1、BRITISH STANDARD BS 5339:1976 ISO 2211:1973 Method of Measurement of colour in Hazen units (platinum-cobalt scale) of liquid chemical products ISO title: Liquid chemical products Measurement of colour in Hazen units (platinum-cobalt scale) UDC 661 404:535.653BS5339:1976 This British Standard, having
2、 been prepared under the directionof the Chemicals Standards Committee and endorsed by the Plastics IndustryStandards Committee, was published under the authorityof the Executive Boardon 30 June 1976 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference CI
3、C/4/-/2 Draft for approval 75/53297 ISBN 0 580 09232 1 Cooperating organizations The Chemicals Standards Committee, under whose supervision this BritishStandard was prepared, consists of representatives of the following Government departments and scientific and industrial organizations: Association
4、of Fatty Acid Distillers Chemical Industries Association Department of Health and Social Security Department of Industry Chemicals and Textiles Division Department of Industry Laboratory of the Government Chemist Fertiliser Manufacturers Association Ltd Ministry of Agriculture Fisheries and Food Nat
5、ional Sulphuric Acid Association Royal Institute of Public Health and Hygiene Soap and Detergent Industry Association Society of Analytical Chemistry The committee directly entrusted with the preparation of this British Standard comprised representatives of those BSI committees which had an interest
6、 in the subject of the test method. Amendments issued since publication Amd. No. Date of issue CommentsBS5339:1976 BSI 08-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii 1 Scope and field of applications 1 2 Principle 1 3 Definition 1 4 Reagents 1 5 Apparatus 1 6 Prepar
7、ation of standard colorimetric solutions 1 7 Procedure 2 8 Expression of results 2 9 Test report 2BS5339:1976 ii BSI 08-1999 Foreword This British Standard is published under the authority of the Chemicals Standards Committee, with endorsement also by the Plastics Industry Standards Committee, in or
8、der to provide a general method for determination of the Hazencolour of liquid chemical products. It can also be used for solutions and clear dispersions, for example of plastics materials. ISO 2211, the text of which is reproduced verbatim as this British Standard, originated as draft ISO Recommend
9、ation ISO/R 2211, prepared by ISO/TC 47 Chemistry, but that draft was so similar in scope to a similar method (ISO/R 1921), prepared by ISO/TC 61 Plastics, that a combined draft was prepared by an ad hoc group of experts comprised of representatives of both ISOCommittees and was circulated as a seco
10、nd draft International Standard. It is pointed out that, for any particular application, the complete range of standard matching solutions (6.2) may not be necessary. A smaller volume of the standard colorimetric solution (6.1) can then be prepared, thus saving on the cost of the platinum. Specifica
11、tions for Nessler cylinders (5.1) and one-mark volumetric flasks have been published as BS 612 “Nessler cylinders” and BS 1792 “One-mark volumetric flasks”, respectively. For the purposes of this British Standard, the text of ISO 2211 should be modified as follows. Terminology. The words “British St
12、andard” should replace “ISORecommendation” or “International Standard” wherever they appear. The decimal point should replace the decimal comma wherever it appears. Reagents. Clause 4; water of acceptable purity is specified in BS 3978 “Water for laboratory use”. In the United Kingdom, the commercia
13、lly available analytical grade of hydrochloric acid (4.2) has a density of approximately 1.18 g/ml, is about36 % (m/m) or 11N and is suitable. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct appli
14、cation. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1and 2 and a back cover. This standard has been updated (see copyright date) and may have had amen
15、dments incorporated. This will be indicated in the amendment table on the inside front cover.BS5339:1976 BSI 08-1999 1 1 Scope and field of application This International Standard specifies a method of measuring the colour in Hazen units of liquid chemical products. It is applicable only to clear, s
16、lightly coloured liquids for which the colour characteristics are close to those of the reference platinum-cobalt scale. Such colour characteristics are generally describable as “brownish-yellow”. This method is applicable whenever specified by an ISO Recommendation or International Standard relatin
17、g to a given product. 2 Principle Visual comparison of the colour of a sample with that of colour standards, and expression of the result in terms of Hazen (platinum-cobalt) colour units. For routine control purposes an instrument such as a comparator, colorimeter or spectrophotometer may be used, p
18、rovided that it has first been established that the results so obtained are identical with those obtained by visual comparison. 3 Definition hazen colour unit the colour of a solution containing 1 mg of platinum per litre in the form of chloroplatinic acid, in the presence of 2 mg of cobalt(II) chlo
19、ride hexahydrate per litre 4 Reagents Distilled water, or water of equivalent purity, shall be used in the test. 4.1 Cobalt(II) chloride hexahydrate (CoCl 2 6H 2 O) 4.2 Hydrochloric acid, approximately 1,19 g/ml, about 38 % (m/m) solution, or approximately 12 N solution. 4.3 Chloroplatinic acid Diss
20、olve 1,00 g of platinum in a sufficient quantity of aqua regia in a glass or porcelain dish by heating on a boiling-water bath. When the metal has dissolved, evaporate the solution to dryness. Add4ml of the hydrochloric acid solution (4.2) and again evaporate to dryness. Repeat this operation twice
21、more. In this way 2,10 g of chloroplatinic acid (H 2 PtCl 6 ) are obtained. or 4.4 Potassium chloroplatinate (K 2 PtCl 6 ) 5 Apparatus Ordinary laboratory apparatus and 5.1 Two colorimetric tubes, flat based if possible, with a graduation mark at least 100 mm above the base and matched especially wi
22、th respect to colour of glass and height of graduation mark above the base. Suitable tubes are available commercially as50 ml or 100 ml Nessler cylinders. For the measurement of low colorations (lessthan50 Hazen units), the height of the graduation mark above the base must be greater than for the me
23、asurement of deeper colours and must be sufficient that, on looking through this greater depth of liquid, a clear distinction between the standard Hazen matching solutions can be observed. 6 Preparation of standard colorimetric solutions 6.1 Standard colorimetric solution, 500 Hazen units Dissolve 2
24、,00 g of the cobalt chloride (4.1) and the equivalent of 1,00 g of platinum, i.e. either 2,10 g of the chloroplatinic acid (4.3), or 2,49 g of the potassium chloroplatinate (4.4), in water in a 2000 ml one-mark volumetric flask, add 200 ml of the hydrochloric acid solution (4.2), dilute to the mark
25、and mix. This solution has a colour of 500 Hazen colour units. 6.2 Standard Hazen matching solutions (diluted solutions) Into two series of ten 500 ml and fourteen 250 ml one-mark volumetric flasks, place the volumes of standard colorimetric solution (6.1) shown in the following table, dilute to the
26、 mark and mix.BS5339:1976 2 BSI 08-1999 6.3 Storage Store these solutions (6.1 and 6.2) in the dark in stoppered glass bottles. Under these conditions the colour standard solution (6.1) is stable for 1 year. The standard Hazen matching solutions (6.2), although stable for at least 1 month, shall pre
27、ferably be prepared fresh. 7 Procedure First check visually that the sample has colour characteristics close to those of the standard Hazen matching solutions (6.2). If not, follow the instructions given in the second paragraph of section 8. Pour into one of the colorimetric tubes (5.1) a quantity o
28、f the sample sufficient to fill it to the graduation mark. Similarly pour the standard Hazen matching solution (6.2) which appears to have a similar colour into the other tube, to the mark. Compare the colour of the sample with that of the standard, by looking down the tubes from top to bottom again
29、st a white background strongly illuminated by daylight or by an electric “daylight” lamp, taking care to avoid any side illumination. Repeat, if necessary, with other standard Hazen matching solutions until the closest match is obtained. NOTE 1Instruments are available which permit visual comparison
30、 of a liquid of a given depth, with a moving tinted glass disc corresponding to the different standard Hazen matching solutions. The use of such instruments, whose standards are very stable, is permissible provided that it has been established that using these tinted glass discs gives the same resul
31、ts as do the corresponding standard Hazen matching solutions. NOTE 2For routine control purposes, a colorimeter or spectrophotometer may be used, the instrument being standardized by means of the standard colorimetric solutions(6.1 and 6.2), provided that it has been confirmed that the use of that i
32、nstrument gives the same results as does visual comparison. 8 Expression of results Express the colour of the sample as the number of Hazen colour units corresponding to the standard Hazen matching solution having the closest match to the sample. If the colour of the sample does not correspond with
33、that of any of the standard Hazen matching solutions (brownish-yellow), give, if possible, an estimate of the colour and a description of the observed colour. 9 Test report The test report shall include the following particulars: a) the reference of the method used; b) the result, expressed in Hazen
34、 colour units; c) any unusual features noted during the determination; d) any operation not included in this International Standard or regarded as optional. 500 ml volumetric flasks 250 ml volumetric flasks Volume of standard colorimetric solution (6.1) Corresponding colour Volume of standard colori
35、metric solution (6.1) Corresponding colour ml Hazen units ml Hazen units 0 5 10 15 20 25 30 35 40 50 0 5 10 15 20 25 30 35 40 50 30 35 40 45 50 62,5 75 87,5 100 125 150 175 200 225 60 70 80 90 100 125 150 175 200 250 300 350 400 450blankBS 5339:1976 ISO2211:1973 BSI 389 Chiswick High Road London W4
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