DRAFT UGANDA STANDARD DRAFT UGANDA STANDARD  
  FDUS 307  
Third  Edition  
2013-08-20 
 
 Reference numbe r 
FDUS 307: 201 3 
© UNBS 201 3  
  
Mosquito nets — Specification  
 DRAFT UGANDA STANDARDDRAFT UGANDA STANDARDFDUS 307:2013 
© UNBS 2013 – All rights reserved Compliance with this standard does not of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users 
are responsible for its correct application  
© UNBS  2013  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in 
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written permission from UNBS. 
Requests for permission to reproduce this document should be addressed to 
The Executive Director 
Uganda National Bureau of Standards 
P.O. Box 6329 
Kampala 
Uganda 
Tel: 256 31 262688/689 
Fax: 256 41 286 123 
E-mail: info@unbs.go.ug DRAFT UGANDA STANDARDFDUS 307:2013 
© UNBS 2013 – All rights reserved Foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Tourism, Trade and 
Industry established by the Act of Parliament of 1983, of the Laws of Uganda.  UNBS is mandated to co-
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agreements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of 
representatives of consumers, traders, academicians, manufacturers, government and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and 
the general public for comments. The committee reviews the comments before recommending the draft 
standards for approval and declaration as Uganda Standards by the National Standards Council. The 
Technical Committee on the Textile and Apparels (TC 7) elaborated this Uganda Standard and the 
following institutions were represented.  
Committee membership 
The following organisations were represented on the Textile and Apparels Standards Technical 
Committee, UNBS/TC 7, during the development of this standard: 
 Kyambogo University  
 Busitema University 
 Ministry of Health (National Malaria Control Programme) 
 Nett shoppe Uganda Limited 
 Sumitomo Chemical 
 Vestergaard 
 Uganda Industrial Research Institute 
 Uganda National Bureau of Standards 
 DRAFT UGANDA STANDARDFDUS 307:2013 
© UNBS 2013 – All rights reserved   DRAFT UGANDA STANDARDDRAFT UGANDA STANDARDDRAFT UGANDA STANDARD  FDUS 307: 201 3 
 
© UNBS 20 13 – All rights reserved  1 
 Mosquito nets — Specification 
1 Scope 
This Draft Uganda Standard prescribes requirements for long lasting insecticidal Mosquito nets intended for 
malaria vector control.  
2 Normative references 
The following referenced documents are indispensable for the application 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. 
ISO 1833, Textiles — Binary fibre mixtures — Quantitative chemical analysis 
ISO 2060, Textiles — Yarn from packages — Determination of linear density (mass per unit length) by skein 
method 
ISO 2960, Textiles — Determination of bursting strength and bursting distension — Diaphragm methods  
ISO 3758  Textiles — Care labelling code using symbols 
ISO 3801, Textiles — Woven fabrics — Determination of mass per unit length and mass per unit area 
ISO 5077,  Textiles — Determination of dimensional change in washing and drying  
ISO 6330,  Textiles — Domestic washing and drying procedure for textile testing 
ISO 6941, Textile fabrics — Burning behaviour — Measurement of flame spread properties of vertically 
orientated specimens 
ISO 8388  Textiles — Knitted fabrics. Types. Vocabulary 
US 417,  Glossary of terms for defects in fabrics – Woven fabrics 
US 418, Glossary of terms for defects in fabrics – Knitted fabrics 
3 Terms and definitions 
For the purpose of this standard the definitions given in US 417 and US 418 and the following definitions shall 
apply.  
3.1 Long Lasting Insecticidal Nets (LLIN) 
factory treated mosquito net made with a netting material that has insecticide incorporated within the yarn or 
wound around the fibres. The LLIN must have the capacity to retain its effective biological activity without re-
treatment for at least twenty WHO standard washes under laboratory conditions and three years of 
recommended use under field conditions hence fulfilling the WHOPES 2 test. DRAFT UGANDA STANDARDFDUS 307:2013 
2 ©UNBS 201 3 – All rights reserved  
 3.2 Combination nets  
are finished nets compos ed of  different netting materials 
4 Symbols (and abbreviated terms) 
The abbreviations below are found throughout this standard. 
 WHO  World Health Organization 
 WHOPES  World Health Organization Pesticides Evaluation Scheme 
 PBO    Piperonyl butoxide 
5 Requirements 
5.1 General 
5.1.1 Textile netting materials 
The textile materials used for the manufacture of mosquito netting and any other textile products intended for 
malaria vector control  shall fulfil the requ iremen ts as specified in table s 1 to 5 below.  DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  3 
 Table 1 — Specification for netting materials 
 Specifications   
Parameter  Polyester  Polyethylene  Test method ( ISO)  
Fibre  100 % polyester  100 % polyethylene  ISO 1833  
Denier   100  ≥ 100  
 ISO 2060  
Filaments  Multi -filament ≥ 36 Mono/multi -filament   
Mesh size  24 holes/cm2 Min. 6.25 holes/cm2, min 
 ISO 1833  
Weight (g/m2) 40 g/m2.(min)  
  40 g/m2.(min) 
 ISO 3801  
Bursting strength  350 Kpa.(min)  
  350 Kpa.(min)  
 ISO 2960  
Dimensional stability  Threshold/range of  5  % Max 
 Threshold/range of 5 % pa 
Max.  
 ISO 6330  
ISO 3801  
ISO 5077  
Flammability ( Fire 
safety ) Not inflammable (class 1)  Not inflammable (class 1)  16 CFR Part 1610  
Weave / netting  type Warp knitted  Raschel1) ISO 8388  
Colour fastness to:  
Light  
Washing   
   4 or better  
    4 or better  
  
4 or better  
 4 or better  
 ISO 105  
Seam  sewn using 100% polyester thread  sewn using 100% polyester 
thread   
  
1) Raschel knit is a warp knitted fabric that produces fabric similar to tricot but usually of coarser texture and with openwork patterns  
. 
 
 
 
 
 
 
 
 
 DRAFT UGANDA STANDARDFDUS 307:2013 
4 ©UNBS 201 3 – All rights reserved  
  
Table 2 – Specification for netting materials for combination nets 
Parameter  Requirement  Test Method  
Fibre  Roof: 100 Polyethylene  
Side: 100 Polyester  ISO 1833 or ASTM D276  
Denier  100D  ASTM D 1907 -1 / ISO 2060 - 
Option 1  
 
Filaments  Roof: Monofilament  
Sides: Multifilament  
 Counting  
Mesh size  Roof: Min. 20 holes/cm2 
Side: Min. 24 holes/cm2 ISO 1833  
 
Weight (gm2) Roof: Min. 30 g/m2 
 
Sides: Min. 36 g/m2 
  
ISO 3801  
 
 
Bursting  strength  
 Roof: Min. 400 kPa  
 
Sides: Min. 350 kPa  
  
ISO 13938 - 1, head area = 7.3 cm2 
 
Dimensional stability of netting to 
wash  
 Max. 5 %, either shrinkage or 
expansion  
 ISO 3759, ISO 6330, 8A / Flat 
drying, ISO 5077.  
 
 
Flammability (Fire safe ty)* 
  
Class I  
  
16 CFR Part 1610  
 
 
Weave / netting type  
  
Warp knitted  
  
ISO 8388  
 
 
Colour fastness to  light 
  
4 or better  
  
ISO 105, B02, Test method 2  
 
 
Seam  
  
sewn using 100% polyester thread  
  
Visual check  
 
 
 
Active Ingredients of the combination Net  
 
 
SL NO  
  
Ingredient  
 Dosage  
 
 
 
g/Kg  
  
Mg/m2 
 
 
Roof  
  
Deltamethrin  
  
3.00 - 5.00  
  
105 - 175 
 
 
PBO  
  
18.75 - 31.25  
  
656.25 - 1093.75  
 
 
Sides  
  
Deltamethrin  
  
2.1 - 3.5 
  
63.0 - 105 
 
 DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  5 
 5.1.2 Defects 
5.1.2.1 The mosquito nets shall be free from any non-acceptable defects.  
5.1.2.2 Defects allowed shall only be classified into major and minor defects as per the relevant Uganda 
standards 
5.2 Sizes and dimensions for mosquito nets 
5.2.1 Sizes 
The mosquito nets shall be of any of the following sizes: 
(a) X-small; 
(b) Small; 
(c) Medium; 
(d) Large; and 
(e) X- large. 
5.2.2  Dimensions 
The dimensions of the mosquito nets shall be as given in tables 5 and 6 for the respective nets. 
Table 3 — Rectangular net dimensions 
Net Size  Width , min, 
cm  Length , min, 
cm  Height , min, 
cm  
X small  70 180 170 
Small  100 180 170 
Medium  130 180 170 
Large  160 180 170 
X- Large  190 180 170 
NOTE  For manufacturers, sizes not conforming with the above dimensions will be considered special orders  
The text/column  in re d to be deleted, it is not relevant  
 
Table 4 
 — Conical nets dimensions  
Net Size  Height , Min  
Cm Circumference  
diameter , Min  
cm Ring diameter , Min  
cm 
Single fitted conical  220 850 56 
Double fitted conical  250 1050  56 
Extra double fitted  250 1250  65 
 DRAFT UGANDA STANDARDFDUS 307:2013 
6 ©UNBS 201 3 – All rights reserved  
 5.3 Active ingredients 
For treated nets, the active ingredients of nets shall comply with requirements of table 5 when tested 
in accordance with annexes A, B and C 
Table 5: Active ingredients of nets 
  
SL NO  Ingredient  Dosage  
g/Kg Mg/m2  
1 Deltamethrin  , 1.05-1.75 , 41.25 - 68.75  
2 Permethrin  17-23 510-1150  
3 Alpha –cypermethrin  3.75-8.4 150-250 
    
 
5.4 Manufacture and workmanship 
5.4.1 General requirements 
5.4.1.1 The mosquito net shall be rectangular or conical in shape unless otherwise agreed between the 
purchaser and the supplier.  
5.41.2 The hem shall be firm and capable of withstanding the normal conditions of use. 
5.5 Reinforcement at bottom  
The bottom edge of the walls shall be stitched, hemmed, given a finished edge or be reinforced.  
Note A sheeting border is sometimes required to improve the lifespan of nets. 
5.6 Net attachments or tying tapes  
Rectangular nets shall be equipped with non-rusting metal rings or fabric loops . Each ring/loops shall have a 
corresponding string for suspensions. Conical nets shall be equipped with a loop/ non-rusting ring with 
sufficient strength.  
5.7 Top support ring 
Conical nets shall have a top support ring made of non-rusting metal and which has sufficient strength to 
withdraw the net when hanged at the required position. 
6 Packing and labelling 
6.1 Packing 
The packaging material shall be leak proof and shall be sufficiently large to wrap completely the mosquito net 
bundles. The individual nets’ packaging materials should  be biodegradable. DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  7 
 6.2 Labelling 
6.2.1  General 
The labelling shall include 
(a) a permanent  label attached to the net (tag); and 
(b) a pictorial leaflet relating to insecticide treatment and care of nets. 
6.2.2  Label tag 
The label tag attached to the net shall contain the following information: 
(a) type of netting materia l; 
(b) net dimensions in centimetres (height, width and length for rectangular nets, net diameter and height for 
conical nets and surface area); 
(c) country of origin; 
(d) name and physical address of the manufacturer and/or importer/distributor; 
(e) status of treatment that is , insecticide used, formulation and dosage;  
(f) the efficacy of the chemical shall be indicated in term of number of washes;  
(g) lot/ batch number ; and  
(h) pictograms or simple instructions in accordance with ISO 3758 giving warning to avoid frequent washing, 
high temperature or dry cleaning (solvents), bleaching and exposure to sun light. 
6.2.3  Pictorial leaflet 
The pictorial leaflet shall contain information relating to insecticide treatment and the care of nets. The 
following information shall appear: 
(a) size in centimetres and surface area in square metres; 
(b) washing instructions in pictograms ( temperature for washing, no bleach, no ironing, no dry cleaning and 
no tumble; 
(c) instructions not to leave the net in the sun; and 
(d) a warning that frequent washing removes the insecticide. 
7 Sampling  
7.1 Lot  
The quantity of mosquito nets delivered to a consignee against the same dispatch note shall constitute a lot.  DRAFT UGANDA STANDARDFDUS 307:2013 
8 ©UNBS 201 3 – All rights reserved  
 7.2 Scale of sampling 
7.2.1 Samples shall be tested for each lot for ascertaining its conformity to the requirements of this 
standard. 
7.2.2 The number of pieces to be selected from a lot shall be in accordance with Table 7. 
Table 7 – Scale of sampling 
Number of pieces in the lot  Number of pieces to be selected  
Up to 8  
9 to 15  
16 to 25  
26 to 50  
51 and above  2 
3 
4 
5 
7 
 
 DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  9 
 Annex A 
(normative)  
 
Determination of Deltamethrin content in Insecticide treated Mosquito 
nets by High performance Liquid Chromatography 
A.1 Sampling  
A sample is defined as one finished bed net taken randomly from a batch of bed net.  Sub sample by cutting 
18 pieces of size 100cm2 from a net either randomly from the whole net or at recommended position as in 
appendix 1.  Cut 18 pieces into half, one portion is used for Deltamethrin content analysis and the other is 
used for washing test if required. 
The portion used for Deltamethrin content analysis is cut into pieces of less than 2cm x 2cm each.  Mix well . 
Sample shall be separately packed in aluminium foil and kept out of direct sunlight at room temperature or 
lower. 
A.2 Identification tests. 
Use the HPLC method below.  The retention time of Deltamethrin in the sample solution should not deviate by 
more than 15 s from that of the calibration solution if column oven is available. 
A.3 Active ingredient 
A.3.1 Outline of Method 
The sample is extracted in a mixture of  iso-octane and 1,4-dioxane. 
The Deltamethrin content is determined by normal phase high performance liquid chromatography using 
dipropyl  phthalate as internal standard and detection at 236 nm. 
A.3.2 Scope 
This method is used for Deltamethrin determination  in net sample, before and after washing. 
A.3.3 Reagents 
A.3.3.1  Iso Octane, HPLC grade  
A.3.3.2  1,4 Dioxan, HPLC grade.  Add 0.15% (v/v) water before use 
A.3.3.3  Deltamethrin, neat standard,  
A.3.3.4  Dipropyl Phthalate,  
A.3.3.5  Water ,HPLC grade or high  
A.3.3.6  Extraction solvent (ES): iso octane + 1,4 dioxane=80+20 
A.3.3.7  Mobile Phase (MP):iso octan + 1,4 dioxane = 95 + 5 DRAFT UGANDA STANDARDFDUS 307:2013 
10 ©UNBS 201 3 – All rights reserved  
 A.3.3.8  Internal Standard solution  (IS)0.5 mg/ml of dipropyl  phthalate in extraction solvent. 
A.3.3.9  Deltamethrin standard solution 0.6 mg/ml(DS) 
Weight 0.03 g(to the nearest of 0.01` mg) of Deltamethrin neat standard, quantitatively transfer to 50 
volumetric  flask, dissolve completely with extraction  solvent , keep regulated by water bath at 20oC, fill up to 
mark with extraction solvent. 
A.3.4 Apparatus 
A.3.4.1  Shaker 
A.3.4.2  Ultrasonic  bath 
A.3.4.3  HPLC, equipment  with pump, auto-injector , column oven (optional) and UV detector, Guard              
Column (Supelguard Si). Analytical Column Supelco Si 5 µm, 150 x 4.6 or Lichrosorb Si60, 5 µm, 150 x 4.6 
A.4 Procedure 
A.4.1 Operating conditions 
A.4.1.1   Mobile Phase:  iso octan + 1,4 dioxane =95 + 5 
A.4.1.2   Flow rate 1.3ml/min, isocratic 
A.4.1.3  Guard Column Superguard Si 
A.4.1.4   Analytical Column Licherosorb Si60, 5µm, 150 x 4.6 40oC if column oven is available, or room 
temperature 
A.4.1.5  Inject Volume 5µl 
A.4.1.6  Wavelength 236 nm 
A.4.1.7  Run time 6-8 minute 
A.4.2 Preparation of calibration curve 
A.4.2.1  Into a series of clean 20ml PTFE liner screw cap vials, add accordingly as table below.  Filter 
through 0.45µm syringe filter before use. 
Code  IS DS ES Delta(mg)  Total Volume  
C1 1ml 0.5ml  13.5 ml  0.30 15 ml  
C2 1ml 0.7ml  13.2 ml  0.42 15 ml  
C3 1ml 0.9ml  12.8 ml  0.54 15 ml  
C4 1ml 1.1ml  12.4 ml  0.66 15 ml  
C5 1ml 1.3ml  12.1 ml  0.78 15 ml  
 
A.4.2.2  All standards should be kept in the refrigerator if not in use in WELL-TIGHTEN, paraffin film 
sealed cap. DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  11 
 A.4.3 Calibration 
A.4.3.1  Daily calibrate HPLC system with full series of 05 standards, beginning with the lowest level 
standard.  The correlation coefficient should be less than 0.99 over this range. 
A.4.4 Preparation of sample 
A.4.4.1 Weigh (to the nearest 0.1 mg) into an Erlenmeyer or a screw cap neutral glass bottle (50ml) 
sufficient sample to contain about 0.5 mg of Deltamethrin.  For 75D, 100D and 150D netting sample, suitable 
weight (w g) is 0.3 g, 0.4 g and 0.6 g respectively.  Add by pipette 1.0 ml internal standard solution.  Add 14 ml 
extract solvent.  Replace the cap closely. 
Put the bottles into the ultrasonic bath, setting temperature 80oC, running time 15 min.  Vigorously shake the 
bottle using the shaker in 30 min at room temperature, speed of shaking is at level of 150-200 beats per 
minute. 
Using a syringe membrane filter with pore size of 0.45 µm or finer, filter c.a 1ml of extract solution into clean 
amber. Sample shall be injected within 24 hours since extraction, for longer waiting time the vial should be 
kept in a refrigerator. 
 
A.4.5 Determination 
A.4.5.1  Inject sample with HPLC configured as in (a) 
Deltamethrin  content(g/kg)= 
wa  
a=Deltamethrin reading from the analysis in mg 
w=mass of sample taken (g) 
Note :  Conventional unit of active ingredient content (deltamethrin) for netting is mg/m2.  The conversion from g/kg to 
mg/m2 is made as follows: 
Deltamethrin content (mg/m2) = Deltamethrin content (g/kg) x D 
D=weight per square meter 
D of typical polyester netting 
75 Denier netting, D=30g/m2 
100 Denier netting, D=40g/m2 
150 Denier netting, D=60g/m2 
A.4.6 Method Validation Summary 
A.4.6.1  Precision 
Analyze 05 replicates RSD is 1.8% 
A.4.6.2  Accuracy 
Recovery of 04 Laboratory Synthetic samples is in the range of 97% to 101% DRAFT UGANDA STANDARDFDUS 307:2013 
12 ©UNBS 201 3 – All rights reserved  
 Averaged at 99.3% 
A.4.6.3  Linearity 
Over the range of Deltamethrin from 0.30 t0 0.78 mg, the correlation coefficient R2 is observed not less than 
0.995. 
  Determination of release /Retention Index 
 
Figure 1:Chromatogram of calibration solution 
 DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  13 
  Figure 2: Chromatogram of sample 
 
 DRAFT UGANDA STANDARDFDUS 307:2013 
14 ©UNBS 201 3 – All rights reserved  
 Annex B 
(normative) 
 
Determination of Permethrin content in Insecticide treated mosquito nets  
B.1 Sampling:  
Take at least 100g 
B.1.2  Identity tests 
B.1.3  GLC. Equipped with a split/splittless and a flame ionization detector. Capillary column fused 
silica,30mx0.25 (i.d) mm, film thickness:0.25 µm, coated with cross linked dimethyl (DB-1 or equivalent) and 
electric integrator or data system 
B.1.4  Infrared. Extract the sample with suitable solvent.  Filter and evaporate the solvent.  Proceed as for 
331/TC/m/2.2 
B.1.5  Permethrin . The content of permethrin in test samples are determined by capillary GC using flame 
ionization detection and triphenyl phosphate as internal standard, and trans-isomer ratio is calculated from the 
chromatogram obtained 
B.2 Reagents  
B.2.1  Heptane analytical grade 
B.2.2  Internal  standard solution .  Dissolve tripheny l  phosphate (1.0g) in heptane (150 ml).  Ensure that a 
sufficient quantity of this solution is prepared for all samples and calibration standards to be analysed. 
B.2.3  Calibration  solution .  Homogenise the permethrin working standard.  When the permethrin working  
standard is waxy solid or partly waxy solid homogenize it by warming it to melting and stirring.  Prepare 
calibration solutions in duplicate.  Weigh (to the nearest 0.1 mg) 72 to 88 mg(s mg) of permethrin working 
standards into a vial or stoppered flask (200 ml).  Add by pipette internal standard solution (10 ml) and 
dissolve completely.  Add by measuring cylinder heptanes (90 ml) and mix well (Solutions C A and C B) 
B.3 Procedure 
B.3.1  Preparation of sample solution .  
Clean scissors with acetone before use.  Cut the sample with the  scissors into 5-10mm square.  Prepare 
sample solutions in duplicate for each sample.  Weigh (to the nearest 0.1mg) sufficient sample to contain 36 
to 44mg (w mg) of permethrin into a vial or stoppered  flask (100ml).  Add by pipette internal standard solution 
(5 ml) and by measuring cylinder heptane(45 ml).  Place the vial or stoppered flask in a water bath(85-90ºC) 
for 45 minutes.  Shake the vial or stoppered flask once or twice during extraction.  Filter a portion of each 
sample solution through a filter paper prior to analysis (Solutions S A and S B) 
B.3.2  Calculation of permethrin content.   
B.3.2.1  Calculate the mean value of each pair of response factors bracketing the two injections of a 
sample and use this value for calculating the  permethrin contents of the bracketed sample injections. DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  15 
 
2HsxlrxsxPfi 
Content of permethrin 
kgglqxwfxHw/  
Where: 
fi = individual response factor 
f= mean response factor 
Hs=total peak area of permethrin (cis-permethrin + trans-permethrin) in the calibration solution 
Hw= total peak  area of permethrin (cis-permethrin + trans -permethrin) in the sample solution 
Ir= peak area of the internal standard in the calibration solution 
Iq=peak area of the internal standard in the sample solution 
s=mass of permethrin working standard in the calibration solution (mg) 
w=mass of sample taken (mg) 
P=purity of permethrin working standard (g/kg) 
B.3.2.2  Precision 
B.3.2.1  Repeatability  r    = 1.6 g/kg at 20.3 g/kg active ingredient content 
= 1.3 g/kg at 20.0  g/kg active ingredient content 
= 0.9  g/kg at 18.7 g/kg active ingredient content 
B.3.2.2  Reproducibility R  = 1.9 g/kg at  20.3 g/kg active ingredient content 
=1.5 g/kg at 20.0 g/kg active ingredient content 
=1.5 g/kg at 18.7 g/kg active  ingredient content 
B.4 Determination of Surface concentration and release index 
B.4.1 Reagents 
Internal standard solution for calibration solution.   
Dissolve triphenyl  phosphate (0.1 g) in acetone (200ml) to prepare a stock solution.  Transfer by pipette the 
stock solution (5 ml) to a volumetric flask (50ml).  Make up to volume with acetone  and mix well.  Ensure that 
a sufficient quantity of this solution is prepared for all calibration standard to be analysed. 
Calibration solution.  Homogenise the permethrin  working standard.  When the  permethrin working  standard 
is always  solid or partly solid homogenise it by warming it to melting and by stirring.  Prepare calibration 
solutions in duplicate.  Weigh (to the nearest 0.1 mg) 90 to 110 mg (s mg) of permethrin  working standard  
into a volumetric flask (100 ml) and make up to volume with acetone and mix well.  Transfer  by pipette this 
solution (1 ml to a volumetric flask (20 ml), make up to volume with acetone and mix well.  Transfer by pipette 
this solution (5 ml) to a vial (20 ml), add by pipette internal standard solution for calibration solution (5 ml) and 
mix well (Solution C A and C B). DRAFT UGANDA STANDARDFDUS 307:2013 
16 ©UNBS 201 3 – All rights reserved  
 B.4.2 Apparatus as for 331/TC/m/3 except: 
Constant temperature oven capable of controlling temperature with the range of ±2oC  is recommended. 
Rotary evaporator 
B.4.3 Procedure as for 331/TC/m/3 except : 
B.4.3.1  Gas  chromatographic conditions (typical): 
B.4.3.2  Injection system 
B.4.3.3  Slit flow  approximately 10ml/min 
B.4.4 Linearity check. 
Check the linearity of the detector response by injecting 1 µl  of solution s with permethrin concentrations 0.1, 
1 and 2.5 times that of the calibration solution before conducting analysis. 
B.4.5 System equilibration.  
Prepare two calibration solutions.  Inject 1 µl  portions of the  first one until the response factors obtained for 
two consecutive injections differ by less than 2.0%.  Then inject a 1 µl portion of the second solution.  The 
response factor for this solution should not deviate by more than 2.0% from that for the first calibration 
solution, otherwise prepare new calibration solutions. 
B.4.6 Preparation of sample solution 
Clean scissors and tweezers with acetone before use.  Prepare sample solutions in tripricate for each sample 
Note 1)   Cut ca .5 cm x 5 cm net samples with the scissors.  Weigh accurately , to the nearest 0.1 mg, of each 
sample (w mg). Transfer it with the tweezers into a vial (20 ml).  Add by pipette internal standard solution for 
sample solution (10 ml).  Cap the vial and shake the solution by hand for 1 minute Note 2.  Take out ht netting 
with the tweezers and discard the solution. 
Let the netting dry at room temperature for ca.  10 minutes. Transfer it into a vial (20ml) with the tweezers.  
Cap the vial and place it in a temperature -controlled  oven set at 70Oc.  Heat the sample for 2 hours Note 3)  . 
After heating , remove the vial from the oven and let it equilibrate to room temperature.  Add by pipette internal 
standard solution for sample solution (10ml) into the vial.  Cap the vial tweezers.  Let the netting dry at room 
temperature for ca.  10 minutes. Transfer the sample solution from the vial into the same round-bottom flask.  
Evaporate the solution in vacuo to dryness.  Add by pipette acetone (2ml) into the flask to dissolve the residue 
(Solutions for “surface concentration at pot -wash 1”, S A1,SBI and S C1).    
Transfer the dried netting into a vial (20ml) with the tweezers.  Repeat heating, internal standard solution 
adding, evaporation and dissolving procedures as above.  (Solutions  for “surface concentration at Post -wash 
2”, S A2, SB2 and S C2). Again, let the netting dry at room temperature for ca.  10 minutes.  Transfer the dried 
netting into a vial (20ml) with the tweezers.  Repeat heating, internal standard solution adding, evaporatio n 
and dissolving procedures as above.  (Solutions for surface concentration at post- wash 3”, S A3,SB3, and  S C3) 
Note 1:  Analytical error is larger than average content determinations 
Triplicate determinations, therefore ,are recommended 
Note 2:   The shaking speed is about 30 times per 10 seconds 
Note 3 :  Put vials in a covered cardboard box while heating so that the vials are not exposed to direct streams of warm   
air. DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  17 
 B.4.7 Determination .  
Inject in duplicate 1 µl portions of each sample solution bracketing them by injections if the calibration 
solutions as follows; calibration solution  CA, sample solution SA1, sample solution SA1, calibration solution 
CB, sample solution SB1, sample solution SB1, calibration solution CA and so on measure the relevant peak 
areas. 
B.4.8 Calculation of surface concentration.  
Calculate the mean value of each pair of response factors bracketing the two injections of a sample and use 
this value for calculating the surface concentration of the bracketed sample injections. 
HslrxsxPfi
 
Surface concentration=
2 lqxwxfxHw µg/g 
Where: 
fi=individual response factor 
f=mean response factor 
Hs=total peak area of permethrin (cis-permethrin + trans-permethrin ) in the calibration solution 
Hw=total peak area of [ermethrin (cis-permethrin + trans-permethrin) in the sample solution 
Ir= peak area of the internal standard in the calibration solution 
Iq=peak area of the internal standard in the sample solution 
s=mass of permethrin working standard taken (mg) 
w=mass of sample taken (mg) 
P=purity of permenthrin working standard (g/kg) 
B.4.9 Calculation of release index.  
Calculate the mean value of the two injections of sample solutions SA3, SB3, and SC3 by the equations 
described in (f) , and the release index for each piece of the netting. 
Release index =
BC  
Where: 
B= mean value of surface concentration at post-wash 2 ( µg/g) 
C=mean value of surface concentration at post-wash 3 (µg /g) DRAFT UGANDA STANDARDFDUS 307:2013 
18 ©UNBS 201 3 – All rights reserved  
 
 
Fig. 1 Infrared Spectrum of permethrin 
 DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  19 
 Fig 2 Example of gas chromatogram of permethrin  TC 
 
Fig 3 Example of gas chromatogram of permethrin LN 
 
 DRAFT UGANDA STANDARDFDUS 307:2013 
20 ©UNBS 201 3 – All rights reserved  
 Annex C 
(normative) 
 
Determination of Alphacypermethrin content in Insecticide treated 
mosquito nets 
C.1 Sampling 
Take net specimens 
C.2 Identity test 
GLC capable of operating over a range 100 to 300ºC, fitted with a flame ionization detet ector 
C.3 Alphacypermethrin 
C.3.1  As for alphacypermethrin 454/TC/(M)3  
C.3.2  Outline of method: As for alphacypermethrin is dissolved in tetrahydrofuran and determined by 
capillary gas chromatography in split injection mode using flame ionization and internal standardization  
C.4 Reagents:  
C.4.1  Tetrahydrofuran 
C.4.2  Aphacypermethrin standard of known purity,Di(2-ethylhexyl)phthalate(dioctyl phthalate, DOP), internal 
standard,purity atleast 980 g/kg and giving no peaks with similar retention times to alphcypermethrin 
C.4.3  Citric acid 5% solution. Dissolve citric acid(25g) in water (500ml) 
C.4.4  Internal standard solution. Disolve dioctyl phthalate (5.0g) intetrahydrofuran (500ml). Ensure sufficient 
quantity of this solution is prepared for all samples and calibration solutions to be analysed  
C.5 Calibration Solutions 
C.5.1  Weigh 50 mg alpha cypermethrin (to the nearest 0.1 mg) in a volumetric flask (25ml). Fill to the mark 
with THF. Place the flask in an ultrasonic bath for 10 min. After temperature equilibrium pipette 1.50 ml, 
4.50ml of this solution into three volumetric flaks (50 ml). Add  0.5 ml of internal standard solution (dioctyl 
phthalate, 1% in acetone) and fill up each to the mark with THF. 
These solutions are used as calibration solutions A (C A), B (C B) and C (C C). Transfer 200 µl out of each flask 
into separate GC vials. Add one drop of citric acid in each case and seal the vials. Place the vials into the 
sample tray (cooled down to 15º C) of the GC apparatus. 
Note: Citric acid is added to stop epimerization of alphacypermethrin in solution 
C.5.2  Description of the calibration solutions: DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  21 
 CA :concentration of approximately 3.0 mg alphacypermethrin in 50ml THF  
CB:concentration of approximately 6.0 mg alphacypermethrin in 50 ml THF  
CC:concentration of approximately 9.0 mg alphacypermethrin in 50 ml THF 
C.5.3  Apparatus 
C.5.3.1  Gas chromatograph with flame ionization detector (e.g. HP6890 Plus) 
C.5.3.2  Automatic sample injector (e.g. HP series 7683) equipped with a sample which is cooled down to 
15ºC 
C.5.3.1  Capillary column fused  silica (e.g. DB-1) 30mx 0.32 mm, film thickness of 0.25µm. 
C.5.3.2  Electronic data evaluation system (e.g. HP ChemStation) 
C.5.3.3  Ultrasonic  bath 
C.5.3.4  Electronic balance 
C.5.3.5  Laboratory glassware 
C.6 Procedure 
C.6.1  Operating conditions. As per alphacypermethrin 454/TC/(M)3  
C.6.1.1  Preparation of the samples 
C.6.1.2  Determination via the water/detergent extraction process 
C.6.1.2.1 First step: Quantification  of the adherent contents of alphacypermethrin on surface fibers  
a) Procedure done by manufacturer 
Place 2 g impregnated net in a beaker (1l).Add soap (commercially available bar soap or as flakes, 
2g/l) and water (500ml). The washing is done for 10 min. at 30º C on a shaker with 155 
movements/min. Directly after the washing, the wash liquor is acidified with 10 ml/l acetic acid 30% in 
order to prevent hydrolysis of the extracted alphacypermethrin (note:there is no difference in 
hydrolysis in neutral water compared to wash liquor after 10 min. at 30 ºC). Transfer 150 ml of the 
washing liquid into a separation funnel (500 ml). The extraction procedure is done twice with 100ml 
ethyl acetate each by shaking twice for 30 seconds. Both portions of ethyl acetate are combined 
together in a flask (250 ml). Ethyl acetate is evaporated in a rotary evaporator. The flask is stoppered 
and sent to the analytical laboratory. 
b) Procedure done by analytical laboratory 
Fill up the flask with THF(50ml). Add 0.5 ml of internal standard solution (dioctyl phthalate, 1% in 
acetone). Transfer 200 µl of sample out of the flask into a separate GC vial. Add 1 drop of citric acid 
into the vial. 
C.6.1.2.2  Second step: Quantification of the total contents of alphacypermethrin 
Weigh (to the nearest 0.1 mg) 1 g of the impregnated net into a volumetric flask (100 ml) and add THF (50 
ml). Place this flask in a refluxing apparatus. Heat up the flask in the apparatus and reflux at approximately 
90º C (oil bath temperature). Sampling will be done after 5 min. refluxing. Add 0.5 ml of internal standard 
solution (dioctyl phthalate, 1 % in acetone). Transfer 200 µl of the sample into separate GC vial. Add 1 drop of 
citric acid into the vial. DRAFT UGANDA STANDARDFDUS 307:2013 
22 ©UNBS 201 3 – All rights reserved  
 C.6.1.3  Determination via the n-hexane extraction process 
C.6.1.3.1 First step: Quantification of the adherent contents of alphacypermethrin on the surface of the 
fibers 
a) Weigh (to the nearest adherent drops of n-hexane ) out of the flask into another volumetric flask (100 
ml) and add THF (50 ml). Place this flask in a refluxing apparatus. Heat up the flask in the apparatus 
and reflux at approximately 90º C. Sampling will be done after 5 min refluxing. Add 0.5 ml of internal 
standard solution (dioctyl phthalate, 1 % in acetone) . Transfer 200 µl of the sample into a separate 
GC vial. Add I drop of citric acid into the vial. 
C.6.1.3.2  Second step:Quantification of the total contents of alpha-cypermethrin 
Transfer the net(without adherent drops of n-hexane) out of the flask in to another volumetric flask (100ml) 
and add THF (5Oml). Place this flask in a refluxing apparatus. Heat up the flask in the apparatus and reflux at 
approximately 90ºC. Sampling will be done after v5 min refluxing. Add 0.5ml of internal standard solution 
(dioctyl phthalate, 1% in actone). Transfer 200µl of the same into a separate GC vial. Add 1 drop of citric acid 
into the vial 
C.6.2.3 System calibration 
As for alphacypermethrin 454/TC/(M3)  
C.6.1.4  Determination 
Each calibration solution C i and each sample solution S J is injected twice. The following sequence is advised: 
CA ,  CA,, CB, CB,CC, CC, SA, SA,SB, SB,SC,SC,… 
C.6.1.5  Calculati on 
As for alphacypermethrin 454/TC/(M)3 and see test of linearity 
Concentration =
lqxwfxHw  
Where: f=response factor 
Hw=total peak area of alphacypermethrin (cis +ll) in the sample solution 
Lq=peak area of internal standard in the sample solution 
w=mass of sample taken 
C.6.1.6  Surface concentration and Release index 
a) Determination 
The determination of alphacypermethrin content is done via the n-hexane extraction process from 
fibers 
Each calibration solution Cj and each sample solution Sj  ai injected twice. The following sequence is 
advised: CA, CA,CB,CB,CB,CC,CC,SA1,SA1,SA2,SA2,SA3,SA3,SB1,SB1,... 
SA=refers to first rinse; S A mean value of S A1, SA2,SA3 
SB=refers to second rinse; S B mean value of S B1,SB2,SB3 DRAFT UGANDA STANDARDFDUS 307: 2013 
©UNBS 201 3 – All rights reserved  23 
 Sc=refers to third rinse;S C mean value of S C1, SC2,SC3 
Where 1,2,3 are net samples 
a) Calculation of the release index 
Calculate the mean value of sample solutions S C and S B by the equations described in 6.2.5 and the 
release index for each piece of netting. 
Release index=
) (1B
SCS S , where 
SB =refers to second rinse; S B  mean S B1,SB2,SB3 
SC=refers to third rinse; S C mean value of S C1, SC2,SC3 
 
 
 
 
 
 
 
 
 
 DRAFT UGANDA STANDARDFDUS 307:2013 
24 ©UNBS 201 3 – All rights reserved  
 Bibliography 
[1] Roll Back Malaria - Specification for Netting materials  – WHO publication  
[2] IS 9886: 1981 Indian Standard Specifications for mosquito nets   
[3] WHO Interim specification 331/LN (July 2006) 
[4] WHO Interim Specification 333/LN (December 2009) 
[5] WHO interim specification 454/LN/1(October 2009  
 
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