1、BRITISH STANDARD BS3762-3.1: 1990 ISO2271:1989 Analysis of formulated detergents Part3: Quantitative test methods Section3.1 Method for determination of anionic-active matter content NOTEIt is recommended that BS3762-0, which is published separately, be read in conjunction with this Section.BS3762-3
2、.1:1990 This British Standard, having been prepared under the directionof the Chemicals Standards Policy Committee, waspublished under the authorityof the Board ofBSIandcomes into effect on 29June1990 BSI10-1999 First published December1983 Second edition June1990 The committees responsible forthis
3、British Standard are shown inPart0. The following BSI references relate to the work on this standard: Committee reference CIC/34 Draft (ref.89/54246) announced inBSI News, October1989 ISBN 0 580 18225 8 National foreword This Section of BS3762 has been prepared under the direction of the Chemicals S
4、tandards Policy Committee. It is identical with ISO2271:1989 “Surface active agents Detergents Determination of anionic-active matter by manual or mechanical direct two-phase titration procedure”, published by the International Organization for Standardization (ISO). This Section of BS3762 supersede
5、s the1983 edition of BS3762-3.1, which is withdrawn. The principal difference between this section of BS3762 and the1983 edition is that provision is now made for a mechanical method in addition to the manual method. The committee has reviewed the provisions of ISO385-1 and ISO648, to which referenc
6、e is made in the text, and has decided that they are acceptable for use in conjunction with this standard. The relevant requirements of ISO385-1:1984 and ISO648:1977 are technically equivalent to those in BS846:1985 “Specification for burettes” and BS1583:1986 “Specification for one-mark pipettes”,
7、respectively. Additional information. With reference to clause4, water complying with grade3 of BS3978 “Specification for water for laboratory use” is suitable. This Section describes a method of test only and should not be used or quoted as a specification defining limits of purity. Reference to th
8、is Section should indicate that the method of test used is in accordance with BS3762-3.1. 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 o
9、f itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, 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
10、indicated in the amendment table on the inside front cover. Cross-references International Standard Corresponding British Standard ISO607:1980 BS3762 Analysis of formulated detergents Part1:1983 Methods of sample division (Identical) ISO1042:1983 BS1792:1982 Specification for one-mark volumetric fla
11、sks (Identical) Amendments issued since publication Amd. No. Date of issue CommentsBS3762-3.1:1990 BSI 10-1999 i Contents Page National foreword Inside front cover 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents 1 5 Apparatus 4 6 Sampling 4 7 Procedure 4 8 Expression of results 5 9 Test
12、report 5 Figure 1 Titration vessel(5.5) 6 Table 1 Mass of test portion 4 Publications referred to Inside back coverii blankBS3762-3.1:1990 BSI 10-1999 1 1 Scope This International Standard specifies a manual or mechanical method for the determination of anionic-active matter present in detergents. T
13、he method is applicable to solids or to aqueous solutions of the active material. The relative molecular mass of the anionic active matter has to be known. The method is not applicable if cationic surface active agents are present. The manual method is thus applicable to the determination of alkylbe
14、nzene sulfonates; alkane sulfonates, sulfates and hydroxysulfates; alkylphenol sulfates; fatty alcohol methoxy- and ethoxysulfates; dialkylsulfosuccinates and other active materials containing one hydrophilic group per molecule. The mechanical method is applicable to all the above mentioned products
15、 provided it gives results comparable with those obtained using the manual method. NOTELow relative molecular mass sulfonates present as hydrotropes (toluene, xylene) do not interfere when present in concentrations of up to15%(m/m) relative to the active matter. At higher levels, their influence sho
16、uld be evaluated in each particular case. Soap, urea and salts of (ethylenedinitrilo)tetraacetic acid do not interfere. In the presence of non-ionic surface agents, their influence should be evaluated in each particular case. Typical inorganic components of detergent formulations, such as sodium chl
17、oride, sulfates, borates, tripolyphosphates, perborates, silicates, etc., do not interfere, but bleaching agents other than perborate should be destroyed before the analysis, and the sample should be completely soluble in water. 2 Normative references The following standards contain provisions which
18、, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility o
19、f applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO385-1:1984, Laboratory glassware Burettes Part1: General requirements. ISO607:1980, Surface active agents and detergents Methods of sample divis
20、ion. ISO648:1977, Laboratory glassware One-mark pipettes. ISO1042:1983, Laboratory glassware One-mark volumetric flasks. 3 Principle Determination of the anionic-active matter in a medium consisting of an aqueous and a chloroform phase by titration with a standard volumetric cationic-active solution
21、 (benzethonium chloride) in the presence of an indicator which consists of a mixture of a cationic dye (dimidium bromide) and an anionic dye (acid blue1). NOTEThe chemical process is as follows: the anionic-active matter forms a salt with the cationic dye which dissolves in the chloroform to give th
22、is layer a reddish pink colour. In the course of the titration, the benzethonium chloride displaces the dimidium bromide from this salt and the pink colour disappears from the chloroform layer as the dye passes into the aqueous phase. Excess benzethonium chloride forms a salt with the anionic dye, w
23、hich dissolves in the chloroform layer and colours it blue. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Chloroform, 20 1,48g/ml, distilling between59,5 C and61,5 C. 4.2 Sulfuric acid, approximately245g/l
24、 solution. Carefully add134ml of sulfuric acid, 20 1,83g/ml, to300ml of water and dilute to1 litre. 4.3 Sulfuric acid, standard volumetric solution, c(1/2 H 2 SO 4 )=1,0mol/l. 4.4 Sodium hydroxide, standard volumetric solution, c(NaOH)=1,0mol/l. 4.5 Sodium lauryl sulfate (Sodium dodecyl sulfate) CH
25、3 (CH 2 ) 11 OSO 3 Na, standard volumetric solution, c(C 12 H 25 NaO 4 S)=0,004mol/l. Check the purity of the sodium lauryl sulfate and simultaneously prepare the standard volumetric solution.BS3762-3.1:1990 2 BSI 10-1999 4.5.1 Determination of purity of sodium lauryl sulfate Weigh, to the nearest1m
26、g,5g 0,2g of the product into a250ml round bottom flask with ground glass neck. Add exactly25ml of the standard volumetric sulfuric acid solution(4.3) and reflux using a water condenser. During the first5min to10min, the solution will thicken and tend to foam strongly; control this by removing the s
27、ource of heat and swirling the contents of the flask. In order to avoid excessive foaming, instead of refluxing, the solution may be left on a boiling water bath for60min. After a further10min, the solution will become clear and foaming will cease. Reflux for a further90min. Remove the source of hea
28、t, cool the flask and carefully rinse the condenser with30ml of ethanol followed by water. Add a few drops of the phenolphthalein solution(4.7), and titrate the solution with the sodium hydroxide solution(4.4). Carry out a blank test by titrating25ml of the sulfuric acid solution(4.3) with the sodiu
29、m hydroxide solution(4.4). Calculate the purity , expressed as a percentage by mass, of the sodium lauryl sulfate using the formula 4.5.2 Preparation of standard volumetric sodium lauryl sulfate solution Weigh, to the nearest1mg, between1,14g and1,16g of sodium lauryl sulfate and dissolve in200ml of
30、 water. Transfer the solution quantitatively to a1000ml one-mark volumetric flask(5.3) fitted with a ground glass stopper, and dilute to the mark with water. Calculate the exact concentration c 2 , expressed in moles of C 12 H 25 NaO 4 S per litre, of the solution thus obtained, using the formula 4.
31、6 Benzethonium chloride 1) , standard volumetric solution, c(C 27 H 42 ClNO 2 )=0,004mol/l. Benzyl dimethyl-2-2-4(1,1,3,3-tetramethylbutyl)phenoxyethoxyethyl ammonium chloride, monohydrate: (CH 3 ) 3 -C-CH 2 -C-(CH 3 ) 2 -C 6 H 4 OCH 2 -CH 2 OCH 2 -CH 2 -N-(CH 3 ) 2 -CH 2 -C 6 H 5 +Cl .H 2 O 4.6.1 P
32、reparation of the solution Weigh, to the nearest1mg, between1,75g and1,85g of benzethonium chloride and dissolve in water. Transfer the solution quantitatively to a1000ml one-mark volumetric flask(5.3) fitted with a ground glass stopper, and make up to the mark with water. NOTEIn order to prepare a0
33、,004mol/l solution, dry the benzethonium chloride at105 C, allow to cool in a desiccator, weigh1,792g to the nearest1mg, dissolve in water and dilute to1000ml. where V 0 is the volume, in millilitres, of sodium hydroxide solution(4.4) used for the blank test; V 1 is the volume, in millilitres, of so
34、dium hydroxide solution used for the test portion of sodium lauryl sulfate taken; c 0 is the exact concentration, expressed in moles of NaOH per litre, of the sodium hydroxide solution(4.4); m 1 is the mass, in grams, of the test portion of sodium lauryl sulfate taken. where m 2 is the mass, in gram
35、s, of sodium lauryl sulfate used to prepare the solution; has the same meaning as in4.5.1. 1) Hyamine1622 is an example of a suitable product available commercially. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of
36、 this product. 2884V 1 V 0 ()c 0 , m 1 -BS3762-3.1:1990 BSI 10-1999 3 Tests indicate that other cationic reagents, such as cetyl trimethyl ammonium bromide and benzalkonium chloride, give results identical to those obtained using benzethonium chloride. However, these tests have not been carried out
37、in sufficient numbers to make it possible to state that the results will be identical no matter what the product analysed; for this reason, if benzethonium chloride is not available it is permitted to use another reagent provided that this is stated in the test report. However, in case of doubt, and
38、 always in case of dispute, only benzethonium chloride shall be used. 4.6.2 Standardization of the solution By means of a pipette(5.4), transfer25ml of the standard volumetric sodium lauryl sulfate solution(4.5) to a bottle or measuring cylinder(5.1) or the titration vessel(5.5), and add10ml of wate
39、r,15ml of chloroform(4.1) and10ml of the mixed indicator solution(4.8). Titrate against the benzethonium chloride solution(4.6.1). If a bottle or measuring cylinder(5.1) is used, stopper the bottle or measuring cylinder after each addition and shake well; if the titration vessel(5.5) with stirrer is
40、 used, run the stirrer for at least4s and then switch it off. The lower layer will be coloured pink. Continue the titration, with repeated vigorous shaking (if using5.1) or stirring (if using5.5). As the end point approaches, the emulsion formed during shaking tends to break easily. Continue the tit
41、ration drop by drop, shaking after each addition of titrant, until the end point is reached. This is at the moment when the pink colour is completely discharged from the chloroform layer, which becomes a faint greyish blue. 4.6.3 Calculation of the concentration Calculate the exact concentration c 1
42、of the benzethonium chloride solution, expressed in moles of C 27 H 42 ClNO 2per litre, using the formula 4.7 Phenolphthalein, ethanolic solution containing10g/l. Dissolve1g of phenolphthalein in100ml of95% (V/V) ethanol. 4.8 Mixed indicator solution 2) 4.8.1 Stock solution This solution shall be pr
43、epared from acid blue1 and dimidium bromide. 4.8.1.1 Acid blue1 3)(Colour Index42045) (disodium-4, 4 -dinitrilodiethyltriphenylmethane-2,4-disulfonate): where V 2 is the volume, in millilitres, of the benzethonium chloride solution used for the titration in4.6.2; c 2 has the same meaning as in4.5.2.
44、 2) This mixed indicator is available commercially in the form of a basic solution, which should be acidified and diluted before use. 3) Acid blue1, VS blue and disulfine blue VN150 are examples of suitable products available commercially. This information is given for the convenience of users of th
45、is International Standard and does not constitute an endorsement by ISO of these products. c 2 25 V 2 -BS3762-3.1:1990 4 BSI 10-1999 4.8.1.2 Dimidium bromide (3,8-diamino-5-methyl-6-phenylphenanthridinium bromide): 4.8.1.3 Preparation of the stock solution Weigh, to the nearest1mg,0,5g 0,005g of dim
46、idium bromide(4.8.1.2) into a50ml beaker, and0,25g 0,005g of acid blue1(4.8.1.1) into a second50ml beaker. Add between20ml and30ml of hot10% (V/V) ethanol to each beaker. Stir until dissolved and transfer the solutions to a250ml onemark volumetric flask. Rinse the beakers into the volumetric flask w
47、ith the ethanol and dilute to the mark with the ethanol. 4.8.2 Acid solution Add200ml of water to20ml of the stock solution(4.8.1) in a500ml one-mark volumetric flask. Add20ml of the approximately245g/l sulfuric acid solution(4.2), mix and dilute to the mark with water. Store in the dark. 5 Apparatu
48、s Ordinary laboratory apparatus and 5.1 Bottles or measuring cylinders,100ml capacity, with ground glass stoppers. 5.2 Burettes, 25ml and50ml capacity, complying with the requirements of class A of ISO385-1. 5.3 One-mark volumetric flask, 1000ml capacity, with ground glass stopper, complying with th
49、e requirements of ISO1042. 5.4 One-mark pipettes, 25ml capacity, complying with the requirements of Class A of ISO648. 5.5 Titration vessel, with suitable stirrer (see Figure 1) driven by a motor. 5.6 Automatic burette, motorized piston type,20ml capacity, of accuracy similar to those specified in5.2. 6 Sampling The laboratory sample shall be prepared and stored in accordance with the instructions given in ISO607. 7 Procedure WARNING Comply with safety regulations
