1、BRITISH STANDARD BS 4427-10: 1976 ISO 3357:1975 Methods of test for Sodium tripolyphosphate (pentasodium triphosphate) and sodium pyrophosphate (tetrasodium pyrophosphate) for industrial use Part 10: Determination of total phosphorus (V) oxide content: quinoline phosphomolybdate gravimetric method U
2、DC 661.833.456 + 661.833.458:546.33185:543.062:546.185 31BS4427-10:1976 This British Standard, having been prepared under the directionof the Chemicals IndustryStandards Committee, was published under the authorityof the Executive Boardon 30 June1976 BSI 11-1999 The following BSI references relate t
3、o the work on this standard: Committee reference CIC/25 Draft for comment 74/51835 DC ISBN 0 580 09193 7 Co-operating organizations The Chemicals Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives of the following Government departme
4、nts and scientific and industrial organizations: Association of Fatty Acids 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 Manufacturer
5、s Association Limited* Ministry of Agriculture, Fisheries and Food National Sulphuric Acid Association Royal Institute of Public Health and Hygiene Soap and Detergent Industry Association Society of Analytical Chemistry The Government department and industrial organizations marked with an asterisk i
6、n the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Pharmacopoeia Commission Campden Food Preservation Research Association Flour Milling and Baking Research Association Institute of Metal Finishin
7、g National Association of Soft Drink Manufacturers Society of Chemical Industry Textile Institute Amendments issued since publication Amd. No. Date of issue CommentsBS4427-10:1976 BSI 11-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope and field of application 1
8、 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Procedure 1 6 Expression of results 2 7 Test report 2 Annex ISO publications relating to condensed sodium phosphates for industrial use 3BS4427-10:1976 ii BSI 11-1999 Foreword This British Standard has been prepared under the authority of the Chemicals Ind
9、ustry Standards Committee in order to provide methods for the analysis of sodium tripolyphosphate and sodium pyrophosphate. For some years the United Kingdom has participated in the work of preparing methods of test applicable to sodium tripolyphosphate and sodium pyrophosphate for industrial use, o
10、rganized by Subcommittee6 (formerly Working Group7) “Phosphoric Acid and Condensed Phosphates” of Technical Committee47 “Chemistry” of the International Organization for Standardization (ISO). As international agreement is reached on the methods, it is proposed to publish them as Parts of this Briti
11、sh Standard. This Part is identical with ISO3357 “Sodium tripolyphosphate and sodium pyrophosphate for industrial use Determination of total phosphorus (V) oxide content Quinoline phosphomolybdate gravimetric method”. For the purposes of this Part of this British Standard, the text of ISO3357given i
12、n this publication should be modified as follows: Terminology. The words “British Standard” should replace “International Standard” wherever they appear. The decimal point should replace the decimal comma wherever it occurs. Cross references. The references to International Standards should be repla
13、ced by references to British Standards as follows: Additional information Water of satisfactory purity (see clause 3) is specified in BS3978 “Water for laboratory use”. In the UnitedKingdom, the commercially available reagent grade of hydrochloric acid (see 3.1) has a density of approximately1.18g/m
14、l, is about36% (m/m) or approximately11N solution. A grade of quinoline which does not require purification by being freshly distilled (see 3.2.4) is commercially available in the United Kingdom. This standard specifies methods of test only and should not be used or quoted as a specification definin
15、g limits of purity. Reference to the standard should be in a form of words indicating that the methods of test used conform to the requirements of BS4427. Reference to InternationalStandard Appropriate British Standard ISO/R 850 BS 4427-1 ISO/R 851 BS 4427-2 ISO/R 852 BS 4427-3 ISO/R 853 BS 4427-4 I
16、SO 2996 BS 4427-5 ISO 2998 BS 4427-8 ISO 2999 BS 4427-6 ISO 3000 BS 4427-7 ISO 3357 BS 4427-10 ISO 3358 BS 4427-11 a a In course of preparationBS4427-10:1976 BSI 11-1999 iii A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are resp
17、onsible for their correct application. 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 to iv, pages1to 3 and a back cover. This standard has been updated (see copyrigh
18、t date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS4427-10:1976 BSI 11-1999 1 1 Scope and field of application This International Standard specifies a gravimetric method using quinoline phosphomolybdate for the determin
19、ation of the total phosphorus(V) oxide content of sodium tripolyphosphate (pentasodium triphosphate) and sodium pyrophosphate (tetrasodium diphosphate) for industrial use. 2 Principle Hydrolysis of a test portion by prolonged boiling in the presence of hydrochloric acid. Precipitation of phosphates
20、in the form of quinoline phosphomolybdate in the presence of acetone. Filtration, washing, drying and weighing of the precipitate. 3 Reagents During the analysis, use only reagents of recognized analytical reagent grade and only distilled water or water of equivalent purity. 3.1 Hydrochloric acid, a
21、pproximately1,19g/ml, about38% (m/m) or approximately12N solution. 3.2 Citromolybdate reagent 3.2.1 Dissolve70g of sodium molybdate dihydrate (Na 2 MoO 4 .2H 2 O) in150ml of water. 3.2.2 Dissolve60g of citric acid monohydrate (C 6 H 8 O 7 .H 2 O) in150ml of water and add85ml of nitric acid solution,
22、 approximately1,40g/ml, about68% (m/m) or approximately14N solution. 3.2.3 Add, with mixing, solution 3.2.1 to solution3.2.2. 3.2.4 Add35ml of nitric acid solution, approximately1,40g/ml, about68% (m/m) or approximately14N solution, followed by5ml of pure quinoline, recently distilled, to100ml of wa
23、ter. 3.2.5 Pour solution 3.2.4 into solution 3.2.3 and mix. Allow to stand for at least12h (for example, overnight) and filter through a sintered glass filter of porosity grade P10 (pore size index4to10m). Store this solution protected from light in a well-stoppered flask. 3.2.6 Add280ml of acetone
24、to solution 3.2.5 and dilute to1000ml with water. Do not keep this solution for more than1week. Store under the same conditions as solution 3.2.5. 4 Apparatus Ordinary laboratory apparatus and 4.1 Filter crucible, with sintered glass disk, porosity grade P10 (pore size index4to10m). 4.2 Electric ove
25、n, capable of being controlled at250 10 C. 5 Procedure WARNING Acetone is very flammable and must be handled only inside a well-ventilated fume cupboard, in the absence of flames. 5.1 Test portion Weigh, to the nearest0,0002g, 1g of the test sample, taking care to avoid any gain or loss of moisture.
26、 5.2 Blank test Carry out a blank test at the same time as the determination, following the same procedure and using the same quantities of all the reagents as used in the determination. 5.3 Determination 5.3.1 Preparation of the test solution Place the test portion (5.1) in a250ml flask with ground
27、 neck, dissolve in about50ml of water, add20ml of the hydrochloric acid solution (3.1), fit a reflux condenser on the flask and boil for at least20min. Cool, transfer the solution quantitatively to a1000ml one-mark volumetric flask, dilute to the mark and mix. Prepare this solution at the time of us
28、e and filter if necessary. NOTEIf hydrochloric acid of the concentration indicated in the list of reagents is not available, solutions of lower concentration may be used, by adding the corresponding stoichiometric quantity of HCl. 5.3.2 Precipitation and filtration Take25,0ml of the test solution (5
29、.3.1) and place in a400ml beaker. Dilute to100ml and add100ml of the citromolybdate reagent (3.2). Cover the beaker with a clock glass, warm inside a fume cupboard, on a hot-plate, until its contents reach75 5 C and maintain at this temperature for about30s. (Do not use a flame and do not mix, eithe
30、r during the addition of the reagent or during the heating, so as to avoid the formation of clots.) Allow to cool to ambient temperature, stirring three or four times with a glass rod during cooling.BS4427-10:1976 2 BSI 11-1999 Heat the filter crucible (4.1) in the oven (4.2), controlled at250 10 C,
31、 for15min, allow to cool in a desiccator containing silica gel in good condition and weigh to the nearest0,0001g. Decant the liquid through the crucible and wash the precipitate six times, by decantation, using about30ml of water each time. Transfer all the precipitate to the filter crucible by mean
32、s of a jet of water from a wash bottle. Then wash the precipitate four times, removing each portion of wash water with the aid of a vacuum pump. 5.3.3 Drying and weighing Place the filter crucible in the oven (4.2), controlled at250 10 C, for15min starting from the stabilization of temperature. Allo
33、w to cool for not more than30min in the desiccator containing silica gel in good condition and weigh to the nearest0,0001g. 6 Expression of results The total phosphorus(V) oxide (P 2 O 5 ) content, expressed as a percentage by mass, is given by the formula: where m 0 is the mass, in grams, of the te
34、st portion(5.1); m 1 is the mass, in grams, of precipitate obtained during the determination (5.3.3); m 2 is the mass, in grams, of precipitate obtained during the blank test (5.2); is the ratio between the volume of the test solution and the aliquot portion taken for the determination; 0,032 07is t
35、he factor for conversion of quinoline phosphomolybdate to phosphorus(V) oxide. 7 Test report The test report shall include the following particulars: a) the reference of the method used; b) the results and the method of expression used; c) any unusual features noted during the determination; d) any
36、operation not included in this International Standard, or regarded as optional. 1 000 25 -BS4427-10:1976 BSI 11-1999 3 Annex ISO publications relating to condensed sodium phosphates for industrial use Sodium pyrophosphate (tetrasodium diphosphate) ISO 2999, Estimation of pyrophosphate content Potent
37、iometric method. Sodium tripolyphosphate (pentasodium triphosphate) ISO/R 850, Determination of matter insoluble in water. ISO/R 851, Measurement of pH Potentiometric method. ISO 3000, Estimation of tripolyphosphate content Tris(ethylenediamine) cobalt(III) chloride gravimetric method. Sodium pyroph
38、osphate and sodium tripolyphosphate (tetrasodium diphosphate and pentasodium triphosphate) ISO/R 852, Determination of iron content 2,2-Bipyridyl spectrophotometric method. ISO/R 853, Determination of loss on ignition. ISO 2996, Determination of particle size distribution by mechanical sieving. ISO
39、2998, Determination of orthophosphate content Photometric method using the reduced molybdophosphate. ISO 3357, Determination of total phosphorus(V) oxide content Quinoline phosphomolybdate gravimetric method. ISO 3358, Separation by column chromatography and determination of the different phosphate
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