Reference number  
DRS 261: 2017 
 
© RSB 201 7 
 
 RWANDA 
STANDARD  DRS 
261 
 
First edition  
2017-mm-dd 
 
Herbal petroleum jelly — Specification  
  DRS 261: 2017 
©RSB 2017All rights reserved                  ii 
 
 In order to match with technological development and to keep continuous progress in industries, 
Standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
 
 
© RSB 2017 
All rights reserved. Unless otherwise specified , no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be  addressed to  
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
Tel. +250 252 586103/582945  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  PD xxx: 2017 
iii                 ©RSB 2017 All rights reserved  
 
 Contents  Page 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Requ irements  ................................ ................................ ................................ ................................ .........  1 
4.1 General requirements  ................................ ................................ ................................ ...........................  1 
4.2 Physical requirements  ................................ ................................ ................................ ..........................  1 
4.3 Specific requirements  ................................ ................................ ................................ ...........................  2 
5 Sampling  ................................ ................................ ................................ ................................ ................  2 
6 Packaging, labelling and storage  ................................ ................................ ................................ ........  3 
6.1 Packaging  ................................ ................................ ................................ ................................ ...............  3 
6.2 Labelling  ................................ ................................ ................................ ................................ .................  3 
6.3 Storage  ................................ ................................ ................................ ................................ ...................  3 
Annex  A (normative )  Method of test for herbal petroleum jelly products  ................................ ...................  4 
A.1 Quality of reagents  ................................ ................................ ................................ ................................  4 
A.2 Determination of kinematic viscosity  ................................ ................................ ................................ .. 4 
A.3 Determination of melting point  ................................ ................................ ................................ ............  4 
A.4 Determination of specific gravity  ................................ ................................ ................................ .........  4 
A.5 Acidity and alkalinity  ................................ ................................ ................................ .............................  5 
A.6 Determination of saponifiable matter  ................................ ................................ ................................ .. 5 
A.7 Test for organic acids  ................................ ................................ ................................ ...........................  6 
A.8 Determination of sulphated ash  ................................ ................................ ................................ ...........  6 
A.9 Determination of sulfur and sulfides  ................................ ................................ ................................ ... 6 
A.10  Determination of arsenic  ................................ ................................ ................................ ......................  6 
A.11  Determination of heavy metals  ................................ ................................ ................................ ............  7 
A.12  Determination of iodine value  ................................ ................................ ................................ ..............  7 
A.13  Determination of light absorption  ................................ ................................ ................................ ........  9 
A.14  Determination of volatile matter  ................................ ................................ ................................ ..........  9 
 DRS 261: 2017 
©RSB 2017All rights reserved                  iv 
 
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards 
adopted by Technical committ ees are ratified by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS 361 was prepared by Technical Committee RSB/TC 011, Cosmetics, toiletries and surface active agents . 
In the preparation of this standard, reference was made to the following standard s: 
IS 15 735: 2006 Herbal cosmetics — General guidelines  
US 191: 2016 Petroleum jelly — Specification (3rd Edition)  
The assistance de rived from the above source is hereby ackno wledged with thanks.  
Committee membership  
The following organizations were represented on the Technical Committee on Cosmetics, toiletries and 
surface active agents  (RSB/TC 011) in the preparation of this standard.  
ALYVO Rwanda Ltd  
Better Home Ltd  
EDEN BUSINESS CENTER Ltd  
Halth Care Pharmacy  
Kacyiru Hospital (KH)  
Ministry of Health (MoH)  
National Industrial Research and Development Agency (NIRDA)  
Pharmacie Conseil  
Pharmacie Nova  
Private Sector Federation/Beauty Makers Association (PSF/BMA)  
Rwanda Biomedical Center (RBC/MPPD)  
Rwanda Dermatology Society (RDS)  
Rwanda National Police (RNP/CID)  
SULFO Rwanda Industries Ltd  
The Ihangane Project (TIP)  
University of Rwanda — College of Science and Technology (UR — CST)  
ZIRUMUZE  Cooperative  
Rwanda Standards Board (RSB) — Secretariat  
 DRS 361 : 2017 
1                 ©RSB 2017 All rights reserved  
 
 Herbal petroleum jelly— Specification  
1 Scope  
This Draft Rwanda Standard specifies the requirements and methods of test ing for herbal  petroleum  jelly. 
This document does not apply to products intended to be used for medicinal purpose.  
2 Normative references  
The following referenced documents are indispensable for the application of this do cument. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies.  
DRS 333, Herbal cosmetics products – General requirements  
ISO 18664 , Traditional Chinese  Medicine — Determination of heavy metals in herbal medicines used in 
Traditional Chinese Medicine  
RS EAS 346 , Labelling  of cosmetics — General requirements  
RS EAS 377 (all parts) , Cosmetic and cosmetic products  
RS 278, Cosmetics – Methods of sampling  
RS EAS 123, Distilled water - Specification  
ASTM D217 – 10, Standard Test Methods for Cone Penetration of Lubricating Grease  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply.  
3.1 
herbal petroleum  jelly 
hereinafter referred to as “petroleum jelly ” is formulated, using various  permissible ingredients and  to form the 
base in which one or more  herb(s)/herbal ingredient (s) are used to provide defined  product  benefits with a 
label declaration as ”herbal  petroleum jelly” 
NOTE  Terms and definitions quoted in DRS 333 should be applied on this document.  
4 Requirements  
4.1 General requirements  
4.1.1  To ensure the quality of the product and the well being of the consumer, herbal petroleum jelly shall 
conform to requirements prescribed in DRS 333.  
4.1.2  All the ingredients used shall conform to the require ments in RS EAS 377 (all parts).  
4.2 Physical  requirements  
4.2.1  Solubility  
Herbal petroleum jelly  shall be insoluble in water and ethanol (96 %), but soluble in ether and chloroform. In 
cosmetic  spirit (boiling range 40 °C – 60 °C) the solution sometimes shows a slight opalescence.  
4.2.2  Colour  
The colour of herbal petroleum jelly shall be characteristic of plant used .  
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 4.2.3  Odour  
The material shall be of acceptable odour at room temperature when rubbed on the skin.  
4.3 Specific requirements  
4.3.1 Herbal  petroleum  jelly shall comply with the requirements given in Table 1 when tested according to  
the methods given in An nex A. Reference to the relevant clauses of Annex A is given in the third column of 
the table.  
Table 1 — Requirements for herbal petroleum jelly  
S/N Characteristics  Requirements  Method of test 
(Clause number 
to be referred  to) 
1.  Herbal content % by mass, min 1.5 - 
2.  Kinematic viscosity at  100°C Cst  4 to 6.8 A.2 
3.  Melting point °C  40 to 60  A.3 
4.  Specific gravity at 60°C, g/cc  0.815 to 0.880  A.4 
5.  pH 4.5 – 7.0 A.5 
6.  Saponifiable matter  Nil A.6 
7.  Organic acids  To pass the test  A.7 
8.  Sulphated ash, % by mass, max  Not greater than 0.10  A.8 
9.  Sulphur and sulphides  To pass test  A.9 
10.  Iodine Value (Wijs) max  1.5 A.12 
11.  Light absorption  Not greater than 0.8  A.13 
12.  Cone penetration value at 25°C  100-275 1/10mm in 
checking for consistency 
and hardness of jellies  ASTM -D 217  
13.  Volatile matter, % m/m, max.  5 A.14 
 
5.5.2  The products shall comply with the requirements for contaminants in accordance with Table 2. 
 
 
Table 2 — Requirements for contaminants  
S/N Characteristic  Requirement  Method of test  
1.  Lead, mg/kg , max 20 A.11 
2.  Arsenic, mg/kg , max  2 A.10 
3.  Mercury, mg/kg , max  2 A.11 
NOTE  The total amount of heavy metals as lead, mercury and arsenic , biological contaminants  and 
prohibited and restricted ingredients  in combination, in the finished product should not exceed 20 mg/kg . 
 
5 Sampling  
For the purpose of this Rwanda Standard, general precaution, scale of sampling and preparation of test 
samples shall be done as prescribed in RS 278 .  DRS 361 : 2017 
3                 ©RSB 2017 All rights reserved  
 
 6 Pack aging, labelling  and storage  
6.1 Pack aging 
Herbal  petroleum  jelly shall be pack aged in containers that shall protect the contents, effectively screen the 
content from UV light when stored and shall not cause any contamination or react with the product.  
6.2 Labelling  
In addition to the  labelling requirements of  RS EAS 346 , the following information shall be indelibly and legibly 
marked on the container:  
a) product name that is “Herbal petroleum jelly ”; 
b) percentage of herbal preparations used;  
6.3 Storage  
During storage all packages shall be cov ered and ingress of water sh all be avoided. The products sh all not be 
stored above 40°C, exposed to hot sun or freezing conditions.  
  
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 Annex  A 
(normative)  
 
Method of test for herbal petroleum jelly products  
A.1 Quality  of reagents  
Unless specified otherwise, analytical grade reagents and distilled water (as described in EAS 123 ) shall be 
employed in test.  
A.2 Determination  of kinematic viscosity  
A.2.1  Determination  
The kinematic viscosity is determined by using the viscometers. The specific d etails of operation vary for 
different types of viscometers.  
A.2.2  Procedure  
The time is measured for a fixed volume of sample, contained in  a glass of viscometer, to flow through a 
calibrated capillary under an accurately reproducible head of liquid and at 100  °C. This temperature must be 
controlled. The viscometer selected should give an efflux time greater than 200 s. The kinematic viscosity is 
calculated from the measured efflux time. The viscometer is calibrated by using standard oil having viscosities 
established with reference to water in master viscometers or by direct comparison with carefully calibrated 
viscometers. The temperatures of the bath used shall be maintained within ± 0.01 °C.  
A.3 Determination  of melting point  
A.3.1  Melt a quantity of the sample slowly while stirring until it reaches a temperature of 90 °C to 92 °C. 
Remove the source of heat and allow the molten sample to cool to a temperature of 8 °C to 10 °C above the 
expected melting point. Chill the bulb of a thermometer (range: 1 °C to 100 °C ) to 5 °C, wipe it dry and while it 
is still cold, dip it into molten sample so that approximately half of the bulb is  “submerged" Withdraw it 
immediately and hold it vertically away from heat until the wax surface dulls,  then dip it for 5 min into a water  
bath having a temperature not higher than 16 °C.  
A.3.2  Fix the thermometer prepared in A.3.1 securely in a test tube so that its lowest point is about 15 mm 
above the bottom of the test tube. Suspend the test tube in a water bath adjusted to 16 °C, and raise the 
temperature of the bath at a rate of 1 degree/mi n and note the temperature at which the first drop of the 
melted sample leaves the thermometer. Repeat the determination twice on a freshly melted portion of the 
sample. If the variation in three determinations is less than one degree take the average of t hree as the 
melting point. If the variation in the three determinations is more than one degree, make two additional 
determinations and take the average of the five.  
A.4 Determination  of specific gravity  
A.4.1  Apparatus  
A.4.1.1  Specific gravity bottle, 25 m L capaci ty, with a well -fitting ground glass stopper with a capillary  
A.4.1.2  Water bath, maintained at 60 °C ± 1 °C  
A.4.2  Procedure  
A.4.2.1  Clean and dry the specific gravity bottle, and weigh it. Then fill it with water, insert the stopper and 
immerse in the water bat h at 60 °C ± 1 °C. Keep the entire bulb completely immersed in water and hold at that 
temperature for 1 h. Carefully remove any water which has exuded from the capillary opening. Remove from 
the bath, wipe completely dry, cool to room temperature and weigh . DRS 361 : 2017 
5                 ©RSB 2017 All rights reserved  
 
 A.4.2.2  Melt approximately 40 g of the material in a porcelain dish and fill the dry specific gravity bottle 
with it. Keep the bottle for 1 h in a water bath at 60 °C ± 1 °C. Carefully remove any material which exudes 
from the capillary opening, wipe the  bottle dry and cool at room temperature and weigh.  
A.4.3  Calculation  
Specific  gravity 60 °C/60 °C=
2 32 1
mmmm
  
Where  
m1 is the mass, in grams, of specific gravity bottle with the material  
m2 is the mass, in grams, of the specific of the gravity bottle  
m3 is the mass, in grams, of the specific  gravity bottle with water  
A.5 Acidity and alkalinity  
A.5.1  Reagents  
A.5.1.1  Phenolphthalein indicator solution, 1 % solution in 95 % rectified spirit.  
A.5.1.2  Methyl orange indicator, dissolve 0.01 g of methyl orange in 100 ml of water.  
A.5.2  Procedure  
A.5.2.1  Take 35 g, of the sample in a 250 m L separating funnel. Add to it 100 m L of boiling water and 
shake vigorously for 5 min. Draw off the separated water layer in the beaker. Wash the sample further with 
two 50 m L portions of boiling water and add the washings again to the beaker. To the collective washings add 
one drop of phenolphthalein indicator solution and boil. If no pink colour is produced, add 0.1 ml of methyl 
orange indicator and see if any red or pink col our is produced.  
A.5.2.2  The sample shall be taken to have passed the test if neither a red colour is produced with 
phenolphthalein nor a pink colour produced.  
A.6 Determination  of saponifiable matter  
A.6.1  Reagents  
A.6.1.1  Methyl ethyl ketone, analytical grade, sto red in amber coloured bottle.  
A.6.1.2  Standard alcoholic potassium hydroxide solution, 0.5 mol/L standardized before use.  
A.6.1.3  Herbal cosmetic  ether, boiling range 80 °C to 100 °C.  
A.6.1.4  Standard hydrochloric acid, 0.5 mol/L accurately standardized.  
A.6.1.5  Phenolphthalein indicator solution, same as in A.5.1.1.  
A.6.2  Procedure  
A.6.2.1  Accurately weigh in flask about 5 g of the sample and add 25 m L ± 1 m L of methyl ethyl ketone, 
followed by 25mL standard alcoholic potassium hydroxide solution from a burette. Connect the flask to a 
condenser and heat for half an hour after refluxing begins. Disconnect the condenser, add 50 m L of petroleum 
ether and titrate the solution while hot (without heating) with standard hydrochloric acid, using three drops of 
phenolphthalein indicator. When the indicator colour is discharged add three drops more of the indicator. If 
this addition restores the colour, continue the titr ation. Proceed in this manner until the end point is reached 
when the indicator colour is discarded and does not immediately reappear upon the addition of three more 
drops of indicator.  
A.6.2.2  The sample shall be taken to have passed the requirement presc ribed in Table 1 if the blank 
reading does not differ from the sample reading by more than 0.1 m L.  
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 A.7 Test for organic acids  
A.7.1  Reagents  
A.7.1.1  Dilute rectified spirit, prepared by diluting one volume of 95 % rectified spirit with two volumes of 
water, and neut ralized to phenolphthalein indicator.  
A.7.1.2  Phenolphthalein indicator, same as in A.5.1.1.  
A.7.1.3  Standard sodium hydroxide solution, exactly 0.1 mol/L . 
A.7.2  Procedure  
A.7.2.1  Add 100 m L of dilute rectified spirit to 20 g of the sample, agitate thoroughly, and heat to boiling. 
Add 1 ml of phenolphthalein indicator and titrate rapidly with standard sodium hydroxide solution with vigorous 
agitation to a sharp pink end point in the alcohol water layer.  
A.7.2.2  The material shall be taken to have passed the test  if not more than 0.4 m L of standard sodium 
hydroxide solution is required for the titration.  
A.8 Determination  of sulphated  ash 
A.8.1  Reagents  
A.8.1 .1 Dilute sulfuric acid, approximately 2.5 mo1/L  
A.8.1.2 Heat a platinum dish to redness for 10 min; allow to cool in  a desiccator and weigh. Place 1 g of 
the sample in the dish, moisten with sulfuric acid, and ignite gently by means of a Bunsen burner. Again 
moisten with sulfuric acid and ignite at about 800 °C in a muffle furnace. Cool and weigh, again ignite for 15 
min and repeat this procedure until two successive weighings do not differ by more than 0.5 mg.  
A.8.2  Calculation  
Sulfated ash, percent by mass =
21100
mxm  
where  
m1 is the mass in grams of the residue;  
m2 is the mass in grams of the sample taken for the test.  
A.9 Determination  of sulfur and sulfides  
A.9.1  Reagents  
Copper strips, 1 cm in width, and freshly polished.  
A.9.2  Procedure  
A.9.2.1  Melt in a beaker about 100 g of the sample and keep on a water bath at a temperature  of 95 °C. 
Then place a strip of copper in the melted sample so that it is partially immersed in it and allow to remain for 
10 min.  
A.9.2.2  The material shall be taken to have passed the test if the copper strip used in the test shows no 
tarnishing when co mpared with another freshly polished copper strip.  
A.10  Determination  of arsenic  
A.10.1  Reagents  
A.10.1.1  Concentrated sulfuric acid, reagent grade.  
A.10.1.2  Concentrated nitric acid, reagent grade.  DRS 361 : 2017 
7                 ©RSB 2017 All rights reserved  
 
 A.10.2  Preparation  of sample  
A.10.2.1  Weigh 2.00 g of the sample in a Kjeldahl flask of 500 ml capacity. Add 15 ml of concentrated 
sulfuric acid followed by 4 ml of concentrated nitric acid. Heat cautiously. Add drop -by-drop more nitric acid, if 
required, from a pipette to speed up the oxidati on of the sample. The total amount of nitric acid shall be noted 
for use in control test. When oxidation is complete the solution is clear and faint yellow, at that stage, add 20 
ml of water and again boil to fuming, Ensure removal of all nitric acid.  
A.10.2.2  Carry out test for arsenic with the solution prepared in A.10.2.1 as per Clause 2  of EAS 101. 
Compare the stain obtained with that produced with 0.004 g of arsenic trioxide.  
A.11  Determination  of heavy metals  
A.11.1  Reagents  
A.11.1.1  Ammonium acetate solution, 1 0 %. 
A.11.1.2  Ammonium citrate solution, dissolve 8.75 g of citric acid in water, neutralize with ammonia and 
dilute with water to 100 m L. 
A.11.1.3  Ammonium hydroxide, 10 % (m/m).  
A.11.1.4  Potassium cyanide solution, 10 %.  
A.11.1.5  Sodium sulfide solution,  10 %.  
A.11.1.6  Standard lead solution, dissolve 16 g of lead nitrate in water and 10 m L of concentrated HNO 3 
and dilute to 1000 ml. Pipette out 10 m L of the solution and dilute again to 1000 m L with water. 1 m L of the 
final solution contains 0.01 mg of lead (as Pb). The solution should be freshly prepared.  
A.11.2  Procedure  
A.11.2.1  In the preparation of sample treat 2.0 g of the sample as prescribed in A.10.2.  
A.11.2.2  Take the solution prepared in A.11.2.1 in a Nessle r tube (with 50 m L capacity); add 10 m L of 
ammonium acetate solution, (5 ml capacity); add 10 m L of ammonium acetate solution, 5 m L of ammonium 
hydroxide and 1 m L of potassium cyanide solution and dilute to 50 m L with water, then add two drops of 
sodium su lfide solution and mix well. In another Nessler tube carry out a control test using 4 m L of standard 
lead solution and same quantities of other reagents as used in the test with the material.  
A.11.2.3  The material shall be taken to have passed the test as given in Table 1 if the intensity of colour 
produced with material is not greater than that produced in the control test.  
A.12  Determination  of iodine value  
A.12.1  Apparatus  
The material is treated with a known excess of iodine monochloride solution in glacial acetic acid. The excess 
of iodine monochloride is determined iodometrlcally. Thermometer, an engraved stem thermometer, calibrated 
between 10 °C and 65 °C in 0.1 degree intervals and with the 0 °C point marked on the steam is 
recommended. The thermometer shall ha ve an auxiliary reservoir at the upper end, and length of about 370 
mm and diameter of about 6 mm.  
A.12.2  Reagents  
A.12.2.1  Carbon tetrachloride or chloroform.  
A.12.2.2  Acetic acid, glacial. 99 %, having a melting point of 14.8 °C and free from reducing impuritie s. 
Determine the melting point of the acetic acid and test it for reducing impurities as it follows:  
A.12.2.2.1  Melting point determination — Take a 15 cm long test tube and fill it to about two thirds with the 
acetic acid. Insert into the acid a thermomet er satisfying the requirements specified in A.12.1 through a cork 
stopper fitting the test tube. The amount of acid should be at least double the quantity required to cover the 
bulb of the thermometer when the bottom of the latter is 12 mm from the bottom of the test tube. Suspend this 
tube within a larger test tube through a cork. Cool the acid by immersing the assembly in ice water until the 
temperature is 10 °C, then withdraw the assembly from the ice water and stir the acid rather vigorously for a 
few m oments, thus causing the super -cooled liquid to crystallize partially and give: a mixture of liquid and solid  
©RSB 2017All rights reserved                  8 
 
 acid. Take thermometer readings every 15 s and consider the temperature at which the reading remains 
constant for at least 2 min as the true melti ng point.  
A.12.2.2.2  Test for reducing impurities — Potassium permanganate test, dilute 2 m L of acetic acid with 10 
mL of water and add 0.1 m L of 0.5 m L potassium permanganate solution and maintain at 27 °C ± 2 °C. The 
test shall be taken as having been s atisfied if the pink colour is not discharged at the end of 2 h.  
A.12.2.3  Potassium dichromate, finely ground.  
A.12.2.4  Starch solution, mix 5 g of starch and 0.01 g of mercuric iodide with 30 m L of cold water and 
slowly pour it while stirring into 1 litr e of boiling water. Boil for 3 min. Allow the solution to cool and decant off 
the supernatant clear liquid.  
A.12.2.5  Standard sodium thiosulfate solution, 0.2 mol/L.  
A.12.2.6  Chlorine gas, dry.  
A.12.2.7  Iodine trichloride.  
A.12.2.8  Wijs iodine monochlorid e solution, prepare this solution by one of the following methods, and 
store in a glass stoppered bottle in a cool place, protected from light and sealed with paraffin until taken for 
use. 
A.12.2.8 .1 Dissolve 3 g of re -sublimed iodine in 1 L of acetic acid , using gentle heat if necessary, and 
determine the length by titration with standard sodium thiosulfate solution. Set aside 50 m L to 100 m L of 
solution and introduce washed and dried chlorine gas into the remainder until the characteristic colour change 
occurs and the halogen content is nearly doubled as ascertained again by titration. If the halogen content has 
been more than doubled, reduce it by adding the requisite quantity of the iodine - acetic acid solution. A 
slightly excess of iodine does not harm , but avoid an excess of chlorine.  
For example, if the titration of 20 m L of original iodine acetic acid solution requires 22 m L of standard sodium 
thiosulfate solution then 20 m L of the finished Wijs solution should require between 43 m L and 44 m L (and no t 
more than 44 m L) of the same sodium thiosulfate.  
A.12.2.8 .2 As an alter native method of preparing Wijs solution dissolve 8 g of iodine trichloride 
inapproximately 450 ml of acetic acid. Dissolve separately 9 g of iodine in 450 ml, of acetic acid using he at if 
necessary. Add gradually the iodine solution to the iodine trichloride solution until the colour has changed to 
reddish brown. Add 50 ml more of iodine solution and dilute the mixture with acetic acid till 10 ml of the 
mixture are equivalent to 20ml standard sodium thiosulfate solution when the halogen content is estimated by 
titration in the presence of an excess to potassium iodine and water. Heat the solution at 100 °C for 20 min 
and cool.Prevent access of water vapour in preparing the solution.  
A.12.3  Procedure  
A.12.3.1  Melt the material and filter through the filter paper to remove any impurities and the last trace of 
moisture. Make sure that the glass apparatus used is absolutely clean and dry. Weigh accurately by 
difference, about 10 g of the sample, into a clean, dry 500 m L glass stoppered bottle to which 25 m L of carbon 
tetrachloride or chloroform have been added, and agitate to dissolve the contents. Add 25 ml of Wijs solution 
(the quantity of Wijs solution added is 50 % - 60% more than the quantity  required).  
A.12.3.2  Replace the glass stopper after wetting with potassium iodine solution, swirl for intimate mixing, 
and allow to stand in the dark for 45 min. Carry out a blank test simultaneously under similar experimental 
conditions. After standing add 15 m L of potassium iodide solution and 100 m L of water, and titrate the 
liberated iodine with standard sodium thiosulfate solution, swirling the contents of the bottle continuously to 
avoid any local excess, until the colour of the solution is straw ye llow. Add 0.5 m L of starch solution and 
continue the titration until the blue colour disappears.  
 
A.12.4  Calculation  
Iodine value =
mMVV ) (69.122 1  
where  DRS 361 : 2017 
9                 ©RSB 2017 All rights reserved  
 
 V1 is the volume, in millilitre, of standard sodium thiosulfate required for the blank;  
V2 is the volume, in millilitre, of standard sodium thiosulfate solution required for the material;  
M is the molarity of standard sodium thiosulphate; and  
M is the mass, in grams, of the material taken for the test.  
A.13  Determination  of light absorption  
A.13.1  Apparatu s 
A.13.1 .1 UV spectrophotometer  
A.13. 1.2 Make of solution of 0.05 % m/v of the herbal petroleum jelly in 2,2,4 – trimethylpentane, then 
determine the absorbency at 290 nm  
A.14  Determination  of volatile matter  
A.14.1  Outline of the method  
The sample is weighed in petri/ glass dish and kept in an oven maintained at 105 ± 10C. the loss in mass is 
calculated as percentage of the mass of the sample taken.  
A.14.2  Apparatus  
A.14.2.1 Petri/Glass dishes – Made of heat resistant glass, 90 to 100 mm in diameter and 7 to 10 mm in 
height.  
A.14.2.2 Thermometer – Any suitable thermometer having a range from 0 to 1100C. 
A.14.2.3 Air -Oven – An electrically or gas heated air oven capable of maintaining temperature at 105 ± 10C. 
A.14.3  Procedure  
Weigh about 10g of the sample, accurately to the nearest 0.1g, in a tare petri/glass dish, distributing the 
sample in as uniform a layer as possible with the help of a spatula over the whole of bottom of the dish. Keep 
it in the oven, maintained at 105 ± 10C for 24 h. cool and weigh the petri/glass dish to a constant mass.  
A.14.4  Calculation and report  
Calculate and report the evaporation loss as follows:  
 Volatile matter per cent =100  M1−M2
M1 
Where,  
M1 = mass in g of the sample taken for the test  
M2 = mass in g of the sample after the test  DRS  361: 2017  
ICS 71.100.70  
 
 
©RSB 2017  All right s reserved