DEAS 1144 : 2023 
ICS 71.100.40  
© EA C 2023                                                                                                                       First Edition 2023 
DRAFT EAST AFRICAN STANDARD  
Baby toilet soap  — Specification  
  
 
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                 
EAST AFRICAN COMMUNITY  
 
   
 
 
 
 
  
 DEAS 1144 : 2023 
ii © EAC  2023 – All rights reserved  
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© EAC 2023 – All righ ts reserved  iii 
 Foreword  
Developm ent of the East Afric an St andards has been necessitated by the need for harmonizing requirements 
governing quality of products and ser vices in  the East African Community. It is envisaged that through 
harmonized standardization, trade barriers that are enco untered when goods an d ser vices are exchanged 
within the Community will be removed.  
In order to achieve this objective, the Community  establi shed  an East African Standards Committee mandated 
to develop and issue East African Standards.   
The Committee is c omposed of representa tives of the National Standards Bodies in Partner States, together 
with the representatives from the private sect ors and cons umer organizations. Draft East African Standards 
are circulated to stakeholders through the National Standards  Bodies in the Partne r Sta tes. The comments 
received are discussed and incorporated before finalization of standards, in accordance wi th the p rocedures 
of the Community.  
East African Standards are subject to review, to keep pace with technological advances . Users of the East 
African Standards are therefore expected to ensure that they always have the latest versions of the standards 
they are imp leme nting.  
DEAS 1144 :2023 was prepared by the Technical Committee Technical Committee EASC/TC 074, Surface 
active agen ts 
Attention  is drawn to the possibility that some of the elements of this document may be subject of patent 
rights. EAC shal l not be  held responsible for identifying any or all such patent rights.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DEAS 1144 : 2023 
iv © EAC  2023 – All rights reserved  
 Introduction  
 
Normally the general requirements f or baby  toilet soap are  similar to those prescribed for toilet soap meant for 
adults. However,  on account of  natural  difference between a baby's skin and an adult's  skin due regard to 
toxicity and dermatological considera tion is given during the manufactur e of baby  toilet soap. This is because 
the skin of  babies, being much thinner and less cornified than that o f an adult is highly susceptible to irritation 
and resistance to bacterial attack is not fully developed in the v ery young ones. If superficial laye rs of the  
epidermis are damaged by any means, for example, by the use of harsh  toiletries, various skin diso rders ma y 
develop. It is however not practicable to prescribe all such factors. It is, therefore, emphasized that  
manufacturers of baby toilet soap shall take the responsibility to establish and ensure dermatological safety of 
the soap.  
 
In order to achiev e dermat ological safety of baby toilet soap the choice and selection of appropriate quality 
and quantity of diffe rent raw materials is very importan t. 
 
In this specification, unlike normal toilet soap, the use of rosin  has not been allowed because of accou nt of it s 
unsaturated nature, its soap  may lead to irritation of the skin. On similar consideration a higher  limit for total 
fatty matter  (76%), low limits  for free caustic alkali and free  carbonated alkali and low limits for heavy metals, 
namely, nickel, copper , iron, lead, mercury and Arsenic  have been prescribed.  
 
 DRAFT EAST AFRICAN STANDARD  DEAS 1144 :2023 
 
© EAC 2023 – All rights reserved  1 
 Baby toilet soap  — Specification  
1 Scope  
This Draft  East African Standard prescribes the requirements , sampling and test methods for baby toilet soap . 
2 Normative references  
The following  referenced docum ents are in dispensable for the application of this document. For dated 
references, only  the edit ion cited applies. For undate d references, the latest edition of the referenced 
document (including any amendments) applies.  
EAS 847 -16, Cosmet ics — Analyt ical methods — Part 16: Determination of lead, mercury and arsenic content  
 
EAS 847 -24, Cosmetics - Analytical methods - Part 24: Determination of matter  insoluble in boiling water  
 
ISO 1067, Analysis of soap — Determina tion of unsaponifiable, unsaponified  and unsaponified saponfiable 
matter  
 
ISO 456, Surface active agents — Analysis of soaps — Determination of free caustic alkali  
 
ISO 457 , Soaps — Determination of chloride content — Titrimetric method  
 
ISO 672, Soaps — Dete rmination o f moisture and volatil e matter content — Oven method  
 
ISO 673, Soaps — Determination of content of ethanol -insolub le matter  
 
ISO 684, Analysis of soap s — Determination of total free alkali  
ISO 685, Analysis of soaps — Determinat ion of total alka li content and total fatty matter  content  
 
EAS 377 (All parts ), Cosmetics and cosme tic products  
 
3 Terms and definitions  
For the purposes of this documen t, the terms and definitions  given in  ISO 862  apply.  
ISO and IEC maintain terminological databases  for use in stan dardization at the fo llowing address es: 
— ISO Online b rowsing platform: available at http://www.iso.org /obp 
 
4 Requirem ents 
4.1 General req uirements  
4.1.1  Baby toilet soap shall be :  
a) mildly perfumed or unperfumed, and  DEAS 1144 :2023 
2 © EAC  2023 – All rights reserved  
 b) free from objectiona ble odour,  
c) not con tain any rosin 
 
4.1.3 All materials used in prepara tion of baby toilet soap shall comply  with EAS 377  
4.2 Specific req uirements  
Baby toilet soap shall comply with the specific requirements giv en in Table 1 whe n tested in  accordance with  
test methods therein  
Table 1 — Specific requireme nts for baby toilet soap  
S. No . Characteristic  Requirements  Method of test  
i.  Total fatty matter, % m/m, min  76 ISO 685  
ii.  Moisture and volatile matter (at 105  °C), % m/m, max  15.0 ISO 672  
iii.  Matter insolubl e in alcohol , % m/m, max  0.2   ISO 673  
iv.  Matter insoluble in water, % m/m, max  0.5 EAS 847-24 
v.  Unsaponified fatty matter content, % m/m, max 0.5 ISO 1067  
vi.  Free caustic alkali , as sodium  hydroxide (NaOH), % m/m, max 0.03 ISO 456  
vii.  Chlorides, as  sodium c hloride (NaCI), % m/m, max 1.0 ISO 457  
viii.  Free carbonated alkali, %m/m, max  0.5 ISO 684  
ix.  Grittiness   To pass the test  Annex A 
x.  Nickel con tent  Not detecte d Annex B 
xi.  Rosins, as % of total fatty matter  To pass the test  Annex  C and D 
xii.  Iron content,  mg/kg , max  10 Annex E  
xiii.  Copper (as Cu) contents, mg/kg , max  3 Annex  F 
xiv.  Lead, mg/kg , max 10 
EAS 847 -16 xv.  Mercury , mg/kg , max 2 
xvi.  Arsenic , mg/kg , max 2 
Note:  
Calcul ation of results  
Baby toilet soap is liable to lose moisture on storage . The results of ana lysis in respect o f other characteristics shall be 
recalculated in relation to the minimum specified total fatty  matter by means of the equa tions:  
matterfatty  total Actualmatterfatty  total specified Minimum result  Actual result ed Recalculat  =
 
Where the minimum specified t otal fatty matter = 76.0 %.  DEAS 1144 :2023 
© EAC 2023 – All righ ts reserved  3 
   
5 Packaging   
Baby toilet soa p shall be so wrapped a s to protect it from damage and excessive loss or gain of moisture . 
6 Labelling  
Each package shall be securely closed, legibly and indelibly labelled in English and/or any other official 
language (French, Kiswahili, etc) used in the importing East  African Partner State with the following 
information:  
a) name of the product  as "Baby  toilet soap ” or Baby soap ”; 
b) manufacturer’s na me and physic al address;  
c) batch o r code number;  
d) list of ingredients  
e) net content ; 
f) country of origin;  
g) date of manuf acture;  
h) best before date ; and 
i) Safety precauti on/warning . 
NOTE  The name, p hysical address  of the distributor/supplier and trade mark may be added.  
7 Sampling  
Samplin g shall be do ne in accordance wit h Annex G. 
 
 
 
 
 
 
 
 
 
 
 DEAS 1144 :2023 
4 © EAC  2023 – All rights reserved  
 Annex A  
(normative)  
 
Test for grittiness 
 
 
A.1 Outline of the metho d 
 
Soap is rubbed  with water  between the hands for  a specified  time and examined for its gritty or rough feel, if 
any. 
 
A.2 Procedure  
 
A.2.1 Hold a bar of soap in running  tap water and rub between both hands for about 3 min. N o gritty or 
rough feel should be perceived  while rubbing t he soap surface. Exami ne the surface of the bar which  shall not 
be rough and shall feel smooth when the fingers a re moved  across the surface.  
 
A.2.2 Set the bar on and l et it dry for 24 h at r oom temperature and examine its sur face.  The soap sh all be 
taken to have passed the t est if there is no  gritty or rough feel on the surface.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DEAS 1144 :2023 
© EAC 2023 – All righ ts reserved  5 
 Annex B 
(normative)  
 
Test for nickel  content  
 
 
B.0 Outline of the method  
 
The met hod is based on the isolation of metal from the  soap and  reaction between nickel  in the oxidized form 
with dimethyl glyoxime  forming a red colour.  
 
B.1 Reagents  
 
B.1.1 Sodium hydroxide — AR grade.  
 
B.1.2 Concentrated hydrochloric acid — Conforming to  relev ant standard . 
 
B.1.3 Dimethyl glyoxime solution  — 0.1 perc ent (v/v) in 95 percen t ethyl alcohol.  
 
B.1.4 Saturated bromine water 
 
B.1.5 Liquor ammonia — Relative density 0. 9. 
 
B.2 Procedure  
 
B.2.1 Isola tion of metals from soap 
 
Weigh 50 g of soap in a  beake r and dissolve in hot water. A dd to this soap s olution 40 mL of concentrated 
hydrochloric acid, stir and keep on steam bath until fatty  acid layer separates. Add 20 g of p araffin wax, stir at 
intervals  and allow it to settle un til phases are clear. Co ol to room temperature.  
 
B.2.1.1  Remove wax cake wit h rod, rins e with water and add rinsing  to aqueous phase. Evaporate, aqueous 
phase to about 60 mL by gentle  boiling. Add 100  mL of water and filter throug h paper washed  previously with 
hydrochloric acid. Evapo rate filtrate and washings to  about 60 mL. Cool  and transf er to volumetric flask . Make 
up the  volume to 100 mL. Take aliquot portions for metal estimation.  
 
B.2.2 Test for  nickel content  
 
Take 50 mL aliquot of the  aqueous solution from the test soluti on in  a 250  mL beaker. Evaporate  the solution 
to abo ut 15 mL by heating. Transfer the  solution to a 50  mL glass stoppered volumetric flask using a small 
quantity of water for  rinsing the solution fr om the beaker into the volumetric flask. Add to the  flask 3 mL of 
saturated bromine water and  allow to stand f or one minu te. Add liquor ammonia  dropwise until excess 
bromine is destroyed as  indicated by the disappearance of  brown colo ur. Then add 5 mL of liquor  ammonia in 
excess. If a precipitation occurs, filter  the solution and wash  the precipit ate with distille d water; co mbine the 
filtrate and  the washings and concentrate to a volume of a few millilitres and transfer  to a 50 mL volumetric 
flask. Add 10 mL of dimethyl  glyoxime solution,  followed by 15 -20 mL of 95 per cent ethyl alcohol. Mix 
thorou ghly and  make up the volume and again mix thorough ly. Allow the solution to  stand for 5 minutes to 
permit full development of colo ur.  
 
The sam ple shall be considere d to have passed the test if no pink colour develops.  
 
 
 
 
 
 
 
 
 
 
 DEAS 1144 :2023 
6 © EAC  2023 – All rights reserved  
  
Annex C 
(normative)  
 
Identi fication of  rosin  content of  fatty mater in soaps  
 
C.1 Scope  
 
This Annex  specifies the Halphen -Grimaldi and Liebermann -Storch method for the identification of rosin in 
fatty matter.  
 
C.2 Reagents  
 
NOTE  Use only analytical  grade reagents and distilled water . 
 
C.2.1 Acetic a nhydride.  
 
C.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 ). 
 
C.2.3 Solution A. Dissolve 10 g of phenol in 27 mL of chloroform.  
 
C.2.4 Solution B. Dissolve 10 mL of bro mine in 40 mL of chloroform.  
 
C.3 Procedure  
 
C.3.1 Halphen -Grimaldi method  
 
C.3.1.1 Place one or two drops of the fatty matter, reserved from  the determination of fatty matter  (ISO 685 ), 
in a porcelain basin and add appro ximately 2 mL of the solution A to dissolve it. Wet  the walls o f the basin by 
tilting  and turnin g it and let it stand for a few seconds so that the walls of  the basin are cover ed with a very thin 
film of the solution.  
 
C.3.1.2 Hold the neck of the flask co ntaining the solution B in such a p osition that the bromine  vapour 
diffuses into the porcelain d ish and comes into contact with the walls. In the presence of  rosin a blueish -grey 
to purple colour develops immediately.  
 
C.3.1.3 Carry out a comparison test w ith a sample of fatty matter to whi ch 2 % ( m/m) of r osin has  been 
added.  
 
NOTE  Should  the colour  reaction in A.3.1.2 be masked by other colours, conduct a second qualitative te st, using the Liebermann -
Storch method.  
 
C.3.2 Liebermann -Storch method  
 
C.3.2.1 Place 1 g - 2 g of the fatty matte r in a test tube,  add 5 mL - 10 mL of the acetic a nhydride,  and heat 
the mixture in a boiling water bath for approximately 3 min. Cool to roo m temperature and  pour 1 mL - 2 mL of 
the solution into a white porcelain basin.  
 
C.3.2.2 Allow one or two drops of  the sulphuric ac id to run d own the side of the ba sin. If ros in is present, a 
violet colour immediately develops where the acid is in contact  with the solution. This  colour then turns brown 
on standing.  
 
C.3.2.3 Carry out  a comparison test with a sample of  fatty matter to which 2 % ( m/m) of rosin has  been  
added.  
 DEAS 1144 :2023 
© EAC 2023 – All righ ts reserved  7 
  
Annex D 
(normative)  
 
Determination of rosin content of fatty mater in soaps  
 
D.1 Scope  
 
This Annex  specifies a method for the determination of the rosin content  of fatty matter in soaps.  
 
NOTE : Before proceeding with the qu antitative determinati on of rosi n, first establish its presence by a qualitative test (see Annex C). 
 
 
D.2 Reagen ts 
 
NOTE  Use only analytical grade reagents and distilled water.  
 
D.2.1 Diethyl ether (Free from peroxides ) 
 
D.2.2 Sodium chloride  
 
D.2.3 Anhyd rous  Sodium sulfate  
 
D.2.4 Hydrochloric acid solution  - Dilute one volume of concentrated hydrochloric acid (dens ity 1.16 
g/mL) with two volumes of  distilled water.  
 
D.2.5 Sodium hydrox ide solu tion - 10 %  w/v. 
 
D.2.6 Naphthal ene-2-sulfonic acid soluti on - Dissolve 40 g of naphthalene -2-sulfonic acid in 1 L of 
absolute methanol.  
 
D.2.7 Sodiu m chloride solution, saturated  - Shake an excess of sodium chloride with distilled water  at 
ambient temper ature until no mo re dissolve s. Keep t he solution over solid sodium ch loride.  
 
D.2.8 Sodium chloride solution, 10 %  w/v - Dissolve 10 g of sodium chloride in a little distilled water  in 
100-mL volumetric flask and top up to the mark . 
 
D.2.9 Standa rd ethanoli c potassium hydro xide solution, 0 .2 N 
 
D.2.9.1 Preparation  
 
Purify 95 % v/v 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 d istillate and stopp ing the distillat ion when  approximately 1 .3 L have been 
distilled. Dissolve 12 g of potass ium hydr oxide 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 ha s 
precipita ted. 
 
D.2.9.2 Standardization  
 
Accurately weigh out approximat ely 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 car bon dioxide -free di stilled water and  
three drop s to five drops of the phenol phthalein indicator, and swirl  gently unt il the solid has dissolved. Titrate 
the solution with the standard ethanolic potassium  hydroxide solution, until a permanent pink colour is  formed.  
 
D.2.9.3 Calculation  
 
Norma lity of the  standard ethanolic potassium  hydroxide solution ( N): 
 
B. AN8974=
 
 
 DEAS 1144 :2023 
8 © EAC  2023 – All rights reserved  
  
where  
 
A is the mass of the potassium hydrogen phthalate, in grams;  
 
B is the volume of the standard ethanolic potassium hydroxi de solution used fo r the titration, in 
millilit res. 
 
D.2.10 Methyl orange indi cator  - Dissolve 0 .2 g of methy l orange in 100 mL of carbon dioxide -free water.  
 
D.2.11 Phenolphthalein indicator  - Dissolve 0 .5 g of phenolphthalein in 100 mL of freshly boiled,  95 % (by 
volume fr action) ethanol.  
 
 
D.3 Proce dure  
 
D.3.1 Preparation of fatty m atter  
 
D.3.1.1 Carbolic soap s 
 
D.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 approximatel y 400 mL of hot w ater, to wh ich 40 mL of the 
sodium hydroxide solution has been added.  
 
D.3.1.1.2  Salt out the soap by adding sufficient sodium chloride to the hot solution to saturate it (at  ambient 
temperature) with sodium chloride. Fi lter the soap quant itatively, and al low it to d rain. 
 
D.3.1.1.3  Dissolve the drai ned soap in approximately 40 0 mL of hot water, and repeat the salting out  and 
filtering procedure.  
 
D.3.1.1.4  Wash the soap thoroughly with the saturated sodium chloride solut ion, and proceed in  accordance 
with D.3.1.2.2 t o D.3.1.2.7. 
 
D.3.1.1.5 Reserve th e combined filtrates and was hings for the determination of carbolic acids.  
 
D.3.1.2 Other soaps  
 
D.3.1.2.1  Weigh accurately into a 600 mL beaker such quantity of the test samp le as contains  approximately 
40 g of  fatty matt er. 
 
D.3.1.2.2  Dissolve the soap i n approximately 400 mL of ho t distilled water, 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 sepa rates into a clear layer, but do not allow th e temperature  to exceed 60 ° C. 
 
D.3.1.2.3  In the cases of liquid and gel soaps, acidify the soap as it is.  
 
D.3.1.2.4 Cool to approximately 25 °C and transfer the contents of the beaker to a sep arating funnel.  Rinse 
the wa tch-glass and the beaker with port ions of the diethyl ether to talling 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 t wo 
phases have sepa rated.  
 
D.3.1.2.5  Draw off a nd d iscard the aqueous layer and w ash the ether extract with 5 0 mL portions of  the 
sodium chloride solution until the last washing is neutral to the methyl orange indicator.  
 
D.3.1.2.6  Filter the washed ether extract into a 250 mL beaker through  a filter p aper containing  approximately 
5 g of anhydrous sodium sulfate,  and wash the separating funnel and the filter with  small portions of the 
diethyl ether.  
 
D.3.1.2.7  Evaporate the ether extract plus washings on a warm water bath. Wh en the residue is  just dry, heat 
it rapidly to 130 °C and imme diately place the beaker in a desiccator to cool.  DEAS 1144 :2023 
© EAC 2023 – All righ ts reserved  9 
  
NOTE  D.3.1.2.2 to D.3.1.2.7 should be completed in the shortest possible period of time, so as to prevent oxidation of 
the fatty acids.  
 
D.3.2 Determination of rosin conte nt 
 
D.3.2.1 Weigh accurately into a 150 mL flask with a ground -glass joint approximately 2 g of the  prepared 
fatty matter ( D.3.1.2.7) and reserve the rest in the case of soap powders for the fatty matter  titre 
determination.  
 
D.3.2.2 Add exactly  25 mL of the n aphthalene -2-sulfonic acid sol ution to the flask and two o r three  glass 
beads, and boil under reflux for 30 min.  
 
D.3.2.3 Carry out a blank test at the same time, using exactly 25 mL of the naphthalene -2-sulfonic  acid 
soluti on only.  
 
D.3.2.4 Cool the c ontents of both flasks (sample and  blank) to ambient temperatu re, add 0 .5 mL of the 
phenolphthalein indicator to each flask, and immediately titrate to the end point with the  standard ethanolic 
potassium hydro xide solution.  
 
D.4 Calculation  
 
Rosin con tent of fatty matter, as a mass fractio n 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 mill ilitres;  
 
B is the volume of the standard ethan olic potassium hydroxide solution u sed 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 ta ken, in grams.  
 
 
 
 
 
 
 
 
 
 
 
 
 DEAS 1144 :2023 
10 © EAC  2023 – All rights reserved  
 Annex E 
(normative)  
 
Deter mination of iron  content  
E.0 Outline of the method  
The method is based on the isolation of metal from the soap by  dissolving in hot water. The aqueous extract is 
treated with citric acid  to sequester aluminium and then thioglycolic acid in ammoniacal  solut ion is added and 
colour measured spectrophotometrically.  
E.1 Apparatus  
Spectrophotometer  
E.2 Reagents  
E.2.1 Liquor Ammonia  — Relative density 0.9.  
E.2.2 Sulfuric acid — 50 percent (v/v). 
E.2.3 Citric acid (aqueous solution)  — 50 percent ( v/v). 
E.2.4 Thiogl ycolic acid (aqueous solution)  
E.2.5 Standard iron solution  — Containing 10 µg of iron per mL prepared from ferric ammonium sulphate 
[Fe 2(SO 4)3.(NH 4)2SO 4.12H 2O] in acid solution.  
E.2.6 Methyl red indicator  — 0.1 percent aqueous solution.  
E.2.7 concentrated  hydrochloric acid  
E.2.8 paraffin wax   
 
E.3 Procedure  
C.3.1  Isolation of metals from soap 
Weigh 50 g of the soap  sample in a beaker and dissolve it with hot water. To this soap solution  add 40 mL of 
concentrated hydrochloric acid with constant stirring and  keep the beaker on steam bath until fatty acid layer 
separates. Add  20 g of paraffin wax to this solution while hot. Stir the solution at  intervals and allow it to settle 
until phases are clear. Cool the mass to  room temperature. Remove the wax cake with rod, rinse with water  
and add the rinsing  to aqueous phase. Evaporate the aqueous phase  to above 60 mL by gentle boiling. Add 
100 mL of water and filter  through paper washed previously with hydrochloric acid. Evaporate  the filtrate and 
washings to about 60  mL. Cool and transfer the  solution to a volumetric flask and make up the volume to 100 
mL. Take  aliquot portion of the solution for metal estimation.  
C.3.2  Determination of iron 
Take 5 mL aliquot of the aqueous  solution from the test solution in a 25  mL volumetric flask. To this add  4 mL 
citric acid solution and 0.02 mL methyl red indicator and liquor  ammonia till the colour of the solution turns 
yellow. Then add 3 mL liquor ammonia in excess. Cool the solution and add 3 mL thioglycolic  acid. Make up 
the v olume to 25 mL and mix the solution tho roughly.  Filter the solution through acid washed and dried filter 
paper. Measure  absorbance of the clear solution at 540 nm in the spectrophotometer  using water as 
reference. Prepare a calibration curve with standard  iron solution and determine the iron content of the soap 
sample from it.  DEAS 1144 :2023 
© EAC 2023 – All righ ts reserved  11 
 Annex F 
(normative)  
 
Determination of copper  content  
 
F.0 Outline of the method  
The method is based on the isolation of metal from the soap and  to make a copper complex using zinc 
dibenzyl dithiocarbamate in  carbon tetrachloride solution and measure the colour of the solution  
spectrophotometrically.  
F.1 Apparatus  
Spectrophotometer  
F.2 Reagent s 
F.2.1 Zinc dibenzyl dithiocarbamate solution  — 0.05 percent in  (v/v) in carbon tetrachloride.  
F.2.2 Standard copper solution  — Containing 1 pg of copper per  mL (prepared from a stock solution of 
100 times the concentration).  concentrated hydrochloric acid  paraffin wax  sulphuric acid  
F.3 Procedure  
F.3.1 Isolation of metal from soap 
Weigh 50 g of so ap sample in  a beaker and dissolve it with hot water. To this soap solution add  40 mL of 
concentrated hydrochloric acid with constant stirring and  keep the beaker on steam bath until fatty acid layer 
separates. Add  20 g of paraffin wax to this solution whi le hot. Stir the solution at  intervals and allow it to settle 
until phases are clear. Cool the mass to  room temperature. Remove the wax cake with rod, rinse with water  
and add the rinsing  to aqueous p hase. Evaporate the aqueous phase  to about 60 mL by gent le boiling. Add 
100 mL of water and filter  through filter paper washed previously with hydrochloric acid.  Evaporate the filtrate 
and washings to about 60 mL. Cool and transfer  the solution to a volume tric flask and made up the volume to 
100 mL. Take aliquo t portion of the solution for metal estimation.  
F.3.2 Determination of copper  
Take 20 mL aliquot of the aqueous solution and to it add 10 mL of zinc dibenzyl  dithiocarbamate solution 
followed by 25 mL sulphuric acid in a separating funnel. Shake the soluti on for one minute and allow it to 
settle. Run the lower carbon tetrachloride layer in to a 25 mL volumetric flask. Wash the aqueous layer with 
carbon tetrach loride and transfer through glass wool  to volumetric flask. Make up the volume and mix well. 
Measur e absorption of the clear solution at 435 nm in the spectrophotometer. Prepare a calibration curve with 
standard copper solution and determine the copper con tent of the soap sample from the curve.  
NOTE  The standard solution shall also be extracted with car bon tetrachloride before estimation of colour.  
 DEAS 1144 :2023 
12 © EAC  2023 – All rights reserved  
 Annex G 
(normat ive) 
Sampli ng  
G.1 Procedure   
G.1.1 In a single co nsignment, all packages  (cartons) containing toilet soap cakes drawn from the same 
batch of production shall constitute a lot. For ascertaining  the conformity of the lot to the requirements  of this 
standard , tests sha ll be carried out on each lot separatel y. The number of packag es to be selected for drawing 
the sample shall be in accordance with Table G.1.  
Table G.1 — Scale of sampling  
Number of  packages (cartons) in 
the lot 
N Number of pac kages (cartons) t o be 
select ed 
n Number of samples  
4 to 15  3 3 
16 to 40  4 4 
41 to 65  5 2 
66 to 110  7 2 
111 and above  10 1 
 
G.1.2 The packages shall be selected at random, using tables of random numbers. I f these are not 
available, the following proce dure shall be app lied:  
Starting from any package, count all the pa ckages in one order as 1, 2, 3.... N, selecting every k th package, 
where k is the integral part of N  n.  
G.1.3 From each package thus select ed, draw at random an equal  number of cakes so  as to obtain a t otal 
mass o f at least 2 kg.  
G.2 Preparation of te st samples  
G.2.1 Compos ite sample  
Weigh each cake separately (including any material that may have adhered to the wrapper), and calculate the 
average mass. Cut each of t he remaining cakes into eight parts by means of  three cuts at right angles to each 
other through the middle. Grate finely  the whole of two diagonally opposite eighths of each specimen. Mix the 
gratings and place in a clean, dry, airtight glass container.  
G.2.2 Samples for t esting  
Immediatel y after pre paration of composite sample ( G.2.1), take at one time all tes t samples required for the 
tests in E.2. Weigh out the test sample required for determination of free alkali or acid con tent, and use it 
immediatel y.  CD/TC 074/0 03: 2023 
© EAC 2023 – All right s reserved  
  
 Bibliography  
[1] TZ 2298: 2018  Baby toile t soap – Specification  
[2] KS 44 -2: 2005 Toilet soaps - Speci fication - Part 2: Baby soap  
[3] RS 89: 2015 Baby soap – Specification