DRAFT AFRICAN 
STANDARD  DARS  
1474  
First Edition 2019  
 
 Reference No. ARS 1474: 2019 (E) 
ICS 71.100.40  
 
 
© ARSO 2019  
  
 
 
 
 
 
 
 
 
 
Antibacterial bathing bars — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DARS 1474: 2019  
ii © ARSO 2019  — All rights reserved   
Table of contents  
 
1 Scope  ................................ ................................ ................................ ................................ ....... 1 
2 Normative references  ................................ ................................ ................................ ................  1 
3 Terms and definitions  ................................ ................................ ................................ ................  1 
4 Requirements  ................................ ................................ ................................ ............................  1 
4.1 General requirements  ................................ ................................ ................................ ....... 1 
4.2 Specific requirements  ................................ ................................ ................................ ....... 2 
5 Sampling  ................................ ................................ ................................ ................................ ... 2 
5.1 Scale of sampling  ................................ ................................ ................................ .............  2 
6 Packaging and labelling ................................ ................................ ................................ .............  3 
6.1 Packaging  ................................ ................................ ................................ .........................  3 
6.2 Labelling  ................................ ................................ ................................ ...........................  3 
Annex A (normative)  Test for lather volume  ................................ ................................ ......................  4 
Annex B (normative)  Evaluation of the mushing properties of a bathing bar ................................ ....... 6 
Annex C (normative)  Determination of grittiness in antibacterial bathing bar  ................................ ...... 8 
Annex D (informative)  Determination of TCC and TCN in antibacterial bathin g bar by HPLC  .............  9 
Annex E (informative)  Determination of chloroaniline  ................................ ................................ ...... 13 
Annex F (informative)  Permitted structuring and processing  aids ................................ .....................  16 
Annex G (informative)  Permitted antibacterial agents  ................................ ................................ ...... 17 
Annex H (normative)  Determination of microbial inhibition of cosm etic soap bars and liquid hand and 
body washes  ................................ ................................ ................................ ................................ ... 18 
Annex J (normative)  Identification of rosin content of fatty matter in soaps  ................................ ...... 22 
Annex K (normative)  Determination of rosin content of fatty matter in soaps ................................ .... 23 
Bibliography  ................................ ................................ ................................ ................................ .... 26 
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  iii  
Foreword  
 
The African Organization for Standardization (ARS O) is an African intergovernmental organization 
established by the United Nations Economic Commission for Africa (UNECA) and the Organization of 
African Unity (AU)  in 1977 . One of the fundamental mandates of ARSO is to develop and harmoniz e 
African Standards (AR S) for the purpose of enhancing Africa’s internal trading capacity, increase 
Africa’s product and service competitiveness globally and uplift the welfare of African communities. 
The work of preparing African  Standards is normally carried out through ARSO  technical committees. 
Each Member State  interested in a subject for which a technical committee has been established has 
the right to be represented on that committee. International organizations, Regional Economic 
Communities (RECs), governmental and non -governmental  organizations , in liaison with ARSO , also 
take part in the work.  
 
ARSO  Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.  
 
The main task of technical committees is to prepare ARSO  Standards. Draft ARSO  Standards 
adopted by the technical committees are circulated to the member bodies for voting. Publication as an 
ARSO  Standard requires approval by at least 75 % of the member bodies casting a vote.  
 
Attention is drawn to the possibility that some of the e lements of this document may be the subject of 
patent rights. ARSO  shall not be held responsible for identifying any or all such patent rights.  
 
This African Standard was prepared by the ARSO Technical Harmonization Committee Number 5 on 
Chemistry and Chem ical Engineering  (ARSO/THC 05).  
 
 
 
 
 
© African Organisation for Standardisation  2019 — All rights reserved* 
 
ARSO Central Secretariat  
International House 3rd Floor  
P. O. Box 57363 — 00200 City Square  
NAIROBI, KENYA  
 
Tel. +254 -20-2224561, +254 -20-3311641, + 254-20-3311608  
 
E-mail: arso@arso -oran.org  
Web: www.arso -oran.org  
                                                
* ©2019 ARSO — All rights of exploitation reserved worldwide for African Me mber States’ NSBs.  DARS 1474: 2019  
iv © ARSO 2019  — All rights reserved   
 
Copyright notice  
 
This ARSO document is copyright -protected by ARSO. While  the reproduction of this document 
by participants in the ARSO standards development process is permitted without prior 
permission from ARSO, neither this document nor any extract from it may be reproduced, stored 
or transmitted in any form for any other p urpose without prior written permission from ARSO.  
 
Requests for permission to reproduce this document for the purpose of selling it should be 
addressed as shown below or to ARSO’s member body in the country of the requester:  
 
 
© African Organisation for S tandardisation 2019 — All rights reserved  
 
ARSO Central Secretariat  
International House 3rd Floor  
P.O. Box 57363 — 00200 City Square  
NAIROBI, KENYA  
 
Tel: +254 -20-2224561, +254 -20-3311641, +254 -20-3311608  
 
 
E-mail: arso@arso -oran.org  
Web: www.arso -oran.org  
 
Reproduction for sales purposes may be subject to royalty payments or a licensing agreement. 
Violators may be p rosecuted.  
 
 
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  v  
Introduction  
 
Performance of soaps, for a long time, has been primarily based on Total Fatty Matter (TFM).  
 
Whereas the above is a fact, technological trends have shown that performance of soap can be 
enhanced by acceptable and safe surface -active  agents where TFM leve ls have been reduced.  
 
In this standard the TFM levels have been reduced from that of antibacterial toilet soap with 
introduction of surface -active  agents whilst serving the same purpose. However,  this does not 
necessarily imply substitution of antibacter ial toilet soap but rather an alternative and affordable 
antibacterial soap product.  
 
This standard therefore sets minimum requirements for performance and safety characteristics of 
antibacterial bathing bar.  
 
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  1  
Antibacterial bathing bars — Specificatio n 
 
 
1 Scope  
 
This African Standard specifies the requirements and methods of sampling and test for solid 
antibacterial bathing bars  used for personal care .  
 
This Standard applies to antibacterial bathing bars supplied in the form of bars and produced from  
vegetable or animal oils or fats, fatty acids, or from a blend of all or part of these materials, with or 
without the addition of rosins or non -soapy /synthetic surfactants . 
 
2 Normative references  
 
The following referenced documents are indispensable for the application of this document. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies.  
 
ARS 1462, Powder detergents — Biodegradability  
 
ARS 1468, Anti-bacterial liquid toilet soap — Specification  
 
ISO 456, Surface active agents — Analysis of soaps — Determination of free caustic alkali  
 
ISO 685, Analysis of soap — Determination of alkali content and total fatty matter content  
 
Regulation (EC) No 1223 /2009 of the European Parliament and of the Council of 30 November 2009 
on Cosmetic Products  
 
3 Terms and definitions  
 
For the purpose of this standard the following definitions apply.  
 
antibacterial bathing bar  
the bathing bar is a product containing soa p of fatty acids with or without synthetic surface -active  
agents which  contains antibacterial agent (s).  
 
4 Requirements  
 
4.1 General requirements  
 
4.1.1  Antibacterial bathing bars shall be in the form of bars .  
 
4.1.2  The colour of the bar shall generally  be uniform, except for multi -coloured bars.  
 
4.1.3  The product shall not be  harmful to skin.  
 
4.1.4    
 
4.1.4 The antibacterial bathing bars shall be firm.  
 
4.1.5 They may contain suitable quantities of colouring matter, perfume, opacifiers and optical 
brightening agents.  
 
4.1.6 Antibacterial bathing bars shall not contain any ingredients in amounts that are harmful to the 
human body and environment  
 AFRICAN STANDARD  DARS 1474: 2019  
2 © ARSO 2019  — All rights reserved  4.1.7 The antibacterial bathing bar shall contain permitted antibacterial agent. The label shall 
clearly state the antibacterial agent used and its level.  
 
4.1.8 The antibacterial bathing bar shall pass the antibacterial activity test when determined by the 
method given in  Annex J.  
 
4.2 Specific requirements  
 
Antibacterial bathing bars shall also comply with  the requirements given in Table 1 when tested 
against the methods prescribed therein.  
 
Table 1 — Specific  requirements  
 
No. Characteristic  Requirement  Test method  
(ii) Lather, ml, min.  200 Annex A  
(iii) Mush (loss in mass due to mushing on a wet 
surface ), g/30 cm2, max.)  10 Annex B  
(iv) Freedom from grittiness  Pass test  Annex C  
(v) Total alkalinity (as NaOH), % by mass, max.  1.0 ISO 685  
(vi) Free caustic alkali (as NaOH), % by mass, max.  0.3 ISO 456  
 
4.3 Ingredients  
 
The antibacterial bathing bar sha ll have one or more of the following surfactants:  
 
4.3.1.1  There is no restriction on the use of soap of fatty acids, fatty acid ester sulphonates, fatty 
alkalonamide, fatty alcohol ethoxylates, sarcosinates, taurides, fatty isothionates, alpha olefin 
sulphonates, alcohol sulphates and amphoterics such as betaines and fatty alcohol ethoxy sulphate, 
linear alkyl benzene sulphonates (LAS) and alkyl poly glycosides (APG) and fatty alcohol 
sulphosuccinate and fatty alkanol amido sulphosuccinate  or any other sa fe surfactant .  
 
4.3.1.2 In addition to the surfactants and perfume, the antibacterial bathing bar may contain other 
Ingredients such as electrolytes, bar structuring and processing aids, colouring matter, permitted 
antioxidants, preservatives, permissible  germicides, super fatting agents, humectants  and plant 
extracts.  
 
4.3.1.3 Rosins, as % of total fatty matter, shall not exceed 2 %  m/m when tested against  annexes J 
and K.  
 
4.3.1.4 The synthetic surface -active  agents shall pass the biodegradability test as given in ARS 1462 . 
 
4.3.2 All ingredients shall be declared on the label .  
 
4.3.3 The bathing bar shall not contain any material s prohibited by applicable regulations .  
 
5 Sampling  
 
5.1 Scale of sampling  
 
The consignment of Antibacterial bathing bar cak es to be sampled shall be divided into lots, each lot 
containing about 20 cakes from the same source and of the same declared weight and brand.  
 
From each lot, a sample of 9 cakes shall be drawn at random. The cakes of soap thus chosen shall 
be kept, until  tested, in a clean closed container, marked so as to identify the lot from which they have 
been chosen.   
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  3 The cakes shall be tested separately for each of the tests mentioned in Table 1.  
 
This scale of sampling will ensure that there are a further 9 sam ples remaining with which to repeat 
any of  the tests that give results not conforming to the criteria for conformity, or in the event of a 
dispute over the results.  
 
6 Packaging and labelling  
 
6.1 Packaging  
 
Each bar shall be wrapped  and packed in suitable  boxes, packages or cartons to avoid contamination 
or damage during transportation.  
 
6.2 Labelling  
 
Each antibacterial bathing bar shall be marked legibly and indelibly with the following particulars:  
 
a) the words “Antibacterial Bathing Bar”;  
 
b) Produ ct Name  
 
c) manufacturer’s name and physical address and trade mark if any;  
 
NOTE  The name, physical address of the distributor/supplier may be added as required.  
 
d) nominal weight of each bar at the time of packaging;  
 
e) number of bars  contained in the package;  
 
f) batch number or code number  
 
g) all ingredients;  
 
h) date of manufacture and expiry date;  
 
i) antibacterial agents used and their levels;  
 
j) country of origin , if different from manufacturer address  
 
 DARS 1474: 2019  
4 © ARSO 2019  — All rights reserved   
Annex A  
(normative)  
 
Test for lathe r volume  
 
 
 
A.1 General  
 
Strict attention shall be paid to all details of the procedure in order to ensure concordant results. 
Particular care should be taken to invert the cylinder exactly as described.  
 
A.2 Outline of the method  
 
A suspension of the ma terial in standard hard water is taken in a graduated cylinder and given 12 
inversions under prescribed conditions. The volume of the foam formed is observed after keeping the 
cylinder for 5 minutes.  
 
A.3 Reagents  
 
A.3.1  Calcium chloride CaCl 2.2H 2O, AR  
 
A.3.2  Magnesium sulphate MgSO 4.7H 2O, AR  
 
A.3.3  Distilled water  
 
A.4 Apparatus  
 
A.4.1  Graduated cylinder — Glass stoppered with graduation from 0 to 250 mL, with 2 mL 
divisions. Overall height about 35 cm and the height of the graduated portion about 20 cm.  
 
A.4.2  100-mL glass beaker  
 
A.4.3  Thermometer of range 0 – 110 C  
 
A.5 Preparation of standard hard water  
 
Dissolve 0.220 g of calcium chloride dihydrate and 0.246 g of magnesium sulphate heptahydrate in 
distilled water. Dilute to 5 L with distille d water.  
 
NOTE  This standard hard water has a hardness of approximately 50 ppm calculated as calcium carbonate.  
 
A.6 Sample preparation  
 
Cut away the outer edges of bathing bar using a knife  
 
Using a stand up type of grater, grate up to 10 g – 15 g of the bathing bar into small chips.  
 
A.7 Procedure  
 
Weigh 1 g of the grated chips antibacterial bathing bar accurately in a 100 -mL glass beaker. Add 10 
mL of the standard hard water. Cover the beaker with a watch glass and allow to stand for 30 min. 
The ope ration is carried out to disperse the antibacterial bathing bar.  
 
Stir the contents of the beaker with a glass rod and transfer the slurry to a 250 -mL graduated cylinder 
ensuring that not more than 2 mL foam is produced. Repeat the transfer of the residue  left in the 
beaker with further portions of 20 mL of standard hard water ensuring that all the matter in the beaker 
is transferred to the cylinder.  
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  5 Adjust the contents in the cylinder to 100 mL by adding sufficient standard hard water. Bring the 
content s of the cylinder to 30  C. Stir the contents of the cylinder with a glass rod or thermometer to 
ensure a uniform suspension.  
 
As soon as the temperature of the contents of the cylinder reach 30  C, stopper the cylinder and give 
it 12 complete inversions,  each inversion comprising movements in a vertical plane, upside down and 
vice versa. After the 12 inversions, let the cylinder stand for 5 min. Take the following readings as 
shown in Figure A.1:  
 
a) foam plus water (V1 mL).  
 
b) water only (V2mL).  
 
 
 
Figure A.1 — Measurement of foam  
 
A.8 Calculation  
 
Lather volume = V1 - V2  
where  
 
V1 = Volume, in mL of foam + water;  
 
V2 = Volume, in mL of water only.  
 
 DARS 1474: 2019  
6 © ARSO 2019  — All rights reserved   
Annex B 
(normative)  
 
Evaluation of the mushing properties of a bathing bar  
 
 
 
 
B.1 Principle  
 
A test piece of defined size is cut from the sample bar to remove harder outer layers. The test piece is 
preconditioned by giving 18 x 180 degree twists under running water at 25 °C or in a bowl of water at 
25 °C. The bar is left for six hours on a piece of fabric that has been wetted and drained of excess 
water. During the six hours the soap/ cloth are covered to prevent drying. At the end of the test period 
mush is removed from the test piece face in contact with the cloth. Weight loss from the test piece i s 
expressed as mush per 30 cm2 of original surface area in contact with the cloth.  
 
B.2 Equipment  
 
B.2.1  For sample preparation  
 
B.2.1.1  Coarse kitchen cheese grater  
 
B.2.1.2  Sharp thin blade knife or carpenters plane  
 
B.2.1.3  Callipers  or ruler, to ensure the sample dimensions  
 
B.2.1.4  Other equipment/ materials for the test  
 
Plastic or non -corrodible trays which are suitable sized for the test piece. Plastic soap dishes 7 cm x 
11 cm x 2 cm are quite suitable.  
 
Cotton cloth pieces cut and folded to  fit as a triple layer inside the trays. Normal, flat weave, cotton 
sheeting as used for bed sheets will be quite suitable.  
 
B.3 Bar preparation  
 
B.3.1  Three (3) individual bars of a type should be tested. A test piece is cut from each bar. The test 
piece should if possible have a working face (to be applied to the fabric) of 6 cm ±1 cm x 4 cm ±1 cm.  
 
All bars in a set shall be cut to have the same face size. If the smallest of the range of bars to be 
tested at a given time is too small to allow a workin g face within these limits, then all bars should be 
cut to the maximum size possible from the smallest bar.  
 
The longest axis of the test piece (6 ±1) cm should be from a direction parallel to the longest axis of 
the original bar sample.  
 
The working fac e should be a fresh surface from the interior of the bar sample. The face opposite the 
working face should be identified by making a small hole with a sharp object. This enables the 
working face to be identified after the preconditioning step.  
 
B.3.2  To cut the bar it is convenient to first trim it to the approximate size using a coarse kitchen 
cheese grater and then to make the final adjustments to a smooth surface with a sharp thin -bladed 
knife or carpenters plane. If a plane is used, it is better to mov e the bar over the plane blade.  
 
B.4 Test procedure  
 
For each test piece  
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  7 B.4.1  The tray plus triple thickness of cloth is filled with demineralised water. The tray is then held 
vertically to drain the water from the cloth. The vertical position is mainta ined until water ceases to run 
from the dish in a continuous stream i.e. starts to drip.  
 
B.4.2  The area of the working face of the test piece is measured (A).  
 
B.4.3  The working face of the bar is placed onto the damp fabric and then the tray plus soap are 
covered e.g. with a sealed plastic bag, to prevent water loss.  
 
B.4.4  The covered test piece and holder are maintained at 25 C for 6 h.  
 
B.4.5  The mushed soap test piece is removed from the tray and is weighed (W 1).  
 
B.4.6  Mush is removed from the working face of the soap test piece by scraping with the edge of a 
blunt sided spatula or plastic ruler.  
 
B.4.7  The test piece is reweighed (W 2) and the amount of mush removed is calculated as in D.5. 
The mush is expressed as grams per 30  cm2 of original test piece surface area.  
 
NOTE  The procedure for weighing the bar and removing the mush will take some minutes. During that time the remaining 
soaps will continue to form mush. While this time is not critical for a set of three test pieces from a given pr oduct, if more than 
one product is under test it is advised to stagger the start of the test for the second product. This will give adequate time  to 
complete work on the first set before the 6 -hour storage time of the subsequent set is completed.  
 
B.5 Calculation  
 
Weight of mush (grams) W = W 1 – W2  
 
Surface area of bar (cm2) A = (width x breadth)  
 
Mush = 
2cm 30 per 30
Ag W  
 
B.6 Criteria for conformity  
 
The test is done with three (3) separate samples of each product type, and the mean value from t hree 
samples is quoted (X). The range of values (R) is quoted as the difference between the highest and 
lowest values obtained for a given product type.  
 
The sample lot of products shall be declared as conforming to the requirements for this standard if X  + 
0.6R is less than the maximum value given in Table 1.  
 DARS 1474: 2019  
8 © ARSO 2019  — All rights reserved   
Annex C 
(normative)  
 
Determination of grittiness in antibacterial bathing bar  
 
 
 
C.1 Procedure  
 
Either  
Hold the antibacterial bathing bar under a smooth stream of running water at a temperature of 30 °C 
and gently rub the two sides of the bar on the palm of one hand for one minute each side.  
 
or  
 
Immerse the soap in a bowl containing 5 L of water at 30 °C and gently rub two opposite bar faces 
with the palm of one hand for 30 s (15 s per bar fac e). Remove the bar from the water and continue to 
gently rub the two opposite bar faces for a further 30 s (15 s per face).  
 
Allow the used bar to dry in the open for 4 hours and examine the surface.  
 
A set of 3 samples will be tested for each product.  
 
NOTE 1  Hands will become hydrated and insensitive with prolonged immersion in water. Testers should wait 15 min between 
testing every 3 sets of products (9 grit tests).  
 
NOTE 2  If using a bowl rather than running water use fresh water after testing every  set of 3 samples.  
 
C.2 Criteria for conformity  
 
The performance criteria are:  
 
During manipulation under running water the washing bar will not have a visibly rough surface and will 
feel smooth to the touch. No gritty particles will be observed on the surface of the dried bar 4 h after 
the washing test.  
 
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  9  
Annex D 
(informative ) 
 
Determination of TCC and TCN in antibacterial bathing bar by HPLC  
 
 
 
D.1 Principle  
 
TCC and TCN are antibacterial agents, which are separated from other components in soap by 
normal phase or reverse phase liquid chromatography, detected spectrophotometrically and 
quantified by comparison with standard TCC and TCN. The method can estimate as low as 1 ppm of 
the above compounds:  
 
Procedures for both normal and reverse HPLC has be en described and provide the option to use 
either method whichever is available to the users. Both methods are comparable.  
 
D.2 Normal phase HPLC  
 
D.2.1  Reagents  
 
D.2.1.1  Iso-octane , HPLC grade.  
 
D.2.1.2  Iso-propanol (2 -propanol) , HPLC grade  
 
D.2.1.3  Hexa ne, HPLC grade.  
 
D.2.1.4  Standard TCC , 99 % pure  
 
D.2.1.5  Standard TCN , 99 % pure  
 
D.2.2  Apparatus  
 
D.2.2.1  High Performance Liquid Chromatograph consisting of a pump, a sample injector of fixed 
volume with UV detector having variable wavelengths and a rec order.  
 
D.2.2.2  Standard volumetric flasks  
 
D.2.2.3  Pipettes  
 
D.2.2.4  Magnetic stirrer  
 
D.2.2.5  Millipore filter apparatus with 0.5 μ filter  
 
D.2.2.6  Column  
 
D.2.2.6.1 Silica column , stainless steel 25 cm x 0.46 cm packed with Normal phase -silica 5 
(Lich rosorb Si -60)  
 
D.2.2.6.2 Cyano column , stainless steel 25 cm x 0.40 cm packed with (Lichrospher 100) cyano 5 . 
 
NOTE  Either, of the above columns can be used depending on the availability.  
 
D.2.2.7  Mobile phase  
 
D.2.2.7.1 For silica column — Transfer 20 ml of iso -propanol into a 500 ml volumetric flash and make 
upto mark with iso -octane and mix well. Assemble millipore filter apparatus and filter the solvent 
system prior to use.  
 DARS 1474: 2019  
10 © ARSO 2019  — All rights reserved  D.2.2.7.2 For cyano column — Transfer 50 ml of HPLC grade iso -propanol (2 -propanol) into a 500 ml 
volumetric flask, fill upto the mark with hexane and mix well assemble milllipore filter apparatus and 
filter the solvent system prior to use.  
 
D.2.2.7.1 For silica column — Transfer 20 ml of iso -propanol into a 500 -ml volumetric fla sk and 
make up to mark with iso -octane and mix well. Assemble millipore filter apparatus and filter the 
solvent system prior to use.  
 
D.2.2.7.2 For cyano column — Transfer 50 ml of HPLC grade iso -propanol (2 -propanol) into a 500 - 
mL volumetric flask, fill  up to the mark with hexane and mix well. Assemble millipore filter apparatus 
and filter the solvent system prior to use.  
 
D.2.2.8  HPLC conditions  
 
Detector wavelength flow rate:  280 nm  
 
Flow rate:  0.5 ml/min  
 
Injection volume:  20 l  
 
Retention time  
 
Silica column  
TCN - 7.5 min  
TCC - 19.2 min  
 
Cyano column  
TCN - 4.0 min  
TCC - 7.5 min  
 
D.2.3  Procedure  
 
D.2.3.1  Standard preparation (see note under D.3.4)  
 
Weigh accurately 25 mg of triclosan (TCN) and 25 mg of TCC into a 100 -ml volumetric flask and  
make up to volume with the mobile phase and mix well. Pipette 1.0 ml of this solution in a 50 ml 
volumetric flask and dilute with mobile phase. Final concentration of TCC and TCN is 250 g/50 ml 
(5.0 ppm).  
 
D.2.3.2  Sample preparation  
 
Weigh accurately 1 g of homogenized sample into a 100 -ml standard flask, and dilute to the mark with 
mobile phase. Pipette 10 ml of the supernatant liquid to a 50 -ml volumetric flask, dilute with mobile 
phase, to the mark, and filter through 0.45 μm filter.  
 
D.2.3.3  Chromatography  
 
Equilibrate the column, maintained at a temperature of 30 °C, with the mobile phase with a flow rate 
of 0.5 ml /min for iso -octane - iso-propanol mobile phase and 1.0 ml/min for Hexane - iso-propanol 
mobile phase for 3 0 min. Set the wavelength at 280 nm. Inject 20 l of standard solution and then 
sample solutions.  
 
Measure area of the peaks of respective retention time for standard and sample.  
 
D.2.4  Calculation  
 
100sample of ion Concentrat  TCN standard of AreaTCN standard of ion Concentrat  TCN for sample of Area  massby  % TCN, 
 
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  11 
100sample of ion Concentrat  TCC standard of AreaTCC standard of ion Concentrat  TCC for sample of Area  massby  % TCC,  
 
D.3 Reverse phase  
 
D.3.1  Reagents  
 
D.3.1.1  Methanol — HPLC grade.  
 
D.3.1.2  Sodium Dihydrogen Phosphate  
Monohydrate — Chemical grade.  
 
D.3.1.3  Standard TCC  
 
D.3.1.4  Standard TCN (TCS)  
 
D.3 Reverse phase  
 
D.3.1  Reagents  
 
D.3.1.1  Methanol , HPLC grade.  
 
D.3.1.2 Sodium Dihydrogen Phosphate Monohydrate , Chemical grade.  
 
D.3.1.3  Standard TCC  
 
D.3.1.4  Standard TCN (TCS)  
 
D.3.2  Apparatus  
 
D.3.2.1  Column  
 
Octyldimethylsilyl (C -DB)  
 
Supercosil LC -8-DB - 15 cm x 4.6 mm. 5  
 
D.3.2.2  Mobile phase  
 
MeOH/0.01 M Phosph ate buffer 62:38 v/v  
 
0.01 M Phosphate buffer: Dissolve 1.38 g sodium dihydrogen phosphate monohydrate in 1 000 ml of 
distilled water. Prepare to pH 3.0 by 10 % phosphate solutions.  
 
D.3.3  Procedure  
 
D.3.3.1  Standard preparation (see Note under D.3.4)  
 
D.3.3.1.1 Weigh accurately about 90 mg of TCN. Dissolve in methanol and make up to 1 000 ml 
volumetric flask with methanol.  
 
D.3.3.1.2 Weigh about 110 mg of TCC, dissolve well with methanol, and make up the volume to 1 000 
ml.  
 
D.3.3.1.3 Accurately pipet te 10 ml of the solution prepared in (D.3.3.1.1) into the (D.3.3.1.2) 
volumetric flask containing TCC. And make up to the volume with methanol. Then accurately pipette 5 
ml of the solution into a 50 -ml volumetric flask. Make up to the volume with methanol.  Filter this 
standard solution through 0.45 m filter.  
 
D.3.3.2  Sample preparation  
 DARS 1474: 2019  
12 © ARSO 2019  — All rights reserved  Weigh accurately about 1.0 g of product, dissolve in methanol and make up to 100 ml in a volumetric 
flask with methanol. Filter this sample solution through 0.45 m filter.   
 
D.3.3.3  HPLC conditions  
 
Detector wavelength  280 nm  
Column temperature  35 ºC  
Flow rate  1.0 ml/min  
Injection volume  10 l  
 
Prepare the standard solution and the sample solution at the same time. Inject the standard solution 
three times and calculate the average of each ingredients peak count. Inject 10 g the sample 
solution and determine each ingredients percentage by the calculation shown.  
 
D.3.4  Calculations  
 
100massby  % TCN,
t sr s
MAFA M
 
 
100massby  % TCC,
t sr s
MAFA M
 
 
where  
Ar is the peak area of the test s ample,  
 
As is the averaged peak area of the standard,  
 
F is the purity of standard (percent).  
 
Ms is the mass, in grams, of the standard, and  
 
Mt is the mass, in grams, of the test sample,  
 
NOTE  Both TCC and TCN are photosensitive, hence standards sho uld be freshly prepared.  
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  13  
Annex E 
(informative ) 
 
Determination of chloroaniline  
 
 
E.1 Principle  
 
The chloroanilines are extracted from soap with dimethyl sulfoxide and diazotized with nitrous acid. 
The reaction products are then coupled with N -1-(naphthy l) ethylenediamine hydrochloride to produce 
coloured compounds which are estimated spectrophotometrically.  
 
E.2 Safety precautions  
 
Dimethyl sulfoxide (DMSO) is readily absorbed into the skin. Inhalation or skin penetration shall be 
avoided.  
 
DMSO should  never be pipette using mouth. Always use pipette bulb. The standard chloroanilines 
and N -1-(naphthyl) – ethylenediamine hydrochloride shall not be allowed to come into contact with the 
skin. If they should, then wash the contaminated parts thoroughly with  soap and water.  
 
A supply of diluted sodium hypochlorite should be at hand at all times to deal with accidental spillages 
of chloraniline solution. Spillage on laboratory surface should be treated immediately with the sodium 
hypochlorite solution, follow ed by water.  
 
E.3 Reagents  
 
E.3.1  Dimethyl Sulphoxide(DMSO) , AR grade.  
 
E.3.2  Hydrochloric Acid – Concentrated (specific gravity — 1.18).  
 
E.3.3  Sodium Nitrite – 0.4 percent w/v analytical grade, freshly prepared (aqueous).  
 
E.3.4  Ammonium Sulphamate , 2 % w/v solution freshly prepared, (aqueous).  
 
E.3.5  N-1-(naphthyl) Ethylene , 0.1 % w/v solution diamine hydrochloride freshly prepared 
(aqueous).  
 
E.3.6  n-Butanol , AR grade  
 
E.3.7  Sand, acid purified 40 — 100 micron mesh.  
 
E.3.8  Solvent mixture  
 
DMSO  5 volumes  
 
n-Butanol  2 volumes  
 
distilled water  2 volumes  
 
hydrochloric acid  1 volume  
 
Mix n -butanol, water and HCL, cool the mixture and add DMSO.  
 
E.3.9  4-Chroroaniline and 3, 4 -Dichloroaniline, AR grade.  
 
E.4 Apparatus  
 
E.4.1  Spectrophotometer, suitable for use at 554 nm  
 
E.4.2  Cuvettes — Glass (matched pair) 10 mm  
 DARS 1474: 2019  
14 © ARSO 2019  — All rights reserved  E.4.3  Water bath — Thermostatically controlled at 25 °C  
 
E.4.4  Stop watch  
 
E.4.5  Standard laboratory glassware  
 
E.4.6  Filter Paper, Whatman No. 541  
 
E.5 Procedure  
 
E.5.1  Preparation  of Calibration Curve  
 
E.5.1.1  Dissolve 0.349 8 g of 3, 4 -dichloroaniline and 0.2753 g of 4 -chloroaniline in solvent mixture 
(see C.2.8) in a 250 ml amber volumetric flask.  
 
Dilute to mark with solvent mixture. 1 ml = 2.5 mg mixed chloroanilines (stock so lution).  
 
E.5.1.2  Dilute this stock solution with solvent mixture as given below:  
 
a) Take 5 ml of stock solution and dilute it to 250 ml with solvent mixture  
 
1 ml = 50 μg mixed chloroanilines.  
 
b) Take 5 ml of the above solution [see E.5.1.2(a)] and further dilute to 250 ml with solvent 
mixture.  
 
1 ml = 1 μg mixed chloroanilines.  
 
Use this solution for preparation of calibration curve.  
 
Transfer using a bur ette 0, 1 ml, 2 ml, 5 ml, 10 ml, 20 ml, 40 ml into 50 ml amber volumetric flasks.  
 
E.5.1.3  From a burette, add sufficient solvent mixture to make total volume to 40 -mL in each flask. 
The flasks are incubated in a water bath at 25 °C for 20 min: After exac tly 20 min, add 2 -mL of 
reagent (see E.3.3) into each flask and return them to the water bath for exactly 10 min (measure with 
a stop watch).  
 
Then add 2 -mL of reagent (see C.3.4) into each flask and return them to the water bath for exactly 10 
min. Swirl  the flask occasionally.  
 
Then add 2 -ml of reagent (see E.3.5) into each flask and remove them from the water bath. Dilute to 
volume with distilled water, mix and allow to stand for 30 min. Measure absorbance at 554 nm against 
the blank solution as prepar ed in E.5.1.4.  
 
E.5.1.4  In preparing the blank solution, take 40 ml of solvent mixture in a 50 ml amber volumetric 
flask. Incubate the flask in a water bath at 25 °C for 20 min. After exactly 20 min, add 2 ml of reagent 
(see E.3.3) into the flask and retu rn it to the water bath for exactly 10 min. Then add 2 ml of reagent 
(see E.3.4) into the flask and return it to the water bath for exactly 10 min (swirl the flask 
occasionally). Then add 2 ml of reagent (see E.3.5) into the flask and remove it from the wa ter bath. 
Dilute to volume with distilled water, mix and allow to stand for 30 min. Use this blank solution for 
preparation of calibration curve only.  
 
E.5.1.5  Prepare a graph by plotting weight ( g) of chloroanilines contained in each 50 ml flask against  
absorbance. The linear calibration will pass through the origin/or determine the average absorbance 
(AA) of 1 g of mixed chloroanilines by dividing sum of absorbances of all different aliquots of the 
standard by sum of g of chloroanilines in all differe nt aliquots of standard.  
 
E.6 Determination of chloroanilines  
 
E.6.1  Weigh to the nearest mg 3.0 - 15 g of finely grated soap add 10.0 g - 15.0 g of acid purified 
sand. Transfer quantitatively the sample and the sand into a mortar and grind the mixture th oroughly 
with a pestle to give a homogenous mass. Transfer the mass to a previously weighed 250 ml flat DARS 1474: 2019  
© ARSO 2019 — All rights reserved  15 bottom flask quantitatively and reweigh. Add DMSO (100 ml), stopper firmly and attach the flask to an 
automatic shaker. Shake for 1 h. Filter the DMSO e xtract through Whatman No. 541 into a 250 ml 
amber volumetric flask. Wash the flask and filter paper with small aliquots of DMSO. Allow the filtrate 
to drain completely, dilute to volume with DMSO and mix. Transfer 20 ml DMSO extract into a 50 ml 
amber vol umetric flask. Add 20 ml of solvent mixture. The flask is incubated in a water bath at 25 °C 
for 20 min. After exactly 20 min, add 2 ml of reagent (see E.3.3) into the flask and return it to the 
water bath for exactly 10 min (measure with a stop watch). Th en add 2 ml of reagent (see E.3.4) into 
the flask and return it to the water bath for exactly 10 min (swirl the flask occasionally). Then add 2 ml 
of reagent (see E.3.5) into the flask and remove it from the water bath. Dilute to volume with distilled 
water, mix and allow to stand for 30 min. Read the absorbance at 554 nm against blank (prepared as 
below).  
 
E.6.2  Prepare the blank solution by mixing 20 ml of DMSO extract of sample and 20 ml of solvent 
mixture in a 50 ml amber volumetric flask. Incubate the  flask in a water bath at 25 °C for 20 min.  
 
After exactly 20 min, add 2 ml of distilled water into the flask and return it to the water bath for exactly 
10 min. Then add 2 ml of reagent (see E.3.4) into the flask and return it to the water bath for exact ly 
10 min (swirl the flask occasionally). Then add 2 ml of reagent (see E.3.5) into the flask and remove it 
from the water bath. Dilute to volume with distilled water, mix and allow to stand for 30 min. Use this 
solution as a blank for reading sample only.   
 
E.6.3  Deduce the amount of chloroanilines ( g) from the calibration graph curve.  
 
NOTE  The determination should be completed in one day.  
 
E.7 Calculations  
 
Determine the amount of mixed chloroanilines in the aliquot of test solution from the calibratio n graph.  
 
Chloroaniline content (in ppm) = 
MMMMM
23 1
20) (250  
 
where  
M is the mass, in grams, of soap  
 
M1 is the mass, in grams, of sand  
 
M2 is the mass, in grams, of soap and sand transferred to the flask  
 
M3 is the mass, in micrograms, (μg) of m ixed chloroanilines found from calibration graph/or it can 
be calculated as given below:  
 
(AA) ine chloroanil mixed g1 of absorbance Averagesample the of Mass
3M
 
 
where  
 
g in ines chloroanil standard of ion concentrat of Sumstandards the of OD the of Sum
3M
 
 
Weight of soap actually used, in g = 
) (12
MMMM
  
 DARS 1474: 2019  
16 © ARSO 2019  — All rights reserved   
Annex  F 
(informative)  
 
Permitted structuring  and processing aids  
 
 
The following is the list of structuring and processing aids used generally in bathing bars.  
 
1) Starch and derivatives  
 
2) Cellulose and derivatives  
 
3) Propylene glycol  
 
4) Sorbitol  
 
5) Glycerol  
 
6) Dextrin  
 
7) Kaolin  
 
8) Talc  
 
9) Bentonite  
 
10) Calcite  
 
11) Sodium lactate  
 
12) Soda ash  
 
13) Vegetable/animal oil fatty acids and salts  
 
14) Phosphates  
 
15) Sodium chloride  
 
16) Sodium sulphate  
 
17) Dolomite  
 
18) Fatty alcohol  
 
19) Rosin and rosin salts  
 
20) Fatty ac id ethanolamide  
 
21) Diethylene glycol monostearate  
 
22) Paraffin  
 
23) Polyoxyethylene glycol  
 
24) Glycerol monostearates  
 
25) Silicates  
 
26) Sodium citrate  
 
27) Chelating agents  
 
28) Any other internationally accepted builder  DARS 1474: 2019  
© ARSO 2019 — All rights reserved  17  
Annex  G 
(informati ve) 
 
Permitted antibacterial agents  
 
 
 
The following is the list of antibacterial agents used generally in antibacterial bathing bars.  
 
a) Triclosan (TCN)  
 
b) Trichlorocarbanilide (TCC)  
 
c) Zinc oxide  
 
d) Hexa chlorophene  
 
e) Chloro xylenols  
 
f) Plant extracts  
 
g) Any other internationally accepted antibacterial agent.  
 DARS 1474: 2019  
18 © ARSO 2019  — All rights reserved   
Annex  H 
(normative)  
 
Determination of microbial inhibition of cosmetic soap bars and liquid hand 
and body washes  
 
 
 
H.1 Scope  
This annex  specifies a method for testing and comparin g the microbial inhibition properties of 
cosmetic soap bars and liquid hand and body washes.  
 
H.2 Application  
 
This method applies to the verification of efficacy claimed by antibacterial soaps in the inhibition of 
microorganisms.  
 
H.3 Principle  
 
When soap  bars and liquid hand and body washes that have antimicrobial properties are inoculated 
into medium No.1 (see J.4.3.1.1), specific active ingredients diffuse into the surrounding agar thereby 
creating a zone of inhibition around the product, which is measu red as an indication of the microbial 
inhibition properties of the product.  
 
NOTE  The organisms referenced in this standard are the indicator organisms used when testing for hygiene purposes.  
 
H.4 Test method  
 
H.4.1 General  
 
Sampling and testing shall be carried out by personnel familiar with microbiological procedures.  
 
H.4.2 Accuracy  
 
Except where otherwise specified, all the following tolerances:  
temperatures  ± 2 °C;  
masses  ± 1.0 %;  
volumes  ± 1.0 %; and  
pH values  ± 0.1 pH unit.  
 
H.4.3 Culture medium, reagents, reference cultures and controls  
 
H.4.3.1  Culture medium  
 
NOTE 1  The culture medium listed in J.4.3.1.1 is commercially available in dehydrated form and is made up in accordance 
with the manufacturer’s instructions.  
 
NOTE 2  Glass distil led water or deionised water should be used  
 
H.4.3.1.1 Medium No. 1  
 
Ingredients  
agar 15.0 g  
beef extract  15.0 g  
glucose  1.0 g  
pancreatic digest of casein  4.0 g  
peptone  6.0 g  
Yeast extract  3.0 g  
Water 1 000 mL  
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  19 H.4.3.1.2  Preparation  
 
H.4.3.1.2.1 Dissolve the ingredients in approximately 900 mL of water and mix.  
 
H.4.3.1.2.2 Make up to 1 L.  
 
H.4.3.1.2.3 Adjust the pH so that after sterilization the pH value is 6.6 ± 0.05.  
 
H.4.3.1.2.4 Dispense 20 mL ± 0.2 mL volumes into suitable containers and sterilize in an autoclave 
for 15 min ± 0.5 min at 121 °C.  
 
H.4.3.2  Horse serum  
 
Sterile inactivated horse serum that is free from preservatives.  
 
H.4.3.3  Reference cultures  
 
H.4.3.3.1 Test organisms  
 
Use the following test organisms:  
Staphylococcus a ureus  Sta 10 ATCC 6538;  
Escherichia coli  Esc 20 ATCC 8739; and  
Pseudomonas aeruginosa  Pse 16 ATCC 15442.  
 
NOTE  Other reference organisms may also be used in addition to the ones specified in J.4.3.3.1.  
 
H.4.3.3.2  Preparation of test organism suspension s  
 
From a newly opened freeze -dried culture or recently received agar culture, subculture the test 
organisms into bottles of 10 mL nutrient medium ( J.4.3.3.2.1)  
 
H.4.3.3.2.1 Nutrient medium  
 
H.4.3.3.2.1.1 Ingredients  
 
peptone  5.0 g  
sodium chloride  5.0 g  
yeast extract  2.0 g  
beef extract  1.0 g  
water  1 000 mL  
 
H.4.3.3.2.1.2 Preparation  
 
Dissolve the ingredients in the water and adjust the pH value to 7.1. Dispense in 10 mL volumes into 
suitable bottles and sterilize by autoclaving at 121 ±2 °C for 15 minutes.  
 
H.4.3.3.3  Incubate the bottles at 37 °C for 24 h. Subculture onto nutrient agar slopes (see J.4.3.3.3.1). 
Incubate the slopes at 37 °C for 24 h.  
 
H.4.3.3.3.1 Nutrient agar  
 
H.4.3.3.3.1.1 Ingredients  
Agar 15.0 g  
peptone  5.0 g  
sodium chloride  5.0 g  
yeast extract  2.0 g  
beef extract  1.0 g  
water  1 000 mL  
 
 
 DARS 1474: 2019  
20 © ARSO 2019  — All rights reserved  H.4.3.3.3.1.2 Preparation  
 
Dissolve the ingredients in the water and adjust the pH value to 7.1.  Dispense 10 mL and 15 mL 
volumes into suitable bottles and sterilize by autoclaving at 121 ±2 °C for 15 minutes. Allow only the 
10 mL volumes to solidify in a sloped position.  
 
H.4.3.3.4  From each of these slope cultures, prepare four subcultures (stock cultures) of each test 
organism onto 10 mL nutrient agar slopes (see J.4.3.3.3.1). Incubate the stock cultures at 37 °C for 
24 h and then store in a refrigerator maintained at 4 °C, except for Pseudomonas aeruginosa which is 
stored at ambient temperature.  
 
H.4.3.3.5  Use the stock cultures to prepare further subcultures for the test, but do not m ake more than 
six serial subcultures from each stock culture. After the sixth serial subculture, resort to n new freeze -
dried culture.  
 
H.4.3.3.6  Preparation of cultures for test suspensions  
 
H.4.3.3.6.1 For each of the test organisms, inoculate a nutrie nt agar slope (see J.4.3.3.3.1) from a 
stock culture (see J.4.3.3.4) and incubate at 37 °C for 24 h.  
 
H.4.3.3.6.2 For the test, use a 24h culture that has been subcultured for two successive days. After 
six subcultures, restart the process using a fresh s tock culture (see J.4.3.3.4).  
 
NOTE  The physiological condition of the test organisms is important and might influence inter -laboratory and intra -
laboratory variations in test results.  
 
H.4.3.3.6.3 After incubation, wash the bacterial growth from the slo pe using 10 mL sterile water and, if 
necessary, scrape the agar surface. Carefully decant the suspension into a sterile Erlenmeyer flask 
and shake vigorously to suspend all growth in the water. Standardize the suspension, by using a 
spectrophotometer in co njunction with a standard curve, a haemocytometer, Petroff -Hausser counting 
chamber or any other suitable means, so that it contains 105 cfu/mL ± 104 cfu/mL. Use the suspension 
within 3 h of preparation.  
 
H.4.3.4  Control  
 
H.4.3.4.1  Positive control  
 
Natur al honey with no additives, e.g. colourants  
 
H.4.3.4.2  Negative control  
 
Sterile deionised water.  
 
H.4.4 Procedure  
 
H.4.4.1  Melt the contents of a bottle of the medium No. 1 (see J.4.3.1.1) and cool to 45 ± 2 °C. Add 1 
mL of the sterile inactivated hors e serum (see J.4.3.2) and 1 mL of S. aureus test organism 
suspension prepared in accordance with J.4.3.3.2. Mix well and avoid the formation of air bubbles, 
then pour the mixture into a Petri dish of 90 mm diameter and allow to solidify.  
 
H.4.4.2  Using as  sterile cutter that produces cylindrical wells (holes) of 8 mm diameter, make five 
evenly spaced straight cylindrical wells in the solidified medium. Remove and discard the plugs of 
medium. Seal the bottom of each well using one or two drops of the molten  medium in J.4.3.1.1 and 
allow to solidify.  
 
H.4.4.3  Introduce the test sample into the wells in such a way that each well is completely filled with 
the sample, taking care not to form bubbles. When the test sample is a soap bar, grind a sufficient 
amount  to a powder, using a sterile pestle and mortar, and introduce the powder into the wells. 
Ensure that the surface of the agar remains free from the sample.  
 
H.4.4.4  Incubate the petri dish at 37 ± 1 °C for 18 h to 24 h.  DARS 1474: 2019  
© ARSO 2019 — All rights reserved  21  
H.4.4.5  At the end of this period  (see J.4.4.4), remove the Petri dish from the incubator. Measure the 
diameter of the zone of inhibition diagonally across the well to the nearest millimeter  
 
H.4.4.6  Take the average of the five diameters and record this to the nearest millimeters .  
 
H.4.4.7 Repeat the procedure described in J.4.4.1 to J.4.4.6 (inclusive) using the E. coli and P. 
aeruginosa test suspensions successively.  
 
H.4.4.8  Repeat the procedure described in J.4.4.1 to J.4.4.6 (inclusive) for the positive control and the 
negative co ntrol  
 
H.5 Interpretation of results  
 
H.5.1 For the product to pass the test, the average diameter of the zone of inhibition for each of the 
test organisms shall be at least 10 mm.  
 
H.5.2 If the zones are not clearly defined for one of the reference org anism (e.g . hazy, incomplete 
zone, or distorted shape), the test shall be repeated for the specified reference organism.  
 
 DARS 1474: 2019  
22 © ARSO 2019  — All rights reserved  Annex J 
(normative)  
 
Identification of  rosin content of fatty mat ter in soaps  
 
 
 
J.1 Scope  
 
This Annex  specifies the Halphen -Grimald i and Liebermann -Storch method for the identification of 
rosin in fatty matter.  
 
J.2 Reagents  
 
NOTE  Use only analytical grade reagents and distilled water.  
 
J.2.1 Acetic anhydride.  
 
J.2.2 Sulphuric acid, density 1 .53 g/mL. Cautiously add 97 mL of sulphuric  acid (density  1.84 
g/mL) to 100 mL of water.  
 
J.2.3 Solution A. Dissolve 10 g of phenol in 27 mL of chloroform.  
 
J.2.4 Solution B. Dissolve 10 mL of bromine in 40 mL of chloroform.  
 
J.3 Procedure  
 
J.3.1 Halphen -Grimaldi method  
 
J.3.1.1 Place one or two dr ops of the fatty matter, reserved from the determination of fatty matter  
(ISO 685 ), in a porcelain basin and add approximately 2 mL of the solution A to dissolve it. Wet  the 
walls of the basin by tilting and turning it and let it stand for a few seconds so  that the walls of  the 
basin are covered with a very thin film of the solution.  
 
J.3.1.2 Hold the neck of the flask containing the solution B in such a position that the bromine  vapour 
diffuses into the porcelain dish and comes into contact with the walls.  In the presence of  rosin a 
blueish -grey to purple colour develops immediately.  
 
J.3.1.3 Carry out a comparison test with a sample of fatty matter to which 2 % ( m/m) of rosin has  
been added.  
 
NOTE  Should the colour reaction in J.3.1.2 be masked by other co lours, conduct a second qualitative test, using the 
Liebermann -Storch method.  
 
J.3.2 Liebermann -Storch method  
 
J.3.2.1 Place 1 g - 2 g of the fatty matter in a test tube, add 5 mL - 10 mL of the acetic anhydride,  and 
heat the mixture in a boiling water bat h for approximately 3 min. Cool to room temperature and  pour 1 
mL - 2 mL of the solution into a white porcelain basin.  
 
J.3.2.2 Allow one or two drops of the sulphuric acid to run down the side of the basin. If rosin is  
present, a violet colour immediately  develops where the acid is in contact with the solution. This  
colour then turns brown on standing.  
 
J.3.2.3 Carry out a comparison test with a sample of fatty matter to which 2 % ( m/m) of rosin has  
been added.  
 
 DARS 1474: 2019  
© ARSO 2019 — All rights reserved  23 Annex K 
(normative)  
 
Determination of rosi n content of fatty ma tter in soaps  
 
K.1 Scope  
 
This Annex  specifies a method for the determination of the rosin content of fatty matter in soaps.  
 
NOTE 1  Before proceeding with the quantitative determination of rosin, first establish its presence by a qual itative test (see 
Annex J). 
 
NOTE 2  The following method is not accurate for rosin concentrations below a mass fraction of 5 %.  
 
K.2 Reagents  
 
NOTE  Use only analytical grade reagents and distilled water.  
 
K.2.1 Diethyl ether  
 
Free from peroxides.  
 
K.2.2 Sodium chloride  
 
K.2.3 Sodium sulfate  
 
Anhydrous.  
 
K.2.4 Hydrochloric acid solution  
 
Dilute one volume of concentrated hydrochloric acid (density 1 .16 g/mL) with two volumes of  distilled 
water.  
 
K.2.5 Sodium hydroxide solution  
 
10 % mass fraction aqueous sol ution.  
 
K.2.6 Naphthalene -2-sulfonic acid solution  
 
Dissolve 40 g of naphthalene -2-sulfonic acid in 1 L of absolute methanol.  
 
K.2.7 Sodium chloride solution, saturated  
 
Shake an excess of sodium chloride with water at ambient temperature until no more dis solves.  Keep 
the solution over solid sodium chloride.  
 
K.2.8 Sodium chloride solution, 10 %  
 
Dissolve 10 g of sodium chloride in 100 mL of water.  
 
K.2.9 Standard ethanolic potassium hydroxide solution, 0.2 N  
 
K.2.9.1 Preparation  
 
Purify 95 % (by volume fra ction) ethanol by boiling 1 .5 L of it over 20 g of potassium hydroxide for  1 h 
under reflux. Distil, discarding the first 50 mL of the distillate and stopping the distillation when  
approximately 1 .3 L have been distilled. Dissolve 12 g of potassium hydroxi de in 1 L of the purified  
ethanol, allow the solution to stand for approximately one week, and then decant the clear  
supernatant liquid from any potassium carbonate that has precipitated.  
 DARS 1474: 2019  
24 © ARSO 2019  — All rights reserved  K.2.9.2 Standardization  
 
Accurately weigh out approximately 1 g of potassium hydrogen phthalate (previously dried at  110 °C ± 
5 °C for 3 h) into a 250 mL Erlenmeyer flask. Add approximately 100 mL of carbon  dioxide -free 
distilled water and three drops to five drops of the phenolphthalein indicator, and swirl  gently until the 
solid has dissolved. Titrate the solution with the standard ethanolic potassium  hydroxide solution, until 
a permanent pink colour is formed.  
 
K.2.9.3 Calculation  
 
Normality of the standard ethanolic potassium hydroxide solution ( N): 
 
B. AN8974
 
 
where  
 
A is the mass of the potassium hydrogen phthalate, in grams;  
 
B is the volume of the standard ethanolic potassium hydroxide solution used for the  
titration, in millilitres.  
 
K.2.10 Methyl orange indicator  
 
Dissolve 0 .2 g of methyl orange in 1 00 mL of carbon dioxide -free water.  
 
K.2.11 Phenolphthalein indicator  
 
Dissolve 0 .5 g of phenolphthalein in 100 mL of freshly boiled, 95 % (by volume fraction) ethanol.  
 
K.3 Procedure  
 
K.3.1 Preparation of fatty matter  
 
K.3.1.1 Carbolic soaps  
 
K.3.1.1.1  Weigh out accurately into a 600 mL beaker such quantity of the test sample as contains  
approximately 40 g of fatty matter and dissolve it in approximately 400 mL of hot water, to which  40 
mL of the sodium hydroxide solution has been added.  
 
K.3.1.1.2  Salt ou t the soap by adding sufficient sodium chloride to the hot solution to saturate it (at  
ambient temperature) with sodium chloride. Filter the soap quantitatively, and allow it to drain.  
 
K.3.1.1.3  Dissolve the drained soap in approximately 400 mL of hot wat er, and repeat the salting out  
and filtering procedure.  
 
K.3.1.1.4  Wash the soap thoroughly with the saturated sodium chloride solution, and proceed in  
accordance with K.3.1.2.2 to K.3.1.2.7.  
 
K.3.1.1.5 Reserve the combined filtrates and washings for the d etermination of carbolic acids.  
 
K.3.1.2 Other soaps  
 
K.3.1.2.1  Weigh accurately into a 600 mL beaker such quantity of the test sample as contains  
approximately 40 g of fatty matter.  
 
K.3.1.2.2  Dissolve the soap in approximately 400 mL of hot distilled wat er, cool the solution, and  
slowly add an excess of the hydrochloric acid solution. Cover the beaker with a watch -glass and  heat 
the contents until the fatty matter separates into a clear layer, but do not allow the temperature  to 
exceed 60 °C.  DARS 1474: 2019  
© ARSO 2019 — All rights reserved  25  
K.3.1.2.3  In the cases of liquid and gel soaps, acidify the soap as it is.  
 
K.3.1.2.4  Cool to approximately 25 °C and transfer the contents of the beaker to a separating funnel.  
Rinse the watch -glass and the beaker with portions of the diethyl ether totalling 100 mL and add  them 
to the separating funnel. Shake the mixture in the separating funnel vigorously for 1 min, and  let it 
stand until the two phases have separated.  
 
K.3.1.2.5  Draw off and discard the aqueous layer and wash the ether extract with 50 mL portions o f 
the sodium chloride solution until the last washing is neutral to the methyl orange indicator.  
 
K.3.1.2.6  Filter the washed ether extract into a 250 mL beaker through a filter paper containing  
approximately 5 g of anhydrous sodium sulfate, and wash the s eparating funnel and the filter with  
small portions of the diethyl ether.  
 
K.3.1.2.7  Evaporate the ether extract plus washings on a warm water bath. When the residue is just  
dry, heat it rapidly to 130 °C and immediately place the beaker in a desiccator to  cool. 
 
NOTE  K.3.1.2.2 to K.3.1.2.7 should be completed in the shortest possible period of time, so as to prevent oxidation of the 
fatty acids.  
 
K.3.2 Determination of rosin content  
 
K.3.2.1 Weigh accurately into a 150 mL flask with a ground -glass joint ap proximately 2 g of the  
prepared fatty matter ( K.3.1.2.7) and reserve the rest in the case of soap powders for the fatty matter  
titre determination.  
 
K.3.2.2 Add exactly 25 mL of the naphthalene -2-sulfonic acid solution to the flask and two or three  
glass b eads, and boil under reflux for 30 min.  
 
K.3.2.3 Carry out a blank test at the same time, using exactly 25 mL of the naphthalene -2-sulfonic  
acid solution only.  
 
K.3.2.4 Cool the contents of both flasks (sample and blank) to ambient temperature, add 0 .5 mL of 
the phenolphthalein indicator to each flask, and immediately titrate to the end point with the  standard 
ethanolic potassium hydroxide solution.  
 
K.4 Calculation  
 
Rosin content of fatty matter, as a mass fraction percentage ( R): 
 
01634.C. N)BA(R 
 
 
where  
A is the volume of the standard ethanolic potassium hydroxide solution used for the 
titration  of the sample solution, in millilitres;  
 
B is the volume of the standard ethanolic potassium hydroxide solution used for the 
titration  of the blank solution, in millilitres;  
 
N is the normality of the standard ethanolic potassium hydroxide solution;  
 
C is the mass of the fatty matter taken, in grams.  
 
 DARS 1474: 2019  
26 © ARSO 2019  — All rights reserved   
Bibliography  
 
 
EAS 794:2013, Kenya Standard — Determination of the microbial inhibiti on of cosmetic soap bars 
and liquid hand and body washes — Test method  
 
EAS 878:2016, Antibacterial bathing bars — Specification  
 
 FDARS 1474: 2019 
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