1、BRITISH STANDARD BS 4651-2: 1987 ISO 7108:1985 Ammonia solution Part 2: Method for determination of ammonia content ISO title: Ammonia solution for industrial use Determination of ammonia content Titrimetric method UDC 546.171.1-145.2:543.241.2BS4651-2:1987 This British Standard, having been prepare
2、d under the directionof the Chemicals Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect on 27 February 1987 BSI 11-1999 The following BSI references relateto the work on this standard: Committee reference CIC/21 Draft for comment 84/50478 DC ISBN 0 580 15
3、884 5 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Chemicals Standards Committee (CIC/-) to Technical Committee CIC/21, upon which the following bodies were represented: British Coal British Pharmacopoeia Commission British Sulphate o
4、f Ammonia Federation Ltd. Chemical Industries Association Fertiliser Manufacturers Association Ltd. Ministry of Defence Textile Institute Amendments issued since publication Amd. No. Date of issue CommentsBS4651-2:1987 BSI 11-1999 i Contents Page Committees responsible Inside front cover National fo
5、reword ii 1 Scope and field of application 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Procedure 1 6 Expression of results 2 9 Test report 2 Figure Spherical glass ampoule 1BS4651-2:1987 ii BSI 11-1999 National foreword This Part of BS 4651 has been prepared under the direction of the Chemicals Sta
6、ndards Committee. It is identical with ISO 7108:1985 “Ammonia solution for industrial use Determination of ammonia content Titrimetric method”, published by the International Organization for Standardization (ISO). This method supersedes clause 3 of BS 4651:1971, which has been deleted by amendment.
7、 It is intended to publish eight Parts of BS 4651 which collectively will supersede the 1971 edition. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions ar
8、e 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 decimal marker. The symbol “l” has been used to denote litre (and
9、in its submultiples). In British Standards it is current practice to use the symbol “L”. In British Standards it is current practice to use the spelling “sulphur”, etc., instead of “sulfur”, etc. Wherever the words “International Standard” appear, referring to this standard, they should be read as “
10、Part of BS 4651”. This standard prescribes a method of test only and should not be used or quoted as a specification defining limits of purity. Reference to this Part should indicate that the method of test used complies with BS 4651-2:1987. A British Standard does not purport to include all the nec
11、essary 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. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, page
12、s1 and 2 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.BS4651-2:1987 BSI 11-1999 1 WARNING Carry out all the operations in a well-ventilated fume cupboard. 1 Scop
13、e and field of application This International Standard specifies a titrimetric method for the determination of the ammonia content of ammonia solution for industrial use. The method is applicable to solutions containing not more than 35 % (m/m) of ammonia. 2 Principle Introduction of a test portion
14、into a solution of boric acid and titration with a standard volumetric solution of sulfuric acid in the presence of methyl red as indicator. 3 Reagents During the analysis use only reagents of recognised analytical grade and only distilled water or water of equivalent purity. 3.1 Boric acid, 20 g/l
15、solution. 3.2 Sulfuric acid, standard volumetric solution, c(1/2 H 2 SO 4 ) = 1 mol/l. 1) 3.3 Methyl red, 1 g/l ethanolic solution. Dissolve 0,1 g of methyl red in 95 % (V/V) ethanol and make up to 100 ml with the same ethanol. 4 Apparatus Ordinary laboratory apparatus and 4.1 Spherical ampoule, of
16、thin glass, of suitable capacity and shape, for example, about 20 mm diameter, with one capillary end about 50 mm in length (a typical example is shown in the Figure). 5 Procedure 5.1 Test portion Weigh the glass ampoule (4.1) to the nearest 0,000 1 g. Gently heat the spherical part of the ampoule o
17、ver a flame and dip the capillary end of the ampoule into the bottle containing the laboratory sample. Ensure that the ampoule is filled to two-thirds of its capacity during cooling. Withdraw the ampoule and dry the capillary tube carefully with filter paper. Seal the end of the capillary tube, with
18、out loss of glass, with an oxidizing flame. Allow the capillary tube to cool, wash it with water and wipe it with filter paper until completely dry. Weigh the sealed ampoule to the nearest 0,000 1 g and calculate, by difference, the mass of the test portion. 5.2 Determination Carefully place the amp
19、oule containing the test portion (5.1) into a 750 ml conical flask, fitted with a ground glass stopper, to which 50 ml of the boric acid solution (3.1), about 250 ml of water and several drops of the methyl red solution (3.3) have already been added. Stopper the conical flask and shake carefully so
20、as to break the ampoule. Continue shaking for about 30 s. Unstopper the flask and rinse the stopper with water, collecting the washings in the same flask. Using a glass rod, grind the pieces of the ampoule, in particular those parts of the capillary tube which may have remained unbroken. Remove the
21、glass rod, rinse it with water, collecting the washings in the same flask. Titrate with the sulfuric acid solution (3.2) until the indicator changes from yellow to red. 1) Hitherto described as “1 N sulfuric acid solution”. Figure Spherical glass ampouleBS4651-2:1987 2 BSI 11-1999 6 Expression of re
22、sults The concentration of the solution, expressed as a percentage by mass of ammonia (NH 3 ), is given by the formula where V is the volume, in millilitres, of the standard volumetric sulfuric acid solution (3.2) used for the titration; m is the mass, in grams, of the test portion (5.1); 0,017 03is
23、 the mass, in grams, of ammonia (NH 3 ) corresponding to 1,00 ml of sulfuric acid solution, c(1/2 H 2 SO 4 ) = 1,000 mol/l. NOTEIf the concentration of the standard volumetric solution used is not exactly as specified in the list of reagents, an appropriate correction should be made. 9 Test report T
24、he test report shall include the following particulars: a) an identification of the sample; b) the reference of the method used; c) the results and the method of expression used; d) any unusual features noted during the determination; e) any operation not included in this International Standard or r
25、egarded as optional. V 0,017 03 100 m - 1,703V m - =blankBS 4651-2: 1987 ISO 7108:1985 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 in
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