Reference number  
DRS 393 -5: 2018  
© RSB 2018  
 
 
 RWANDA 
STANDARD  DRS  
393-5 
 
First edition  
2018 -mm-dd 
 
Spatial application mosquito repellents — 
Specification  — 
Part 5: 
Liquid vaporizers  
  DRS 393 -5: 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 -5: 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 requirements  ................................ ................................ ................................ ..................  3 
4.2 Active ingredients  ................................ ................................ ................................ ........................  3 
4.2.1  Natural repellents  ................................ ................................ ................................ .........................  3 
4.2.2  Synthetic repellents  ................................ ................................ ................................ .....................  4 
4.3 Physical requirements  ................................ ................................ ................................ .................  5 
4.3.1 Cartridge/bottle  ................................ ................................ ................................ .............................  5 
4.3.2  Wick  ................................ ................................ ................................ ................................ ...............  5 
4.3.3  Vaporization rate  ................................ ................................ ................................ ..........................  5 
4.3.4  Minimum effective period  ................................ ................................ ................................ ............  5 
4.4 Specific requirements for liquid content  ................................ ................................ ...................  6 
4.5 Stability  ................................ ................................ ................................ ................................ ..........  6 
4.6 Biological efficacy  ................................ ................................ ................................ ........................  6 
5 Sampling  ................................ ................................ ................................ ................................ ....... 6 
5.1 General  ................................ ................................ ................................ ................................ ..........  6 
5.2 Sampling, testing and acceptance  ................................ ................................ .............................  6 
6 Packaging and labelling ................................ ................................ ................................ ...............  7 
6.1 Packaging  ................................ ................................ ................................ ................................ ...... 7 
6.2 Labelling  ................................ ................................ ................................ ................................ ........  7 
Annex  A (normative)  Determination of allethrin content  ................................ ................................ ..... 9 
A.1 Principle  ................................ ................................ ................................ ................................ ........  9 
A.2 Apparatus  ................................ ................................ ................................ ................................ ...... 9 
A.3 Reagents  ................................ ................................ ................................ ................................ ....... 9 
A.4 Procedure  ................................ ................................ ................................ ................................ ...... 9 
A.4.1  Extraction  ................................ ................................ ................................ ................................ ...... 9 
A.4.2  Prepar ation of Internal standard Solution  ................................ ................................ .................  9 
A.4.3  Preparation of Sample Solution  ................................ ................................ ................................  10 
Annex  B (normative)  Determination of DEET content  ................................ ................................ ........  11 
B.1 General  ................................ ................................ ................................ ................................ ........  11 
B.2 Apparatus  ................................ ................................ ................................ ................................ .... 11 
B.3 Preparation of calibration curve  ................................ ................................ ...............................  11 
B.4 Procedure  ................................ ................................ ................................ ................................ .... 11 
B.5 Calculation  ................................ ................................ ................................ ................................ .. 12 
Annex  C (nor mative)  Determination of permethrin  ................................ ................................ .............  13 
C.1 Reagents  ................................ ................................ ................................ ................................ ..... 13 
C.2 Apparatus  ................................ ................................ ................................ ................................ .... 13 
C.3 Operating conditions  ................................ ................................ ................................ .................  13 
C.4 Procedure  ................................ ................................ ................................ ................................ .... 13 
C.5 Calculation  ................................ ................................ ................................ ................................ .. 14 
 DRS 393 -5: 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 393 -5 was prepared by Technical Committee RSB/TC 015, Pharmaceutical Products . 
DRS 393  consists of th e 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)  
Pharmacie NOVA  
Rwanda Development Board (RDB)  DRS 393 -5: 2018  
v                ©RSB 2018 - All rights reserved  
 AGROPY LTD  
IKIREZI NATURAL PRODUCTS  
HORIZON/SOPYRWA  
Rwanda Social Security Board (RSSB)  
Pharmavie  
University of Rwanda/Col lege 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 -5: 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 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 repellent is the most popular as it has germicidal and disinfect ant 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 'active' (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 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 include movement away from 
a chemical stimulus, attraction -inhibition and/or and feeding inhibition.  
 
 DRS 393 -5: 2018  
1                ©RSB 2018 - All rights reserved  
 Spatial application mosquito repellents  — Specification  — Part 5: Liquid 
vaporizers  
1 Scope  
This Draft Rwanda S tandard prescribes the requirements and test methods  for spatial application mosquito 
repellents formulated and prepared as liquid vaporizers  meant for outdoor and indoor use.  
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 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  
ISO 21149 , Cosmetics —Microbiology — Enumeration and detection of aerobic mesophilic bacteria  
RS EAS 847 -18, Cosmetics — Analytical methods — Part 18: Determination of thermal stability  
RS EAS 847 -17, Cosmetics — Analytical methods — Part 17: Determination of pH  
RS EAS 847 -16, Cosmetics — Analytical methods — Part 16: Determination of lead, mercury and arsenic 
content  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply   
©RSB 2018  - All rights reserved                  2 
 3.1 
liquid vaporizer  
bottle/catridge filled with a liquid containing an insect repelling  substance and meant to be plugged into a heater 
unit in  order to release the repellent  
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 segmented 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 cli mbing on that surface  
3.4 
natural repellents/biopesticides  
repellents that contain natural, plant -based  active ingredients  
3.5 
synthetic repellents  
conventional repellents containing synthetic chemical active ingredients 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  DRS 393 -5: 2018  
3                ©RSB 2018 - All rights reserved  
 3.8 
Metofluthrin  
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  
4 Requirements  
4.1 General  requirements  
4.1.1 The product shall consist of a liquid mosquito repellent  formulation in a cartridge/bottle, designed to fit 
a suitable heater unit, and the formulation shall be effective as it passes up the heated wick and evaporates at 
a suitable rate, over the period claimed by the manufacturer.  
4.1.2 The cartridge/bottle sh all be designed to minimise the risk of accidental ingestion of the contents.  
4.1.3 When the product is vaporized , it shall have the benefit of repelling mosquitoes.  
4.1.3 The bottle/catridge shall allow exit of the content with ease when reasona ble press ure is applied to the 
lid. 
4.2 Active ingredient s 
4.2.1  Natural repellents  
4.2.1.1  Active ingredients used in natural repellents shall be natural and plant based compounds such as 
essential oils or any other  plant extract approved as mosquito repellents.  
4.2.1.3  The manufacturer  shall provide adequate data on the repellence /efficacy  of such ingredients /product . 
4.2.1.4  The manufacturer  shall have adequate data justifying the proportion of ingredient(s) for which claims 
are made, used in the product.   
©RSB 2018  - All rights reserved                  4 
 4.2.1.5  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 . 
4.1.2.6  The pr oportion 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.  
4.1.2.7  Pyrethrum extracts such as pyrethrin s shall be consid ered 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.     
4.2.2  Synthetic repellents  
4.2.2.1  Synthetic repellents shall contain synthetic chemical compounds which are able to discourage 
mosquitoes and send them flying or crawling away.  
4.2.2.2  If the synthetic chemical compound is blended with other active ingredient (s), either natural or 
synthetic, the proportion shall be set by the manufacturer ba sed on scientific research and records shall be 
availed.  
4.2.2.3  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 ingred ient % w/w  Limits  Identification method  
1 Picaridin  0.2 – 5 CIPAC 740  
2 DEET  5 – 50 Annex B 
3 Permethrinmax  13 Annex C 
4 Transfluthrin , max  1 CIPAC 741  DRS 393 -5: 2018  
5                ©RSB 2018 - All rights reserved  
 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  before being released to the market . 
4.3 Physical requirements  
4.3.1  Cartridge/bottle  
The cartridge/bottle:  
a) shall be made of a suitable heat -resistant material;  
b) shall be of a suitable shape and size to fit the heater unit for which it was designed;  
c) shall hold the wick firmly, with a stopper preventing spillage in case the cartridge/bottle is inverted with 
the covering cap; and  
d) shall have a child -proof cap.  
4.3.2  Wick  
The wick:  
a) shall be made of a suitably porous heat -resistant material;  
b) shall draw up sufficient repellent  formulation, when heated at one end, for vaporization to provide a 
suitable level of protection against mosquitoes; and  
c) shall be of material and design such that it can vaporize the total content of the repellent  formulation in 
the bottle/cartridge to which it is attached.  
4.3.3  Vaporization rate  
The wick and cartrid ge/bottle shall be designed and constructed such that the repellent  formulation vaporizes 
from the heated end of the wick at a constant, or close to constant, rate to enable a constant rate of active 
ingredient emission throughout the minimum effective per iod.  
4.3.4  Minimum effective period  
The minimum effective period shall be declared and the cartridge/bottle shall hold sufficient formulation to 
enable the product to function for not less than the minimum effective period declared.   
©RSB 2018  - All rights reserved                  6 
 4.4 Specific requirements  for li quid content  
The liquid content for the liquid vaporisers shall conform to the requirements as prescribed in table 2.  
Table 2 – Specific requirements for liquid content  
S/N Parameters  Requirements  Test methods  
i.  Thermal stability  To pass test  RS EAS 847 -18 
ii.  pH 4.0-6.0 RS EAS 847 -17 
iii.  Heavy metals, 
mg/kg, max  Lead (Pb)  20 RS EAS 847 -16 
iv.  Arsenic (As)  2 
v.  Mercure (Hg)  2 
vi.  Total viable count,  
micro -organisms per g, max.  100 RS ISO 21149  
4.5 Stability  
Stability at elevated temperature : After storage at 54 ºC ±2ºC for 14 days, the determined average active 
ingredient content must not be lower than 95% relative to the determined average content found before storage 
and the formulation shall continue to comply with the requirements of the product.  
4.6 Biological eff icacy  
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 Sampling  
5.1 General  
5.1.1 Samples shall be stored in such a manner that there is no deterioration of the material.  
5.1.2 The sampling instrument shall be clean and dry.  
5.1.3 Samples shall be protected against contamination.  
5.2 Sampling, testing and acceptance  
5.2.1 In any consignme nt, all the master cartons containing liquid vaporizer refill bottles of the same type shall 
constitute a lot.  
5.2.2 Samples shall be drawn from each lot and individually tested to ascertain whether the material complies 
with the specified requirements.  
5.2.3 Any sample failing to comply with the specified requirements shall be termed as “defective ”. The 
acceptance number shall be the maximum number of defective samples permissible for a lot to be accepted.  DRS 393 -5: 2018  
7                ©RSB 2018 - All rights reserved  
 5.2.4 The number of refill bottles to be drawn from the lot and the acceptance number shall be as shown in the 
following Table : 
Table 3— Number of refill bottles to be drawn from the lot and the acceptance number  
Total number of 
containers in lot  Number of 
containers to 
be tested  Acceptance 
number  
300 or less  
301 to 1200  
1201 to 2000  
2001 to 7000  
7001 to 15000  
15001 to 24000  
24001 to 41000  
Over 41000  3 
6 
13 
21 
29 
48 
84 
126 0 
1 
2 
3 
4 
6 
9 
13 
5.2.5 Each of the refill bottles to be tested shall be drawn from a different master carton which shall be selected 
at random. In order to ensure randomness of selection, random number tables shall be used. If such tables are 
not available, the following procedure may be adopted. Starting from any master carton, count the master 
cartons as 1, 2, 3...... r in a systematic manner. Every rth carton shall be drawn, r being the integral part of N/n, 
where N is the total number of master cartons in the lot and n the number of master cartons to be selected.  
6 Packaging and labelling  
6.1 Packaging  
The product  shall be package d in a container which offers protection from breakage and maintains the integrity 
of the product . 
6.2 Labelling  
The containers shall be securely closed and in addition to the labelling requirements of RS 91 , the following 
information shall be indelibly and le gibly 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) active ingredient content ; 
f) net mass of product ; 
g) directions for use;   
©RSB 2018  - All rights reserved                  8 
 h) coverage area for indoor use i) effect of wind on the repellent use  
h) warning and precaution ; 
i) special p opulation  whose exposure is prohibited (children and pregnant women) ; and 
k) storage conditions.  DRS 393 -5: 2018  
9                ©RSB 2018 - All rights reserved  
 Annex  A 
(normative)  
 
Determination of allethrin content  
A.1 Principle  
Allethrin is  extracted with a mixture of toluene  and formic acid from the coil and then a nalyze extract using gas 
chromato graphy - followed by flame  ionization 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 
shaking 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 1 00-mLvolumetric flask and make up the volume to mark with 
toluene. This will give a solution containing 10 mg/mL of dibutyl phthalate.   
©RSB 2018  - All rights reserved                  10 
 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 -5: 2018  
11                ©RSB 2018 - All rights reserved  
 Annex  B 
(normative)  
 
Determination of DEET content  
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  
F.2.1  Double -beam infrared spectrophotometer. Perkin -Elmer model 21 or equivalent.  
F.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  
F.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.  
F.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 b lank measurement with carbon disulfide to correct for any inequality 
in the paired cells and to determine whether a cell correction is required.  
F.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.  
 
F.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 con centration 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                  12 
 B.5 Calculation  
DEET content (g/kg) =𝐶1 𝑥 𝑃 
𝐶2 
Where,  
 C1 = concentration (g/L) of standard D EET found from calibration curve  
 C2 = concentration (g/L) of sample taken  
   P = purity (g/kg) of the reference standard.  DRS 393 -5: 2018  
13                ©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 b y 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, H PLC 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  
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.  
G.4.2 Preparation of Solution   
©RSB 2018  - All rights reserved                  14 
 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 stable, make a minimum of three injections of the standard as well as for the sample 
and av erage 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  𝑝𝑒𝑟𝑚𝑒𝑡 ℎ𝑟𝑖𝑛 =𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑠𝑎𝑚𝑝𝑙𝑒  𝑎𝑟𝑒𝑎 ×𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑡𝑑 ×𝑝𝑢𝑟𝑖𝑡𝑦 (𝑖𝑛%)
Average  std area  × weight  of sample 
Report the concentration of permethrin as the total of Cis and Trans . DRS 393 -5: 2018  
15                ©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 -5: 2018  
ICS 65.100  
 
 
©RSB 2018 - All right s reserved