Reference number  
DRS 382: 2018 
© RSB 2018 
 
 
 RWANDA 
STANDARD  DRS  
382 
 
First edition  
2018-mm-dd 
 
Pyrethrin  and Permethrin based 
insecticides  for space spray application — 
Specification  
 
  DRS 382: 2018 
©RSB 2018- All 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 2018 
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 reprodu ce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 382: 2018 
iii                ©RSB 2018- All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Term s and definitions  ................................ ................................ ................................ ..................  1 
4 Requirements  ................................ ................................ ................................ ..............................  32 
4.1 General requirements  ................................ ................................ ................................ ................  32 
4.2 Specific requirements  ................................ ................................ ................................ ................  32 
5 Packaging and Labelling  ................................ ................................ ................................ .............  3 
5.1 Packaging  ................................ ................................ ................................ ................................ ...... 3 
5.2 Labelling  ................................ ................................ ................................ ................................ ...... 43 
6 Sampling  ................................ ................................ ................................ ................................ ....... 4 
7 Testing  ................................ ................................ ................................ ................................ ...........  4 
Annex  A (normative)  Sampling of insecticidal space spray  ................................ ..............................  65 
 DRS 382: 2018 
©RSB 2018- All 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 382 was prepared by Technical Committee RSB/TC 024, Chemical s and Consumer Products.  
Committee membership  
The following organizations were represented on the Technical Committee on Chemicals and Consumer 
Products (RSB/TC 024) in the preparation of this standard.  
Paragraph of p articipants  
Star Construction and Consu ltancy Ltd  
IKIREZI Natural Products Ltd  
University of Rwanda/College of Sciences and Technology  
University of Rwanda/College of Education  
Rwanda Development Board  
AGROPY Ltd  
Ministry of Health  
Pharmacy NOVA  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 382: 2018 
v                ©RSB 2018- All rights reserved  
 Introduction  
This Rwanda Standard gives a specific composition of an insecticide solution which can be used for household 
purposes, godowns, animal protection, agricultural sprays in the fields/farms, etc. The word ‘space’ has been 
used to show that this spray is made for purpose of controlling the insects that fly or move in ‘space’. It is 
recognized that a variety of insecticidal sprays can be formulated and sold in the market. However, keeping in 
view the factors such as safety, efficacy, ease of analys is and determination of constituents on the basis of 
chemical analysis, this standard has been introduced.  
Several investigations  have proved that continued use of organo -chloro insecticides have created resistance 
with many insects and their residues pois onous to non -targets. As such it was felt that their inclusion should not 
be recommended in the formulation of domestic and agricultural spray solutions.  
Before proceeding with quantitative estimation of pyrethrin and permethrin which have been described a s two 
active ingredient s in this standard, it would be desirable to ensure that the sprays conforming to this standard 
should not include other insecticidal molecules (or active ingredients).  
 
 DRS 382: 2018 
1                ©RSB 2018- All rights reserved  
 Pyrethrin  and Permethrin based insecticides for space spray application 
— Specification  
1 Scope  
This Committee Draft  prescribes the requirements , sampling and  test methods  for a formulation of insecticidal 
space spray whose active ingredients are pyrethrin and permethrin for use in control of both animal and public 
health insects . 
2 Normative references  
The following documents are referred to in the text in such a way that some or all of  their content constitutes 
requirements of this document.  For dated references, only the edition  cited applies. For undated references, the 
latest edition of the reference d document (including any amendments) applies.  
RS EAS 123, Distilled water — Specification  
RS 172, Pyrethrins -based insecticide for  space spray application —Specification  
RS 191, Refined pyrethrum concentrate — Specification  
RS ISO 1523, Determination of flash point – Closed cup equilibrium method  
 
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply . 
3.1 
insecticide  
type of chemical used to kill insects, like those that have infested a house or a farmer's crop s. 
3.2 
active ingredient  
biologically active part of the chemical substance present in an insecticide formulation  
3.3 
formulation  
combination of various chemical ingredients, so designed as to obtain an insecticide   
©RSB 2018- All rights reserved                  2 
 3.4 
pyrethrins  
the six naturally occurring isomers that are esters of pyrethric acid and chrysenthemic acid viz: pyrethrin -I, 
pyrethrin -II, cinerin -I, cinerin -II, jasmolin -I, jasmolin -II; having insecticidal property and are extracted from the 
flower of Chrysanthemum cinerariifolium.  
3.5 
permethrim  
synthetic insecticide of the pyrethroid class, used chiefly against disease -carrying insects.  
3.6 
synergists  
chemical compounds that prevent the breakdown and the biological activity of pyrethrins, pyrethroids and any 
other insecticide  
3.7 
spray  
liquid that is blown or driven through the air in the form of tiny drops.  
3.8 
space spray  
spraying  the product into the air instead of directing the product onto a surface.  
3.9 
propellants  
gases used to discharge the product as an aerosol from the contain er. 
3.10 
knockdown  
the rapid paralysis of ins ect by insecticide, causing them to fall to the floor and lie immobile.  DRS 382: 2018 
3                ©RSB 2018- All rights reserved  
 4 Requirements  
4.1 General requirements  
4.1.1 The product shall be a solution  or emulsion  of pyrethrin and permethrin as active ingredients, dissolved  
or emulsified essentially in refined (quick -drying) solvents with the addition of  propellants,  deodorants  or 
perfumes , antioxidants and if required, a synergist may be used to impart only necess ary efficiency to the 
formulation.  
4.1.2  Pyrethrin used shall meet the requirements of RS 191.  
4.1.3  Solvents and propellants used shall be approved by competent authority. Solvents and propellants not 
allowed in aerosols are listed in annex B.  
4.1.4 The f ormulation shall be clear and light in colour and shall have no unpleasant odour when sprayed; it 
shall be non -irritant and non -toxic to human  beings  and domestic animal s. 
4.1.5 The product  shall be non -reactive and non -staining to household structures, items and fabrics.  
4.1.6 The product shall be registered by competent authority. The registration dossier and certificate shall 
be kept and availed during an inspection.  
4.2 Specific requirements  
The product shall comply with the requirements stipulated in table 1.  
S/N Parameters  Requirements  Test methods  
1 Pyrethrin (%, m/m)  0.25– 5  Annex C  
2 Permethrin (%, m/m)  0.40 – 5  Annex D  
4 Synergist (Piperonyl Butoxide - 
PBO) (%, m/m)  1 – 5  Annex E  
5 pH 4 – 10  Annex F   
6 Flash point ( oC), min.  32 RS ISO 1523  
7 Acidity , g/kg, max  4 Annex G  
8 Alkalinity , g/kg, max  8 
5 Packaging and Labelling  
5.1 Packaging  
5.1.1  The product shall be pack aged in clean, dry and leak proof containers made of mild steel or tinplate or 
any other non -corrosive/non -reactive containers.  
5.1.2  The package  shall be opaque and air -tight after filling. It shall preserve  the integrity of the product.   
©RSB 2018- All rights reserved                  4 
 5.2 Labelling  
5.2.1  The containers shall bear legibly and indelibly marked with the  following information.  
a) name  indicating the nature of the product  
b) name and address of the manufacturer and/or trade mark  
c) chemical name and percentage composition of active ingredients  
d) chemical n ame of the synergist, if used in formulation  
e) manufacture and expiry dates  
f) batch number  
g) net mass of contents/net volume  
h) storage conditions  
i) A minimum cautionary notice, legibly and clearly marked. The notice shall be worded as under or closely 
similar:  
1) Flamm able, keep away from fire or heat. Do not keep this product exposed to air or direct sunlight . 
2) Not to be ingested or inhaled, keep away from children. Do not direct into eyes.  
3) In case of eye contact, flush immediately with plenty of water, and get medical attention. For skin, wash 
thoroughly with soap and water. If affected by inhalation of vapour or spray, remove the subject to fresh 
air and seek medical attention, if swallowed, do not induce vomiting, get medical attention.  
4) Harmful to aquatic life, do not  discharge into water bodies. Destroy empty container and dispose 
according to national regulations.  
5.2.2  Expressions such as “non -toxic’ or “non -poisonous” or “harmless to humans” or “safe” or any word or 
expression, pictorial or otherwise, that may conv ey similar information shall not appear on the product, package 
or on any material accompanying the product.  
5.2.3  Information as to the intended use of the product, the types of insects it is supposed to control.  
5.2.4  Maximum instructions on the product usage including on protective gears. Use of standard pictorial 
instructions is encouraged.  
5.2.5  A material Safety Data Sheet (MSDS) shall accompany the product.  
6 Sampling 
Representative samples of the product shall be drawn as prescribed in the Annex A.  
7 Testing  
7.1 Test shall be carried out by the appropriate methods  of analysis described in Table 1 . 
7.2 Unless specified otherwise, pure chemicals and distilled water complying with RS EAS 123  shall be used.  
NOTE Pure chemicals shall mean chemicals that do not contain impurities which will affect the results of analysis.  
 DRS 382: 2018 
5                ©RSB 2018- All rights reserved  
   
©RSB 2018- All rights reserved                  6 
 Annex  A 
(normative)  
 
Sampling of insecticidal space spray  
A.1 General  precautions  
A.1.1  In drawing, preparing, storing and handling test samples, the following precautions and directions shall 
be observed.  
A.1.2  The sampling equipment shall be clean and dry when used.  
A.1.3  Proper precautions shall be taken while drawing sample since the material is toxic.  
A.1.4  Precautions shall be taken to protect the samples, the material being sampled, the sampling equipment 
and the containers for samples from adventitious contamination.  
A.1.5  To draw a representative sample, the contents of each container selected for sampling shall be mixed 
as thoroughly as possible by shaking or stirring or both, by suita ble means or by rolling so as to bring all portions 
into uniform distribution (See A.3.3.1);  
A.1.5 To draw a representative sample, the contents of each container selected for sampling shall be mixed 
as thoroughly as possible by shaking or stirring or both , by suitable means or by rolling so as to bring all portions 
into uniform distribution (See A.3.3.1)  
A.1.6 The samples shall be placed in suitable, clean, dry and air -tight amber coloured glass containers, on 
which the material has no action.  
A.1.7 The sa mples shall be placed in suitable, clean, dry and air -tight amber coloured glass containers, on 
which the material has no action.  
A.1.8 The sample containers shall be of such a size that they are almost, but not completely, filled by the 
sample.  
A.1.9  Each  sample containers shall be closed tightly with a stopper after filling and marked with full details 
of sampling, the date of manufacturer, name of the manufacturer and other particulars of the consignment.  
A.1.10  Samples shall be stored in such a manner t hat the temperature of the material does not vary unduly 
from the normal temperature. It should preferably be refrigerated at 0°C or below.  
A.1.11 Samples shall be protected from light.  
A.2 Sampling  
A.2.1 A pipette of convenient volume may be used for drawing the sample.  DRS 382: 2018 
7                ©RSB 2018- All rights reserved  
 A.2.2 All the containers in a single consignment of the material drawn from the same batch of manufacture 
shall constitute a lot. If a consignment is declared or is known to consist of diffe rent batches these shall be 
grouped together and each such group shall constitute a separate lot.  
A.2.3 Samples shall be tested for each lot for ascertaining the conformity of the material to the requirements 
of the specification.  
A.2.4 The number (n) of c ontainers to be chosen from the lot shall depend on the size of the lot and shall be 
in accordance with cool 1 and 2 of Table 1.  
A.2.5 These containers shall be chosen at random from the lot and in order to ensure that randomness of 
selection, some random number table, as agreed to between the purchaser and the vendor  shall be used. In 
case such a table is not available, the following procedure shall be adopted.  
A.2.6 Starting from any container in the lot, count them as 1,2,3….etc, up to r in a systematic manner, where 
is equal to the integral part of the value of N/n. N being the total number of containers in the lot and n the number 
of containers to be chosen (see Table 1). Every rth container thus counted shall be separated until the requisite 
number of containers is obtained from the lot to give samples for test.  
TABLE 1 Number of containers to be chosen for sampling  
 
 
A.3 Test samples and reference samples  
A.3.1 Before drawing the test sample, mix thoroughly the contents of each container selected (see Table 1) 
by shaking or stirring by suitable means or by rolling. Draw, by inserting the pipette through the bung hole or 
any other convenien t opening, small portions of the material from different parts of each container selected.  
The total quantity of the material drawn from each container shall be sufficient to conduct the tests for all the 
characteristics . 
A.3.2 Mix thoroughly all portions  of the material drawn from the same container. Out of these portions, a 
small but equal quantity shall be taken for each selected container and shall be well mixed together so as to 
form a composite sample shall be divided into three equal parts, one for the purchaser, another for the vendor 
and the third for the referee.  
A.3.3 The remaining portions of the material from each container latter a small quantity needed for the 
formation of the compos ite sample has been taken out) shall be divided into three e qual portions. These shall 
be immediately transferred to thoroughly dried bottles which are then sealed air -tight with stoppers and label led 
with all the particulars of sampling given under (A -1.8). The material in each such sealed bottle shall constitute 
a test sample. These individual samples shall be separated into three identical sets of test samples in such a 
way that each set has a sample representing each container selected (see Table 1). One of these three sets 
shall be marked for the purchaser, ano ther for the vendor and the third for the referee.  Lot Size  No. of Containers to 
be chosen  
N (1)  
3 to 15  
16 to 40  
41 to 65  
66 to 110  
Over 110  n (2) 
3 
4 
5 
7 
10  
©RSB 2018- All rights reserved                  8 
 A.3.4 Referee samples ━ Referee samples shall consist of the composite sample (see A .3.2) and a set of 
individual test samples (see A .3.3) marked for this purpose and shall bear the identification mark of the 
purchaser and the vendor. These shall be kept at a place agreed to between the two.  DRS 382: 2018 
9                ©RSB 2018- All rights reserved  
 Annex  B 
(normative)  
 
Solvents not permitted for use in aerosols  
1) Benzene  
1) 2-butoxyethanol (ethylene glycol monobutyl ether)  
2) 2-butoxyethylacetate (ethylene glycol monobutyl ether  acetate)  
3) carbon tetrachloride  
4) chlorobenzene  
5) chloroform  
6) 1,2-dichloroethane (ethylene dichloride)  
7) 2-ethoxyethanol (ethylene glycol monoethyl ether)  
8) 2-ethoxyethylacetate (ethylene glycol monoethyl ether acetate)  
9) n-hexane  
10) 2-hexanone (methyl n -butyl ketone)  
11) 2-methoxyethanol (ethylene glycol monomethyl ether)  
12) 2-methoxyethylacetate (ethylene glycol monomethyl ether acetate)  
13) tetrachloroethylene  
14) trichloroethylene  
2) Propellants  
NOTE  The Montreal Protocol and EU 1 directive on the withdrawal of chlorofluorocarbons (CFCs) from 
aerosols were noted. Hydrocarbon propellants are recommended  for insecticide aerosols, provided international 
safety standards are met by the aerosol producer. Industry should be encouraged to develop alternative and 
safer propellants and deliv ery systems.  
  
©RSB 2018- All rights reserved                  10 
 Annex  C 
(normative)  
 
Determination of total Pyrethrins  
C.1 General  
The total pyrethrins in the product  may be determined using a HPLC system first by injecting a solution of the 
analyte into the chromatograph, followed by the separation and comparison o f peaks areas of the analytes in 
the sample with that of an external standard containing a known amount of the analytes. The peaks are eluted 
in the following order: Cinerin II, Pyrethrin II, Jasmolin II (total Pyrethrins II) and Cinerin I, Pyrethrin I, Ja smolin 
I (total Pyrethrins I ). 
C.2 Reagents.  
World Pyrethrum Standard , 50%  
Acetonitrile, HPLC grade  
Water, HPLC grade.  
C.3 Apparatus  
A Liquid chromatography System equipped with an auto -sampler, a Variable Wavelength Detector (or 
equivalent) and a Column (Phenomen ex, 250 x 4.6 mm Luna Phenyl -Hexyl 5µ Reverse Phase (or equivalent )) 
C.4 Operating Conditions  
Flow rate:  1.5 ml/min  
Composition:  40:60 (%, v/v Water : Acetonitrile)  
Elution:  Isocratic  
Oven Temperature:  40 oC 
Wavelength:  240 nm  
Injection Volume:  15µl 
Stop time:  22 minutes  
Post time:  1 minute  
C.5 Preparation of the Standard  
Weigh 20 mg of the pyrethrum standard to the nearest 0.0001g in a 100 mL volumetric flask and dilute to volume 
with Acetonitrile and label it. Transfer a small portion to a sample vial and  label it accordingly.  
 DRS 382: 2018 
11                ©RSB 2018- All rights reserved  
 C.6 Sample preparation  
In a 100 ml volumetric flask, weigh 4.6g to the nearest 0.0001g of the sample to be analysed and dilute to 
volume with Acetonitrile. Sample this solution using a vial and label it accordingly.  Note: Ensure the sol ution is 
filtered to avoid damage of the auto -sampler.  
C.7 Procedure  
After the chromatograph is stable, make a minimum of three injections for the standard solution as well as for 
the analyte and average the area counts. The relative Standard Deviation between  injections should be within 
2% 
C.8 Calculation of the % Total Pyrethrins (Active Ingredient)  
The % Total Pyrethrins is calculated as follow:  
% 𝐴𝑐𝑡𝑖𝑣𝑒  𝐼𝑛𝑔𝑟𝑒𝑑𝑖𝑒𝑛𝑡𝑠 =𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑆𝑎𝑚𝑝𝑙𝑒  𝑎𝑟𝑒𝑎  𝑥 𝑤𝑒𝑖𝑔 ℎ𝑡 𝑜𝑓 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑥 𝑃𝑢𝑟𝑖𝑡𝑦  𝑜𝑓 𝑡ℎ𝑒 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  (𝑖𝑛 %)
𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑎𝑟𝑒𝑎  𝑥 𝑊𝑒𝑖𝑔 ℎ𝑡 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒  
©RSB 2018- All rights reserved                  12 
 Annex  D 
(normative)  
 
Determination of permethrin  
Permethrin as one of t he active ingredient s in this product may be determined using HPLC by injecting a solution 
of analyte into a chromatograph, followed by separation and comparison of peak areas of the analyte in the 
sample with that of an external standard.  
D.1 Reagents   
Cis – Permethrin, 99%  
Trans - Permethrin, 99%  
Methanol HPLC grade  
Water, HPLC grade  
D.2 Apparatus  
An HPLC equipped with an autosampler, a variable wavelenght detector (or equivalent) and a column 
(phenomena x, 250 x 4.6mm Luna Phenyl 5μ Reverse phase (or eq uivalent)  
D.3 Operating conditions  
Flow rate  1.0mL/min  
Solvent composition  60% : 40% (Methanol: Water)  
Elution  Isocratic  
Column temperature  40oC  
Wavelength  240nm  
Injection volume  25 μL  
Stop time  50 minutes  
Post time  2 minutes  
 
D.4 Procedure  
B.4.1Preparation of standard solution  
Weigh about 0.001g (to the nearest 0.0001g) Permethrin standard in beaker, use methanoldissolved and 
transfer them into a separate volumetric flasks (50 ml), dilute to the mark and mix well.  DRS 382: 2018 
13                ©RSB 2018- All rights reserved  
 B.4.2 Preparation of Soluti on 
Weigh about 0.02 g (to the nearest 0.0001g) Permethrin test sample into beaker, use methanol dissolved and 
transfer them into a separate volumetric flasks (50 ml), dilute to the mark and mix well.  
B.4.3 Determination  
After the chromatograph is stable, m ake a minimum of three injections of the standard as well as for the sample 
and average the area counts. The relative standard deviation between injections should be within 2%.  
D.5 Calculation  
The % of either cis or trans isomers is calculated as follows;  
%𝑐𝑖𝑠𝑜𝑟𝑡𝑟𝑎𝑛𝑠𝑝𝑒𝑟𝑚𝑒𝑡 ℎ𝑟𝑖𝑛 =𝐴𝑣𝑒𝑟𝑎𝑔𝑒𝑠𝑎𝑚𝑝𝑙𝑒𝑎𝑟𝑒𝑎 ×𝑤𝑒𝑖𝑔 ℎ𝑡𝑜𝑓𝑠𝑡𝑑 ×𝑝𝑢𝑟𝑖𝑡𝑦 (𝑖𝑛%)
Average  std area  × weight  of sample 
Report the concentration of permethrin as the total of Cis and Trans .  
©RSB 2018- All rights reserved                  14 
 Annex  E 
(normative)  
 
Determination of Total Piperonyl butoxide (PBO)  
E.1 General  
The Synergist – Piperonyl Butoxide (PBO) may be determined using a HPLC system first by injecting a solution 
of the analyte into the chromatograph, followed by the separation and compariso n of peaks areas of the analyte  
in the sample with that of an external standard containin g a known amount of the analyte. In the standard there 
only one peak of PBO . In the sample t he peaks are eluted in the following order: Cineri n II, Pyrethrin II, Jasmolin 
II, PBO  followed by Cinerin I, Pyrethrin I, Jasmolin I (total Pyrethrins I).  
E.2 Reagents.  
PBO  Standard , 95%  
Acetonitrile, HPLC grade  
Water, HPLC grade.  
E.3 Apparatus  
A Liquid chromatography System equipped with an auto -sampler, a Variable Wavelength Detector (or 
equivalent) and a Column (Phenomenex, 250 x 4.6 mm Luna Phenyl -Hexyl 5µ Reverse Phase (or equivalent )) 
E.4 Operating Conditions  
Flow rate:  1.5 ml/min  
Composition:  40:60 (%, v/v Water : Acetonitrile)  
Elution:  Isocratic  
Oven Temperature:  40 oC 
Wavelength:  240 nm  
Injection Volume:  15µl 
Stop time:  22 minutes  
Post time:  1 minute  
E.5 Preparation of the Standard  
Weigh 0.050g of the pyrethrum standard to the nearest 0.0001g in a 100 mL volumetric flask and dilute to volume 
with Acetonitrile and label it. Transfer a small portion to a sample vial and label it accordingly.  
 DRS 382: 2018 
15                ©RSB 2018- All rights reserved  
 E.6 Sample preparation  
In a 100 ml volumetric flask, weigh 4.6g to the nearest 0.0001g of the sample to be analysed and dilute to 
volume with Acetonitrile. Sample this solution using a vial and label it accordingly.  Note:  Ensure the solution is 
filtered to avoid damage of the auto -sampler.  
E.7 Procedure  
After the chromatograph is stable, make a minimum of three injections for the standard solution as well as for 
the analyte and average the area counts. The relative Standard Deviation between injections should be within 
2% 
E.8 Calculation of the % PBO (Active Ingredient)  
The % Total Pyrethrins is calculated as follow:  
% 𝐴𝑐𝑡𝑖𝑣𝑒  𝐼𝑛𝑔𝑟𝑒𝑑𝑖𝑒𝑛𝑡𝑠 =𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑆𝑎𝑚𝑝𝑙𝑒  𝑎𝑟𝑒𝑎  𝑥 𝑤𝑒𝑖𝑔 ℎ𝑡 𝑜𝑓 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑥 𝑃𝑢𝑟𝑖𝑡𝑦  𝑜𝑓 𝑡ℎ𝑒 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  (𝑖𝑛 %)
𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑎𝑟𝑒𝑎  𝑥 𝑊𝑒𝑖𝑔 ℎ𝑡 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒 
  
©RSB 2018- All rights reserved                  16 
 Annex  F 
(normative)  
 
Determination of pH value  
F.1 General  
F.1.1  Reagents  
F.1.1.1  Potassium hydrogen phthalate (COOH -C6H4-COOK) 0.05 mol/l (0.05M)  
Dissolve 10.21 g in fr eshly boiled distilled water, an d make up to 1000 ml. Do not keep the solution for longer 
than one month.  
 
F.1.1.2  Disodium tetraborate (Na 2B4O7.10H 2O 0.05) mol/l (0.05)  
 
Dissolve 19.07 g in freshly boiled and cooled distilled  water and make up to 1000 ml. Do not keep the solution 
for longer than one month.  
 
F.1.1.3  Water  
 
Freshly boiled and cooled distilled water of pH 5.5 to 7.0  
 
F.1.2  Apparatus  
 
F.1.2.1  pH meter  
 
F.1.2.2  Glass electrode and reference electrode  
 
F.1.3  Procedure  
 
Operate the pH meter and electrode system inaccordance with the manufacturer’s instructions . Standardize 
the meter and electrodes with the 0.05 mol/l phthalate (pH 4.00) when an acid solution is being measured or 
0.05 mol/l borate when an alkaline solution is being measured (see table F.1). The reading should not differ by 
more than 0.02 pH units from the original value at which the apparatus was standardized. If the difference is 
greater than 0.05, then repeat the measurements.  
 
Check the pH/mV relationship of the glass electrode daily as follows:  
 
Standardize with the 0.05 mol/l (0.05M) phthalate and measure the pH of the 0.05 mol/l borate. If the reading 
is higher by 0.02 or more, or lower by 0.05 or more, than the appropriate value in Ta ble F.1, correct the pH 
values of all solutions measured that day, assuming the potential of the glass electrode to be in a linear 
relationship with the pH of the solution being measured.  
  DRS 382: 2018 
17                ©RSB 2018- All rights reserved  
 Table F.1 – pH values of 0.05 mol/l (0.05M) diosodium tetraborate  
Temperature 
(ºC) 10 15 20 25 30 
pH 9.32 9.28 9.22 9.18 9.14 
Unless otherwise specified, all solutions must be brought to laboratory temperature before measurement.  
The temperature coefficient of the 0.05 mol/l phthalate can be neglected but that of the 0.05 mol/l borate must 
be taken into account (see table F.1).  
When measuring pH values above 10, use a glass electrode designed for use at the alkaline end of the pH 
scale and apply any necessary correction.  
F.2 pH of aqueous dispersions (Method A)  
F.2.1  Reagent  
As for F.1.1  
F.2.2  Apparatus  
As for F.1.2  
Stoppered measuring cylinder 100 ml.  
F.2.3  Procedure  
Weigh 1 g of sample, transfer to the measuring cylinder containing water (about 50 ml), make up to 100 ml with 
water, and shake vigorously for 1 min. All ow any suspension to settle for 1 min and then measure the pH of the 
supernatant liquid.  
F.3 pH of aqueous dispersion (Mathod B*)  
F.3.1  Reagents  
As for F.1.1  
F.3.2  Apparatus  
As for F.1.2 together with:   
©RSB 2018- All rights reserved                  18 
 F.3.2.1  Mixing jar  
A screw cap, glass jar, 295 to 300 ml capacity, substantially cylindrical, approximately 9 cm deep, and without 
abrupt shoulders.  
F.3.2.2  Tumbling machine  
Any mechanical davice for rotating the mixing jar around its centre, end over ent, at 60 rpm.  
F.3.3  Procedure  
Deposite 8 g (wg) of sample o n to distilled water (50 ml) in the mixing jar and allow to stand for 3 min for the 
powder to sink and/or soak undisturbed. Close the jar and tumble it on the machine at 60 rpm for 5 min. dilute 
with distilled water 9185 ml). tumble as before for 1 min. wh en the final  tumbling is complete, allow the 
suspension to stand for 1 h, then measure the pH of the supernatant liquid by the method given in F.1 . DRS 382: 2018 
19                ©RSB 2018- All rights reserved  
 Annex  G 
(normative)  
 
Determination of free acidity or alkalinity  
G.1 Methyl red indicator method  
G.1.1  Reagents  
Use analytical grade reagents unless otherwise specified.  
G.1.1.1  Acetone (CH 3CHOCH 3) 
G.1.1.2  Sodium hydroxide (NaOH)  
0.02 mol/l (0.02 N) standardized solution  
G.1.1.3  Hydrochloric acid (HCl)  
0.02 mol/l (0.02 N) standardized solution  
G.1.1.4  Methyl red indicat or solution  
G.1.2  Apparatus  
G.1.2.1  Measuring cylinder, 50 ml and 100 ml.  
G.1.2.2  Two conical flasks, 250 ml.  
G.1.2.3  Burette, 25 ml.  
G.1.2.4  Bushner filter funnel.  
G.1.2.5  Filter flask, 500 ml.  
G.1.3  Determination for technical material  
G.1.3.1  Procedure  
Weigh (to the nearest 10 mg) about 10 g (w/g) of sample and dissolve in acetone (25 ml), with gentle warning 
if necessary. Add distilled water (75 ml), and titrate immediately with sodium hydroxide solution (t/ml), in the 
presence of methyl red.   
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 Carry out a blank determination on acetone (25 ml) and distilled water (75 ml) with sodium hydroxide ( b ml) 
G.1.3.2  Calculation  
 Acidity, calculated as H 2SO 4 =4.904  𝑥 𝑐1(𝑡−𝑏)
𝑤% 𝑚/𝑚 
Where,  
 b is volume of sodium hydroxide consumed for blank determination;  
 c1 is c(NaOH), mol/l (normality) of the sodium hydroxide solution;  
 t is volume of sodium hydroxide consumed; and  
 w is the weight of sample  
NOTE 1  the blank solution may be alkaline, in which case it should be titrated with the hydrochloric acid (v, ml), then:  
 𝐴𝑐𝑖𝑑𝑖𝑡𝑦 ,𝑐𝑎𝑙𝑐𝑢𝑙𝑎𝑡𝑒𝑑  𝑎𝑠 𝑁𝑎2𝑆𝑂4=4.9.4(𝑡𝑐1+𝑣𝑐2)
𝑤 
 𝑎𝑙𝑘𝑎𝑙𝑖𝑛𝑖𝑡𝑦 ,𝑐𝑎𝑙𝑐𝑢𝑙𝑎𝑡𝑒𝑑  𝑎𝑠 𝑁𝑎𝑂𝐻 =4.001  𝐶2(𝑠−𝑣)
𝑤 
Where,   
C2 is c(HCl), mol/l (normality) of the hydrochloric acid, and  
S is volume of hydrochloric acid cons umed.  
NOTE 2  The method determines the content of free mineral acids and does not necessarily determine all free organic acids.  
G.2  Electrometric procedure  
G.2.1  Reagents  
G.2.1.1  Buffer solution  
Mix acetic acid (100 ml or 2 mol/l solution) and sodium hydroxide (1oo ml of 1 mol/l solution) and make up to 
1000 ml with de -mineralized water. Determine the apparent pH, at 20 ºC, of a mixture of acetone (50 ml) and 
the buffer solution (5 ml) with the el ectrodes and pH meter to be used in the titration.  
G.2.1.2  Acetone (CH 3COCH 3) DRS 382: 2018 
21                ©RSB 2018- All rights reserved  
 G.2.1.3  Sodium hydroxide (NaOH)  
0.02 mol/l (0.02N) standardized solution  
G.2.1.4  Hydrochloric acid (HCl)  
0.02 mol/l (0.02 N) standardized solution  
G.2.2  Apparatus  
G.2.2.1  Conical  flask 200 ml  
G.2.2.2  Filter flasks 250 and 500 ml  
G.2.2.3  Buchner funnel  
G.2.3  Determination for technical materials  
G.2.3.1  Procedure  
Dissolve the material (10 g0 in acetone (50 ml; Note 3) in the titration vessel of the pH meter. Add distilled water 
(5ml) and titrate electrometrically with sodium hydroxide to the apparent pH of the acetone/buffer mixture at 20 
ºC (t ml). 
NOTE 3  Some technical pr oducts may require more solvent to prevent precipitation during totration. For these products 
use 100 ml of acetone and 10 ml of water.  
G.2.3.2  Calculation  
 Acidity, calculated as H 2SO 4 = 0.4904.t.c 1 % m/m  
Where,  
 C1 is c(NaOH), mol/l (normality) of the sodium hydroxide solution  
  
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  DRS 382: 2018 
23                ©RSB 2018- All rights reserved  
 Bibliography  
[1] KS 03 -653, Household insecticidal aerosols  — Specification  
[2] ES 757, Pesticides — Determination of pH value  
[3] ES 757, Pesticides — Determination of free acidity and alkalinity  DRS 382: 2018 
ICS 65.100.10  
 
 
©RSB 2018- All right s reserved