1、BRITISH STANDARD CONFIRMED JUNE1993 BS3762-3.19: 1983 ISO4313:1976 Analysis of formulated detergents Part3: Quantitative test methods Section3.19 Method for determination of total phosphorus (V) oxide content ISO title: Washing powders Determination of total phosphorus(V) oxide content Quinoline pho
2、spomolybdate gravimetric method NOTEIt is recommended that this Section be read in conjunction with the information in the “General introduction”, published separately as BS3762-0. UDC 661.185:543.21:546.18531BS3762-3.19:1983 This BritishStandard, having been prepared under the directionof the Chemi
3、cals Standards Committee, was published under the authority ofthe Board of BSI and comesintoeffect on 30December1983 BSI12-1999 The committees responsible forthis BritishStandard are shown inPart0. The following BSI references relate to the work on this standard: Committee reference CIC/34 Draft for
4、 comment75/53721 DC ISBN 0 580 13560 8 Amendments issued since publication Amd. No. Date of issue CommentsBS3762-3.19:1983 BSI 12-1999 i Contents Page National foreword ii 1 Scope and field of application 1 2 Reference 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Sampling 1 7 Procedure 1 8 Expressio
5、n of results 2 9 Test report 2 Publications referred to Inside back coverBS3762-3.19:1983 ii BSI 12-1999 National foreword This Section of BS3762 has been prepared under the direction of the Chemicals Standards Committee. It is identical with ISO4313:1976 “Washing powders Determination of total phos
6、phorus(V) oxide content Quinoline phosphomolybdate gravimetric method”, published by the International Organization for Standardization (ISO). This Section supersedes method D10 of BS3762:1964 and determines the total inorganic phosphorus content by precipitation of phosphates (after acid hydrolysis
7、 of polyphosphates) in the form of quinoline phosphomolybdate. The two procedures which are superseded were: Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a BritishStandard without deviation. Some terminology and certain conventi
8、ons are not identical with those used in BritishStandards; attention is drawn especially to the following. The comma has been used as a decimal marker. In BritishStandards, it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” a
9、ppear, referring to this standard, they should be read as “Section of this BritishStandard”. NOTEThe footnotes to clause2 and5.6 are no longer applicable now that ISO607 and ISO4793 have been published. The Technical Committee has reviewed the provisions of ISO/R648 (nowISO648) to which reference is
10、 made in5.4, and has decided that they are suitable for use in conjunction with this standard. A related BritishStandard to ISO/R648 is BS1583 “One-mark pipettes”. Additional information Reagents. With reference to clause4, water complying with BS3978 “Water for laboratory use” is suitable. Nitric a
11、cid, approximately1.42g/ml which is the corresponding reagent normally available in the United Kingdom, is suitable for use in place of the reagent specified in4.1. This standard describes a method of test only and should not be referred to as a specification defining limits of purity. Reference to
12、the standard should indicate that the method of test used is in conformity withBS3762-3.19. Procedure A. Determination by titration with alkali. Procedure B. Gravimetric determination, based on weighing as magnesium pyrophosphate. Cross-references International Standard Corresponding BritishStandard
13、 ISO607:1980 BS3762 Analysis of formulated detergents Part1:1983 Methods of sample division (Identical) ISO1042:1981 BS1792:1982 Specification for one-mark volumetric flasks (Identical) ISO4793:1980 BS1752:1983 Specification for laboratory sintered or fritted filters including porosity grading (Iden
14、tical)BS3762-3.19:1983 BSI 12-1999 iii 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 confer immunity from legal obligations. Su
15、mmary of pages This document comprises a front cover, an inside front cover, pagesi to iv, pages1and 2, 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 fro
16、nt cover.iv blankBS3762-3.19:1983 BSI 12-1999 1 1 Scope and field of application This International Standard specifies a gravimetric method for the determination of the total phosphorus(V) oxide content of commercial washing powders. 2 Reference ISO607, Surface active agents Detergents Methods of sa
17、mple division 1) . 3 Principle Hydrolysis of polyphosphates by nitric acid. Precipitation of phosphates in the form of quinoline phosphomolybdate in acetone solution. Drying and weighing of the precipitate. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only dis
18、tilled water or water of equivalent purity. 4.1 Nitric acid, 20approximately1,40g/ml, about68% (m/m) or approximately14N solution. 4.2 Citromolybdic reagent 4.2.1 Dissolve70g of sodium molybdate dihydrate (Na 2 MoO 4 .2H 2 O) in150ml of water in a400ml beaker. 4.2.2 Dissolve60g of citric acid monohy
19、drate (C 6 H 8 O 7 .H 2 O) in150ml of water in a1000ml beaker and add85ml of the nitric acid solution(4.1). 4.2.3 Pour solution(4.2.1) into solution(4.2.2), while stirring. 4.2.4 Place100ml of water in a400ml beaker and add35ml of the nitric acid solution(4.1), followed by5ml of pure quinoline. 4.2.
20、5 Pour solution(4.2.4) into solution(4.2.3), while stirring, and allow to stand overnight. Without rinsing with water 2) , filter all the liquid through the filter crucible(5.6) into the1000ml one-mark volumetric flask(5.2). 4.2.6 Add to solution(4.2.5)280ml of acetone, dilute to the mark with water
21、 and mix. 5 Apparatus Ordinary laboratory apparatus and 5.1 Polyethylene beakers, of capacity400,600,1000 and2000ml. A polyethylene beaker is preferable to a glass beaker, as the active solution has to be prevented from coming into contact with glass if determination of the silica content is also to
22、 be carried out. 5.2 One-mark volumetric flask, of capacity1000ml, complying with the requirements of ISO1042. 5.3 One-mark volumetric flask, of capacity 100 ml, complying with the requirements of ISO1042. 5.4 One-mark pipettes, of capacity5,10,20,25 and50ml, checked periodically and complying with
23、the requirements of Class A of ISO/R648. 5.5 Filter flask, of capacity500ml. 5.6 Filter crucible, with sintered glass disks having a porosity of P16 (pore size index10 to16m), complying with the requirements of ISO4793 3) . Before use, dry this crucible for1h in the oven(5.7), controlled at260 20 C,
24、 and cool in a desiccator. 5.7 Oven, capable of being controlled at260 20 C. 5.8 Mechanical stirrer 6 Sampling The laboratory sample of washing powder shall be prepared and stored according to the instructions given in ISO607. 7 Procedure 7.1 Test portion Weigh, to the nearest0,01g, about10g of the
25、laboratory sample. 7.2 Determination Transfer the test portion(7.1) to the2000ml beaker(5.1). Fill the one-mark volumetric flask(5.2) to the mark with water at35 to40 C and add to the test portion, allowing a few seconds for drainage. Stir vigorously with the stirrer(5.8) for about3min so as to diss
26、olve the test portion, apartfrom possible small amounts of insoluble silicate, etc., (solution L 1 ). Take25,0ml of the test solution (L 1 ) by means of the25ml pipette(5.4), transfer to the100ml one-mark volumetric flask(5.3) and dilute to the mark with water (solution L 2 ). Using one of the pipet
27、tes(5.4), take a volume of solution L 2 , containing between5 and20mg of phosphorus(V) oxide for example20ml for a washing powder containing about20% (m/m) of phosphorus(V) oxide. 1) In preparation. (Revision of ISO/R607.) 2) If necessary, the first portions should be passed through the filter cruci
28、ble again until a clear filtrate is obtained. 3) In preparation.BS3762-3.19:1983 2 BSI 12-1999 Transfer this solution to600ml tall-form beaker. Add15ml of the nitric acid solution(4.1) and diluteto about100ml. Cover the beaker with a watch-glass, bring the contents gently to the boil and keep boilin
29、g gently for30min. If necessary, filter the solution to remove any silica that may have been precipitated and wash the filter with a volume of water corresponding approximately to the amount evaporated during the hydrolysis. Place the beaker containing the warm solution in a fume cupboard and add50m
30、l of the citromolybdic reagent(4.2), without stirring. Cover with a watch-glass and heat immediately with a suitable apparatus (not a flame) so that a temperature of about75 C (incipient boiling) is reached in10 to15min. Maintain this temperature for not more than30s. Remove the beaker from the heat
31、er and allow to cool to ambient temperature, stirring it three or four times while it is cooling. Allow the precipitate that has formed to settle. Fit the filter crucible(5.6), which has been previously weighed, on the flask(5.5) with a vacuum connection. Transfer the decanted solution to the crucib
32、le, leaving as much of the precipitate as possible in the beaker. Wash the precipitate six times by decanting it, using30ml of water each time. Transfer the precipitate quantitatively to the crucible with the aid of a wash-bottle. In order to do this, wash the beaker four times with water, adding ea
33、ch portion of the washing water to the crucible only after it has been sucked dry. Finally, pack the precipitate thoroughly in the filter crucible(5.6), place it in the oven(5.7), controlled at260 20 C, and heat for1h. Remove the crucible from the oven, cool in a desiccator and weigh. Repeat the pro
34、cesses of heating, cooling and weighing until two successive weighings do not differ by more than0,001g. NOTEIt is advisable to leave the filter crucible to cool in the desiccator for the same length of time prior to weighing the precipitate as the crucible was left before weighing. 7.3 Blank test I
35、n parallel with the determination, carry out a blank test following the same procedure and using the same quantities of all the reagents but omitting the test portion. The mass of the precipitate should not be greater than1,5mg. If it is greater, renew the reagents. 8 Expression of results 8.1 Metho
36、d of calculation The total phosphorus(V) oxide content of the washing powder, expressed as a percentage by mass, is given by the formula where m O is the mass, in grams, of the test portion(7.1) m 1 is the mass, in grams, of the quinoline phosphomolybdate precipitate obtained in(7.2); m 2 is the mas
37、s, in grams, of the precipitate obtained in the blank test(7.3); V is the volume, in millilitres, of solution L 2used for the determination; 0,03207is the mass, in grams, of phosphorus(V) oxide corresponding to1g of quinoline phosphomolybdate (C 9 H 7 N) 3 H 3(PO 4 .12MoO 3 ). 8.2 Repeatability The
38、maximum difference found between the results of two determinations carried out simultaneously or in rapid succession on the same sample, by the same analyst using the same apparatus, shall not exceed0,5% for phosphorus(V) oxide contents between18 and30% (m/m). 8.3 Reproducibility The difference betw
39、een the results obtained with the same sample in two different laboratories shall not exceed1,1% for phosphorus(V) oxide contents between18 and30% (m/m). 9 Test report The test report shall include the following particulars: a) all information necessary for complete identification of the sample; b)
40、the reference of the method used; c) the results and the method of expression used; d) the test conditions; e) any operations not included in this International Standard, or regarded as optional, as well as any incidents likely to have affected the results. m 1 m 2 ()0,03207 1000 100 100 V 25 m O -
41、m 1 m 2 ()12828 Vm O - =BS3762-3.19:1983 BSI 12-1999 Publications referred to See national foreword.BS3762-3.19: 1983 ISO4313:1976 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the
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