1、BRITISH STANDARD BS 3900-B12: 1986 ISO 3856-7: 1984 Methods of test for paints Part B12: Determination of “soluble” mercury content ISO title: Paints and varnishes Determination of “soluble” metal content Part 7: Determination of mercury content of the pigment portion of the paint and of the liquid
2、portion of water-dilutable paints Flameless atomic absorption spectrometric method It is recommended that this Part be read in conjunction with the general information in the Introduction to BS3900, issued separately UDC 667.61:620.1BS3900-B12:1986 This British Standard, having been prepared under t
3、he directionof the Pigments, Paintsand Varnishes StandardsCommittee, was published under the authority ofthe Board of BSI and comes into effect on 31January1986 BSI 07-1999 The Committees responsible for this British Standard are shown inBS 3900: Introduction The following BSI references relate to t
4、he work on this standard: Committee reference PVC/10 Draft for comment 82/55556 DC ISBN 0 580 14951 X Amendments issued since publication Amd. No. Date of issue CommentsBS3900-B12:1986 BSI 07-1999 i Contents Page National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 References 1
5、 3 Principle 1 4 Reagents and materials 1 5 Apparatus 2 6 Procedure 2 7 Expression of results 4 8 Test report 5 Figure 1 Firing adapter 6 Figure 2 Example of apparatus for the determination of mercurybyflamelessatomic absorption spectrometry 7 Figure 3 General view of the combustion apparatus 8 Publ
6、ications referred to Inside back coverBS3900-B12:1986 ii BSI 07-1999 National foreword This Part of BS3900 has been prepared under the direction of the Pigments, Paints and Varnishes Standards Committee. It is identical with ISO 3856-7:1984 “Paints and varnishes Determination of “soluble” metal cont
7、ent” Part7:“Determination of mercury content of the pigment portion of the paint and of the liquid portion of water-dilutable paints Flameless atomic absorption spectrometric method” published by the International Organization for Standardization (ISO). It is assumed in the drafting of this standard
8、 that it will be used and applied by those who are appropriately qualified and experienced. The procedures described in this standard are intended to be carried out by suitably trained and/or supervised personnel. The substances and procedures described may be injurious to health if inadequate preca
9、utions are taken. This standard refers only to its technical suitability and does not absolve the user from statutory obligations relating to health and safety. Terminology and conventions. The text of the international standard has been approved as suitable for publication as a British Standard wit
10、hout deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards, it is current practice to use a full point on the baseline as the decima
11、l marker. In British Standards it is current practice to use the symbol “L” for litre rather than “l”, and to use the spelling “sulphur”, etc., instead of “sulfur”, etc. Wherever the words “International Standard” and “part of ISO 3856” appear, referring to this standard, they should be read as “Bri
12、tish Standard” and “Part of BS 3900” respectively, and wherever the identification “ISO 3856-7” appears, it should be read as “BS 3900-B12”. The Technical Committee has reviewed the provisions of ISO 385-1:1984, and ISO648:1977 to which reference is made in the text, and has decided that they are ac
13、ceptable for use in conjunction with this standard. ISO 385-1 is related to BS 846 “Specification for burettes” and ISO 648 is related to BS 1583 “One-mark pipettes”. The Technical Committee has reviewed the proposed provisions of ISO 3696 to which reference is made in clause4 and has decided that t
14、hey are acceptable for use in conjunction with this standard. ISO 3696 is related to BS 3978 “Water for laboratory use”. Cross-references International standards Corresponding British Standards ISO 1042:1983 BS 1792:1982 Specification for one-mark volumetric flasks (Identical) ISO 6713:1984 BS 3900
15、Methods of test for paints Part B5:1986 Preparation of acid extracts from liquid paints or coating powders (Identical)BS3900-B12:1986 BSI 07-1999 iii ISO 3856, to which reference is made in clause0, is published in a number of Parts of BS 3900. At the time of publication of this standard, the relati
16、onship between other Parts of BS 3900 and Parts of ISO 3856 was as follows: A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confe
17、r immunity from legal obligations. Part of ISO 3856 Corresponding Part of BS 3900 BS 3900 Methods of test for paints ISO 3856-1:1984 a Part B6:1986 Determination of “soluble” lead content (Identical) ISO 3856-2:1984 Part B7:1986 Determination of “soluble” antimony content (Identical) ISO 3856-3:1984
18、 Part B8:1986 Determination of “soluble” barium content (Identical) ISO 3856-4:1984 Part B9:1986 Determination of “soluble” cadmium content (Identical) ISO 3856-5:1984 Part B10:1986 Determination of hexavalent chromium content of solid matter (Identical) ISO 3856-6:1984 Part B11:1986 Determination o
19、f total chromium content of liquid matter (Identical) a Attention is drawn to a similar standard, BS 3900-B3 “Determination of “soluble” lead in the solid matter in liquid paints”: method for use in conjunction with The Control of Lead at Work Regulations,1980 (S.I. 1980 No. 1248)”. Summary of pages
20、 This document comprises a front cover, an inside front cover, pages i to iv, pages1to 8, an inside 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.iv bl
21、ankBS3900-B12:1986 BSI 07-1999 1 0 Introduction This International Standard is a part of ISO 3856, Paints and varnishes Determination of “soluble” metal content. 1 Scope and field of application This part of ISO 3856 describes a flameless atomic absorption spectrometric method for the determination
22、of the mercury content of the test solutions, prepared according to ISO 6713 or other suitable International Standards. The method is applicable to paints having “soluble” mercury contents in the range of about 0,005 to0,05% (m/m), but the part of this method covering the examination of the liquid p
23、ortion of the paint is restricted to water-dilutable paints. CAUTION The procedures described in this part of ISO 3856 are intended to be carried out by qualified chemists or by other suitably trained and/or supervised personnel. The substances and procedures used in this method may be injurious to
24、health if adequate precautions are not taken. Attention is drawn in the text (see4.6 and 4.7) to certain specific hazards. This part of ISO3856 refers only to its technical suitability and does not absolve the user from statutory obligations relating to health and safety. 2 References ISO 385-1, Lab
25、oratory glassware Burettes Part1: General requirements 1) . ISO 648, Laboratory glassware One-mark pipettes. ISO 1042, Laboratory glassware One-mark volumetric flasks. ISO 3696, Water for laboratory use Specifications 2) . ISO 6713, Paints and varnishes Preparation of acid extracts from paints in li
26、quid or powder form. 3 Principle Oxidation of the mercury compounds contained in the test solution obtained from the pigment portion of the paint or combustion with oxygen in an enclosed system of the evaporation residue of the test solution obtained from the liquid portion of water-dilutable paints
27、. Reduction of the mercury(II) compounds contained in the resulting solutions to elementary mercury. Entrainment of the mercury in a current of gas at ambient temperature and determination of the mercury, as the monoatomic vapour, by cold vapour (flameless) atomic absorption spectrometry at a wavele
28、ngth in the region of 253,7nm. 4 Reagents and materials During the analysis, use only reagents of recognized analytical grade and water of at least grade3 purity according to ISO3696. 4.1 Oxygen, commercial grade, in a steel cylinder. 4.2 Tin(II) chloride dihydrate, 100g/l solution. Dissolve 25g of
29、tin(II) chloride dihydrate (SnCl 2 .2H 2 O) in 50ml of 35% (m/m) (A approximately 1,18g/ml) hydrochloric acid and dilute to 250ml with water. Add a few granules of metallic tin and heat until any precipitate disappears. Ensure that a few granules of bright tin are present to stabilize the solution a
30、nd, before use, that there is no precipitate. 4.3 Sulfuric acid, 5% (m/m). 4.4 Nitric acid, approximately 65% (m/m) (A approximately 1,40g/ml). 4.5 Potassium permanganate, 60 g/l solution. Dissolve 60g of potassium permanganate (KMnO 4 ) in water and dilute to 1litre. 4.6 Hydroxylammonium chloride,
31、20% (m/m) solution. WARNING Hydroxylammonium chloride is toxic, corrosive and an irritant. Avoid contact with eyes and skin. Dissolve 20g of hydroxylammonium chloride (NH 3 OHCl) in about 75ml of water and dilute to100ml. 4.7 Mercury, standard stock solution containing100mg of Hg per litre. WARNING
32、Mercury, particularly in its vapour form, and its solutions are toxic. Avoid breathing mercury vapour. Avoid contact of mercury or its solutions with eyes and skin. Carry out all procedures in a well-ventilated fume cupboard. Either 1) At present at the stage of draft. (Partial revision of ISO/R 385
33、:1964.) 2) At present at the stage of draft. a) transfer the contents of an ampoule of a standard mercury solution containing exactly0,1g of Hg into a 1000 ml one-mark volumetric flask, dilute to the mark with the5%(m/m) sulfuric acid (4.3) and mix well;BS3900-B12:1986 2 BSI 07-1999 1ml of this stan
34、dard stock solution contains 0,1mg of Hg. 4.8 Mercury, standard solution containing 1mg of Hg per litre. Prepare this solution on the day of use. Pipette 10ml of the standard stock solution (4.7) into a 1000ml one-mark volumetric flask, dilute to the mark with the sulfuric acid (4.3) and mix well. 1
35、ml of this standard solution contains 1 4g of Hg. 5 Apparatus Ordinary laboratory apparatus and 5.1 Atomic absorption spectrometer, suitable for measurements at a wavelength of 253,7nm and capable of operating with the measuring cell specified in5.2. NOTEIf special commercial mercury analyzers using
36、 the cold vapour AAS principle are used (seenote to6.1.2.1), appropriate amendment of the procedure described in 6.1.2 and 6.3.2 may be necessary and this should be recorded in the test report. 5.2 Measuring cell, with windows (for example of quartz) transparent to ultraviolet radiation (in the regi
37、on of 253,7 nm), the optical path length of which should be appropriate to the spectrometer being used, but not less than 100mm. 5.3 Mercury hollow-cathode lamp or mercury discharge lamp. 5.4 Potentiometric chart recorder. NOTEA suitable peak measuring device such as an electronic integrator may be
38、used as an alternative. 5.5 Combustion flask or separating funnel, of capacity 500ml, with a ground-glass joint. 5.6 Test portion holder (platinum gauze combustion basket) and firing adapter, suitable for fitting to the combustion flask (5.5) (seeFigure 1). 5.7 Spark generator NOTEA high-frequency v
39、acuum tester has been found to be satisfactory. 5.8 Flowmeter, fitted with a stainless steel needle valve and capable of measuring flow rates within the range 0,4to3l/min. 5.9 Pump, diaphragm type, capable of giving controlled air flow rates of 0,4to3l/min, or cylinder of compressed air or nitrogen
40、equipped with a suitable pressure regulating valve. 5.10 Reaction vessel, comprising a test tube, of capacity 25ml, with a ground-glass joint neck to fit an interchangeable head and a four-way stopcock (seeFigure 2). 5.11 Equipment, to prevent any condensation of water vapour in the measuring cell.
41、Any appropriate system may be used for this purpose (for example an infra-red lamp, a black electrical heating element, or a rod heater). 5.12 Flexible acid-resistant tubing (for example silicone rubber tubing), suitable for connecting the apparatus (seeFigure 2). 5.13 Capsules, of hardened gelatine
42、, pharmaceutical grade. 5.14 Rotary evaporator, water cooled, capable of operation under vacuum with a rotation rate of150r/min. 5.15 Water-bath, capable of being maintained at45 5 C. 5.16 Burettes, of capacity 10ml and 25ml, complying with the requirements of ISO 385-1. 5.17 One-mark volumetric fla
43、sks, of capacity25ml,100ml and 500ml, complying withthe requirements of ISO1042. 5.18 Pipettes, of capacity 1ml, 5ml and 25ml, complying with the requirements of ISO648. 5.19 Balance, capable of weighing to 0,1mg. 6 Procedure 6.1 Preparation of the calibration graph 6.1.1 Preparation of the standard
44、 matching solutions Prepare these solutions on the day of use. Into a series of six25ml one-mark volumetric flasks(5.17), introduce from the 10ml burette(5.16), respectively, the volumes of the standard mercury solution (4.8) shown in the following table, dilute each to the mark with the sulfuric ac
45、id (4.3) and mix well. or b) weigh, to the nearest 0,1mg, 0,1354g of mercury(II) chloride, dissolve in the sulfuric acid(4.3) in a 1000ml one-mark volumetric flask, dilute to the mark with the same sulfuric acid and mix well. Standard matching solution No. Volume of the standard mercury solution(4.8
46、) Corresponding concentration of Hg in the standard matchingsolution ml 4g/ml 0 a 0 0 1 1 0,04 2 2 0,08 3 3 0,12 4 4 0,16 5 5 0,20 a Blank matching solution.BS3900-B12:1986 BSI 07-1999 3 6.1.2 Spectrometric measurement 6.1.2.1 Install the measuring cell (5.2) and the mercury spectral source (5.3) in
47、 the spectrometer(5.1) and optimize the conditions for the determination of mercury. Adjust the instrument in accordance with the manufacturers instructions and adjust the monochromator to the region of253,7nm in order to obtain the maximum absorbance. Connect the flowmeter (5.8), pump(5.9), reactio
48、n vessel (5.10) and measuring cell (5.2) with the minimum lengths of flexible tubing (5.12) as shown in Figure 2. NOTEA closed-circuit measuring system may be used in which the mercury is recirculated by means of a pump. This will be particularly effective when the release of mercury vapour is delay
49、ed by interfering substances, e.g. bromide ions. 6.1.2.2 Switch on the pump and move the four-way stopcock to the by-pass position. Adjust the needle valve or open the gas regulating valve to give a suitable flow rate (for example1l/min). Set the potentiometric chart recorder (5.4) to the appropriate range. Adjust the zero of the recorder to a suitable position on the chart and check for baseline drift and noise level (see6.1.2.4). 6.1.2.3 Disconnect the reaction vessel and, using a pipette (5.18), place 5ml of the standard matching solut
