Reference number  
DRS 393 -6: 2018  
© RSB 2018  
 
 
 RWANDA 
STANDARD  DRS  
393-6 
 
First edition  
2018 -mm-dd 
 
Spatial application mosquito repellents — 
Specification  — 
Part 6: 
Vaporiz ing mats 
  DRS 393 -6: 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  
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Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rs b.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 393 -6: 2018  
iii                ©RSB 2018  - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Symbols and abbreviated terms  ................................ ..................  Error! Bookmark not defined. 2 
5 Requirements  ................................ ................................ ................................ ..............................  32 
5.1 General  ................................ ................................ ................................ ................................ ........  32 
5.2 Active ingredi ents ................................ ................................ ................................ ......................  32 
5.2.1  Natural repellents  ................................ ................................ ................................ .......................  32 
5.2.2 Synthetic repellents  ................................ ................................ ................................ ...................  43 
5.3 Physical requirements  ................................ ................................ ................................ ...............  54 
5.3.1  Size of mat  ................................ ................................ ................................ ................................ ... 54 
5.3.2  Evaporation rate  ................................ ................................ ................................ .........................  54 
5.4 Storage stability  ................................ ................................ ................................ ..........................  54 
5.5 Biological efficacy  ................................ ................................ ................................ ......................  54 
6 Packaging and labelling ................................ ................................ ................................ .............  54 
6.1 Packaging  ................................ ................................ ................................ ................................ .... 54 
6.2 Labelling  ................................ ................................ ................................ ................................ ...... 54 
7 Sampling  ................................ ................................ ................................ ................................ ..... 65 
Annex  A (normative)  Determination of allethrin content  ................................ ................................ ... 76 
A.1 Principle  ................................ ................................ ................................ ................................ ...... 76 
A.2 Apparatus  ................................ ................................ ................................ ................................ .... 76 
A.3 Reagents  ................................ ................................ ................................ ................................ ..... 76 
A.4 Procedure  ................................ ................................ ................................ ................................ .... 76 
A.4.1  Extraction  ................................ ................................ ................................ ................................ .... 76 
A.4.2  Prepar ation of Internal standard Solution  ................................ ................................ ...............  76 
A.4.3  Preparation of Sample Solution  ................................ ................................ ................................  87 
Annex  B (normative)  Determination of DEET  ................................ ................................ ......................  98 
B.1 General  ................................ ................................ ................................ ................................ ........  98 
B.2 Apparatus  ................................ ................................ ................................ ................................ .... 98 
B.3 Preparation of calibration curve  ................................ ................................ ...............................  98 
B.4 Procedure  ................................ ................................ ................................ ................................ .... 98 
B.5 Calculation  ................................ ................................ ................................ ................................  109 
Annex  C (normative)  Determination of permethrin  ................................ ................................ .........  1110 
C.1 Reagents  ................................ ................................ ................................ ................................ . 1110 
C.2 Apparatus  ................................ ................................ ................................ ................................  1110 
C.3 Operating conditions  ................................ ................................ ................................ .............  1110 
C.4 Procedure  ................................ ................................ ................................ ................................  1110 
C.5 Calculation  ................................ ................................ ................................ ..............................  1211 
 DRS 393 -6: 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 o f 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 393 -6 was prepared by Technical Committee RSB/TC 015, Pharmaceutical Products . 
In the preparation of this standard, reference was made to the following standard:  
1) IS 13439, Allethrin ― Mosquito Mats ― Specification  
The assistance de rived from the above source is hereby acknowledged with thanks.  
DRS 393  consists of the following parts, under the general title : Spatial application mosquito repellents — 
Specification : 
 Part 1: Coils  
 Part 2: Spray  
Part 3: Candles  
Part 4: Papers  
Part 5: Liquid vaporizers  
Part 6: Vaporizing m ats 
 Part 7: Tablets  
 Part 8: Liquid detergents  
Committee membership  
The following organizations were represented on the Technical Committee on Pharmaceutical Products 
(RSB/TC 015) in the preparation of this standard.  
National Industrial Research and Development Agency (NIRDA)  
National Pharmacy Council (NPC)  
University of Rwanda/College of Sciences and Technology (UR/CST)  DRS 393 -6: 2018  
v                ©RSB 2018  - All rights reserved  
 Pharmacie NOVA  
Rwanda Development Board (RDB)  
AGROPY LTD  
IKIREZI NATURAL PRODUCTS  
HORIZON/SOPYRWA  
Rwanda Social Security Board (RSSB)  
Pharmavie  
University of Rwanda/College of Medicine and Health Sciences (UR/CMHS)  
Rwanda Biomedical Center/ Malaria and Other Parasitic Diseases Division  (RBC/MOPDD)  
Society for Family Health  (SFH) – Rwanda  
Rwanda Biomedical Center/Medical Procurement and Production Division (RBC/MPPD)  
Institut d’Enseignement Superieur (INES) - RUHENGERI  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 393 -6: 2018  
©RSB 2018 - All rights reserved                  vi 
 Introduction  
Insecticides are used either for killing or controlling harmful insects. The insecticides which are applied for 
repelling inse cts are termed as “Repellents". Mosquito is one of the most harmful insects for mankind. To destroy 
them, many preparations are available on the market in various recipes like pest killer spray, soap, oil, powder, 
repellent etc. Out of these, mosquito repe llents is the most popular as it has germicidal and disinfectant 
properties and is able to repel mosquitoes and is convenient to use.  
 
The mosquito repellent is used for warding off mosquitoes which is the most harmful insect. Nowadays, 
mosquito repellents  are used for controlling mosquito and are complimenting  other mosquito destroyers 
gradually. With the rise in the standard of living, increasing urbanization and population, the demand of mosquito 
repellent mat is constantly increasing particularly in tropical places. It is a convenient method for protection 
against mosquito, so it has a tremendous market potential. Thus , there is a very good scope for development 
of such units in the country . 
Spatial repellent are chemical products designed to be 'acti ve' (requiring heat or electricity) or 'passive' (requiring 
no heat or electricity) and  release volatile chemicals into the air  within the treated space. Product examples that 
are currently available  include mosquito coils, spray, candles , papers, liquid v aporizers, vaporizing mats, tablet 
and liquid detergents,  among others . However, many more  types of spatial repellent products are waiting to 
be developed.   
Spatial repellents elicit ‘spatial repellency’ which refers to a range of insect behavio urs induced  by airborne 
chemicals that result in a reduction in human -mosquito contact.  These behavio urs include movement away from 
a chemical stimulus, attraction -inhibition and/or, and feeding inhibition.  
 DRS 393 -6: 2018  
1                ©RSB 2018  - All rights reserved  
 Spatial application mosquito repellents  — Specification  — Part 6: 
Vaporiz ing mats 
1 Scope  
This Draft Rwanda S tandard prescribes the requirements and test methods for spatial application mosquito 
repellents formulated and prepared as mosquito vaporizing mat s. 
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 referenced document (including any amendments) applies.  
RS 337 -1, Mosquito repellents  — Specif ication —Part1: Mats containing allethrin  
RS 91, Labeling and marking of pharmaceutical products — Specification  
RS 191, Refined pyrethrum concentrate — Specification  
AOAC 973.12, d-trans -Allethrin in pesticides formulations  
CIPAC 741, Determination of transfluthrin content  
CIPAC 743 , Determination of prallethrin (etoc) content  
CIPAC 993, Determination of Metofluthrin (S1264)  
CIPAC 742, Determination of d -allethrin  
CIPAC 977, Determination of Meperfluthrin  
CIPAC 760, Determination of picaridin  
RS ISO 24153, Random sampling and randomization procedures  
3 Terms and definitions  
For the purposes of this standard, the terms and definitions given in RS 337 -1 and the following apply.   
©RSB 2018 - All rights reserved                  2 
 3.1 
vaporizing mat  
made from fibreboard impregnated with active ingredi ents with the aim to repel mosquito es by heating  
3.2 
mosquito  
any of numerous arthropod animals of the class mosquito, having an adult stage characterized by three pairs 
of legs and a body se gmented into head, thorax, and abdomen and usually having one or two pairs of wings.  
3.3 
mosquito repellent  
substance applied to skin, clothing, or other surfaces which discourages mosquito  (and arthropods  in general) 
from landing or climbing on that surface  
3.4 
picaridin  
1-(1-methylpropoxycarbonyl) -2-(2-hydroxyethyl) piperidine or 2 -(2-hydroxyethyl) -1-piperidinecarboxylic  acid 1 -
methylpropyl ester  
 
3.5 
Transfluthrin  
(1R,3S)-3-(2,2-Dichlorovinyl) -2,2-dimethyl -1-cyclopropanecarboxylic acid (2,3,5,6 -tetrafluorophenyl)methyl 
ester  
3.6 
Etoc  
Prallethrin. (S)-2-methyl -4-oxo-3-prop-2-ynylcyclopent -2-enyl(1R) -cis, trans -2,2-dimethyl -3-(2-methylprop -1-
enyl) cyclopropanecarboxylate  
3.7 
Metofluthrin  
C18H20F4O3 , 2,3,5,6-Tetrafluoro -4-(methoxymethyl)benzyl 2,2 -dimethyl -3-(prop -1-en-1-yl) 
cyclopropanecarboxylate  DRS 393 -6: 2018  
3                ©RSB 2018  - All rights reserved  
 3.8 
d-Alethrin  
(RS)-3-allyl-2-methyl -4-oxocyclopent -2-enyl (1R) -cis, trans -chrysanthemate  
3.9 
Meperfluthrin  
C17H16Cl2F4O3, [2,3,5,6 -tetrafluoro -4-(methoxymethyl)phenyl]methyl (1R,3S) -3-(2,2-dichloroethenyl) -2,2-
dimethylcyclopropane -1-carboxylate  
4 Requirements  
4.1 General  
The vaporising mat shall consist of a pulp -made mat, or a mat made of other suitable inert materials, 
impregnated with a  mosquito repellent .  
NOTE  Stabilisers, synergists, slow -release agents, perfumes and colouring agents may be added. The mat is intended 
for use in a heating unit designed to produce slow volatilisation of the active ingredient.  
4.2 Active ingredient s 
4.2.1  Natural repellents  
5.2.1.1  Active ingredients used in natural repellents shall be natural plant based active ingredients  such as 
essential oils or any other  plant extract approved as mosquito repellents.  
5.2.1.3  The manufacturer  shall provide adequate data on the repellence /efficacy  of such ingredients /product . 
5.2.1.4  The manufacturer  shall have adequate data justifying the  proportion of ingredient(s) for which claims 
are made, used in the product.  
5.2.1.5  The essential oils and other plant extracts used in natural repellents shall be, but not limited to:  
a) Cedarwood oil ; 
b) Tea tree oil ; 
c) Geranium oil ; 
d) Rosemary oil ;  
©RSB 2018 - All rights reserved                  4 
 e) Lemongrass oil; 
f) Citronella oil ; 
g) Soybean oil;  
h) Eucalyptus oil ;  
i) Cinnamon oil ; and  
j) Neem oil.  
5.2.1.6 The proportion of single or blended essential oil in natural repellent shall be set by the manufacturer in 
accordance with specific standard  (s) of the essential oil used  and records shall be availed.  
5.2.1.7 Pyrethrum extracts such as pyrethrin s shall be considered in natural repellents. The limits of pyrethrin s 
in natural repellents shall not be less than 0.5 % and the extract used shall mee t the requirements of RS 191.     
4.2.2  Synthetic repellents  
5.2.2.1  Synthetic repellents shall contain synthetic chemical compounds which are able to discourage 
mosquitoes and send them flying or crawling away.  
5.2.2.2  If the synthetic chemical compound is blen ded with other active ingredient (s), either natural or 
synthetic, the proportion shall be set by the manufacturer based on scientific research and records shall be 
availed.  
5.2.2.3  Active ingredients and their content in synthetic repellents shall meet th e requirements prescribed in 
table 1.  
Table 1 — Active ingredients content for synthetic repellents  
S/N Active ingredient  % w/w  Limits  (%, w/w)  Identification method  
1 Picaridin  0.2 – 5 CIPAC 740  
2 DEET  5 – 50 Annex B 
3 Permethrin, max  13 Annex C  
4 Transfluthrin , max  1 CIPAC 741  
5 Etoc 0.5 – 1.5 CIPAC 743  
6 Metofluthrin  (S1264) , max  1.82 CIPAC 993  
7 d-Alethrin  (Pynamin Forte), max  0.5 Annex A  
8 Meperfluthrin , max  0.05 – 0.1 CIPAC 977  
 
5.2.2.4  Synthetic repellents and their active ingredients shall be approved and registered by competent 
authority.  DRS 393 -6: 2018  
5                ©RSB 2018  - All rights reserved  
 4.3 Physical requirements  
4.3.1  Size of mat  
The size of the mat sh all be compatible with the associated heater.  
4.3.2  Evaporation rate  
After heating the mat on the appropriate heating unit for 4 h, a minimum of 20% of the active ingredient content 
shall remain.  
4.4 Stability  
Stability at elevated temperature : After storage at 54 ºC ±2ºC for 14 days, the average active ingredient 
content shall not decline to less than 95% of the average content measured prior to the test, and relevant 
physical properties shallnot change to an extent that might adversely affect the effectiveness  and safety.  
 
4.5 Biological efficacy  
When tested in accordance with DRS 394-2, the product shall repel 100 % of the mosquitoes available in space, 
within  protection time indicated by the manufacturer.  
5 Packaging and labelling  
5.1 Packaging  
Each mat shall be packaged individually in laminated polyester film or metal foils. The packed mats shall 
appear in strip form. Thirty packaged mat s shall be further packed in duplex -board box.  
5.2 Labelling  
The containers shall be securely closed and in addition to the labelling requirements of RS 91, the following 
information shall be  legibly  and indelibly marked on the container:  
 
a) name of the product ; 
b) indication of the source of manufacture;  
c) batch number;  
d) date of manufacture;  
e) date of expiration;  
f) total number of mats in the box;   
©RSB 2018 - All rights reserved                  6 
 g) active ingredient  content;  
h) protection time;  
i) directions for use;  
j) special p opulation  whose exposure is prohibited (children and pregnant women) ; and 
k) each mat shall bear the name or the manufacturer, brand name and trade mark.  
6 Sampling  
Random samples of the product shall be drawn for test in accordance with RS ISO 24153 f rom the market, 
factory  or anywhere else . 
 DRS 393 -6: 2018  
7                ©RSB 2018  - All rights reserved  
 Annex  A 
(normative)  
 
Determination of allethrin content  
A.1 Principle  
Allethrin is extracted with a mixture of tolueneand formic acid from the coil and then a nalyze extract using gas 
chromato graphy - followed by flameionizat ion detector ( GC-FID).  
A.2 Apparatus  
A.2.1 Centrif uge with 50 cm tubes  
A.2.2 Mechanical shaker  
A.2.3 Microlitre  syringe 5-10µl capacity  
A.3 Reagents  
A.3.1 Toluene  
A.3.2 Formic acid - 99 % (v/v) 
A.3.3 Sodium sulphate - anhydrous  
A.3.4 Internal standard - dibutyl  phthalate,analytical reagent  grade,  
A.3.5 Activated charcoal  
A.4 Procedure  
A.4.1  Extraction  
Accurately weigh 10g finely powdered mosquito coil sample in a 250m L Erlenmeyer flask fitted with a glass 
stopper and add 44mL toluene and 5 mL formic acid. Stopper the flask and shake the contents on a mechanical 
shaker for 30 min. Add 15  g -20 g anhydrous sodium sulphate and 2  g -3 g activated charcoal and continue 
shaki ng for another 10 min.Transfer the contents to a 50-mLcentrifuge tube and centrifuge at 2500  rotations per 
minute for 10 min.  
A.4.2  Preparatio n of Internal standard Solution  
Weigh accurately 1·0 g dibutyl phthalate in a 100 -mLvolumetric flask and make up the vol ume to mark with 
toluene. This will give a solution containing 10 mg/mL of dibutyl phthalate.   
©RSB 2018 - All rights reserved                  8 
 A.4.3  Preparation of  Sample Solution  
Take 9 mL supernatant solution ( A.4.1) into a10 -mLvolumetric flask, add 1 mL of internal standard solution and 
mix the  contents thoroughly.  
 
  DRS 393 -6: 2018  
9                ©RSB 2018  - All rights reserved  
 Annex  B 
(normative)  
 
Determination of DEET  
B.1 General  
The sample is dissolved in carbon disulfide and the difference in absorbance at 14.18 µm and at 14.48 µm is 
determined. The quantity of meta -isomer is obtained from this value by means of  a calibration curve prepared 
by the use of a reference standard.  
B.2 Apparatus  
B.2.1 Double -beam infrared spectrophotometer. Perkin -Elmer model 21 or equivalent.  
B.2.2 Two equivalent infrared absorption cells, with sodium chloride windows and a path length of  
approximately 0.4 mm.  
B.3 Preparation of calibration curve  
B.3.1 Weigh (to the nearest 0.1 mg) into four volumetric flasks sufficient amounts of the reference DEET 
standard of known  purity to give concentrations of approximately 20, 40, 60 and 80 g/L when dissolved in carbon 
disulfide.  
B.3.2 Fill the reference cell with carbon disulfide and the sample cell with each of the standard solutions in 
turn, and record the spectra. The spect rum may be scanned rapidly, except for the region 12 – 15 µm, where a 
normal speed should be used. Carry out a blank measurement with carbon disulfide to correct for any inequality 
in the paired cells and to determine whether a cell correction is required.  
B.3.3 Measure the absorbance at 14.18 µm and at 14.48 µm and calculate the difference between these 
value s, ΔA, for each of the solutions. Plot the values of ΔA against the concentration (g/l) of the meta -isomer.  
 
B.3.4 If a cell correction is required, the value of ΔA is determined from the formula:  
 
  ΔA = [A 14.18 – A14.48]ref. - [A14.48]blank 
 
  Where ref. = determination with reference standard  
    blank = determination on CS 2 blank  
 
B.4 Procedure  
Weigh (to the nearest 0.1 mg) about 0.5 g of the sample, transfer quantitatively to a 10 mL volumetric flask, 
and make up to the mark with carbon disulfide. Measure the infrared absorption at 14.18 μm and 14.48 μm 
using the same conditions as described in section A.3. Determine the concentration of meta -isomer by 
comparing this value with the calibration curve. A standard sample should be run each day to check the 
calibration of the instrument.   
©RSB 2018 - All rights reserved                  10 
 B.5 Calculation  
DEET content (g/kg) =𝐶1 𝑥 𝑃 
𝐶2 
Where,  
 C1 = con centration (g/L) of standard DEET found from calibration curve  
 C2 = concentration (g/L) of sample taken  
   P = purity (g/kg) of the reference standard.  DRS 393 -6: 2018  
11                ©RSB 2018  - All rights reserved  
 Annex  C 
(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.  
C.1 Reagents  
Cis – Permethrin, 99%  
Trans - Permethrin, 99%  
Methanol HPLC grade  
Water, HPLC grade  
C.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 equivalent)  
C.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  
 
C.4 Procedure  
C.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.  
C.4.2 Preparation of Solution   
©RSB 2018 - All rights reserved                  12 
 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.  
C.4.3 Determination  
After the chromatograph is stable, make a minimum of three inject ions of the standard as well as for the sample 
and average the area counts. The relative standard deviation between injections should be within 2%.  
C.5 Calculation  
The % of either cis or trans isomers is calculated as follows;  
% 𝑐𝑖𝑠 𝑜𝑟 𝑡𝑟𝑎𝑛𝑠  𝑝𝑒𝑟𝑚 𝑒𝑡ℎ𝑟𝑖𝑛 =𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑠𝑎𝑚𝑝𝑙𝑒  𝑎𝑟𝑒𝑎 ×𝑤𝑒𝑖𝑔 ℎ𝑡 𝑜𝑓 𝑠𝑡𝑑 ×𝑝𝑢𝑟𝑖𝑡𝑦 (𝑖𝑛%)
Average  std area  × weight  of sample 
Report the concentration of permethrin as the total of Cis and Trans . 
 DRS 393 -6: 2018  
13                ©RSB 2018  - All rights reserved  
 Bibliography  
[1] Manual on development and use of FAO and  WHO specifications for pesticides, November 2010, 2nd 
Edition.  
[2] Official Methods of Analysis of AOAC International, 19th Edition, 2012, volume I  
 
 DRS 393 -6: 2018  
ICS 65.100  
 
 
©RSB 2018  - All right s reserved