Reference number  
DRS 393 -3: 2018  
© RSB 2018  
 
 
 RWANDA 
STANDARD  DRS  
393-3 
 
First edition  
2018 -mm-dd 
 
Spatial application mosquito repellents  — 
Specification  — 
Part 3: 
Candles  
  DRS 393 -3: 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 393 -3: 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  ................................ ................................ ................................ ................................  3 
4.1 General  ................................ ................................ ................................ ................................ ..........  3 
4.2 Active Ingredients  ................................ ................................ ................................ ........................  4 
4.2.1  Natural repellents  ................................ ................................ ................................ .........................  4 
4.2.2  Synthetic repellents  ................................ ................................ ................................ .....................  5 
4.3 Performance requirements  ................................ ................................ ................................ ..........  5 
4.4 Biological efficacy  ................................ ................................ ................................ ........................  6 
5 Packaging and labelling ................................ ................................ ................................ ...............  6 
5.1 Packaging  ................................ ................................ ................................ ................................ ...... 6 
5.2 Labelling  ................................ ................................ ................................ ................................ ........  6 
Annex  A (normati ve)  Determination of mean horizontal luminous intensity (MHLI) .........................  8 
A.1 Principle  ................................ ................................ ................................ ................................ ........  8 
A.2 Apparatus  ................................ ................................ ................................ ................................ ...... 8 
A.3 Procedure  ................................ ................................ ................................ ................................ ...... 8 
Annex  B (normati ve)  Determination of breaking stress of candle  ................................ ......................  9 
B.1 Principle  ................................ ................................ ................................ ................................ ........  9 
B.2 Procedure  ................................ ................................ ................................ ................................ ...... 9 
B.3 Calculation  ................................ ................................ ................................ ................................ .... 9 
Annex  C (norma tive)  Determination of deflection  ................................ ................................ ..............  10 
C.1 Apparatus  ................................ ................................ ................................ ................................ .... 10 
C.2 Procedure  ................................ ................................ ................................ ................................ .... 10 
Annex  D (normative)  Determination Bending tendency  ................................ ................................ ..... 11 
Annex  E (normative)  Determination of DEET content  ................................ ................................ ........  12 
E.1 General  ................................ ................................ ................................ ................................ ........  12 
E.2 Apparatus  ................................ ................................ ................................ ................................ .... 12 
E.3 Preparation of calibration curve  ................................ ................................ ...............................  12 
E.4 Procedure  ................................ ................................ ................................ ................................ .... 12 
E.5 Calculation  ................................ ................................ ................................ ................................ .. 13 
Annex  F (normative)  Determination of permethrin  ................................ ................................ .............  14 
F.1 Reagents  ................................ ................................ ................................ ................................ ..... 14 
F.2 Apparatus  ................................ ................................ ................................ ................................ .... 14 
F.3 Operating conditions  ................................ ................................ ................................ .................  14 
F.4 Procedure  ................................ ................................ ................................ ................................ .... 14 
F.5 Calculation  ................................ ................................ ................................ ................................ .. 15 
 DRS 393 -3: 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 ratifie d by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS 393 -3 was prepared by Technical Committee RSB/TC 015, Pharmaceutical Products . 
In the preparation of this standard, reference was made to the following standard s: 
1) IS 11359, Specification for wax candles  
2) KS 1265, Specification for paraffin wax candles for illuminating purposes  
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: Vaporiz ing mats  
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)  DRS 393 -3: 2018  
v                ©RSB 2018 - All rights reserved  
 University of R wanda/College of Sciences and Technology (UR/CST)  
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)  
INES - RUHENGERI  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 393 -3: 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 insects are termed as “Repellents". Mosquito is one of the most harmful insects for mankind. To destro y 
them, many preparations are available on the market in various recipes like pest killer spray, soap, oil, powder, 
repellent etc. Out of these, mosquito repellent is the most popular as it has germicidal and disinfectant properties 
and is able to repel mo squitoes 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 mar ket potential. Thus there is a very good scope for development of 
such units in the country . 
Spatial repellent are chemical products designed to be 'active' (requiring heat or electricity) or 'passive' (requiring 
no heat or electricity) and  release volatil e chemicals into the air  within the treated space. Product examples that 
are currently available  include mosquito coils, spray, candles , papers, liquid vaporizers, vaporizing mats, tablet s 
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 includ e: movement away 
from a chemical stimulus, attraction -inhibition and/or, and feeding inhibition.  
 DRS 393 -3: 2018  
1                ©RSB 2018 - All rights reserved  
 Spatial application mosquito repellents  — Specification  — Part 3: 
Candles  
1 Scope  
This Draft Rwanda S tandard prescribes the requirements , sampling and test methods  for spatial application 
mosquito repellents formulated and prepared as candles . 
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 91 , Labelling and marking of pharmaceutical products — Specification  
RS 191 , Refined pyrethrum concentrate ― Specification  
DRS 394-2, Mosquito repellents ― Performance Test Guidelines ― Part 2: Spatial  repellents  
AOAC 986.03, Permethrin in pesticide formulations  
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  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply . 
3.1 
mosquito   
©RSB 2018 - All rights reserved                  2 
 any of numerous arthropod animals of the  class mosquito, having an adult stage characterized by three pairs 
of legs and a body segmented into head, thorax, and abdomen and usually having one or two pairs of wings.  
3.2 
mosquito repellent  
a substance applied to skin, clothing, or other surfaces w hich discourages mosquito  (and arthropods  in general) 
from landing or climbing on that surface  
3.3 
candle  
block of wax or tallow with a central wick which is lit to produce light as it burns.  
3.4 
natural repellents/biopesticides  
repellents that contain natural, plant -based active ingredients  
3.5 
synthetic repellents  
conventional repellents containing synthetic chemical act ive ingriedients and carrier synthetic chemical 
compounds as approved by a competent authority  
3.6 
Transfluthrin  
(1R,3S)-3-(2,2-Dichlorovinyl) -2,2-dimethyl -1-cyclopropanecarboxylic acid  (2,3,5,6 -tetrafluorophenyl)methyl 
ester  
3.7 
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  
3.8 
Metofluthrin  DRS 393 -3: 2018  
3                ©RSB 2018 - All rights reserved  
 C18H20F4O3 , 2,3 ,5,6-Tetrafluoro -4-(methoxymethyl)benzyl 2,2 -dimethyl -3-(prop -1-en-1-yl) 
cyclopropanecarboxylate  
3.9 
d-Alethrin  
(RS)-3-allyl-2-methyl -4-oxocyclopent -2-enyl (1R) -cis, trans -chrysanthemate  
3.10 
Meperfluthrin  
C17H16Cl2F4O3, [2,3,5,6 -tetrafluoro -4-(methoxymethyl)phenyl]methyl (1R,3S) -3-(2,2-dichloroethenyl) -2,2-
dimethylcyclopropane -1-carboxylate  
3.11 
PBO  
Piperonyl butoxide  
3.12 
MGK 264  
N-octyl Bicycloheptene Dicarboximide  
4 Requirements  
4.1 General  
4.1.1  The product shall be clean, free from dirt and foreign matter, uniform, free from fracture (breaks) and 
distortions (warps, sags, runs, two or more fused together) and free from trapped air bubbles.  
4.1.2  The product shall be solid and made from wax (paraffin, soy and bees) with a melting point in the range 
of 49 ºC to 82 ºC.  
4.1.3 The product shall consist of active ingredients,  together with organic fillers capable of smouldering 
well, a binder and additives such as synergists, dye and fungicide, f ormulated in the form of a candle . 
4.1.4 The wick shall be properly centred and shall not be visible along the shaft of the candle. The wick shall 
be visible on the bottom of the candle and shall extend the entire length of the candle at least 6 mm beyond the 
tip.  
©RSB 2018 - All rights reserved                  4 
 4.1.4  The finished product shall be free from unpleasant odour (pungent and unsavoury) during burning and 
non-burning. The flame shall be non -smoking and non -sputtering.  
4.2 Active Ingredients  
4.2.1  Natural repellents  
5.2.1.1  Active ingredients used in natu ral repellents shall be natural plant based compounds 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.  
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 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 ; 
e) Lemongrass oil ; 
f) Citronella oil ; 
g) Soybean oil;  
h) Eucalyptus oil ; 
i) Cinnamon oil ; and  
j) Neem oil  
5.1.2.6  The proportion of single or blended essential oil in natural repellent shall be set by the manufacturer in 
accordance with spe cific standard  (s) of the essential oil used and records shall be availed.  
5.1.2.7  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 meet the requirements of RS 191.     DRS 393 -3: 2018  
5                ©RSB 2018 - All rights reserved  
 4.2.2  Synthetic repellents  
5.2.2.1  Synthetic repellents shall contain synthetic chemical compounds which are able to discourage 
mosquitoes and sen d them flying or crawling away.  
5.2.2.2  If the synthetic chemical compound is blended 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 the requirements prescribed in 
table 1.  
Table 1 — Active ingredients content for synthetic repellents  
S/N Active ingredient   Limits  (%, w/w)  Identification method  
2 Picaridin  0.2 – 5 CIPAC 740  
3 DEET  5 – 50 Annex E 
4 Permethrin, max  13 Annex E 
5 Transfluthrin , max  1 CIPAC 741  
6 Etoc 0.5 – 1.5 CIPAC 743  
7 Metofluthrin  (S1264) , max  1.82 CIPAC 993  
8 d-Alethrin  (Pynamin Forte), max  0.5 CIPAC 742  
9 Meperfluthrin, max  0.05 – 0.1 CIPAC 977  
10 Synergists  As declared  AOAC 997.07  
 
5.2.2.4  Synthetic repellents and their active ingredients shall be approved and registered by competent 
authority.  
4.3 Performance  requirements  
5.3.1 The performance requirement for candles  shall be as given in Table 1 when tested  as prescribed  
in Table 2. 
 
 
Table 2 — Performance requirements  
S/N Parameters  Requirement s Test method  
(i) Mean horizontal luminous 
intensity, cd, min.  1.5 Annex A 
(ii) Lighting efficiency, cd/g/h , min.  0.15 Annex A 
(iii) Drip Nil Visual  
(iv) Smoking  Absent  Visual  
(v) Breaking stress, kN/m2, min.  1500  Annex B 
(vi) Bending tendency  Nil Annex D  
(vii) Deflections, angular degrees, 
max. 3 º  Annex C  
©RSB 2018 - All rights reserved                  6 
 (viii) Duration of burning, min.  1 h Visual  
 
4.4 Biological efficacy  
5.4.1  When tested in accordance with DRS 394 -2, the product shall have repelled 100 % of the 
mosquitoes available in space, after protection time indicated by the manufacturer.  
5.4.2  The protection time of the product shall be indicated on the label.  
5 Packaging and labelling  
5.1 Packaging  
The candles shall be pack aged in such a manner as not to compromise their quality.  
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) name and full address of the manufacture;  
c) batch number;  
d) date of manufacture and expiry;  
e) total number of c andles  in the box;  
f) active ingredient content ; 
g) protection time;  
h) net mass of content ; 
i) directions for use;  
j) safety caution ; 
k) special population whose exposure is prohibited  (children and pregnant women) ; 
l) ; and  DRS 393 -3: 2018  
7                ©RSB 2018 - All rights reserved  
 m) storage conditions.  
 
  
©RSB 2018 - All rights reserved                  8 
 Annex  A 
(normative)  
 
Determination of mean horizontal luminous intensity (MHLI)  
A.1 Principle  
The mean horizontal luminous intensity of the burning candles is measured against a metal filament, sub -
standard electric lamp mounted on a sub -standard photometer bench, with suitable form of photometer head.  
A.2 Apparatus  
Photometric equipment  
A.3 Procedure  
A.3.1  Mount the test candle on a candle stand straight, placed on a table fixed on one of the carriages of the 
photometer bench.  The candle shall be lit and kept burning free from draught for 10 min.  
A.3.2  It shall then be extinguished and weigh ed with candle stand. The candle shall be relit and kept burning 
for 5 min to attain steady state condition, free from draughts. The middle portion of the flame photometer head 
and sub -standard electric lamp shall be in the same horizontal plane and the ph otometer head shall be placed 
perpendicular to the incident light from the flame.  
A.3.3  The sub -standard lamp and the photometer head shall be kept at any convenient position on the bench.  
A.3.4  The burning shall be moved to and from one side of the photom eter head until the position of balance 
is reached. Measurement shall be made in a horizontal plane by changing the position of the candle in four 
directions at the right angles to the axis of the candle differing by 90 degrees . A number of readings in eac h 
direction shall be taken and the average of all these measurements in four directions shall be the mean 
horizontal luminous intensity (MHLI).  Duration of complete burning, smoking tendency of the flame in the initial 
burning for 10 minutes and dripping,  if any, shall also be observed.  
Lighting efficiency shall be calculated as follows:  
Lighting efficiency, cd/g/h = 
)/()() ( int min
hgn consumptio Waxcd MHLI ensity ous lu horizontal Mean  
 
  DRS 393 -3: 2018  
9                ©RSB 2018 - All rights reserved  
 Annex  B 
(normative)  
 
Determination of breaking stress of candle  
B.1 Principle  
The breaking stress of the candle is determined with the help of a test ring  
B.2 Procedure  
The candle is supported at two ends and tied at the middle with a thread passing over a pulley and attached to 
a pan for applying load. The mass in the pan shall be added gradually. The load at which the candle breaks  
from the centre is noted.  
B.3 Calculation  
The breaking stress of the candle is calculated as follows:  
Breaking stress, kN/m2 = 
280
DgWL  
 where,  
  W     =     the force applied in N;  
  L      =     the distance between the supporting ends in m;  
  D     =     the diameter of the candle in m;  
  g     =     the gravitational force.   
©RSB 2018 - All rights reserved                  10 
 Annex  C 
(normative)  
 
Determination of deflection  
C.1 Apparatus  
C.1.1  Deflection tester – Consisting of an accurate protractor chart marked off at each 10 degrees, with the 
first 10 d egrees sub -divided into 10 equal parts.  A suitable clamp arrangement shall be used to hold the candle 
and protractor chart.  The protractor shall be in a vertical position . 
C.1.2  Constant temperature cabinet – Large enough to hold the deflection tester or  assembly and shall be 
capable of maintaining a temperature of 35 °C ± 1 °C throughout the cabinet, continuously for 24 h.  
C.2 Procedure  
C.2.1  The candle shall be placed in the deflection tester above the top of the clamp.  The candle shall be at 
an angle of 5  degrees  from the vertical, and so placed that an angular deflection of the specimen can be 
accurately noted on the protractory chart.  The assembly shall be placed in the constant temperature cabinet 
maintained at 35 °C ± 1 °C.  Allow to remain at this te mperature for 24 h with periodic observation for possible 
failure -deflection.  
C.2.2  Record the angular deflection.  The angular deflection shall be considered as the increase from the 
initial 5 -degree position.  DRS 393 -3: 2018  
11                ©RSB 2018 - All rights reserved  
 Annex  D 
(normative)  
 
Determination Bending tendency  
Bending tendency of the candle shall be determined by suspending the candle horizontally with one end fixed 
and kept in an air oven at 40 °C for 24 h with periodic observations for possible failure    
©RSB 2018 - All rights reserved                  12 
 Annex  E 
(normative)  
 
Determination  of DEET content  
E.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.  
E.2 Apparatus  
D.2.1  Double -beam infrared spectrophotometer. Perkin -Elmer model 21 or equivalent.  
D.2.2  Two equivalent infrared absorption cells, with sodium chloride windows and a path length of 
approximately 0.4 mm.  
E.3 Preparation of calibration curve  
D.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.  
D.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 spectrum 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 disulf ide to correct for any inequality 
in the paired cells and to determine whether a cell correction is required.  
D.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.  
 
D.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 standar d 
    blank = determination on CS 2 blank  
 
E.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.  DRS 393 -3: 2018  
13                ©RSB 2018 - All rights reserved  
 E.5 Calculation  
DEET content (g/kg) =𝐶1 𝑥 𝑃 
𝐶2 
Where,  
 C1 = concentration (g/L) of standard DEET found from calibration curve  
 C2 = concentration (g/L) of sample taken  
   P = purity (g/kg) of the reference standard.   
©RSB 2018 - All rights reserved                  14 
 Annex  F 
(normative)  
 
Determination of perm ethrin  
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 stan dard.  
F.1 Reagents  
Cis – Permethrin, 99%  
Trans - Permethrin, 99%  
Methanol HPLC grade  
Water, HPLC grade  
F.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)  
F.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  
 
F.4 Procedure  
G.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 393 -3: 2018  
15                ©RSB 2018 - All rights reserved  
 G.4.2 Preparation of Solution  
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.  
G.4.3 Determination  
After the chromatograph is sta ble, make 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%.  
F.5 Calculation  
The % of either cis or trans isomers is calculated as follows ; 
% 𝑐𝑖𝑠 𝑜𝑟 𝑡𝑟𝑎𝑛𝑠𝑝𝑒𝑟𝑚𝑒𝑡 ℎ𝑟𝑖𝑛 =𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑠𝑎𝑚𝑝𝑙𝑒  𝑎𝑟𝑒𝑎 ×𝑤𝑒𝑖𝑔 ℎ 𝑡𝑜 𝑓 𝑠𝑡𝑑 ×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                  16 
 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 -3: 2018  
ICS 65.100  
 
 
©RSB 2018 - All right s reserved