1、BRITISH STANDARD BS ISO 6101-5:2006 Rubber Determination of metal content by atomic absorption spectrometry Part 5: Determination of iron content ICS 83.060 BS ISO 6101-5:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2006 B
2、SI 2006 ISBN 0 580 49634 1 National foreword This 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 It supersedes BS 7164-27.1:1991 which is withdrawn.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 in its preparation was entrusted to Technical Committee PRI/23, Test methods for rubber an
3、d 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 contract. Users are responsible for its correct application. Compliance with a British Standa
4、rd cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. Date CommentsINTERNATIONAL STANDARD ISO 6101-5 Second edition 2006-10-01 Reference number ISO 6101-5:2006(E) Rubber Determination of metal content by atomic absorption spectrometry Part 5: Determination of
5、 iron content Caoutchouc Dosage du mtal par spectromtrie dabsorption atomique Partie 5: Dosage du ferBS ISO 6101-5:2006ii iii Contents Page 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents . 1 5 Apparatus . 2 6 Sampling . 3 7 Procedure . 3 7.1 Preparation of test portion . 3 7.2 Preparati
6、on of test solution 3 7.3 Preparation of the calibration curves 4 7.4 Determination 5 8 Expression of results 5 9 Test report 6 BS ISO 6101-5:2006iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work
7、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. International organizations, governmental and non-government
8、al, 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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The mai
9、n task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Att
10、ention 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. ISO 6101-5 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2,
11、 Testing and analysis. This second edition cancels and replaces the first edition (ISO 6101-5:1990), which has been revised to update the normative references. ISO 6101 consists of the following parts, under the general title Rubber Determination of metal content by atomic absorption spectrometry: P
12、art 1: Determination of zinc content Part 2: Determination of lead content Part 3: Determination of copper content Part 4: Determination of manganese content Part 5: Determination of iron content BS ISO 6101-5:20061 Rubber Determination of metal content by atomic absorption spectrometry Part 5: Dete
13、rmination of iron content 1S c o p e This part of ISO 6101 specifies an atomic absorption spectrometric method for the determination of the iron content of rubbers. It is applicable to raw rubber, rubber products and latex having iron contents of to . Higher concentrations may be determined, provide
14、d that suitable adjustments are made to the mass of the test portion and/or the concentrations of the solution used. 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 ref
15、erences, the latest edition of the referenced document (including any amendments) applies. ISO 123, Rubber latex Sampling ISO 247:2006, Rubber Determination of ash ISO 648:1977, Laboratory glassware One-mark pipettes ISO 1042:1998, Laboratory glassware One-mark volumetric flasks ISO 1795, Rubber, ra
16、w natural and raw synthetic Sampling and further preparative procedures 3 Principle A test portion is ashed at in accordance with ISO 247:2006, method A or B. The ash is dissolved in hydrochloric acid and if any silicates are present they are decomposed with a mixture of sulfuric acid and hydrofluor
17、ic acid to remove them. The solution obtained is aspirated into an atomic absorption spectrometer and the absorption is measured at a wavelength of for concentrations up to or (by mass), or for concentrations of to or (by mass) to (by mass). NOTE ISO 6955, Analytical spectroscopic methods Flame emis
18、sion, atomic absorption, and atomic fluorescence Vocabular y, defines the spectrometric terms used in this part of ISO 6101. 4R e a g e n t s During the analysis, unless otherwise stated, use only reagents of recognized analytical grade, and only distilled water or water of equivalent purity. 5,0 mg
19、/kg 1 000 mg/kg 550 C 25 C 248,3 nm 10 mg/kg 0,001 % 372,0 nm 10 mg/kg 1 000 mg/kg 0,001 % 0,1 % BS ISO 6101-5:20062 4.1 Sulfuric acid, . 4.2 Hydrochloric acid, . 4.3 Hydrochloric acid, dilute, (by volume). Dilute 1 volume of concentrated hydrochloric acid (4.2) with 3 volumes of water. 4.4 Hydroflu
20、oric 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 iron, purity greater than (by mass). Weigh to the nearest in a conical flask (5.11) and
21、 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 solution contains of Fe. 5 Apparatus Use ordinary laboratory apparatus and the follo
22、wing, ensuring that all apparatus and laboratory implements are non-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-stoppered, of capacity , , , and , complying with the requirements of ISO 1042:
23、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 or gas burner with sand bath. 5.11 Conical flask, of capacity . 5.12
24、Atomic absorption spectrometer, fitted with a hollow-cathode lamp capable of emitting radiation of the required wavelengths and a burner fed with acetylene and compressed air. A high-brightness lamp is advisable. The instrument shall be operated in accordance with the manufacturers instructions for
25、optimum performance. Alternatively, an electrothermal atomization device (graphite furnace) may be used. It shall be operated by a competent person in accordance with the manufacturers instructions for optimum performance. = 1,84 Mg/m 3 = 1,19 Mg/m 3 1 + 3 = 1,13 Mg/m 3 38 % 40 % = 1,42 Mg/m 3 1g 99
26、 % 1g 0,01 mg 250 cm 3 100 ml 1 + 3 10 ml 1 000 cm 3 1 + 3 1cm 3 1 000 g 0,01 mg 550 C 25 C 250 cm 3 50 cm 3 100 cm 3 200 cm 3 500 cm 3 1 000 cm 3 150 cm 3 50 cm 3 150 cm 3 150 mm 250 cm 3 BS ISO 6101-5:20063 5.13 Volumetric pipettes, of capacity , , , and , complying with the requirements of ISO 64
27、8:1977, class A. 5.14 Watch glasses, for covering the crucibles (5.6 and 5.7). 5.15 Heated water bath. 6 Sampling Carry 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 Procedure WARNING All rec
28、ognized health and safety precautions shall be observed when carrylng out the procedures specified in this part of ISO 6101. 7.1 Preparation of test portion 7.1.1 Wash the test portion with hydrochloric acid (4.3) to remove surface contamination, wash with water and allow to dry in a desiccator. 7.1
29、.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 the test portion to maximum to obtain more reliable absorbances. 7.1.3 If the rubber contains silicates,
30、 proceed in accordance with 7.1.2 but use the platinum crucible (5.7). 7.2 Preparation of test solution 7.2.1 Destruction of organic matter Ash in accordance with methodA or B of ISO247:2006 in the muffle furnace (5.2) maintained at . lf the ash is black, caused by small amounts of carbon black, sti
31、r carefully with the platinum rod (5.8) and continue heating. 7.2.2 Dissolution of inorganic residue After 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.
32、14) to avoid 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 hydrochlori
33、c acid (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 ac
34、id (4.4). Heat on the electric heating plate or sand bath (5.10) in a fume cupboard and evaporate to dryness, while stirring with the platinum rod (5.8). Repeat this procedure twice. 5cm 3 10 cm 3 20 cm 3 50 cm 3 100 cm 3 1 + 3 0,01 mg 1,0 g 5 mg/kg 5g 550 C 25 C 20 cm 3 1 + 3 30 min 50 cm 3 1 + 3 3
35、0 min 100 cm 3 1 + 3 5cm 3 BS ISO 6101-5:20064 Cool, 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 aci
36、d (4.3) and mix thoroughly. Proceed in accordance with 7.4. 7.3 Preparation of the calibration curves 7.3.1 Preparation of standard calibration solutions 7.3.1.1 Primary calibration solution Pipette carefully of the standard iron solution (4.6) into a one-mark volumetric flask (5.4) and dilute to th
37、e mark with hydrochloric acid (4.3).of this primary calibration solution contains of Fe. 7.3.1.2 Standard calibration solutions Into a series of eight one-mark volumetric flasks (5.4), place the volumes of the primary calibration solution (7.3.1.1) as indicated in Table 1, add hydrochloric acid (4.3
38、) to the mark and mix thoroughly. 7.3.2 Spectrometric measurements Switch 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
39、air and of the acetylene according to the characteristics of the aspirator/burner in order 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 mea
40、sure the absorbance of each solution twice, averaging the readings. Take care to ensure that the rate of aspiration is constant throughout this process. It should be ensured that at least one standard is at or below the level corresponding to the rubber being tested. It is important that water be as
41、pirated through the burner after each measurement. Table 1 Volume of primary calibration solution with corresponding concentration of iron Volume of primary calibration solution (7.3.1.1) Corresponding concentration of iron 100 1 000 50 500 20 200 10 100 55 0 2 a 20 a 1 a 10 a 0 b 0 a Only if the se
42、nsitivity of the spectrometer is high enough for accurate results. b Calibration blank solution. 50 cm 3 1 + 3 10 min 1 + 3 100 cm 3 1 + 3 10 cm 3 1dm 3 1 + 3 1cm 3 10 g 100 cm 3 1 + 3 cm 3 g/100 cm 3 248,3 nm 372,0 nm BS ISO 6101-5:20065 7.3.3 Plotting the calibration curves Plot two curves (one fo
43、r each of the concentration ranges given below) having, for example, the masses, in micrograms, of iron contained in of the standard calibration solutions as abscissae from a) to for , b) to for , and the corresponding values of absorbance, corrected for the absorbance of the calibration blank solut
44、ion (see Table 1), as ordinates. Represent the points on the graph by the best straight line as judged visually, or calculated by the least-square fit method. 7.4 Determination 7.4.1 Spectrometric measurements Carry out duplicate spectrometric measurements at a wavelength of or on the test solution
45、(7.2.2), following the procedures specified in 7.3.2. 7.4.2 Dilution If the instrument response for the test solution is greater than that found for the standard calibration solution having the highest iron content (see Table 1), dilute as appropriate with hydrochloric acid (4.3) in accordance with
46、the following procedure. Pipette carefully a volume of the test solution (7.2.2) into a one-mark volumetric flask so that the iron concentration 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 d
47、etermination Carry out a blank determination in parallel with the determination, using hydrochloric acid (4.3), but omitting the test portion. If sulfuric acid and hydrofluoric acid were used for the test portion preparation, the same quantities of these acids shall be used in the preparation of the
48、 blank determination solution. 8 Expression of results 8.1 Read the iron content of the test solution directly from the appropriate calibration graph (see 7.3.3). The iron content of the test portion, expressed in parts per million by mass, is given by the formula: where is the iron concentration, i
49、n micrograms per , of the test solution (7.2.2), read from the calibration graph; is the iron concentration, in micrograms per , of the blank determination solution (7.4.3), read from the calibration graph; 100 cm 3 10 g/100 cm 3 100 g/100 cm 3 248,2 nm 100 g/100 cm 3 1 000 g/100 cm 3 372,0 nm 248,3 nm 372,0 nm 1 + 3 V 100 cm 3 1 + 3 1 + 3 Fe,t Fe,b 100m f 10 4 Fe,t 100 cm 3 Fe,b 10
