by small amounts of carbon black, s
31、tir carefully with the platinumrod (5.8) and continue heating.7.2.2 Dissolution of inorganic residueAfter ashing, allow the crucible and its contents to cool to ambient temperature. Add carefully of hydrochloric acid (4.3) to the ash and heat for on a water bath (5.15). Cover with a watch glass (5.1
32、4) toavoid losses, for example due to carbonates, which cause splashing and foaming.Transfer the solution and the residue to a beaker (5.3) with of hydrochloric acid (4.3) and heat for.If the residue dissolves completely, transfer to a volumetric flask (5.4), dilute to the mark with hydrochloric aci
33、d (4.3) and proceed in accordance with 7.4.If the ash is not totally dissolved, i.e. silicates are present, ash a new portion in accordance with 7.1.3 and 7.2.1.Add a few drops of sulfuric acid (4.1) and heat to fuming. Cool and add a further three drops of sulfuric acid andof hydrofluoric acid (4.4
34、). Heat on the electric heating plate or sand bath (5.10) in a fume cupboard andevaporate to dryness, while stirring with the platinum rod (5.8). Repeat this procedure twice.5cm310 cm320 cm350 cm3100 cm31 + 30,01 mg 1,0 g5 mg/kg5g550C 25C20 cm31 + 330 min50 cm31 + 330 min100 cm31 + 35cm3BS ISO 6101-
35、5:20064Cool, and add of hydrochloric acid (4.3). Cover with a watch glass (5.14) and heat for .Filter, washing the filter with hydrochloric acid (4.3), and combine the filtrate and washings in a volumetric flask (5.4). Dilute to the mark with hydrochloric acid (4.3) and mix thoroughly. Proceed inacc
36、ordance with 7.4.7.3 Preparation of the calibration curves7.3.1 Preparation of standard calibration solutions7.3.1.1 Primary calibration solutionPipette carefully of the standard iron solution (4.6) into a one-mark volumetric flask (5.4) anddilute to the mark with hydrochloric acid (4.3).of this pri
37、mary calibration solution contains of Fe.7.3.1.2 Standard calibration solutionsInto a series of eight one-mark volumetric flasks (5.4), place the volumes of the primary calibrationsolution (7.3.1.1) as indicated in Table 1, add hydrochloric acid (4.3) to the mark and mix thoroughly.7.3.2 Spectrometr
38、ic measurementsSwitch on the spectrometer (5.12) sufficiently in advance to ensure stabilization. Adjust the wavelength toor , and the sensitivity and the slit aperture according to the characteristics of the instrument.Adjust the pressure of the air and of the acetylene according to the characteris
39、tics of the aspirator/burner inorder to obtain a clear, reducing flame.Adjust the flow rate according to the characteristics of the instrument.Aspirate the series of standard calibration solutions (7.3.1.2) in succession into the flame, and measure theabsorbance of each solution twice, averaging the
40、 readings. Take care to ensure that the rate of aspiration isconstant throughout this process. It should be ensured that at least one standard is at or below the levelcorresponding to the rubber being tested.It is important that water be aspirated through the burner after each measurement.Table 1 Vo
41、lume of primary calibration solution with corresponding concentration of ironVolume of primary calibration solution (7.3.1.1)Corresponding concentration of iron100 1 00050 50020 20010 1005502a20a1a10a0b0aOnly if the sensitivity of the spectrometer is high enough for accurate results.bCalibration bla
42、nk solution.50 cm31 + 3 10 min1 + 3 100 cm31 + 310 cm31dm31 + 31cm310g100 cm31 + 3cm3g/100 cm3248,3 nm 372,0 nmBS ISO 6101-5:200657.3.3 Plotting the calibration curvesPlot two curves (one for each of the concentration ranges given below) having, for example, the masses, inmicrograms, of iron contain
43、ed in of the standard calibration solutions as abscissae froma) to for ,b) to for ,and the corresponding values of absorbance, corrected for the absorbance of the calibration blank solution(see Table 1), as ordinates.Represent the points on the graph by the best straight line as judged visually, or
44、calculated by the least-squarefit method.7.4 Determination7.4.1 Spectrometric measurementsCarry out duplicate spectrometric measurements at a wavelength of or on the test solution(7.2.2), following the procedures specified in 7.3.2.7.4.2 DilutionIf the instrument response for the test solution is gr
45、eater than that found for the standard calibration solutionhaving the highest iron content (see Table 1), dilute as appropriate with hydrochloric acid (4.3) inaccordance with the following procedure.Pipette carefully a volume of the test solution (7.2.2) into a one-mark volumetric flask so that the
46、ironconcentration lies within the range covered by the standard calibration solutions. Dilute to the mark with hydrochloric acid (4.3). Repeat the measurement.7.4.3 Blank determinationCarry out a blank determination in parallel with the determination, using hydrochloric acid (4.3), butomitting the t
47、est portion.If sulfuric acid and hydrofluoric acid were used for the test portion preparation, the same quantities of theseacids shall be used in the preparation of the blank determination solution.8 Expression of results8.1 Read the iron content of the test solution directly from the appropriate ca
48、libration graph (see 7.3.3).The iron content of the test portion, expressed in parts per million by mass, is given by the formula:whereis the iron concentration, in micrograms per , of the test solution (7.2.2), read from thecalibration graph;is the iron concentration, in micrograms per , of the bla
49、nk determination solution (7.4.3),read from the calibration graph;100 cm310g/100 cm3100g/100 cm3248,2 nm100g/100 cm31 000g/100 cm3372,0 nm248,3 nm 372,0 nm1 + 3V 100 cm31 + 31 + 3Fe,tFe,b100mf 104Fe,t100 cm3Fe,b100 cm3BS ISO 6101-5:20066is the mass, in grams, of the test portion;is a dilution factor, if required (see 7.4.2), for the test solution, given by:being the volume, in cubic centimetres, of the test solution pipetted out in 7.4.2.8.2 Report the results to thre
