ISO-6101-2-1997.pdf
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1、INTERNATIONAL STANDARD IS0 6101-2 Second edition 1997-06-01 Rubber - Determination of metal content by atomic absorption spectrometry - Part 2: Determination of lead content Caoutchouc - D a=4OOnet; p=iso; o=isocs; s=central Printed in Switzerland -,-,- INTERNATIONAL STANDARD 0 IS0 IS0 6101-2:1997(E
2、) Rubber - Determination of metal content by atomic absorption spectrometry - Part 2: Determination of lead content WARNING - Persons using this part of IS0 6101 should be familiar with normal laboratory practice. This part of IS0 6101 does not purport to address all of the safety problems, if any,
3、associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. 1 Scope This part of IS0 6101 specifies an atomic absorption spectrometric method for the determination of the lead con
4、tent of rubbers. The method is applicable to raw rubber and rubber products. There is no limit to the concentration of lead that can be determined. High or low concentrations may be determined, provided that suitable adjustments are made to the mass of the test portion and/or the concentration of th
5、e solutions used. The use of the standard-additions method may lower the bottom limit of detection. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of IS0 6101. At the time of publication, the editions indica
6、ted were valid. All standards are subject to revision, and parties to agreements based on this part of IS0 6101 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid Internatio
7、nal Standards. IS0 123: 1985, Rubber latex - Sampling. IS0 247:1990, Rubber - Determination of ash. IS0 648:1977, Laboratory glassware - One-mark pipettes. IS0 1042:1983, Laboratory glassware - One-mark volumetric flasks. IS0 1772:1975, Laboratory crucibles in porcelain and silica. IS0 1795:1992, Ru
8、bber, raw, natural and synthetic - Sampling and further preparative procedures. IS0 6101-2:1997(E) IS0 3 Principle M the rubber does not contain halogenated compounds, a test portion is directly ashed at 550 “C + 25 “C as specified in IS0 247:1990, method A. If the rubber contains halogenated compou
9、nds, a test portion is first mineralized with sulfuric and nitric acids, the acids are removed by evaporation, and the portion is ashed at 550 “C + 25 “C. NOTE - The presence of even small amounts of halogens may lead to the loss of volatile lead salts during dry ashing. The ash obtained is boiled w
10、ith ammonium acetate solution to dissolve the lead. Insoluble lead silicates, if present, are converted to chloride by boiling with a mixture of hydrochloric acid, nitric acid and hydrogen peroxide. The solution is aspirated into an atomic absorption spectrometer and the absorbance is measured at a
11、wavelength of 283,3 nm, using a lead hollow-cathode lamp as the lead emission source. NOTE - IS0 69551982, Analytical spectroscopic methods - Flame emission, atomic absorption, and atomic fluorescence - Vocabulary, defines the spectrometric terms used in this part of IS0 6101. 4 Reagents During the
12、analysis, unless otherwise stated, use only reagents of recognized analytical grade, and only distilled water or water of equivalent purity. 4.1 Sulfuric acid, 20 = 1,84 Mg/ms. 4.2 Nitric acid, 20 = 1,40 Mgim3. 4.3 Hydrochloric acid, 20 = 1 ,18 Mg/m3. 4.4 Hydrochloric acid, diluted 1 + 2. Dilute 1 v
13、olume of concentrated hydrochloric acid (4.3) with 2 volumes of water. 4.5 Hydrogen peroxide, 30 % (m/m) solution. 4.6 Ammonium acetate, 180 g/dm3 solution. 4.7 Standard lead stock solution, containing 1 g of Pb per cubic decimetre. Either use a commercially available standard lead solution, or prep
14、are as follows: Weigh, to the nearest 0,l mg, 1 g of metallic lead (purity 2 99,95 %) and transfer to a 100 cm3 beaker (5.12). Add 30 cm3 of water and 20 cm3 of nitric acid (4.2) and boil on a sand-bath (5.10). If the lead is dissolved, continue boiling until the solution is reduced to about 20 cm3
15、or less. No nitrogen oxides should be observed. Otherwise, add water and continue boiling. Transfer to a 1 000 cm3 one-mark volumetric flask (see 5.7) with 1 + 2 hydrochloric acid (4.4) and fill to the mark with 1 + 2 hydrochloric acid (4.4). 1 cm3 of this standard stock solution contains 1 mg of Pb
16、. 4.8 Standard lead solution, containing 10 mg of Pb per cubic decimetre. Carefully pipette 10 cm3 of the standard lead stock solution (4.7) into a 1 000 cm3 one-mark volumetric flask (see 5.7) dilute to the mark with 1 + 2 hydrochloric acid (4.4), and mix thoroughly. Prepare this solution on the da
17、y of use. 1 cm3 of this standard stock solution contains 10 pg of Pb. 2 -,-,- IS0 IS0 6101-2:1997(E) 5 Apparatus Ordinary laboratory apparatus, plus the following: 5.1 Atomic absorption spectrometer, fitted with a burner fed with acetylene and air, compressed to at least 60 kPa and 300 kPa, respecti
18、vely, and also fitted with a lead hollow-cathode lamp as the lead emission source. The instrument shall be operated in accordance with the manufacturer s instructions for optimum performance. Alternatively, an electrothermal atomization device (graphite furnace) may be used. It shall be operated by
19、a competent person in accordance with the manufacturer s instructions for optimum performance, during drying, ashing and volatilization of the test portion. 5.2 Balance, accurate to 0,l mg. 5.3 Muffle furnace, capable of being maintained at 550 “C -t 25 “C. 5.4 Evaporating dish, of capacity about 10
20、0 ems, made of quartz glass, with a clock-gtass cover. 5.5 Conical flask, of capacity 250 ems, made of silica or borosilicate glass. 5.6 Measuring cylinder, of capacity 25 ems, graduated in 0,5 cm3 divisions. 5.7 One-mark volumetric flasks, glass-stoppered, of capacities 50 ems, 100 ems, 200 ems, 50
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- ISO 6101 1997
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