AFRICAN 
STANDARD  DARS  
1601:202 4 
First Edition 202 4 
 
 Reference No. DARS 1601 :2024(E) 
ICS 55.080  
 
 
 
© ARSO 202 4 
 
 
 
 
 
 
 
 
 
 
 
Long Lasting Insecticide Treated Mosquito Nets — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
  
 
 
Table of contents  
 
 
1 Scope  ................................ ................................ ................................ ................................ .................  viii 
2 Normative references  ................................ ................................ ................................ .........................  viii 
3 Terms and definitions  ................................ ................................ ................................ ..........................  ix 
3.1 Long Lasting Insecticidal Nets (LLIN)  ................................ ................................ ...................  ix 
3.2 mono -treated net  ................................ ................................ ................................ ..................  ix 
3.3 Multi -treated  net ................................ ................................ ................................ ....................  ix 
3.4  active ingredients  ................................ ................................ ................................ ..................  ix 
3.5 top ring  ................................ ................................ ................................ ................................ .. ix 
3.6 height  ................................ ................................ ................................ ................................ .... ix 
3.7  circumference  ................................ ................................ ................................ .......................  ix 
4 Requirements  ................................ ................................ ................................ ................................ . x 
4.1 Mono-treated nets  ................................ ................................ ................................ ..................  x 
4.1.1 General requirements  ................................ ................................ ................................ ............  x 
4.1.2  Specific requirements  ................................ ................................ ................................ ........  x 
4.1.3  Active ingredients  ................................ ................................ ................................ .............  xi 
4.2 Multi -treated  nets ................................ ................................ ................................ ..................  xi 
4.3 Shapes, sizes and dimensions  ................................ ................................ ............................  xii 
4.3.1  Shape  ................................ ................................ ................................ ..............................  xii 
4.3.2  Sizes and dimensions  ................................ ................................ ................................ ..... xii 
4.4 Manufacture and workmanship  ................................ ................................ ...........................  xiii 
4.4.1  Construction  ................................ ................................ ................................ ....................  xiii 
4.4.2  Net attachments or tying tapes  ................................ ................................ .......................  xiv 
4.4.3  Top support ring  ................................ ................................ ................................ .............  xiv 
4.4.4  Defects  ................................ ................................ ................................ ...........................  xiv 
5 Restricted colorants  ................................ ................................ ................................ .....................  xiv 
6 Packaging  ................................ ................................ ................................ ................................ .... xiv 
7 Labelling  ................................ ................................ ................................ ................................ ...... xiv 
7.1 Outside packaging  ................................ ................................ ................................ ..............  xiv 
7.2 Tag ................................ ................................ ................................ ................................ ....... xv 
8 Sampling  ................................ ................................ ................................ ................................ ....... xv 
8.1 Lot ................................ ................................ ................................ ................................ ........  xv 
8.2 Scale of sampling and testing  ................................ ................................ ..............................  xv 
A.1 Sampling  ................................ ................................ ................................ ................................ . xvi 
A.2 Identity test  ................................ ................................ ................................ ..............................  xvi 
A.3 Active ingredient (deltamethrin)  ................................ ................................ ..............................  xvii 
A.3.1  Outline of method  ................................ ................................ ................................ ...........  xvii 
A.3.2  Reagents  ................................ ................................ ................................ .......................  xviii 
A.3.3  Apparatus  ................................ ................................ ................................ ......................  xviii 
A.4 Procedure  ................................ ................................ ................................ ................................  xix 
A.4.1  Operating conditions (typical)  ................................ ................................ .........................  xix 
A.4.2  Preparation of calibration curve  ................................ ................................ ......................  xix 
A.4.3  Preparation of sample  ................................ ................................ ................................ .... xix 
A.4.4  Determination  ................................ ................................ ................................ .................  xix 
A.4.5  Calculation  ................................ ................................ ................................ .......................  xx 
B.1 Sampling  ................................ ................................ ................................ ................................ . xxi 
B.2 Identity test  ................................ ................................ ................................ ..............................  xxi 
B.3 Active ingredient (deltamethrin)  ................................ ................................ ..............................  xxi 
B.3.1  Outline of method  ................................ ................................ ................................ ...........  xxi 
B.3.2  Reagents  ................................ ................................ ................................ ........................  xxii 
B.3.3  Apparatus  ................................ ................................ ................................ .......................  xxii 
B.4 Procedure  ................................ ................................ ................................ ................................  xxii 
B.4.1  Operating conditions (typical)  ................................ ................................ .........................  xxii 
B.4.2  Preparation of calibration curve  ................................ ................................ .....................  xxiii 
B.4.3  Preparation of sample  ................................ ................................ ................................ ... xxiii 
B.4.4  Calculation  ................................ ................................ ................................ .....................  xxiii DARS 1601 :2024 
  C.1 Sampling  ................................ ................................ ................................ ................................  xxiv 
C.2 Identity tests  ................................ ................................ ................................ ...........................  xxiv 
C.3 Permethrin  ................................ ................................ ................................ ..............................  xxv 
C.3.1  Outline of method  ................................ ................................ ................................ ..........  xxv 
C.3.2  Reagents  ................................ ................................ ................................ .......................  xxv 
C.3.3  Apparatus  ................................ ................................ ................................ ......................  xxv 
C.3.4  Procedure  ................................ ................................ ................................ ......................  xxvi 
C.3.4.1  Gas chromatographic conditions (typical)  ................................ ................................ . xxvi 
C.3.4.2  Linearity check  ................................ ................................ ................................ ..........  xxvi 
C.3.4.3  System equilibration  ................................ ................................ ................................ .. xxvi 
C.3.4.4  Preparation of sample solution  ................................ ................................ .................  xxvi 
C.3.4.5  Determination  ................................ ................................ ................................ ...........  xxvii 
C.3.4.6  Calculation of permethrin content  ................................ ................................ ............  xxvii 
D.1 Sampling  ................................ ................................ ................................ ................................  xxix 
D.2 Identity tests  ................................ ................................ ................................ ...........................  xxix 
D.3 Permethrin  ................................ ................................ ................................ ..............................  xxxi 
D.3.1  Outline of the method  ................................ ................................ ................................ .... xxxi 
D.3.2  Reagents  ................................ ................................ ................................ .......................  xxxi 
D.3.3  Apparatus  ................................ ................................ ................................ .................  xxxii 
D.3.4  Procedure  ................................ ................................ ................................ .....................  xxxii 
D.3.4.1  Gas chromatographic conditions (typical)  ................................ ................................  xxxii 
D.3.4.2  Linearity check  ................................ ................................ ................................ ........  xxxiii  
D.3.4.3  System equilibration  ................................ ................................ ................................  xxxiii  
D.3.4.4  Preparation of sample solution  ................................ ................................ ...............  xxxiii  
D.3.4.5  Determination  ................................ ................................ ................................ ..........  xxxiii  
D.3.4.6  Calculation of permethrin content  ................................ ................................ ...........  xxxiii  
D.3.4.7  Calculation of trans -isomer fraction percentage  ................................ .....................  xxxiv  
E.1 Sampling  ................................ ................................ ................................ ...............................  xxxv 
E.2 Identity tests  ................................ ................................ ................................ ..........................  xxxv 
E.3 Alphacypermethrin  ................................ ................................ ................................ ................  xxxv 
E.3.1  Outline of method  ................................ ................................ ................................ .........  xxxv 
E.3.2  Reagents  ................................ ................................ ................................ ......................  xxxv 
E.3.2.1  Tetrahydrofuran.  ................................ ................................ ................................ ....... xxxv 
E.3.3  Apparatus  ................................ ................................ ................................ ....................  xxxvi  
E.3.4  Procedure  ................................ ................................ ................................ ....................  xxxvi  
E.3.4.1  Operating conditions (typical)  ................................ ................................ .................  xxxvi  
E.3.4.2  Preparation of the sample  ................................ ................................ ......................  xxxvii  
E.3.4.3  Equilibration of the system  ................................ ................................ .....................  xxxvii  
E.3.4.4  Determination  ................................ ................................ ................................ .........  xxxvii  
E.3.4.5  Calculation  ................................ ................................ ................................ .............  xxxvii  
F.1 Identity test  ................................ ................................ ................................ ...........................  xxxix  
F.2 Alphacypermethrin  ................................ ................................ ................................ ...............  xxxix  
F.2.1  Outline of method  ................................ ................................ ................................ ........  xxxix  
F.2.2  Reagents  ................................ ................................ ................................ .....................  xxxix  
F.2.3  Apparatus  ................................ ................................ ................................ ....................  xxxix  
F.2.4  Procedure  ................................ ................................ ................................ .........................  xl 
F.2.4.2  Preparation of the sample. ................................ ................................ .......................  xl 
F.2.4.3   Equilibration of the system  ................................ ................................ ....................  xli 
G.2 Identity tests  ................................ ................................ ................................ ........................  xliii 
G.3 Piperonyl butoxide  ................................ ................................ ................................ ..............  xliii 
G.3.1  Outline of method  ................................ ................................ ................................ ....... xliii 
G.3.2  Reagents  ................................ ................................ ................................ ....................  xliii 
G.3.3  Apparatus  ................................ ................................ ................................ .......................  xliii 
G.3.4  Procedure  ................................ ................................ ................................ ...................  xliv 
G.3.5  Calculation  ................................ ................................ ................................ .................  xlv 
H.1 Rectangular nets: Length, width and height  ................................ ................................ ....... xlix 
H.1.1  Apparatus  ................................ ................................ ................................ ...................  xlix 
H.1.2  Conditioning  ................................ ................................ ................................ ...............  xlix 
H.1.3  Procedure  ................................ ................................ ................................ ...................  xlix 
H.1.4  Calculation  ................................ ................................ ................................ .................  xlix  
 H.1.5  Report  ................................ ................................ ................................ ........................  xlix 
H.2 Circular nets: Top ring diameter, bottom circumference and conical height  ......................  xlix 
H.2.2  Conditioning  ................................ ................................ ................................ ...............  xlix 
H.2.3  Procedure  ................................ ................................ ................................ .......................  l 
I.1 Principle  ................................ ................................ ................................ ................................ . li 
I.2 Procedure  ................................ ................................ ................................ ..............................  li 
I.1 Principle  ................................ ................................ ................................ ................................  liii 
I.2 Procedure  ................................ ................................ ................................ .............................  liii 
 
  DARS 1601 :2024 
  Foreword  
 
The African Organization for Standardization (ARSO) is an African intergovernmental organization 
established by the United Nations Economic Commission for Africa (UNECA) and the Organization of 
African Unity (AU) in 1977. One of the fundamental mandates of  ARSO is to develop and harmonize 
African Standards (ARS) for the purpose of enhancing Africa’s internal trading capacity, increase 
Africa’s product and service competitiveness globally and uplift the welfare of African communities. The 
work of preparing A frican Standards is normally carried out through ARSO technical committees. Each 
Member State interested in a subject for which a technical committee has been established has the 
right to be represented on that committee. International organizations, Regio nal Economic Communities 
(RECs), governmental and non -governmental organizations, in liaison with ARSO, also take part in the 
work.  
 
ARSO Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.  
 
The main task of technical committees is to prepare ARSO Standards. Draft ARSO Standards adopted 
by the technical committees are circulated to the member bodies for voting. Publication as an ARSO 
Standard requires approval by at least 75 % of the member bodies casting a vo te. 
 
Attention is drawn to the possibility that some of the elements of this document may be the subject of 
patent rights. ARSO shall not be held responsible for identifying any or all such patent rights.  
 
This African Standard was prepared by ARSO TC 053, Textiles, textile products and accessories  
 
 
 
 
 
 
© African Organisation for Standardisation 202 4 — All rights reserved1* 
 
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P. O. Box 57363 — 00200 City Square  
NAIROBI, KENYA  
 
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Copyright notice  
 
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addressed as shown below or to ARSO’s member body in the country of the requester:  
 
 
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P.O. Box 57363 — 00200 City Square  
NAIROBI, KENYA  
 
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  DARS 1601 :2024 
  Introduction  
 
 
 
Malaria is a serious and sometimes fatal disease  in Africa. More than 200 million  children, and adults 
are affected yearly by malaria.  
 
As there is need to eradicate malaria, long lasting insecticidal treated mosquito nets has been 
developed to protect and prevent malaria infections and reduce  death rates.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 Long Lasting Insecticide Treated Mosquito Nets — Specification  
 
1 Scope  
 
This committee  Draft African Standard specifies requirements, sampling , and test methods for treated 
Long Lasting Insecticide  Nets (LLIN).  
 
 
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.  
 
ISO 105 -B01, Textiles — Tests for colour fastness — Part B01: Colour fastness to light: Daylight  
 
ISO 105 -B02, Textiles — Tests for colour fastness — Part B02: Colour fastness to artificial light: Xenon 
arc fading lamp test   
 
ISO 105 -C10, Textiles — Tests for colour fastness — Part C10: Colour fastness to washing with soap 
or soap and sod a 
  
ISO 139, Textiles — Standard atmospheres for conditioning and testing  
  
ISO 1833 -1, Textiles — Quantitative chemical analysis — Part 1: General principles of testing  
  
ISO 1833 -2, Textiles — Quantitative chemical analysis — Part 2: Ternary fibre mixtures  
  
ISO 1833 -16, Textiles — Quantitative chemical analysis — Part 16: Mixtures of polypropylene fibres 
with certain other fibres (method using xylene)  
 
ISO 1833 -24, Textiles — Quantitative chemical analysis — Part 24: Mixtures of polyester and certain 
other fibres (method using phenol and tetrachloroethane)   
 
ISO 1833 -25, Textiles — Quantitative chemical analysis — Part 25: Mixtures of polyester with certain 
other fibres (method using trichloroacetic acid and chloroform)  
  
ISO 2060, Textiles — Yarn from packages — Determination of linear density (mass per unit length) by 
the Skein method   
 
ISO 2076, Textiles — Man-made fibres — Generic names   
 
ISO 3758, Textiles — Care labelling code using symbols  
  
ISO 3759, Textiles — Preparation, marking and measuring of fabric specimens and garments in tests 
for determination of dimensional change   
 
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 procedures for textile testing   
 
ISO 6938, Textiles — Natural fibres — Generic names and definitions   
 
ISO 8388, Knitted fabrics — Types — Vocabulary   
 DARS 1601 :2024 
  ISO 8499, Knitted fabrics — Description of defects — Vocabulary   
 
ISO 13938 -1, Textiles — Bursting properties of fabrics — Part 1: Hydraulic method for determination of 
bursting strength and bursting distension   
 
ISO 13938 -2, Textiles — Bursting properties of fabrics — Part 2: Pneumatic method for determination 
of bursting strength and bursting distension   
 
ISO 16373 -1, Textiles — Dyestuffs — Part 1: General principles of testing coloured textiles for dyestuff 
identification  
 
ISO 16373 -2, Textiles — Dyestuffs — Part 2: General method for the determination of extractable 
dyestuffs including allergenic and carcinogenic dyestuffs (method using pyridine -water)  
 
ISO 16373 -3, Textiles — Dyestuffs — Part 3: Method for determination of certain carcinogenic dyestuffs 
(method using triethylamine/methanol ) 
 
ISO/TR 11827, Textiles — Composition testing — Identification of fibres   
 
3 Terms and definitions  
 
For the purposes of this document, the terms and definitions given in ISO 6938, ISO 2076 and the 
following apply. ISO and IEC maintain terminological databases for use in standardization at the 
following addresses:  
 
— ISO Online browsing platform: available at http://www.iso.org/obp   
 
3.1 Long Lasting Insecticidal Nets (LLIN)  
 
factory treated mosquito nets made with a netting material that has insecticide incorporated in the yarn 
or coated on the net.  
 
3.2 mono -treated net  
 
finished net treated with a single active ingredient .  
 
3.3 multi-treated  net  
finished net treated with two or more active ingredients .  
 
3.4  active ingredients  
 
biologically active substances that form part of the formulation mixture that are incorporated or coated 
in LLIN as approved by World Health Organization or any other internationally recognized body  
 
3.5 top ring  
 
ring used in conical nets and made of non-corrosive, anti -rust and anti -buckling material, fixed to the 
roof of the net . 
  
3.6 height  
 
dimension measured along a vertical seam from the top to the bottom edge of the net.  
 
3.7  circumference  
 
perimeter of the net at its bottom edge.    
  
4 Requirements  
 
4.1 Mono-treated nets  
 
4.1.1 General requirements  
 
For long lasting insecticidal mosquito nets, the type of filaments for the fabrics (determined through 
visual examination) shall be as follows:  
 
a) polypropylene: mono/multi -filament;  
b) polyester: multi -filament; and  
c) polyethylene: mono/multi -filament.  
 
4.1.2  Specific requirements  
 
Long lasting insecticidal mosquito nets shall comply with the specific requirements given in Table 1 
when tested in accordance with the test methods specified therein .  
 
Table 1 — Specific requirements for long lasting insecticidal mosquito nets  
 
Parameter  Requirement  
Test method  Polyester net  Polypropylene net  Polyethylene net  
Fibre composition  100 % polyester  100 % polypropylene  100 % polyethylene  ISO 1833 -1, 
ISO 1833 -2, 
ISO 1833 -16, 
ISO 1833 -24, 
ISO/TR 11827   
Linear density, D, min.  75 100 100 ISO 2060  
Mesh count, holes/cm2, min.  For 75D and 
100D  24 20 8 
Annex I  
For 150D  10.6 
Mass per unit area, g/m2, 
min. 28.8 35 28.8 ISO 3801  
Bursting strength at 7.3 cm2, 
kPa, min.  For 75D  250 350 250 
ISO 13938 -1 
ISO 13938 -2  For 100D  350 
For 150D  380 
Dimensional 
stability after 
one wash at 
30 °C Normal, 
%, max.  Shrinkage  10 10 10 ISO 5077, ISO 
6330, ISO 
3759  
Expansion  5 5 10 
Colour 
fastness (if 
coloured) to:  Light  4 or better  ISO 105 -B01, 
ISO 105 -B02, 
ISO 105 -C10   Washing  4 or better  DARS 1601 :2024 
  Seam  Sewn using 100 % polyester or100 % polypropylene filament thread  ISO 1833 -24, 
ISO 1833 -16 
 
 
4.1.3  Active ingredients   
 
Active ingredients used in mono -treated nets shall comply with the requirements given in Table 2 when 
tested in accordance with the test methods specified therein.  
Table 2 ― Requirements for active ingredients used in mono -treated nets  
 
S/N  Active ingredienta  Requirement  
g/kg  Test method  
I  Deltamethrin  1.05 – 3.50 Annex A, Annex B  
ii  Permethrin  15.00 – 25.00 Annex C  
iii  Alpha -cypermethrin  3.38 – 5.63 Annex E, Annex F  
a In the event that an active ingredient other than those already mentioned above is used, it shall be as 
recommended by World Health Organisation or any other internationally recognized body and their affiliated entities 
published specifications for public health pesticides for treated mosquito nets.  
 
4.2 Multi -treated  nets  
 
4.2.1  multi -treated  nets with single fibre construction shall comply with the requirements given in 
Table 1, when tested in accordance with the test methods specified therein.  
4.2.2  multi -treated  nets constructed with more than one fibre shall comply with the requirements 
given in Table 3 when tested in accordance with the methods prescribed therein.  
 
Table 3 — Requirements for Multi -treated  nets 
   
Parameter  Requirement  Test method  
Roof  Sides  
Fibre composition  Polyethylene  Polyester  ISO 1833 -1, ISO 
1833 -2, ISO 
1833 -16, ISO 
1833 -24, ISO 
1833 -25, 
ISO/TR 11827  
Linear density, D, min.  100  75 with strengthened 70 cm lower 
border or 100 without border  ISO 2060  
Mesh count, holes/cm2, min.  15.5 For 75 D and 
100 D  24 Annex I  
For 150D  10.6 
Mass per unit area, g/m2 , min. 28.8 28.8 ISO 3801   
 Bursting strength at 7.3 cm2, kPa, 
min.  300 For 75 D  250 ISO 13938 -1 
ISO 13938 -2  
For 100 D  350 
Dimensional 
stability after one 
wash at 30 °C 
Normal, %, max.  Shrinkage  10 10 
ISO 5077, ISO 
6330  Expansion  5 5 
Colour fastness (if 
coloured) to:  Light  4 or better  ISO 105 -B01, 
ISO 105 -B02, 
ISO 105 -C10  Washing  4 or better  
Active ingredienta, g/kg  Piperonyl butoxide (PBO):  
25.0 ± 25 %,  
Deltamethrin (DM): 4.0 ± 
25 % For 75D and  Deltamethrin: 
2.8 ± 25 %  Annex G, Annex 
A, Annex B  
For 100D and 
150D  Deltamethrin: 
2.1 ± 25 %  
a As per World Health Organisation or any other internationally recognized body and their affiliated entities 
published specifications for public health pesticides for treated mosquito nets.  
 
4.2.3  Active ingredients used in  multi -treated  nets with single fibre construction  shall comply with the 
requirements given in Table 4 when tested in accordance with the test methods specified therein.  
Table 4 ― Requirements for active ingredients used in multi -treated  nets with single fibre 
construction  
S/N Active ingredienta  Requirement  
g/kg Test method  
i  Permethrin  20 ± 25 %  Annex D  
ii  Piperonyl butoxide 
(PBO)  10 ± 25 %   Annex G  
a In the event that an active ingredient other than those already mentioned above is used, it shall be as 
recommended by World Health Organisation or any other internationally recognized body and their affiliated entities 
published specifications for public health pesticides for treated mosquito nets.  
 
4.3 Shapes, sizes and dimensions  
 
4.3.1  Shape  
 
Long lasting insecticidal mosquito nets shall be rectangular or conical in shape unless otherwise agreed 
between the purchaser and the supplier.  
4.3.2  Sizes and dimensions  
 
Long lasting insecticidal mosquito nets shall be supplied in sizes and dimensions as specified in Table 
5 and Table 6 for rectangular and conical nets respectively or in other sizes, as the purchaser may 
require.  DARS 1601 :2024 
  Table 5 — Sizes and dimensions for rectangular net   
S/N Net size  Width, min.  
cm  Length, min.  
cm   Height, min  
cm   Test method  
i  X-small  70  120  150  Annex H  
ii  Small  100  180  170  
iii  Medium  130  180  170  
iv  Large  160  180  170  
v  X-Large  190  180  170  
 
 
Table 6 — Sizes and dimensions for conical nets  
 
S/N Net size  Height, cm, 
min.  Bottom 
circumference,  cm, 
min.  Centre 
circumference, 
cm, min.  Top ring 
diameter,  
cm, min.   Test method  
i  Dome shaped cover net  50  230  -  -  Annex H  
ii  X-small  120  300  170  40  
iii  Single fitted conical  180  850  470  56  
iv  Double fitted conical  220  1 050  550  56  
v  Extra double fitted  250  1 250  655  65  
 
4.4 Manufacture and workmanship  
 
4.4.1  Construction   
 
4.4.1.1  Reinforcement at bottom  
 
The bottom edge of the walls shall be over -lock stitched or reinforced (self -edge finish or self -binding 
selvedge). The hem shall be firm and capable of withstanding the normal conditions of use.  A sheeting 
border may be used to improve the lifespan of nets.  
4.4.1.2  Seams and stitching  
 
When visually examined, the seams shall be of even tension throughout and loose ends securely 
fastened off. The net seams shall be made with overlock stitch and the number of stitches per decimetre 
shall be 27 to 40. The stitching shall be made by using po lyester or polypropylene multifilament sewing 
thread of matching shade.  
4.4.1.3  Knit type  
 
Long lasting insecticidal mosquito nets shall be in any one of the warp knitted constructions, for 
example, raschel and tricot as specified in ISO 8388.   
 4.4.2  Net attachments or tying tapes   
 
4.4.2.1   Rectangular nets shall be equipped with non -rusting rings or fabric loops.  
4.4.2.2   Conical nets shall be equipped with a loop and non -rusting rings.  
4.4.2.3  Each ring/loop shall have a corresponding string for suspensions.  
4.4.3  Top support ring  
 
Conical nets shall have a top support ring made of non -rusting material which can securely hold the 
net when hanged at the required position.  
4.4.4  Defects  
 
Long lasting insecticidal mosquito nets shall appear clean, be free from visible extraneous matter, 
visible damage (such as splitting or tearing) and visible manufacturing defects (such as poorly made 
seams) as described in ISO 8499.  
5 Restricted colorants  
 
The fabric for Long lasting insecticidal mosquito nets ( when  coloured) shall be free from listed amines 
and carcinogenic dyestuffs specified in ISO 16373 -1, ISO 16373 -2, and ISO 16373 -3. Dyestuff classes 
are identified in accordance with ISO 16373 -1. 
6 Packaging  
 
Long lasting insecticidal mosquito nets shall be packaged in suitable materials so as to prevent soiling 
and damage during transportation and storage.  
7 Labelling  
 
7.1 Outside packaging  
 
The following information shall be legibly and indelibly labelled on the outside packaging of individual 
nets:  
a) fibre composition;  
b) linear density;  
c) mass per unit area;  
d) net size and dimensions in centimetres (height, width and length for rectangular nets or 
diameter and height for conical nets);   
e) country of origin;  
f) colour;  
g) name and physical address of the manufacturer and/or importer/distributor;  
h) lot or batch number;  
i) name and amount (in grams per kilogram) of insecticide incorporated in the net; and  DARS 1601 :2024 
  j) care instructions in accordance with ISO 3758.  
7.2 Tag  
 
The following information shall be legibly and indelibly labelled on a permanent tag attached to individual 
nets:  
a) brand name or registered trademark;  
b) fibre composition;  
c) linear density;  
d) mass per unit area;  
a) net size and dimensions in centimetres (height, width and length for rectangular nets or 
diameter and height for conical nets;  
b) country of origin;  
c) name of the manufacturer and/or importer/distributor;  
d) lot or batch number;  
e) name and amount (in grams per kilogram) of insecticide incorporated or coated in the net;  
f) efficacy of the chemical indicated in terms of the number of washes; and  
g) care instructions in accordance with ISO 3758.  
8 Sampling   
8.1 Lot  
 
In any consignment, all the pieces of long lasting insecticidal mosquito nets delivered to a consignee 
against the same Dispatch Note shall constitute a lot.  
8.2 Scale of sampling and testing  
 
The number of pieces to be selected from a lot shall be in accordance with Table 7. Samples shall be 
tested from each lot for ascertaining conformity to the requirements of this standard.  
Table 7 — Sampling plan  
Number of pieces in a lot  Number of pieces to be sampled  
Up to 8  2  
9 - 15  3  
16 - 25  4  
26 - 50  5  
51 and above  7  
  
 Annex A  
(normative)  
 
Determination of deltamethrin content in impregnated long lasting 
insecticide treated mosquito nets by High Performance Liquid 
Chromatography (HPLC)  
A.1 Sampling  
 
A sample is defined as one finished bed net taken randomly from a batch of bed nets. Sub -sample by 
cutting five pieces of netting from the recommended positions shown in Figure A.1.  
 
 
 
 
Figure A.1 — Recommended positions for cutting netting pieces  
 
A.2 Identity test  
 
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.  
 
Chromatogram of sample solution and calibration solution are as shown in Figure A.2 and Figure A.3.  
DARS 1601 :2024 
   
Figure A.2 ― Chromatogram of a calibration solution  
 
Figure A.3 ― Chromatogram of sample solution  
A.3 Active ingredient (deltamethrin)  
 
A.3.1  Outline of method  
 
 
 The sample is extracted by refluxing with xylene. The solvent is evaporated and the residue is dissolved 
in mobile phase. The deltamethrin content is determined by normal phase high performance liquid 
chromatography using internal standardisation and detection at 254 nm.  
 
WARNING — Safe handling precautions provided on xylene material safety data sheet are to be 
observed when handling xylene, one of the hazardous reagents.  
 
A.3.2  Reagents  
 
A.3.2.1  1,4-Dioxane (HPLC grade). Add 0.15 % (v/v) water before use.  
A.3.2.2  2,2,4 -Trimethylpentane (isooctane), HPLC grade.  
A.3.2.3  Water  (HPLC grade).  
A.3.2.4  Mobile phase isooctane – 1,4-dioxane  (+ 0.15 % water), 94 + 6 (v/v).  
A.3.2.5  Dibutyl phthalate internal standard.  
A.3.2.6  Deltamethrin standard  of known purity.  
A.3.2.7  Internal standard solution , prepare a solution of dibutyl phthalate in mobile phase at a 
concentration of 2.0 g/L.  
A.3.2.8  Deltamethrin stock solution (DS) , weigh (to the nearest of 0.01 mg) 0.06 g deltamethrin 
standard ( s mg) into a volumetric flask (25 ml), add mobile phase (20 ml) and dissolve. Place the flask 
in a water bath at 20 °C for 15 min and fill to the mark with mobile phase stored at 20 °C. Mix well  
A.3.2.9  Calibration solutions , transfer using a graduated pipette 0.3 ml, 0.4 ml, 0.5 ml, 0.6 ml and 
0.7 ml of the deltamethrin stock solution to 5 polytetrafluoroethylene (PTFE) lined screw cap vials (20 
ml). Add by pipette internal standard solution (2.0 ml) to each vial and by grad uated pipette respectively 
17.7 ml, 17.6 ml, 17.5 ml, 17.4 ml, and 17.3 ml mobile phase (solutions C 1, C2, C 3, C4, and C 5) [see 
Table A.1]. Mix well. Filter the solutions through 0.45 µm syringe filters before use.  
 
Table A.1 — Calibration solutions  
Solution  Internal (Int.) 
standard  
ml Deltamethrin 
solution  
ml Mobile phase  
ml Deltamethrin  
mg 
C1 2.00 0.3 17.7 0.012s  
C2 2.00 0.4 17.6 0.016s  
C3 2.00 0.5 17.5 0.020s  
C4 2.00 0.6 17.4 0.024s  
C5 2.00 0.7 17.3 0.028s  
 
A.3.3  Apparatus  
 
A.3.3.1  High performance liquid chromatograph,  equipped with an automatic loop injector (20 
µl) and a UV spectrophotometric detector capable of measuring at 254 nm.  DARS 1601 :2024 
  A.3.3.2  Column , stainless steel, 150 mm x 4.6 mm (i.d.), packed with Lichrosorb Si60 5 µm, or 
Supelco  Si, 5 µm, or equivalent.  
A.3.3.3  Guard column  Supel guard or equivalent.  
A.3.3.4  Hot plate with magnetic stirrer.  
A.3.3.5  Reflux condenser.  
A.3.3.6  Electronic integrator or data system.  
A.3.3.7  Disposable syringe,  with 0.45 µm filter.  
A.4 Procedure  
 
A.4.1  Operating conditions (typical)  
 
Column     150 x 4.6 mm (i.d.), Lichrosorb Si60, 5 µm, or Supelco Si, 5 µm  
Mobile phase    isooctane – 1,4-dioxane (+ 0.15 % water), 94 + 6 (v/v)  
Flow rate    1.5 ml/min  
Column temperature   ambient  
Injection volume   5 µl 
Detector wavelength   254 nm  
Retention time    deltamethrin: 5.5 min  
    Internal standard: 3.7 min  
 
A.4.2  Preparation of calibration curve  
 
Inject 5 µl portions of calibration solutions C 1, C 2, C 3, C 4 and C 5 beginning with the solution with the 
lowest concentration. Prepare a calibration curve by plotting the deltamethrin to dibutyl phthalate peak 
area ratios versus the mass of the standards (mg). Using the method of least squares, calculate the 
equation for the straight line that best fits the experimental calibration data. The correlation coefficient 
should be 0.99 or better. Prepare the calibration curve daily with the full series of five standards.  
 
A.4.3  Preparation of sample  
 
Cut the sample into small pieces of less than 2 cm × 2 cm and homogenise. Weigh (to the nearest 0.1 
mg) 0.3 g (w mg) of the sample into a reflux flask (100 ml). Add xylene (18 ml) and by pipette internal 
standard solution (2.0 ml). Attach the flask to the reflux condenser and reflux the sample for about 30 
min while stirring. Cool the sample to room temperature and filter the solution through a 0.45 µm filter 
membrane. Take 0.5 ml of the filtered solution and evaporate the solvent using a stream of nitrogen . 
Dissolve the residue quantitatively in 0.5 ml of mobile phase.  
 
A.4.4  Determination  
 
Inject in duplicate 5 -µl portions of the sample solution, determine the deltamethrin to internal standard 
response ratios and calculate the average (R).   
 A.4.5  Calculation  
 
Deltamethrin content, expressed in grams per kilogram shall be calculated using the formula below:  
 
Deltamethrin  content =(𝑅−𝑏)×𝑃
𝑎×𝑤 
 
where  
R is the average deltamethrin to dibutyl phthalate peak area ratio, in the sample;  
a is the slope of calibration curve;  
b is the intercept of calibration curve;  
P is the purity, in grams per kilogram (g/kg), of the deltamethrin standard.  
 DARS 1601 :2024 
  Annex B  
(normative)  
 
Determination of deltamethrin content in coated long lasting 
insecticide treated mosquito nets by High Performance Liquid 
Chromatography  
B.1 Sampling  
 
Sampling shall be done in accordance with A.1.  
 
B.2 Identity test  
 
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.  
 
Chromatogram of deltamethrin in an insecticidal net is as shown in Figure B.1.  
 
 
Figure B.1 — Chromatogram of deltamethrin in an insecticidal net  
 
B.3 Active ingredient (deltamethrin)  
 
B.3.1  Outline of method  
 
The sample is extracted by refluxing with xylene. The solvent is evaporated and the residue is dissolved 
in mobile phase. The deltamethrin content is determined by normal phase high performance liquid 
chromatography using internal standardisation and detection at 254 nm.  
 
 
 WARNING — Safe handling precautions provided on xylene material safety data sheet are to be 
observed when handling xylene, one of the hazardous reagents.  
 
 
B.3.2  Reagents  
 
B.3.2.1  1,4-Dioxane (HPLC grade). Add 0.15 % (v/v) water before use.  
B.3.2.2  2,2,4 -Trimethylpentane (isooctane), HPLC grade.  
B.3.2.3  Water  (HPLC grade).  
B.3.2.4  Mobile phase isooctane – 1,4-dioxane  (+ 0.15 % water), 94 + 6 (v/v).  
B.3.2.5  Dibutyl phthalate internal standard.  
B.3.2.6  Deltamethrin standard  of known purity.  
B.3.2.7  Internal standard solution , prepare a solution of dibutyl phthalate in mobile phase at a 
concentration of 2.0 g/l.  
B.3.2.8  Deltamethrin stock solution (DS) , weigh (to the nearest of 0.01 mg) 0.06 g deltamethrin 
standard ( s mg) into a volumetric flask (25 ml), add mobile phase (20 ml) and dissolve. Place the flask 
in a water bath at 20 0C for 15 min and fill to the mark with mobile phase stored at 20 0C. Mix well.  
B.3.2.9  Calibration solution, weigh (to the nearest 0.1 mg) in duplicate about 50 mg deltamethrin 
standard ( s mg) into a volumetric flask (50 ml). Dissolve and fill to mark with solvent mixture. Transfer 
by pipette 1.0 ml of these solutions into separate volumetric flasks (50 ml) and dilute to the mark with 
solvent mixture. Mix well (solutions C 1 and C 2). 
B.3.3  Apparatus  
 
B.3.3.1  High performance liquid chromatograph,  equipped with an automatic loop injector (20 
µl) and a UV spectrophotometric detector capable of measuring at 254 nm.  
B.3.3.2  Column , stainless steel, 150 x 4.6 mm (i.d.), packed with Lichrosorb Si60 5 µm, or Supelco 
Si, 5 µm, or equivalent.  
B.3.3.3  Guard column,  supel guard or equivalent.  
B.3.3.4  Hot plate with magnetic stirrer.  
B.3.3.5  Reflux condenser.  
B.3.3.6  Electronic integrator or data system.  
B.3.3.7  Disposable syringe,  with 0.45 µm filter.  
B.3.3.8  Screw capped bottle,  of neutral glass with PTFE screw cap liner.  
B.4 Procedure  
 
B.4.1  Operating conditions (typical)  
 
Column     150 x 4.6 mm (i.d.), Lichrosorb Si60, 5 µm, or Supelco Si, 5 µm  
Mobile phase    isooctane – 1,4-dioxane (+ 0.15 % water), 94 + 6 (v/v)  DARS 1601 :2024 
  Flow rate    1.5 ml/min  
Column temperature   ambient  
Injection volume   5 µl 
Detector wavelength               254 nm  
Retention time                deltamethrin: 5.5 min  
    Internal standard: 3.7 min  
B.4.2  Preparation of calibration curve  
 
Inject 5 -µl portions of calibration solutions C 1, C 2, beginning with the solution with the lowest 
concentration. Prepare a calibration curve by plotting the deltamethrin to dibutyl phthalate peak area 
ratios versus the mass of the standards (mg). Using the method of least squares, calculate the equation 
for the straight line that best fits the experimental calibration data. The correlation coefficient should be 
0.99 or better.  
 
B.4.3  Preparation of sample  
 
B.4.3.1  Weigh (to the nearest 0.1 mg) sufficient sample to contain about 1 mg deltamethrin ( w mg) into 
a well tightened screw capped neutral glass bottle (100 ml). Add by pipette solvent mixture (50.0 ml). 
Place the cap and tighten it well. Check for any loss of solvent during the extraction procedure by 
weighing the bottle before and after the ex traction. Wipe out the bottle before weighing. The weight 
before and after the extraction should not differ by more than 0.05 g.  
 
B.4.3.2  Place the bottle into an ultrasonic bath for 15 min. Then place the bottle in a shaker and shake 
at ambient temperature for 30 min at a frequency of 155 beats per min. Allow to cool to ambient 
temperature. Filter the solution through a 0.45 -μm filter prio r to injection.  
 
B.4.4  Calculation  
 
Deltamethrin content, expressed in grams per kilogram shall be calculated using the formula below:  
 
 
Deltamethrin  content =𝑓×𝐻𝑤
𝑤×50 
  
 Annex C  
(normative)  
 
Determination of permethrin content in long lasting insecticide 
treated mosquito nets  
C.1 Sampling  
 
Take at least 500 g.  
 
C.2 Identity tests  
 
C.2.1  Use the Gas liquid chromatography (GLC) method below. The retention times of cis- 
and trans -permethrin should not deviate by more than 1 % from those of the permethrin 
standard and the intensities of the permethrin isomers should give the same pattern as in the 
standard (Figure C.1).  
 
 
Figure C.1 ― Example of gas chromatogram of permethrin LN  
 
C.2.2  Infrared, extract the sample with a suitable solvent. Filter and evaporate the solvent. Prepare 
a film between NaCl plates and scan from 4 000 cm-1 to 400 cm-1. The spectrum produced from the 
sample should not differ significantly from that of the standard (Figure C.2).  
DARS 1601 :2024 
   
Figure C.2 ― Infrared spectrum of permethrin  
C.3 Permethrin  
 
C.3.1  Outline of method  
 
The content of permethrin (sum of cis- and trans -isomers) is determined by capillary Gas 
Chromatography (GC) using flame ionisation detection and triphenyl phosphate as internal standard. 
The trans -isomer fraction is calculated from the chromatogram obtained.  
 
C.3.2  Reagents  
 
C.3.2.1  Heptane.  
C.3.2.2  Acetone.  
C.3.2.3  Permethrin working standard, technical product of certified purity; store refrigerated.  
C.3.2.4  Triphenyl phosphate internal standard , shall not show peaks with the same retention 
times as cis- and trans -permethrin.  
C.3.2.5  Internal standard solution , dissolve triphenyl phosphate (1.0 g) in heptane (150 ml). 
Ensure that a sufficient quantity of this solution is prepared for all samples and calibration standards to 
be analysed.  
C.3.2.6  Calibration solution , homogenise the permethrin working standard. When the permethrin 
is waxy solid or partly waxy solid homogenise it by warming it to melting and by stirring. Prepare 
calibration solutions in duplicate. Weigh (to the nearest 0.1 mg) 72 mg to 88 mg ( s mg) of permethrin 
standard into a vial or stoppered flask (200 ml). Add by pipette internal standard solution (10.0 ml) and 
dissolve. Add by measuring cylinder heptane (90 ml) and mix well (solutions C A and C B). 
C.3.3  Apparatus  
 
 
 C.3.3.1  Gas chromatograph , equipped with a split/split less injection and a flame ionisation 
detector.  
C.3.3.2  Capillary column , fused silica, 30 m x 0.25 mm (i.d.), film thickness: 0.25 μm, coated with 
crosslinked dimethyl polysiloxane (DB -1 or equivalent).  
C.3.3.3  Electric integrator or data system.  
C.3.4  Procedure  
 
C.3.4.1  Gas chromatographic conditions (typical)  
 
C.3.4.1.1  Column , fused silica, 30 m x 0.25 mm (i.d.), film thickness: 0.25 μm, coated with cross 
linked dimethyl polysiloxane (DB -1 or equivalent).  
C.3.4.1.2  Injection system:  
a) injector, split injection;  
b) split flow, approximately 100 ml/min; and  
c) injection volume, 1 μm.  
C.3.4.1.3  Detector, flame ionisation  
C.3.4.1.4  Temperatures, column oven, 240 °C  
C.3.4.1.5  Injection port, 265 °C  
C.3.4.1.6  Detector, 265 °C  
C.3.4.1.7  Carrier gas, helium, 30 cm/s  
C.3.4.1.8  Retention times:  
a) triphenyl phosphate: about 6.5 min;  
b) cis-permethrin: about 12.4 min; and  
c) trans -permethrin: about 12.9 min . 
C.3.4.2  Linearity check  
 
Check the linearity of the detector response by injecting 1 μl of solutions with permethrin concentrations 
0.5, 1 and 2 times that of the calibration solution before conducting analysis.  
C.3.4.3  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 1.0 %. Then inject a 1 μl portion of the second solution. 
The response factor for this solution should not deviate by more than 1.0 % from that for the first 
calibration solut ion, otherwise prepare new calibration solutions.  
C.3.4.4  Preparation of sample solution  
 
Clean a pair of scissors with acetone before use. Cut the sample with scissors into 5 mm – 10 mm 
squares. Prepare sample solutions in duplicate for each sample. Weigh (to the nearest 0.1 mg) sufficient DARS 1601 :2024 
  sample to contain 36 mg to 44 mg ( w mg) of permethrin into a vial or stoppered flask (100 ml). Add by 
pipette internal standard solution (5.0 ml) and by measuring cylinder heptane (45 ml). Place the vial or 
stoppered flask in a water bath (85 °C - 90 °C) for 45 min. Shake the vial or stoppe red flask once or 
twice during the extraction. Filter a portion of each sample solution through a filter paper prior to analysis 
(solutions S A and S B). 
C.3.4.5  Determination  
 
Inject in duplicate 1 -μl portions of each sample solution bracketing them by injections of the calibration 
solutions as follows; calibration solution C A, sample solution S A, sample solution S A, calibration solution 
CB, sample solution S B, sample solution S B, calibration solution C A, and so on. Measure the relevant 
peak areas.   
 
C.3.4.6  Calculation of permethrin content  
 
C.3.4.6.1  Calculate the mean value of each pair of response factors bracketing the two injections of 
a sample using the formula below:  
𝑓1= ℎ ×𝑆 ×𝑃
𝐻𝑠 ×2 
where  
f1 is the individual response factor;  
s is the mass, in milligrams, of permethrin working standard in the calibration solution;  
P is the purity, in grams per kilograms, of permethrin working standard; and  
Hs is the total peak area, of permethrin (cis -permethrin + trans -permethrin) in the calibration 
solution;  
C.3.4.6.2  Use the value obtained above for calculating the permethrin contents, expressed in grams 
per kilogram, using the formula below:  
𝐶𝑜𝑛𝑡𝑒𝑛𝑡  𝑜𝑓 𝑝𝑒𝑟𝑚𝑒𝑡 ℎ𝑟𝑖𝑛 = 𝑓 × 𝐻𝑤
𝑙𝑞 ×𝑊 
where  
f is the mean response factor;  
Hw is the total peak area, of permethrin (cis -permethrin + trans -permethrin) in the sample solution;  
Ir is the peak area, of the internal standard in the calibration solution;  
Iq is the peak area, of the internal standard in the sample solution;  
w is the mass, in milligrams, of sample taken; and  
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  
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  
 
 DARS 1601 :2024 
  Annex D  
(normative)  
 
Determination of permethrin content in incorporated insecticidal 
nets in the presence of piperonyl butoxide  
D.1 Sampling  
 
Take at least 500 g.  
 
D.2 Identity tests  
 
D.2.1  Use the GLC method below. The retention times of cis- and trans -permethrin should not deviate 
by more than 1% from those of the permethrin standard and the intensities of the permethrin isomers 
should give the same pattern as in the standard (Figure D.1).  
 
Figure D.1 — Gas chromatogram of permethrin/piperonyl butoxide LN  
 
D.2.2  Use a Gas Chromatography -Mass Spectrometry  (GC-MS) apparatus connected to a mass 
spectrometer with an electron impact ion source and separate the components by the GLC method 
below. Record the mass spectra of the peaks found at the retention times assigned to cis- and trans -
permethrin. The mass spectra should match those found from the standard (Figures D.2 to D.5).  
 
  
Figure D.2 — Mass spectrum of cis -permethrin from chromatogram of sample solution  
 
 
Figure D.3 — Mass spectrum of cis -permethrin from chromatogram of calibration solution  
DARS 1601 :2024 
   
Figure D.4 — Mass spectrum of trans -permethrin from chromatogram of sample solution  
 
Figure D.5 — Mass spectrum of trans -permethrin from chromatogram of calibration solution  
D.3 Permethrin  
 
D.3.1  Outline of the method  
 
The content of permethrin (sum of cis- and trans -isomers) is determined by capillary GC using flame 
ionisation detection and dicyclohexyl phthalate as internal standard. The trans -isomer fraction is 
calculated from the chromatogram obtained.  
 
D.3.2  Reagents  
 
D.3.2.1  Heptane.  
 
 D.3.2.2  Permethrin standard  technical product,  of certified purity, store refrigerated.  
D.3.2.3  Dicyclohexyl phthalate  internal standard , shall not show peaks with the same retention 
times as cis-permethrin, trans - permethrin and piperonyl butoxide.  
D.3.2.4  Internal standard solution , dissolve dicyclohexyl phthalate (0.73 g) in heptane (100 ml). 
Ensure that a sufficient quantity of this solution is prepared for all samples and calibration standards 
to be analysed.  
D.3.2.5  Calibration solution,  homogenise the permethrin working standard. When the permethrin 
is waxy solid or partly waxy solid homogenise it by warming it to melting and by stirring. Prepare 
calibration solutions in duplicate. Weigh (to the nearest 0.1 mg) 72 mg to 88 mg ( s mg) of permethrin 
standard into a vial or stoppered flask (200 ml). Add by pipette internal standard solution (10.0 ml) and 
dissolve. Add by measuring cylinder heptane (90 ml) and mix well (solutions C A and C B). 
D.3.3  Apparatus  
D.3.3.1  Gas chromatograph,  equipped with a split/split less injection and a flame ionisation 
detector.  
D.3.3.2  Capillary column,  fused silica, 30 m x 0.25 mm (i.d. ), film thickness: 0.25 μm, coated with 
crosslinked dimethyl polysiloxane (DB -1 or equivalent).  
D.3.3.3  Electric integrator or data system.  
D.3.4  Procedure  
 
D.3.4.1  Gas chromatographic conditions (typical)  
 
D.3.4.1.1  Column,  fused silica, 30 m x 0.25 mm ( i.d.), film thickness: 0.25 μm, coated with cross 
linked dimethyl polysiloxane (DB -1 or equivalent).  
D.3.4.1.2  Injection system  
a) Injector, split injection;  
b) Split flow, approximately 100 ml/min; and  
c) Injection volume, 1 μm.  
D.3.4.1.3  Detector,  flame ionisation  
D.3.4.1.4  Temperatures  
Column oven,  240 °C (use a short temperature program to remove formulants, if necessary)  
D.3.4.1.5  Injection port,  265 °C  
D.3.4.1.6  Detector,  265 °C  
D.3.4.1.7  Carrier gas,  helium, 30 cm/s  
D.3.4.1.8  Retention times  
a) dicyclohexyl phthalate: about 8.4 min;  
b) cis-permethrin: about 12.4 min; and  
c) trans -permethrin: about 12.9 min.  DARS 1601 :2024 
  D.3.4.2  Linearity check  
 
Check the linearity of the detector response by injecting 1 μl of solutions with permethrin concentrations 
0.5, 1 and 2 times that of the calibration solution before conducting analysis.  
D.3.4.3  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 1.0 %. Then inject a 1 -μl portion of the second solution. 
The response factor for this solution should not deviate by more than 1.0 % from that for the first 
calibration solution, otherwise prepare new calibration solutions.  
D.3.4.4  Preparation of sample solution  
 
Clean a pair of scissors with acetone before use. Cut the sample with scissors into 5 mm – 10 mm 
squares. Prepare sample solutions in duplicate for each sample. Weigh (to the nearest 0.1 mg) sufficient 
sample to contain 36 to 44 mg ( w mg) of permethrin into a vial or stoppered flask (100 ml). Add by 
pipette internal standard solution (5.0 ml) and by measuring cylinder heptane (45 ml). Place the vial or 
stoppered flask in a water bath (85 °C – 90 °C) for 45 min. Shake the vial or stoppe red flask once or 
twice during the extraction. Filter a portion of each sample solution through a filter paper prior to analysis 
(solutions S A and S B). 
D.3.4.5  Determination  
 
Inject in duplicate 1 -μl portions of each sample solution bracketing them by injections of the calibration 
solutions as follows; calibration solution C A, sample solution S A, sample solution S A, calibration solution 
CB, sample solution S B, sample solution S B, calibration solution C A, and so on. Measure the relevant 
peak areas.   
D.3.4.6  Calculation of permethrin content  
 
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 (expressed in grams per kilogram) of the 
bracketed sample injections. Calculate the sum of the ci s- and trans - permethrin peak areas for each 
injection.  
𝑓1= ℎ ×𝑆 ×𝑃
𝐻𝑠 ×2 
𝐶𝑜𝑛𝑡𝑒𝑛𝑡  𝑜𝑓 𝑝𝑒𝑟𝑚𝑒𝑡 ℎ𝑟𝑖𝑛 = 𝑓 × 𝐻𝑤
𝑙𝑞 ×𝑊 
where  
f1 is the individual response factor;  
f is the mean response factor;  
Hs is the total peak area of permethrin (cis -permethrin + trans -permethrin) in the calibration 
solution;  
Hw is the total peak area of permethrin (cis -permethrin + trans -permethrin) in the sample solution;  
Ir is the peak area of the internal standard in the calibration solution;  
Iq is the peak area of the internal standard in the sample solution;  
s is the mass, in milligrams, of permethrin working standard in the calibration solution;   
 w is the mass, in milligrams, of sample taken; and  
P is the purity, in grams per kilograms, of permethrin working standard.  
 
D.3.4.7  Calculation of trans -isomer fraction percentage  
 
trans −isomer  fraction  percentage = 𝐻𝑤𝑡
(𝐻𝑤𝑡+ 𝐻𝑤𝐶)×100 
where  
Hwt is the peak area of trans -permethrin in the sample solution; and  
HwC is the peak area of cis-permethrin in the sample solution.  
 
 DARS 1601 :2024 
  Annex E  
(normative)  
 
Determination of alphacypermethrin content in coated long lasting 
insecticide treated mosquito nets  
E.1 Sampling  
 
Take at least 100 g.  
E.2 Identity tests  
 
E.2.1  Use the GLC method below. The relative retention times of alpha -cypermethrin with respect to 
the internal standard for the sample solution should not deviate by more than 1 % from those of the 
calibration solution.  
E.2.2  Infrared , prepare potassium bromide discs from the sample and from alpha -cypermethrin 
standard, using approximately 15 mg material and 300 mg potassium bromide. Scan the discs from 4 
000 cm-1 to 400 cm-1. The spectrum produced from the sample should not differ significantly from that 
of the standard.  
E.3 Alphacypermethrin  
 
E.3.1  Outline of method  
 
Alphacypermethrin is dissolved in tetrahydrofuran and determined by capillary gas chromatography in 
split injection mode using flame ionization and internal standardization.  
E.3.2  Reagents   
 
E.3.2.1  Tetrahydrofuran.  
 
E.3.2.2  Aphacypermethrin standard  of known purity, Di(2 -ethylhexyl)phthalate [Dioctyl Phthalate 
(DOP)], internal standard, purity at least 980 g/kg and giving no peaks with similar retention times to 
alphcypermethrin.  
E.3.2.3  Citric acid  5 % solution, dissolve citric acid (25 g) in water (500 ml).  
E.3.2.4  Internal standard solution , dissolve dioctyl phthalate (5.0 g) intetrahydrofuran (500 ml). 
Ensure sufficient quantity of this solution is prepared for all samples and calibration solutions to be 
analysed.  
E.3.2.5  Calibration solutions , weigh 50 mg alpha cypermethrin (to the nearest 0.1 mg) in a volumetric 
flask (25 -ml). Fill to just below the mark with tetrahydrofuran and place the flask in an ultrasonic bath 
for 10 min. Allow to cool to room temperature and fill to the mark with tetra hydrofuran. Transfer by 
pipette 1.50 ml, 3.00 ml and 4.50 ml of this solution into separate volumetric flasks (50 ml). Add 0.5 ml 
of internal standard solution and fill each to the mark with tetrahydrofuran (solutions C A, CB and C C).  
Transfer 200 µl from 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 15 °C) of the GC apparatus.  
NOTE  Citric acid is added to stop epimerization of alphacypermethrin in solution.   
 E.3.3  Apparatus  
 
E.3.3.1  Gas chromatograph,  capable of operating over the range 100 °C to 300 °C, fitted with a 
flame ionisation detector, split/splitless injector and autosampler.  
E.3.3.2  Capillary column fused silica 30 m x 0.25 mm with DB -1 of 0.25 µm film thickness (or 
equivalent dimethyl polysiloxane phase).  
E.3.3.3  Electronic integrator or data system.   
E.3.3.4  Reflux condenser.  
E.3.4  Procedure  
 
E.3.4.1  Operating conditions (typical)  
 
Column  Fused  silica,  30 m × 0.25 mm (i.d.) and 0.25 m film thickness  
coated  with dimethyl  poly- siloxane  packing  
Injection  system  
Injector  Split/splitless  with fused  silica  liner containing a 1 cm plug of 
glass wool. It is  important  that the split liner is thoroughly  deactivated  and conditioned  before  use, 
to ensure no degradation of alpha -cypermethrin  occurs.  
 
Split ratio approximately  75-100 : 1 
Split vent approximately  75 ml/min  
Injection  volume  1 l 
   Detector  Flame  ionisation  
   Temperatures  
      Column  oven  225 °C to 235 °C, isothermal  
     Injection  port 260 °C 
Detector  300 °C 
Gas flow rates  
Helium  (carrier  gas) approximately  0.8 ml/min  (140 kPa at 230 °C)       Helium  (make  up)
 60 ml/min  or optimum  for instrument  
Septum  purge  2 ml/min  
Hydrogen  25 ml/min to 30 ml/min.)  or as recommended  for 
Air 200 ml/min to 300 ml/min)  the particular  instrument  
Retention  times  alpha -cypermethrin  cis I: approximately    27 min 
alpha -cypermethrin  cis II: approximately      29 min 
DOP:  approximately:  14 min 
 
Purify all gases through molecular sieves. Purify the carrier gas further through an oxygen trap.  DARS 1601 :2024 
  E.3.4.2  Preparation of the sample  
 
Weigh samples in triplicate. Weigh (to the nearest 0.1 mg) 1 g of the impregnated net ( w mg) into a 
round bottomed flask (100 ml) and add tetrahydrofuran (50 ml). Connect the flask to a reflux condenser. 
Heat the flask in an oil bath at approximately 90 °C for 5 min. Allow the flask to cool to room temperature 
and transfer the contents quantitatively to a volumetric flask (100 ml). Add internal standard solution 
(0.5 ml) and fill to the mark with tetrahydrofuran. Transfer 200 µl from each flask into separa te GC vials 
(solutions S 1, S2 and S 3). Add one drop of citric acid in each case and seal the vials. Place the vials into 
the sample tray (cooled to 15 °C) of the GC apparatus   
E.3.4.3  Equilibration of the system  
 
Inject a portion of one of the calibration solutions. Adjust the column oven temperature to obtain 
retention time windows for dioctyl phthalate 12.2 min to 14.9 min, for the cis II isomer 24.0 min to 29.7 
min and for the cis I isomer 22.7 min to 27.7 min. In order to obtain adequate resolution the retention 
times of the cis I and the cis II peaks relative to the DOP peak should be not less than 1.9 and 2.0 
respectively. Carry out alternate 1.0 l injections of the calibration solutions C A and C B until the r esponse 
factors consistently (at least two injections of each) differ by less than ± 1 % of the mean.  
E.3.4.4  Determination  
 
Inject into the gas chromatograph 1.0 -l portions of the calibration solutions C A and C B and the sample 
solutions S A and S B in the following sequence and record the alpha -cypermethrin integrated peak areas. 
Injection sequence: C A1, SA1, SA2, CB1, CA2, SB1, SB2, CB2. 
Calculate the relative response factors ( f1, f2,…) for the pair of calibration solutions which bracket the 
sample solutions for example, use C A1 and C B1 for sample injections S A1 and S A2…, and obtain the 
mean response factor f. Repeat sample analysis if calibration response factors f1 and f2 differ by more 
than ±2 % of the mean f. Calculate for each sample injection for example, S A1 the alpha - cypermethrin 
cis II content (expressed in grams per kilogram).  
E.3.4.5  Calculation  
 
f= 𝐼𝑟×𝑠×𝑃×𝑣
𝐻𝑠 
Content  of alpha −cypermethrin = 𝑓×𝐻𝑤×2
𝐼𝑞×𝑤 
where  
f is the average relative response factor;  
Hs is the area of alpha -cypermethrin cis II peak in the calibration solution;  
Hw is the area of alpha -cypermethrin cis II peak in the sample solution;  
Ir is the area of the internal standard peak in the calibration solution;  
Iq is the area of the internal standard peak in the sample solution;  
s is the mass, in milligrams, of alpha -cypermethrin standard taken for the calibration solution;  
w is the mass, in milligrams, of sample taken;  
P is the purity, in grams per kilogram, of alpha -cypermethrin reference substance;   
 v is the dilution factor (0.06, 0.12, and 0.18 for calibration solutions C A, CB and C C respectively).  
Calculate the alpha -cypermethrin cis II content of the sample as the mean of the four determinations as 
follows:  
Sample  injection  Use response  factor  from Content,  g/kg  
SA1 CA1 and CB1 Q ) 
) X 
SA2 CA1 and CB1 R ) 
SB1 CA2 and CB2 S ) 
) Y 
SB2 CA2 and CB2 T ) 
Take the mean of the values X and Y as the alpha -cypermethrin content.  
Repeatability r      = 17 g/kg at 954 g/kg active ingredient content  
Reproducibility R = 20 g/kg at 954 g/kg active ingredient content  
 
 
 
 
 
 DARS 1601 :2024 
  Annex F  
(normative)  
 
Determination of Alphacypermethrin content in incorporated long 
lasting insecticide treated mosquito nets  
F.1 Identity test  
 
F.1.1  Use the GLC method below. The relative retention times of alpha -cypermethrin with respect to 
the internal standard for the sample solution should not deviate by more than 1 % from those of the 
calibration solution.  
F.1.2  Infrared , prepare potassium bromide discs from the sample and from alpha -cypermethrin 
standard, using approximately 15 mg material and 300 mg potassium bromide. Scan the discs from 4 
000 cm-1 to 400 cm-1. The spectrum produced from the sample should not differ significantly from that 
of the standard.  
F.2 Alphacypermethrin  
 
F.2.1  Outline of method  
 
The net sample is extracted with xylene.  
F.2.2  Reagents   
 
F.2.2.1  Tetrahydrofuran.  
F.2.2.2  Aphacypermethrin standard  of known purity. Store below 4 °C. 
F.2.2.3  Di(2-ethylhexyl) phthalate (dioctyl phthalate, DOP), internal standard , purity at least 
980 g/kg and giving no peaks with similar retention times to alphcypermethrin.  
F.2.2.4  Citric acid  5 % solution, dissolve citric acid (50 g) in tetrahydrofuran (500 ml).  
F.2.2.5  Internal standard solution , dissolve dioctyl phthalate (50 mg) in tetrahydrofuran (1 000 
ml). Ensure sufficient quantity of this solution is prepared for all samples and calibration solutions to be 
analysed.  
F.2.2.6  Xylene (mixed isomers)  
F.2.2.7  Calibration solutions,  weigh (to the nearest 0.1 mg) 110 mg alpha -cypermethrin ( s mg) 
into a volumetric flask (1 000 ml). Dissolve and fill to the mark with xylene. Transfer using a graduated 
pipette 40 ml, 60 ml and 80 ml of this solution into three separate volumetric flasks (100 ml). Fill to the 
mark with xylene and mix well (soluti ons C 1, C2, C3). Transfer by pipette (45.0 ml) of each solution to 
separate glass stoppered flasks (150 ml), add by pipette internal standard solution (50.0 ml) and citric 
acid 10 % solution (5 ml) to each flask. Mix well and fill to the mark with xylene ( solutions C A, CB and 
CC respectively).  
F.2.3  Apparatus  
 
F.2.3.1  Gas chromatograph,  capable of operating over the range 100 °C to 300 °C, fitted with a 
flame ionisation detector, split/splitless injector and autosampler.   
 F.2.3.2  Capillary column fused silica 30 m x 0.25 mm with DB -1 of 0.25 µm film thickness (or 
equivalent dimethyl polysiloxane phase).  
F.2.3.3  Reflux condenser.  
F.2.4  Procedure  
 
F.2.4.1  Operating conditions (typical)  
Column  Fused  silica,  30 m × 0.25 mm (i.d.) and 0.25 m film thickness  
coated  with dimethyl  poly- siloxane  packing.  
Injection  system  
Injector  Split/splitless  with fused  silica  liner containing a 1 cm plug of 
glass wool. It is  important  that the split liner is thoroughly  
deactivated  and conditioned  before  use, to ensure no 
degradation of alpha -cypermethrin  occurs.  
Split ratio approximately  75-100 : 1 
Split vent approximately  75 ml/min  
Injection  volume  1 l 
Detector  Flame  ionisation  
Temperatures  
Column  oven  225 °C  to 235 °C, isothermal  
Injection  port 260 °C 
Detector  300 °C 
Gas flow rates  
Helium  (carrier  gas) approximately  0.8 ml/min  (140 kPa at 230 0C) Helium  (make  up)
 60 ml/min  or optimum  for instrument  
Septum  purge  2 ml/min  
Hydrogen  25 ml/min to 30 ml/min  or as recommended  for 
Air 200 ml/min to 300 ml/min  the particular  instrument  
Retention  times  alpha -cypermethrin  cis I: approximately  27 min 
alpha -cypermethrin  cis II: approximately  29 min 
DOP:  approximately:  14 min 
Purify all gases through molecular sieves. Purify the carrier gas further through an oxygen trap.  
F.2.4.2  Preparation of the sample.  
Weigh (to the nearest 0.1 mg) 1 g ( w mg) of the impregnated net into a 250 ml ground glass round 
bottomed flask. Add xylene (90 ml) and citric acid 10 % solution (10 ml). Attach the flask to a reflux 
condenser and reflux for 30 min. Cool to room temperature and stir. Add by pipette internal standard 
solution C B (100.0 ml) and stir. Filter through a 0.45 μm filter before analysis (solution S). Transfer a 
quantity of the solution to a GC vial.  DARS 1601 :2024 
  F.2.4.3   Equilibration of the system  
Linearity check, check the linearity of the detector response by injecting in duplicate 1 μl of the 
calibration solutions C A, C B and C C. Prepare a curve by plotting the alpha -cypermethrin to internal 
standard peak area ratio versus the mass of alpha -cypermethrin in the calibration solutions. Using the 
method of least squares calculate the equation for the straight line that best fits the experimental data. 
The correlation coefficient should be 0.999 or better.  
Inject a portion of one of the calibration solutions. Adjust the column oven temperature to obtain 
retention time windows for dioctyl phthalate 12.2  min to 14.9 min, for the cis II isomer 24.0 min to 29.7 
min and for the cis I isomer 22.7  min to 27.7 min. In order to obtain adequate resolution the retention 
times of the cis I and the cis II peaks relative to the DOP peak should be not less than 1.9 and 2.0 
respectively. Carry out alternate 1.0 l injections of the calibration solutions C A and C B until the r esponse 
factors consistently (at least two injections of each) differ by less than ±1 % of the mean.  
F.2.4.4  Determination  
Inject into the gas chromatograph 1.0 l portions of the calibration solutions C A and C B and the sample 
solutions S A and S B in the following sequence and record the alpha -cypermethrin integrated peak areas. 
Injection sequence: C B, CB, S1, S1, CB, CB, S2, S2,….. 
Calculate the relative response factors ( f1, f2,…) for the pair of calibration solutions which bracket the 
sample solutions for example, use C A1 and C B1 for sample injections S A1 and S A2 etc and obtain the 
mean response factor f. Repeat sample analysis if calibration response factors f1 and f2 differ by more 
than ±2 % of the mean f. Calculate for each sample injection for example, S A1 the alpha - cypermethrin 
cis II content (expressed in grams per kilogram).  
F.2.4.5  Calculation  
f= 𝐼𝑟×𝑠×𝑃×𝑣
𝐻𝑠 
Content  of alpha −cypermethrin = 𝑓×𝐻𝑤×2
𝐼𝑞×𝑤 
where  
f is the mean response factor;  
Hs is the peak area of alpha -cypermethrin in the calibration solution;  
Hw is the peak area of alpha -cypermethrin in the sample solution;  
Ir is the peak area of the internal standard in the calibration solution;  
Iq is the peak area of the internal standard in the sample solution;  
s is the mass, in milligrams, of alpha -cypermethrin standard taken for the calibration solution;  
w is the mass, in milligrams, of sample taken;  
P is the purity, in grams per kilogram, of alpha -cypermethrin reference substance;  
v is the dilution factor (0.027 for calibration solution C B). 
Calculate the alpha -cypermethrin cis II content of the sample as the mean of the four determinations as 
follows:   
 Sample  injection  Use response  factor  from Content,  g/kg  
SA1 CA1 and CB1 Q ) 
) X 
SA2 CA1 and CB1 R ) 
SB1 CA2 and CB2 S ) 
) Y 
SB2 CA2 and CB2 T ) 
 
 
Take the mean of the values X and Y as the alpha -cypermethrin content.  
Repeatability r      = 17 g/kg at 954 g/kg active ingredient content  
Reproducibility R = 20 g/kg at 954 g/kg active ingredient content  
 
 DARS 1601 :2024 
  Annex G  
(normative)  
 
Determination of Piperonyl butoxide in impregnated insecticidal 
nets in the presence of deltamethrin  
G.1 Sampling  
Sample in accordance with A.1.  
G.2 Identity tests  
GLC  
GC-MS 
G.3 Piperonyl butoxide  
G.3.1  Outline of method  
The sample is extracted by refluxing with xylene. The piperonyl butoxide content is determined by 
capillary gas chromatography using flame ionisation detection and internal standard.   
WARNING — Safe handling precautions provided on xylene material safety data sheet are to be 
observed when handling xylene, one of the hazardous reagents.  
G.3.2  Reagents  
G.3.2.1  Xylene.  
G.3.2.2  Piperonyl butoxide standard  of known purity, store below 0 °C.  
G.3.2.3  Octadecane internal standard . 
G.3.2.4  Internal standard solution , weigh (to the nearest 0.1 mg) into a volumetric flask (50 ml) 
octadecane (0.4 g). Fill to the mark with xylene and mix well.   
G.3.2.5  Calibration solutions , allow piperonyl butoxide to equilibrate to ambient temperature. 
Then weigh (to the nearest 0.1 mg) 0.25 g piperonyl butoxide ( s mg) into a volumetric flask (50 ml). Fill 
to the mark with xylene and mix well. Transfer using a graduated pipette 0.50 ml, 1.50 ml, 2.00 ml, 3.00 
ml and 4.00 ml of this solution to 5 volumetric flasks (25 ml). Add 2 ml of internal standard solution to 
each flask, fill each to the mark with xylene and mix well (solutions C A, CB, CC, CD and C E). Filter  the 
solutions through a 0.45 µm PTFE filter membrane and transfer 200 µl portions into GC vials.  
G.3.3  Apparatus  
G.3.3.1  Gas chromatograph,  capable of operating over the range of 180 °C to 250 °C fitted with 
flame ionisation detection.  
G.3.3.2  Capillary column fused silica , 30 m x 0.32 mm (i.d.) coated with 100% methyl 
polysiloxane, cross -linked, surface bonded stationary phase and 0.25 µm film thickness (TRI or 
equivalent).   
G.3.3.3  Electronic integrator or data system.   
 G.3.3.4  Reflux condenser.  
G.3.3.5  Disposable syringe,  with 0.45 µm filter.  
G.3.4  Procedure  
G.3.4.1  Operating conditions (typical)  
Column  Fused silica, 30 m x 0.32 mm (i.d.) with 100 % methyl polysiloxane, 
cross -linked, surface bonded stationary phase and 0.25 µm film 
thickness (Durabond -1 or equivalent)  
Injection system      
 Injector     Split injection  
 Injector temperature   250 °C  
 Split ratio     0:1 
 Purge flow     1 ml/min  
 Injection volume    1 µl 
Detection system  
 Type     Flame ionisation  
 Temperature     300 °C  
Oven temperatures  
 Initial      180 °C  
 Program      180 °C hold for 11 min  
         200 °C at 10 °C/min, hold for 8 min  
         210 °C at 10 °C/min, hold for 18 min  
         245 °C at 30 °C/min, hold for 4 min  
 Total run time    45 min  
Gas flow rates  
 Helium (carrier)    linear velocity: 39 cm/min at 180 °C  
 Helium (make up)    30 ml/min  
 Hydrogen     40 ml/min  
 Air     400 400 ml/min  
 Total flow    35 ml/min  
Retention times     
 Piperonyl butoxide  about 23 min  DARS 1601 :2024 
   Octadecane    about 6 min  
G.3.4.2  Preparation of sample  
Cut the sample into small pieces of less than 2 cm × 2 cm and homogenise. Weigh (to the nearest 0.1 
mg) about 0.5 g ( w g) of the sample into a reflux flask (100 ml). Add xylene (23.0 ml) and by pipette, 
2.0 ml of internal standard solution. Attach the flask to the reflux condenser and reflux the sample about 
30 min while stirring. Cool the sample to room temperature and f ilter the solution through a 0.45 -µm 
PTFE filter membrane. Transfer 200 µl of the sample to a GC vial.   
G.3.4.3  System equilibration  
Inject into the gas chromatograph a 1 -µl portion of the sample solution to condition the column and to 
check for the appropriate flow rates and integration events.  
G.3.4.4  Determination and preparation of calibration curve  
Inject in duplicate into the gas chromatograph 1 -µl portions of the calibration and sample solutions in 
the following sequence; C A, CA, CB, CB, CC, CC, CD, CD, CE, CE, S1, S1, S2, S2, etc.  
Prepare a curve by plotting the piperonyl butoxide to internal standard peak area ratios versus the mass 
of piperonyl butoxide in the calibration solutions (0.01 s, 0.03 s, 0.04s, 0.06 s, and 0.08 s mg respectively). 
Using the method of least squares, calculate the equation for the straight line that best fits the 
experimental piperonyl butoxide to internal standard response ratios of the sample solutions and 
calculate the average ( R) for each sample.  
G.3.5  Calculation   
Piperonyl butoxide, expressed in grams per kilogram, shall be calculated using the formula below:  
Content  of piperonly  butoxide = (𝑅−𝑏)×𝑃
𝑎×𝑤 
where  
R is the average piperonyl butoxide to octadecane peak ratio in the sample;  
a is the slope of calibration curve;  
b is the intercept of calibration curve;  
P is the purity, in grams per kilogram, of the piperonyl butoxide standard.  
Illustrations for the Chromatogram are as shown in Figures G.1 to G.4.  
NOTE  A deltamethrin peak will not be visible on the chromatogram at the conditions given.   
  
Figure G.1 — GC chromatogram of calibration solution  
 
Figure G.2 — GC chromatogram of sample solution  
DARS 1601 :2024 
   
Figure G.3 — GC-MS chromatogram of sample solution  
 
  
Figure G.4 — Full scan MS spectrum of piperonyl butoxide (a) in the standard solution and (b) 
in the sample solution  
 
 
 
DARS 1601 :2024 
  Annex  H 
(normative)  
 
Measurement of mosquito net dimensions  
H.1 Rectangular nets: Length, width and height  
H.1.1  Apparatus  
H.1.1.1  Flat table.  
H.1.1.2  Measuring tape or steel rule.  
H.1.2  Conditioning  
Condition the net samples in accordance with ISO 139.  
H.1.3  Procedure  
Lay the conditioned net sample on a flat table (H.1.1.1), and take measurements of height, width and 
diameter.  
H.1.4  Calculation  
If more than one net sample is tested, take the average measurement for each 
dimension.  
H.1.5  Report  
Report the value of the net dimension as the average calculated in H.1.4 in centimetres.  
H.2 Circular nets: Top ring diameter, bottom circumference and conical height  
H.2.1  Apparatus  
H.2.1.1  Hook  supported at a vertical distance of at least more than the height of the net sample to 
be tested.  
H.2.1.2  Measuring tape or steel rule.  
H.2.1.3  Twine , of measuring at least 10 m.  
H.2.1.4  Felt pen marker.  
H.2.2  Conditioning  
Condition the net sample in accordance with ISO 139.   
 H.2.3  Procedure  
H.2.3.1  Top ring diameter  
H.2.3.1.1  Procedure  
Place the top portion of the net sample on a flat table (see H.1.1.1) and put the twine (see H.2.1.3) 
around the circumference of the top ring of the net sample, identifying the two ends with a marker (see 
H 2.1.4) which represent the dimension of the top ring. Using a measuring tape (see H.2.1.2) determine 
the top ring circumference (s) of the net as the distance between the two points marked on the twines. 
Repeat the test on each of the other net samples.  
H.2.3.1.2  Calculation  
Take the average of the individual measurements as the top circumference of the conical nets.  
H.2.3.1.3  Report  
Report the top ring circumference as the value(s) calculated in H.2.3.1.2 in centimetres.  
H.2.3.2  Bottom circumference  
H.2.3.2.1  Procedure  
Lay the bottom part of the net on a flat table removing any curls and take the measurement (N) from 
one end of the flattened net to the other using a twine. Repeat the procedure for other net samples.  
H.2.3.2.2  Calculation  
Take the average of the measurements ( N) taken in H.2.3.2.1.  
Calculate the bottom circumference as: N x 2.  
H.2.3.2.3  Report  
Report the value of bottom circumference of the net as the value ( N x 2) calculated in H.2.3.2.2 in 
centimetres.  
H.2.3.3  Conical net height   
H.2.3.3.1  Procedure  
Hang the net with the loop from a hook. Take measurements of height along all the vertical seams.  
H.2.3.3.2  Report  
Report the least measurement taken as the conical net height.  DARS 1601 :2024 
  Annex  I 
(normative)  
 
Determination of mesh count  
I.1 Principle  
Mesh size is determined by counting the number of holes in a square of the fabric. Counting may be 
done directly on the fabric or indirectly by scanning/photocopying the fabric. Indirect methods may ease 
counting and provide a permanent record. Before coun ting, the fabric should be conditioned in 
accordance with ISO 139 (4 h, 20 ºC, 65 % relative humidity).   
I.2 Procedure  
Use a template to define the square of netting, taking care not to stretch or distort the fabric. The 
template should be a rigid sheet, 1 mm - 2 mm thick, in or on which an accurately calibrated (±1 % in 
each dimension) square (for example, 2 cm x 2 cm or 5 cm x 5 cm) has been cut or marked. If a template 
is not available and a ruler shall be used, great care is required to ensure that the area counted is 
square. If possible, at least one edge of the square to be counted should be aligned with a row of 
comp lete holes in the fabric. Count replicate squares in pieces selected and calculate the average and 
note the lowest value.  
Rectangular and conical mosquito nets are illustrated in Figure I.1 and Figure I.2  
 
Figure I.1 — Typical illustration of a rectangular mosquito net  
 
 
  
Figure I.2 — Typical illustration of a conical mosquito net  
 
 
DARS 1601 :2024 
  Annex I  
(normative)  
 
Determination of mesh count  
I.1 Principle  
Mesh size is determined by counting the number of holes in a square of the fabric. 
Counting may be done directly on the fabric or indirectly by scanning/photocopying 
the fabric. Indirect methods may ease counting and provide a permanent record. 
Before coun ting, the fabric should be conditioned in accordance with ISO 139 (4 h, 
20 ºC, 65 % relative humidity).  
I.2 Procedure  
Use a template to define the square of netting, taking care not to stretch or distort the 
fabric. The template should be a rigid sheet, 1 mm - 2 mm thick, in or on which an 
accurately calibrated (±1 % in each dimension) square (for example, 2 cm x 2 cm or 
5 cm x 5 cm) has been cut or marked. If a template is not available and a ruler shall 
be used, great care is required to ensure that the area counted is square. If possible, 
at least one edge of the square to be counted should be aligned with a row of 
comp lete holes in the fabric. Count replicate squares in pieces selected and 
calculate the average and note the lowest value.  
Rectangular and conical mosquito nets are illustrated in Figure I.1 and Figure I.2.  
 
Figure I.1 — Typical illustration of a rectangular mosquito net  
 
  
 
Figure I.2 — Typical illustration of a conical mosquito net  
  
 
 
 
 
 
 
  
DARS 1601 :2024 
   
 
 
Bibliography  
 
EAS 455: 2022, Long lasting insecticide treated mosquito nets — Specification