BS 3900-B11-1986 Methods of test for paints - Tests involving chemical examination of liquid paints and dried paint films - Determination of total chromium content of liquid matter.pdf

1、BRITISH STANDARD CONFIRMED AUGUST 1991 BS 3900-B11: 1986 ISO 3856-6: 1984 Methods of test for paints Part B11: Determination of total chromium content of liquid matter ISO title: Paints and varnishes Determination of “soluble” metal content Part 6: Determination of total chromium content of the liqu

2、id portion of the paint Flame 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-B11:1986 This British Standard, having been prepared under the directiono

3、f the Pigments, Paintsand Varnishes StandardsCommittee, was published under the authority ofthe Board of BSI and comes into effect on 31January1986 BSI 08-1999 The Committees responsible for this British Standard are shown inBS3900: Introduction The following BSI references relate to the work on thi

4、s standard: Committee reference PVC/10 Draft for comment 78/51518 DC ISBN 0 580 14950 1 Amendments issued since publication Amd. No. Date of issue CommentsBS3900-B11:1986 BSI 08-1999 i Contents Page National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 References 1 3 Principle 1

5、 4 Reagents and materials 1 5 Apparatus 1 6 Procedure 1 7 Expression of results 2 8 Test report 3 Publications referred to Inside back coverBS3900-B11:1986 ii BSI 08-1999 National foreword This Part of BS3900 has been prepared under the direction of the Pigments, Paints and Varnishes Standards Commi

6、ttee. It is identical with ISO3856-6:1984 “Paints and varnishes Determination of “soluble” metal content” Part6“Determination of total chromium content of the liquid portion of the paint Flame atomic absorption spectrometric method” published by the International Organization for Standardization (IS

7、O). It is assumed in the drafting of this standard 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 descri

8、bed may be injurious to health if inadequate precautions 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

9、suitable for publication as a British Standard without 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

10、 to use a full point on the baseline as the decimal marker. In British Standards it is current practice to use the symbol “L” for litre rather than “l”. Wherever the words “International Standard” and “part of ISO3856” appear, referring to this standard, they should be read as “British Standard” and

11、 “Part of BS3900” respectively, and wherever the identification “ISO3856-6” appears, it should be read as “BS3900-B11”. The Technical Committee has reviewed the provisions of ISO385-1:1984, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with t

12、his standard. ISO385-1 is related to BS846 “Specification for burettes”. The Technical Committee has reviewed the proposed provisions of ISO3696 to which reference is made in clause4 and has decided that they are acceptable for use in conjunction with this standard. ISO3696 is related to BS3978 “Wat

13、er for laboratory use”. Cross-references International standards Corresponding British Standards ISO 1042:1983 BS1792:1982 Specification for one-mark volumetric flasks (Identical) ISO 6713:1984 BS3900 Methods of test for paints Part B5:1986 Preparation of acid extracts from liquid paints or coating

14、powders (Identical)BS3900-B11:1986 BSI 08-1999 iii ISO3856, to which reference is made in clause 0, is published in a number of Parts of BS3900. At the time of publication of this standard, the relationship between other Parts of BS3900 and Parts of ISO3856 was as follows: A British Standard does no

15、t 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 confer immunity from legal obligations. Part of ISO3856 Corresponding Part of BS3900 BS3900 Methods of test

16、 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 Part B8:1986 Determination of “soluble” barium content (Identical) ISO 3856-4:1984 Part B9:1986 Determin

17、ation of “soluble” cadmium content (Identical) ISO 3856-5:1984 Part B10:1986 Determination of hexavalent chromium content of solid matter (Identical) ISO 3856-7:1984 Part B12:1986 Determination of “soluble” mercury content (Identical) a Attention is drawn to a similar standard, BS3900-B3 “Determinat

18、ion 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 This document comprises a front cover, an inside front cover, pages i to iv, pages1to 4, an inside back cover and a back c

19、over. 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 blankBS3900-B11:1986 BSI 08-1999 1 0 Introduction This International Standard is a part of ISO3856, Paints and varnishes Dete

20、rmination of “soluble” metal content. 1 Scope and field of application This part of ISO3856 describes a flame atomic absorption spectrometric (AAS) method for the determination of the total chromium content of the liquid portion of the paint, prepared in accordance with sub-clause9.3 of ISO6713 or o

21、ther suitable International Standards. The method is applicable to paints having total chromium contents in the liquid portion in the range of about0,05 to5% (m/m). Other methods can be used by agreement between the interested parties but this AAS method is the referee method in cases of dispute. 2

22、References ISO 385-1, Laboratory glassware Burettes Part1: General requirements 1) . 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 liquid or powder form. 3 P

23、rinciple Aspiration of the test solution into a dinitrogen monoxide/acetylene flame. Measurement of the absorption of the selected spectral line, emitted by a chromium hollow-cathode lamp or chromium discharge lamp, in the region of357,9nm. 4 Reagents and materials During the analysis, use only reag

24、ents of recognized analytical grade and only water of at least grade3 purity according to ISO3696. 4.1 Hydrochloric acid, c(HCl) = 0,07mol/l. Use the hydrochloric acid, identical to that used for the preparation of the test solutions in accordance with ISO6713. (See6.2.) 4.2 Acetylene, commercial gr

25、ade, in a steel cylinder. 4.3 Dinitrogen monoxide, commercial grade, in a steel cylinder. 4.4 Chromium, standard stock solution containing100mg of Cr per litre. Either a) transfer the contents of an ampoule of standard chromium solution containing exactly0,1g of Cr into a 1000ml one-mark volumetric

26、flask, dilute to the mark with the hydrochloric acid (4.1) and mix well; or b) weigh, to the nearest0,1mg, 282,9mg of dry potassium dichromate, dissolve in the hydrochloric acid (4.1) in a1000ml one-mark volumetric flask, dilute to the mark with the same hydrochloric acid and mix well. 1ml of this s

27、tandard stock solution contains 1004g of Cr. 4.5 Chromium, standard solution containing10mg of Cr per litre. Prepare this solution on the day of use. Pipette10ml of the standard stock solution (4.4) into a100ml one-mark volumetric flask, dilute to the mark with the hydrochloric acid (4.1) and mix we

28、ll. 1ml of this standard solution contains10 4g of Cr. 5 Apparatus Ordinary laboratory apparatus and 5.1 Flame atomic absorption spectrometer, suitable for measurements at a wavelength of357,9nm and fitted with a burner fed with dinitrogen monoxide and acetylene. 5.2 Chromium hollow-cathode lamp or

29、chromium discharge lamp 5.3 Burette, of capacity25ml, complying with the requirements of ISO385-1. 5.4 One-mark volumetric flasks, of capacity100ml, complying with the requirements of ISO1042. 6 Procedure 6.1 Preparation of the calibration graph 6.1.1 Preparation of the standard matching solutions P

30、repare these solutions on the day of use. 1) At present at the stage of draft. (Partial revision of ISO/R385:1964.) 2) At present at the stage of draft.BS3900-B11:1986 2 BSI 08-1999 Into a series of six100ml one-mark volumetric flasks (5.4), introduce from the burette (5.3), respectively, the volume

31、s of the standard chromium solution (4.5) shown in the following table, dilute each to the mark with the hydrochloric acid (4.1) and mix well. 6.1.2 Spectrometric measurements Install the chromium spectral source (5.2) in the spectrometer (5.1) and optimize the conditions for the determination of ch

32、romium. Adjust the instrument in accordance with the manufacturers instructions and adjust the monochromator to the region of357,9nm in order to obtain the maximum absorbance. Adjust the flow of the acetylene (4.2) and of the dinitrogen monoxide (4.3) according to the characteristics of the aspirato

33、r-burner, and ignite the flame. Set the scale expansion, if fitted, so that the standard matching solution No.5 (see table) gives almost a full-scale deflection. Aspirate into the flame each of the standard matching solutions (see6.1.1) in ascending order of concentration, and repeat with the standa

34、rd matching solution No.4 to verify that the instrument has achieved stability. Aspirate water through the burner between each measurement, taking care to keep the rate of aspiration uniform. 6.1.3 Calibration graph Plot a graph having the masses, in micrograms, of Cr contained in1ml of the standard

35、 matching solutions as abscissae and the corresponding values of the absorbances, reduced by the reading for the blank matching solution, as ordinates. 6.2 Test solutions Use the solutions obtained by the procedure described in sub-clause9.3 of ISO6713 or other specified or agreed procedures. 6.3 De

36、termination Measure first the absorbance of the hydrochloric acid (4.1) in the spectrometer (5.1) after having adjusted it as described in 6.1.2. Then measure the absorbance of each test solution (6.2) three times and, afterwards, that of the hydrochloric acid again. Finally, re-determine the absorb

37、ance of standard matching solution No.4 (see6.1.1) in order to verify that the response of the apparatus has not changed. If the absorbance of a test solution is higher than that of the standard matching solution with the highest chromium concentration, dilute the test solution appropriately (diluti

38、on factor F) with a known volume of the hydrochloric acid (4.1). 7 Expression of results 7.1 Calculations Calculate the mass of chromium in the solution (extract) obtained by the method described in sub-clause9.3 of ISO6713, using the equation where Calculate the chromium content of the liquid porti

39、on of the paints, using the equation where Standard matching solution No. Volume of the standard chromium solution (4.5) Corresponding concentration of Cr in the standard matching solution ml 4g/ml 0 a 1 2 3 4 5 0 2 5 10 15 20 0 0,2 0,5 1 1,5 2 a Blank matching solution. b 0 is the chromium concentr

40、ation, in micrograms per millilitre, of the blank test solution prepared by the method described in sub-clause6.5 of ISO6713; b 1 is the chromium concentration, in micrograms per millilitre, of the test solution obtained from the calibration graph; F is the dilution factor referred to in6.3; m 2 is

41、the mass, in grams, of chromium in the liquid portion of the paint; V 2 is the volume, in millilitres, of the solution obtained by the method described in sub-clause9.3 of ISO6713 (=100ml). is the chromium content of the liquid portion of the paint, expressed as a percentage by mass of the paint; m

42、3 is the total mass, in grams, of paint comprising a “set” as described in sub-clause 6.4 of ISO6713. m 2 b 1 b 0 10 6 -V 2 F = c Cr 2 m 2 m 3 -10 2 = c Cr 2BS3900-B11:1986 BSI 08-1999 3 NOTEThe total “soluble” chromium content of the liquid paint, consisting of the “soluble” hexavalent chromium con

43、tent of the pigment portion plus the total chromium content of the liquid portion of the paint and expressed as a percentage by mass of the paint, is given by the sum of the results obtained according to ISO3856-5 and this part of ISO3856. If the test solutions were prepared by methods other than th

44、at given in ISO6713 (see6.2), it will be necessary to modify the equations for the calculation of chromium content given above. 7.2 Precision No precision data are currently available. 8 Test report The test report shall contain at least the following information: a) the type and identification of t

45、he product tested b) a reference to this International Standard (ISO3856-6); c) the method for the separation of the solid portion of the product under test according to ISO6713, clause6 (method A, B or C); d) the solvent or the solvent mixture used for the extraction; e) the results of the test, ex

46、pressed as a percentage by mass of the product, i.e.the chromium content of the liquid portion of the paint; f) any deviation, by agreement or otherwise, from the test procedure specified; g) the date of the test.4 blankBS3900-B11:1986 BSI 08-1999 Publications referred to See national foreword.BS 39

47、00-B11: 1986 ISO 3856-6: 1984 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. R

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