spray (aerosol dispensers)...containing propellant(s), synergist(s) and other formulants as...

Reference number

DRS 393-2: 2018

© RSB 2018

RWANDA STANDARD

DRS

393-2

First edition

2018-mm-dd

Spatial application mosquito repellents —

Specification —

Part 2

Spray (aerosol dispensers)

DRS 393-2: 2018

©RSB 2018 - All rights reserved ii

In order to match with technological development and to keep continuous progress in industries, standards are subject to periodic review. Users shall ascertain that they are in possession of the latest edition

© RSB 2018

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without prior written permission from RSB.

Requests for permission to reproduce this document should be addressed to:

Rwanda Standards Board

P.O Box 7099 Kigali-Rwanda

KK 15 Rd, 49

Tel. +250 788303492

Toll Free: 3250

E-mail: [email protected]

Website: www.rsb.gov.rw

ePortal: www.portal.rsb.gov.rw

mailto:[email protected]

http://www.rsb.gov.rw/

http://www.portal.rsb.gov.rw/

DRS 393-2: 2018

iii ©RSB 2018 - All rights reserved

Contents Page

Foreword .................................................................................................................................................... v

1 Scope ............................................................................................................................................. 1

2 Normative references ................................................................................................................... 1

3 Terms and definitions .................................................................................................................. 1

4 Requirements ................................................................................................................................ 3 4.1 General .......................................................................................................................................... 3 4.2 Active ingredient and synergist .................................................................................................. 4 4.2.1 Natural repellents ......................................................................................................................... 4 4.2.2 Synthetic repellents ..................................................................................................................... 4 4.2.3 Synergist content ......................................................................................................................... 5 4.3 Specific requirements .................................................................................................................. 5 4.4 Stability .......................................................................................................................................... 6 4.5 Biological efficacy ........................................................................................................................ 6

5 Sampling ....................................................................................................................................... 6 5.1 General .......................................................................................................................................... 6 5.2 Sampling, testing and acceptance ............................................................................................. 6

6 Packaging and Labelling ............................................................................................................. 7 6.1 Packaging ...................................................................................................................................... 7 6.2 Labelling ........................................................................................................................................ 7

Annex A (normative) Solvents not permitted for use in aerosols ....................................................... 9

Annex B (normative) Determination of pressure in finished aerosol packs .................................... 11 B.1 Introduction ................................................................................................................................. 11 B.2 Objective ..................................................................................................................................... 11 B.3 Scope ........................................................................................................................................... 11 B.4 Apparatus .................................................................................................................................... 11 B.5 Working operation ...................................................................................................................... 11 B.6 Accuracy of measurement ........................................................................................................ 12 B.7 Test report ................................................................................................................................... 12

Annex C (normative) Evaluation of discharge rate of filled aerosol dispensers ............................. 13 C.1 Scope ........................................................................................................................................... 13 C.2 Principle ...................................................................................................................................... 13 C.3 Apparatus .................................................................................................................................... 13 C.4 Procedure .................................................................................................................................... 13 C.5 Calculation .................................................................................................................................. 14 C.6 Reporting ..................................................................................................................................... 14

Annex D (normative) Testing of valves of filled aerosol dispensers for clogging .......................... 15 D.1 Apparatus .................................................................................................................................... 15 D.2 Procedure .................................................................................................................................... 15

Annex E (normative) Determination of DEET content ........................................................................ 16 E.1 General ........................................................................................................................................ 16 E.2 Apparatus .................................................................................................................................... 16 E.3 Preparation of calibration curve ............................................................................................... 16 E.4 Procedure .................................................................................................................................... 16

DRS 393-2: 2018

©RSB 2018 - All rights reserved iv

E.5 Calculation .................................................................................................................................. 17

Annex F (normative) Determination of permethrin ............................................................................ 18 F.1 Reagents ..................................................................................................................................... 18 F.2 Apparatus ................................................................................................................................... 18 F.3 Operating conditions ................................................................................................................. 18 F.4 Procedure ................................................................................................................................... 18 F.5 Calculation .................................................................................................................................. 19

Annex G (normative) Flame propagation ............................................................................................ 20 G.1 Principle ...................................................................................................................................... 20 G.2 Apparatus ................................................................................................................................... 20 G.3 Procedure ................................................................................................................................... 20

Annex H (normative) Determination of pH value ................................................................................ 21 H.1 General ........................................................................................................................................ 21 H.2 pH of aqueous dispersions (Method A) ................................................................................... 22 H.3 pH of aqueous dispersion (Mathod B*) ................................................................................... 22

DRS 393-2: 2018

v ©RSB 2018 - All rights reserved

Foreword

Rwanda Standards are prepared by Technical Committees and approved by Rwanda Standards Board (RSB) Board of Directors in accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT agreement on the preparation, adoption and application of standards.

The main task of technical committees is to prepare national standards. Final Draft Rwanda Standards adopted by Technical committees are ratified by members of RSB Board of Directors for publication and gazettment as Rwanda Standards.

DRS 393-2 was prepared by Technical Committee RSB/TC 015, Pharmaceutical Products.

DRS 393 consists of the following parts, under the general title Spatial application mosquito repellents— Specification:

Part 1: Coils

Part 2: Spray (aerosol dispensers)

Part 3: Candles

Part 4: Papers

Part 5: Liquid vaporizers

Part 6: Vaporizing mats

Part 7: Tablets

Part 8: Liquid detergents

Committee membership

The following organizations were represented on the Technical Committee on Pharmaceutical Products (RSB/TC 015) in the preparation of this standard.

National Industrial Research and Development Agency (NIRDA)

National Pharmacy Council (NPC)

University of Rwanda/College of Sciences and Technology (UR/CST)

Pharmacie NOVA

Rwanda Development Board (RDB)

AGROPY LTD

DRS 393-2: 2018

©RSB 2018 - All rights reserved vi

IKIREZI NATURAL PRODUCTS

HORIZON/SOPYRWA

Rwanda Social Security Board (RSSB)

Pharmavie

University of Rwanda/College of Medicine and Health Sciences (UR/CMHS)

Rwanda Biomedical Center/ Malaria and Other Parasitic Diseases Division (RBC/MOPDD)

Society for Family Health (SFH) – Rwanda

Rwanda Biomedical Center/Medical Procurement and Production Division (RBC/MPPD)

INES - RUHENGERI

Rwanda Standards Board (RSB) – Secretariat

DRS 393-2: 2018

vii ©RSB 2018 - All rights reserved

Introduction

Insecticides are used either for killing or controlling harmful insects. The insecticides which are applied for repelling insects are termed as “Repellents". Mosquito is one of the most harmful insects for mankind. To destroy them, many preparations are available on the market in various recipes like pest killer spray, soap, oil, powder, repellent etc. Out of these, mosquito repellent is the most popular as it has germicidal and disinfectant properties and is able to repel mosquitoes and is convenient to use. The mosquito repellent is used for warding off mosquitoes which is the most harmful insect. Nowadays, mosquito repellents are used for controlling mosquito and are complementing other mosquito destroyers gradually. With the rise in the standard of living, increasing urbanization and population, the demand of mosquito repellent mat is constantly increasing particularly in tropical places. It is a convenient method for protection against mosquito, so it has a tremendous market potential. Thus there is a very good scope for development of such units in the country.

Spatial repellent are chemical products designed to be 'active' (requiring heat or electricity) or 'passive' (requiring no heat or electricity) and release volatile chemicals into the air within the treated space. Product examples that are currently available include mosquito coils, sprays, candles, papers, liquid vaporizers, vaporizing mats, tablets, liquid detergents, among others. However, many more types of spatial repellent products are waiting to be developed.

Spatial repellents elicit ‘spatial repellency’ which refers to a range of insect behaviours induced by airborne chemicals that result in a reduction in human-mosquito contact. These behaviours include: movement away from a chemical stimulus, attraction-inhibition and/or, and feeding inhibition.

DRS 393-2: 2018

1 ©RSB 2018 - All rights reserved

Spatial application mosquito repellents — Specification — Part 2: Spray

(Aerosol dispensers)

1 Scope

This Draft Rwanda Standard prescribes the requirements sampling and test methods for spatial application mosquito repellents formulated and prepared as aerosol dispensers.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

RS 91, Labeling and marking of pharmaceutical products — Specification

AOAC 997.07, N-octyl Bicycloheptene dicarboximide (MGK 264), Pyrethrins and Piperonyl Butoxide (PBO) in Technical materials, concentrates and Finished Products.

DRS 394-2, Mosquito repellents ― Performance Test Guidelines ― Part 2: Spatial repellents

RS 191, Refined pyrethrum concentrate ― Specification

AOAC 973.12, d-trans-Allethrin in pesticides formulations

CIPAC 741, Determination of transfluthrin content

CIPAC 743, Determination of prallethrin (etoc) content

CIPAC 993, Determination of Metofluthrin (S1264)

CIPAC 742, Determination of d-allethrin

CIPAC 977, Determination of Meperfluthrin

3 Terms and definitions

For the purposes of this standard, the following terms and definitions apply

3.1

mosquito

©RSB 2018 - All rights reserved 2

any of numerous arthropod animals of the class mosquito, having an adult stage characterized by three pairs of legs and a body segmented into head, thorax, and abdomen and usually having one or two pairs of wings.

3.2

mosquito repellent

substance applied to skin, clothing, or other surfaces which discourages mosquito (and arthropods in general) from landing or climbing on that surface

3.3

natural repellents/biopesticides

repellents that contain natural, plant-based active ingredients

3.4

synthetic repellents

conventional repellents containing synthetic chemical active ingredients and carrier synthetic ingredient as approved by a competent authority.

3.5

aerosol dispenser

device designed to produce a fine spray of liquid or solid particles that can be suspended in a gas such as the atmosphere. When a valve is released, the propellant forces the substance through an atomizer and out of the dispenser in the form of a fine spray.

3.6

Transfluthrin

(1R,3S)-3-(2,2-Dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid (2,3,5,6-tetrafluorophenyl)methyl ester

3.7

Etoc

Prallethrin. (S)-2-methyl-4-oxo-3-prop-2-ynylcyclopent-2-enyl(1R)-cis, trans-2,2-dimethyl-3-(2-

methylprop-1-enyl) cyclopropanecarboxylate

3.8

https://en.wikipedia.org/wiki/Insect

https://en.wikipedia.org/wiki/Arthropod

DRS 393-2: 2018


Metofluthrin

C18H20F4O3, 2,3,5,6-Tetrafluoro-4-(methoxymethyl)benzyl 2,2-dimethyl-3-(prop-1-en-1-yl) cyclopropanecarboxylate

3.9

d-Alethrin

(RS)-3-allyl-2-methyl-4-oxocyclopent-2-enyl (1R)-cis, trans-chrysanthemate

3.10

Meperfluthrin

C17H16Cl2F4O3, [2,3,5,6-tetrafluoro-4-(methoxymethyl)phenyl]methyl (1R,3S)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate

3.11

PBO

Piperonyl butoxide

3.12

MGK 264

N-octyl Bicycloheptene Dicarboximide

4 Requirements

4.1 General

4.1.1 The product shall consist of a liquid formulation in a pressurised, non-refillable aerosol dispenser, containing propellant(s), synergist(s) and other formulants as required, intended for release of the active ingredient into the air in the form of an aerosol.

4.1.2 The aerosols shall not contain solvents and propellants listed in annex A.

4.1.3 The formulation shall be of uniform colour and shall be free from visible impurities.

4.1.4 When applied, the product shall have the benefit of repelling mosquitoes.


4.2 Active ingredient and synergist

4.2.1 Natural repellents

4.2.1.1 Active ingredients used in natural repellents shall be natural plant based compounds such as essential oils or any other plant extract approved as mosquito repellents.

4.2.1.2 The manufacturer shall provide adequate data on the repellence of such ingredients.

4.2.1.3 The manufacturer shall have adequate data justifying the proportion of ingredient(s) for which claims are made, used in the product.

4.2.1.4 The essential oils and plant extracts used in natural repellents shall be, but not limited to:

a) Cedarwood oil;

b) Tea tree oil;

c) Geranium oil;

d) Rosemary oil;

e) Lemongrass oil;

f) Citronella oil;

g) Soybean oil;

h) Eucalyptus oil;

i) Cinnamon oil. and

j) Neem oil

4.1.2.5 The proportion of single or blended essential oil in natural repellent shall be set by the manufacturer in accordance with specific standards of the essential oil used and records shall be availed.

4.1.2.6 Pyrethrum extracts such as pyrethrins shall be considered in natural repellents. The limits of pyrethrins in natural repellents shall not be less than 0.25 % and the extract used shall meet the requirements of RS 191.

4.2.2 Synthetic repellents

4.2.2.1 Synthetic repellents shall contain synthetic chemical compounds which are able to discourage mosquitoes and send them flying or crawling away.

DRS 393-2: 2018


4.2.2.2 If a synthetic chemical compound is blended with other active ingredient (s), either natural or synthetic, the proportion shall be set by the manufacturer based on scientific research and records shall be availed.

4.2.2.3 Active ingredients and their content in synthetic repellents shall meet the requirements prescribed in table 1.

Table 1 — Active ingredients content for synthetic repellents

S/N Active ingredient Limits (%, w/w) Identification method

1 Pyrethrins, % by mass, max 0.5 RS 191

2 Picaridin, % by mass 0.2 – 5 CIPAC 740

3 DEET, % by mass 5 – 50 Annex E

4 Permethrin, % by mass, max 13 Annex F

5 Transfluthrin, % by mass, max 1 CIPAC 741

6 Etoc, % by mass 0.5 – 1.5 CIPAC 743

7 Metofluthrin (S1264), % by mass, max

1.82 CIPAC 993

8 d-Alethrin (Pynamin Forte), % by mass, max

0.5 CIPAC 742

9 Meperfluthrin , % by mass, max 0.05 – 0.1 CIPAC 977

10 Synergists, % by mass As declared AOAC 997.07

4.2.2.4 Synthetic repellents and their active ingredients shall be approved and registered by competent authority before being released to the market.

4.2.3 Synergist content

4.2.2.1 The synergist content shall be declared and, when determined, the average content measured shall not differ from those declared.

4.2.2.2 The synergist shall be PBO, sesame seed oil (sesamin, sesamolin) and/or MGK 264. The synergist shall be tested in accordance with AOAC 997.07. The ratio of the active ingredient to the synergist shall be indicated and records availed.

4.3 Specific requirements

The product shall comply with the quality requirements given in table 2.

Table 2 – Specific requirements

S/N Parameters Requirements Test methods

i. Internal pressure, ºC 30 ± 2 Annex B

ii. Discharge rate, g formulation/sec 1 Annex C

iii. pH 5.5 – 7 Annex H

iv. Clogging of aerosol dispenser valves No clogging shall occur

Annex D


4.4 Stability

Stability at elevated temperature; After storage at 54 ±2ºC for 14 days, the determined average active ingredient content must not be lower than 95% relative to the determined average content found before storage and the formulation shall continue to conformto the requirements of the product.

4.5 Biological efficacy

When tested in accordance with DRS 394-2, the product shall repel 100 % of the mosquitoes available in space, within protection time indicated by the manufacturer.

5 Sampling

5.1 General

5.1.1 Samples shall be stored in such a manner that there is no deterioration of the material.

5.1.2 The sampling instrument shall be clean and dry.

5.1.3 Samples shall be protected against contamination.

5.2 Sampling, testing and acceptance

5.2.1 In any consignment, all the master cartons containing containers of the same type shall constitute a lot.

5.2.2 Samples shall be drawn from each lot and individually tested to ascertain whether the material complies with the specified requirements.

5.2.3 Any sample failing to comply with the specified requirements shall be termed as defective. The acceptance number shall be the maximum number of defective samples permissible for a lot to be accepted.

5.2.4 The number of containers to be drawn from the lot and the acceptance number shall be as shown in the following Table.

Table 1 — Number of containers to be drawn from the lot and the acceptance number

Total number of containers in lot

Number of containers to

be tested

Acceptance number

300 or less 301 to 1200 1201 to 2000 2001 to 7000 7001 to 15000 15001 to 24000 24001 to 41000

Over 41000

3 6

13 21 29 48 84 126

0 1 2 3 4 6 9

13

DRS 393-2: 2018


5.2.5 Each of the containers to be tested shall be drawn from a different master carton which shall be selected at random. In order to ensure randomness of selection, random number tables shall be used. If such tables are not available, the following procedure may be adopted: starting from any master carton, count the master cartons as 1, 2, 3...... r in a systematic manner. Every rth carton shall be drawn, r being the integral part of N/n, where N is the total number of master cartons in the lot and n the number of master cartons to be selected.

6 Packaging and Labelling

6.1 Packaging

6.1.1 The product shall be packaged in aerosol containers that shall protect the contents and shall not react with the product or cause any contamination during storage, handling, transportation or use.

6.1.2 Filled aerosol containers shall be appropriately classified in terms of flame propagation characteristics of their contents when tested in accordance with annex G.

a) Highly flammable — if the average length of the flame is greater than 0.45 m or if the flame burns back to the actuator, or continues to burn when the test flame is extinguished.

b) Flammable — if the average length of the flame is between 0.20 m and 0.45 m

c) Non-flammable — if the product does not burn in the manner described above (a) and (b)

6.2 Labelling

The containers shall be securely closed and in addition to the labelling requirements of RS 91 the following information shall be indelibly and legibly marked on the container:

a) name of the product;

b) name and full address of the manufacture;

c) batch number;

d) date of manufacture and expiry;

f) quantity in the container;

g) active ingredient content,

h) List of other ingredients used

i) net mass of content;

j) directions for use, including indoor or outdoor use;

k) safety precaution;


l) special population whose exposure is prohibited (out of reach of children and pregnant women); and

m) storage conditions.

DRS 393-2: 2018


Annex A (normative)

Solvents not permitted for use in aerosols

1) benzene

2) 2-butoxyethanol (ethylene glycol monobutyl ether)

3) 2-butoxyethylacetate (ethylene glycol monobutyl ether acetate)

4) carbon tetrachloride

5) chlorobenzene

6) chloroform

7) 1,2-dichloroethane (ethylene dichloride)

8) 2-ethoxyethanol (ethylene glycol monoethyl ether)

9) 2-ethoxyethylacetate (ethylene glycol monoethyl ether acetate)

10) n-hexane

11) 2-hexanone (methyl n-butyl ketone)

12) 2-methoxyethanol (ethylene glycol monomethyl ether)

13) 2-methoxyethylacetate (ethylene glycol monomethyl ether acetate)

14) tetrachloroethylene

15) trichloroethylene

16) Propellants

17) NOTE The Montreal Protocol and EU1 Directive on the withdrawal of chlorofluorocarbons (CFCs) from aerosols were noted. Hydrocarbon propellants are recommended for insecticide aerosols, provided international safety standards are met by the aerosol producer. Industry should be encouraged to develop alternative and safer propellants and delivery systems.

DRS 393-2: 2018


Annex B (normative)

Determination of pressure in finished aerosol packs

B.1 Introduction

The determination of the pressure existing in the finished aerosol packs is necessary to verify that the true pressure is compatible with the pressure limitations of the pack, and in accordance with the regulations in force.

True pressure is the relative pressure given by an accurate manometer, at a given temperature.

B.2 Objective

The determination of the true pressure in the finished aerosol pack:

a) in such a way that the measurement affects as little as possible the value of the real pressure;

b) in such a way that the manometer will not be polluted by the product under pressure present in the pack.

B.3 Scope

The method is recommended for determination of the true pressure of all filled aerosol packs.

B.4 Apparatus

The following are required:

a) a source of reference gas (nitrogen for instance) from which the pressure can be regulated by means of a control valve;

b) a manometer of high accuracy, if possible cushioned by an oil-bath and adapted to fit the aerosol container on which the measurement will be effected (Figure 1).

The apparatus must be assembled in such a way that, in the state of rest, the manometer is connected to the reference gas (the pressure of this gas being slightly higher than the actual pressure in the pack) and, for taking the measurement, the manometer is connected to the interior of the pack to show the actual pressure.

B.5 Working operation

a) Make sure that the aerosol dispenser is thoroughly equilibrated to 30 ± 2ºC.


b) The measuring apparatus must be fitted with an appropriate adaptor for the valve employed

c) The pressure of the reference gas must be regulated to a value slightly higher than the anticipated pressure of the dispenser.

d) Apply the measuring apparatus to the valve and press lightly in order to open the valve and the slide of the apparatus.

e) Read the true pressure on the manometer, when the needle has stabilized.

B.6 Accuracy of measurement

The measurement of the true pressure will be the more accurate:

a) with larger aerosol dispenser sizes;

b) with only a small difference in pressure between the reference gas and the true pressure of the dispenser (if required, measurements can be made on additional dispensers after adjusting the reference gas pressure to a value very close to the true pressure);

c) if the dead volume of the manometer is small (less than 2 ml).

B.7 Test report

The test report must indicate, in addition to the results and test conditions, any relevant working details not specified in the method, especially if they are suspected of having influenced the results.

Note 1 It is necessary to recalibrate the manometer frequently, for example with the aid of a manometric balance.

Note 2 A non-return valve can be inserted in the apparatus to avoid the aerosol product penetrating the manometer if

the pressure of the reference gas is inadvertently much lower than the true pressure in the dispenser.

DRS 393-2: 2018


Annex C (normative)

Evaluation of discharge rate of filled aerosol dispensers

C.1 Scope

The method is applicable to the majority of aerosols marketed at present. It may be used, with discretion, for dispenser fitted with vapour-phase taps where there will be a continually changing composition as the contents are discharged. It is not suitable for use in the inverted position for dispensers with vapour phase taps, as there will be a erratic discharge dependent upon the liquid content of the dip tube. Where dispensers are intended to be used in an inverted position, it is vital that the test shall be done in that way. It is important that discharge tests follow the instructions for use given on the dispenser. The method is not intended for use with metering valves.

C.2 Principle

The discharge rate of an aerosol dispenser is determined by measuring the quantity of material expelled through the valve in the given time. The exact duration of discharge, normally 10 sec, and the temperature of the dispenser must be carefully controlled for good reproducibility. Normally the test is repeated three times to give three determinations but, in the case of products filled with vapour phase tap valves, it is preferable to reduce the discharge interval to 5 sec and the number of determinations to two. This is to minimise the variation in composition that will occur as the contents are sprayed off. There will be some loss of accuracy using the shorter duration of discharge.

Alternatively, the discharge rate may be determined at different stages in the emptying of the dispenser (e.g. 90%, 70%, 50%, 30% and 10% fill) which then allows the values to be plotted graphically. Where the composition changes with the emptying of the packs, this offers a particularly convenient way of showing the effect of this change. In the case of storage test samples, a single test is normally performed at each examination to conserve the contents.

C.3 Apparatus

A water bath at 25°C ± 0.5°C, a stop watch accurate to 0.2 sec, a balance weighing to 0.1 g and a pressure gauge accurate to 2 psig (0.1 kg.cm-2) are required.

C.4 Procedure

a) The valve of the aerosol dispenser shall be handled according to label instructions and the valve shall be operated for five sec to remove material in the dip tube which may not be homogenous with the bulk of the filling.

b) The aerosol dispenser shall be immersed in a water bath maintained at 25°C ± 0.5°C for half an hour, or for sufficiently long for the contents to attain the temperature of the water bath.

c) The aerosol dispenser shall be removed from the water bath, wiped completely dry, the valve

operated for one second to remove any water in the valve, the internal pressures of the dispenser shall be measured and the dispenser shall be weighed to within 0.1g.


d) The aerosol dispenser shall then be shaken for 3 sec by hand or other suitable means and the

valve shall be operated fully open for 10 sec, timed by the stop watch. During the discharge, the dispenser shall be positioned as indicated in the instructions for use.

e) The aerosol dispenser shall be wiped clean of any liquid and re-weighed to within 0.1 g.

Procedures (b) to (d) shall be repeated twice or more and the internal pressure of the dispensers shall be measured again.

C.5 Calculation

The difference in weights derived from procedure (e) and procedure (c) shall be divided by 10 (sec). Results should not differ by more than 0.1 g from the mean of the three results. If a greater difference is found at least two more readings should be taken.

C.6 Reporting

Report valve discharge rates as g.sec-1at the measured mean pressure of the dispenser. The method, e.g. 3 x 10 sec, 2 x 5 sec or 1 x 5 sec (90%....50%....10%) spraying, etc., shall be quoted.

Notes 1. Where discharge rates are to be determined at various stages of pack emptying it is advisable to allow

the pack to reach equilibrium at 25°C in the water bath, shake and spray for 5 sec, re-shake vigorously and re-spray for another 5 sec and replace in water bath. This procedure may then be repeated until the correct pack content is reached. This rather tedious procedure avoids errors arising from the fall in temperature of the contents of the pack during prolonged spraying.

2. Results may show variations from sample to sample that are greater than might be expected from normal manufacturing tolerances. This may be due variations in the valve orifice diameter.

3. The discharge rate of freshly prepared aerosol dispensers will not normally be the same as for samples allowed to ―mature‖, due to the effect of solvents on the gasket.

DRS 393-2: 2018


Annex D (normative)

Testing of valves of filled aerosol dispensers for clogging

D.1 Apparatus

a) Fume hood b) Protective clothing and mask.

D.2 Procedure

Shake the aerosol dispensers thoroughly and, keeping them in an upright position, disperse the contents of each into the fume hood. Actuate the valve in a series of cycles (30 sec on, 30 sec off) until the dispenser is emptied. Examine the valves for clogging.


Annex E (normative)

Determination of DEET content

E.1 General

The sample is dissolved in carbon disulfide and the difference in absorbance at 14.18 µm and at 14.48 µm is determined. The quantity of meta-isomer is obtained from this value by means of a calibration curve prepared by the use of a reference standard.

E.2 Apparatus

F.2.1 Double-beam infrared spectrophotometer. Perkin-Elmer model 21 or equivalent.

F.2.2 Two equivalent infrared absorption cells, with sodium chloride windows and a path length of approximately 0.4 mm.

E.3 Preparation of calibration curve

F.3.1 Weigh (to the nearest 0.1 mg) into four volumetric flasks sufficient amounts of the reference DEET standard of known purity to give concentrations of approximately 20, 40, 60 and 80 g/L when dissolved in carbon disulfide.

F.3.2 Fill the reference cell with carbon disulfide and the sample cell with each of the standard solutions in turn, and record the spectra. The spectrum may be scanned rapidly, except for the region 12 – 15 µm, where a normal speed should be used. Carry out a blank measurement with carbon disulfide to correct for any inequality in the paired cells and to determine whether a cell correction is required.

F.3.3 Measure the absorbance at 14.18 µm and at 14.48 µm and calculate the difference between these values, ΔA, for each of the solutions. Plot the values of ΔA against the concentration (g/l) of the meta-isomer. F.3.4 If a cell correction is required, the value of ΔA is determined from the formula: ΔA = [A14.18 – A14.48]ref. - [A14.48]blank Where ref. = determination with reference standard blank = determination on CS2 blank

E.4 Procedure

Weigh (to the nearest 0.1 mg) about 0.5 g of the sample, transfer quantitatively to a 10 mL volumetric flask, and make up to the mark with carbon disulfide. Measure the infrared absorption at 14.18 μm and 14.48 μm using the same conditions as described in section A.3. Determine the concentration of meta-isomer by comparing this value with the calibration curve. A standard sample should be run each day to check the calibration of the instrument.

DRS 393-2: 2018


E.5 Calculation

DEET content (g/kg) =𝐶1 𝑥 𝑃

𝐶2

Where,

C1 = concentration (g/L) of standard DEET found from calibration curve

C2 = concentration (g/L) of sample taken

P = purity (g/kg) of the reference standard.


Annex F (normative)

Determination of permethrin

Permethrin as one of the active ingredients in this product may be determined using HPLC by injecting a solution of analyte into a chromatograph, followed by separation and comparison of peak areas of the analyte in the sample with that of an external standard.

F.1 Reagents

Cis – Permethrin, 99%

Trans - Permethrin, 99%

Methanol HPLC grade

Water, HPLC grade

F.2 Apparatus

An HPLC equipped with an autosampler, a variable wavelenght detector (or equivalent) and a column (phenomena x, 250 x 4.6mm Luna Phenyl 5μ Reverse phase (or equivalent)

F.3 Operating conditions

Flow rate 1.0mL/min

Solvent composition 60% : 40% (Methanol: Water)

Elution Isocratic

Column temperature 40oC

Wavelength 240nm

Injection volume 25 μL

Stop time 50 minutes

Post time 2 minutes

F.4 Procedure

G.4.1Preparation of standard solution

Weigh about 0.001g (to the nearest 0.0001g) Permethrin standard in beaker, use methanoldissolved and

transfer them into a separate volumetric flasks (50 ml), dilute to the mark and mix well.

DRS 393-2: 2018


G.4.2 Preparation of Solution

Weigh about 0.02 g (to the nearest 0.0001g) Permethrin test sample into beaker, use methanol dissolved and

transfer them into a separate volumetric flasks (50 ml), dilute to the mark and mix well.

G.4.3 Determination

After the chromatograph is stable, make a minimum of three injections of the standard as well as for the sample

and average the area counts. The relative standard deviation between injections should be within 2%.

F.5 Calculation

The % of either cis or trans isomers is calculated as follows;

%𝑐𝑖𝑠𝑜𝑟𝑡𝑟𝑎𝑛𝑠𝑝𝑒𝑟𝑚𝑒𝑡ℎ𝑟𝑖𝑛 =𝐴𝑣𝑒𝑟𝑎𝑔𝑒𝑠𝑎𝑚𝑝𝑙𝑒𝑎𝑟𝑒𝑎 × 𝑤𝑒𝑖𝑔ℎ𝑡𝑜𝑓𝑠𝑡𝑑 × 𝑝𝑢𝑟𝑖𝑡𝑦(𝑖𝑛%)

Average std area × weight of sample

Report the concentration of permethrin as the total of Cis and Trans.


Annex G (normative)

Flame propagation

G.1 Principle

The filled aerosol container is sprayed as a test flame under controlled conditions and length of the burning spry cone is measured.

G.2 Apparatus

H.2.1 In its simplest form, the apparatus consists of a base marked at 0.15 m intervals, an adjustable stand to carry the aerosol container which may be raised or lowered to accommodate differences in container height, a means of measuring the burning spray cone (usually a one metre fuel placed horizontally at the same level as the top third of the flame, the hottest part) a means of igniting the spray cone in the form of a test flame 0.05 m ± 0.005 m in height (usually a candle flame is used).

H.2.2 Water bath maintained at 20 °C .This equipment shall be used to bring the aerosol container and its contents to equilibrium at 20 °C (Heat the cans to 20 °C in the water bath).

G.3 Procedure

H.3.1 Place the aerosol container on the stand. Depress the actuator and adjust the height of the stand so that the spray cone will pass through the upper third test flame (hottest part).

H.3.2 Bring the aerosol container and its content to the equilibrium temperature of 20 °C. Place the container on the stand so that the point where the spray emerges is 0.15 m from the test flame. Then light the test flame and depress the actuator for 15 seconds to 20 seconds. Record the total length of the burning spray cone and specify whether or not it burns back to the actuator. H.3.3 Extinguish the test flame and record whether the spray cone continues to burn while the actuator is depressed. H.3.4 Repeat each test twice and record the flame length as the average of the three tests.

DRS 393-2: 2018


Annex H (normative)

Determination of pH value

H.1 General

I.1.1 Reagents

I.1.1.1 Potassium hydrogen phthalate (COOH-C6H4-COOK) 0.05 mol/l (0.05M)

Dissolve 10.21 g in freshly boiled distilled water, and make up to 1000 ml. Do not keep the solution for longer than one month.

I.1.1.2 Disodium tetraborate (Na2B4O7.10H2O 0.05) mol/l (0.05)

Dissolve 19.07 g in freshly boiled and cooled distilled water and make up to 1000 ml. Do not keep the solution for longer than one month.

I.1.1.3 Water

Freshly boiled and cooled distilled water of pH 5.5 to 7.0

I.1.2 Apparatus

I.1.2.1 pH meter

I.1.2.2 Glass electrode and reference electrode

I.1.3 Procedure

Operate the pH meter and electrode system inaccordance with the manufacturer’s instructions. Standardize the meter and electrodes with the 0.05 mol/l phthalate (pH 4.00) when an acid solution is being measured or 0.05 mol/l borate when an alkaline solution is being measured (see table F.1). The reading should not differ by more than 0.02 pH units from the original value at which the apparatus was standardized. If the difference is greater than 0.05, then repeat the measurements. Check the pH/mV relationship of the glass electrode daily as follows: Standardize with the 0.05 mol/l (0.05M) phthalate and measure the pH of the 0.05 mol/l borate. If the reading is higher by 0.02 or more, or lower by 0.05 or more, than the appropriate value in Table F.1, correct the pH values of all solutions measured that day, assuming the potential of the glass electrode to be in a linear relationship with the pH of the solution being measured.

Table F.1 – pH values of 0.05 mol/l (0.05M) diosodium tetraborate

Temperature (ºC)

10 15 20 25 30

pH 9.32 9.28 9.22 9.18 9.14

Unless otherwise specified, all solutions must be brought to laboratory temperature before measurement.


The temperature coefficient of the 0.05 mol/l phthalate can be neglected but that of the 0.05 mol/l borate must be taken into account (see table F.1).

When measuring pH values above 10, use a glass electrode designed for use at the alkaline end of the pH scale and apply any necessary correction.

H.2 pH of aqueous dispersions (Method A)

I.2.1 Reagent

As for I.1.1

I.2.2 Apparatus

As for I.1.2

Stoppered measuring cylinder 100 ml.

I.2.3 Procedure

Weigh 1 g of sample, transfer to the measuring cylinder containing water (about 50 ml), make up to 100 ml with water, and shake vigorously for 1 min. Allow any suspension to settle for 1 min and then measure the pH of the supernatant liquid.

H.3 pH of aqueous dispersion (Mathod B*)

I.3.1 Reagents

As for F.1.1

I.3.2 Apparatus

As for I.1.2 together with:

I.3.2.1 Mixing jar

A screw cap, glass jar, 295 to 300 ml capacity, substantially cylindrical, approximately 9 cm deep, and without abrupt shoulders.

I.3.2.2 Tumbling machine

Any mechanical device for rotating the mixing jar around its centre, end over ent, at 60 rpm.

I.3.3 Procedure

DRS 393-2: 2018


Deposite 8 g (wg) of sample on to distilled water (50 ml) in the mixing jar and allow to stand for 3 min for the powder to sink and/or soak undisturbed. Close the jar and tumble it on the machine at 60 rpm for 5 min. dilute with distilled water 9185 ml). tumble as before for 1 min. when the final tumbling is complete, allow the suspension to stand for 1 h, then measure the pH of the supernatant liquid by the method given in F.1.


Bibliography

[1] ES 757, Rules Pesticides — Determination of pH value

[2] Manual on development and use of FAO and WHO specifications for pesticides, November 2010, 2nd Edition.

[3] Official Methods of Analysis of AOAC International, 19th Edition, 2012, volume I

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