Reference number  
DRS 405: 2019  
© RSB 2019  
 
 
 RWANDA 
STANDARD  DRS 
405 
 
First edition  
2019 -mm-dd 
 
Pesticides — Methods of sampling  
 
  DRS 405: 2019  
©RSB 2019  - 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 2019  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reprodu ce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw   
ePortal: www.portal.rsb.gov.rw   DRS 405: 2019  
iii                ©RSB 2019  - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................  v 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and defi nitions  ................................ ................................ ................................ ...........................  1 
4 Objective  ................................ ................................ ................................ ................................ ................  5 
5 Safety precautions  ................................ ................................ ................................ ................................  5 
6 General principles of sampling  ................................ ................................ ................................ ............  5 
6.1 Sampling protocol for on -site examination of packaging  ................................ ................................ . 6 
6.2 Sampling protocol for laboratory testing  ................................ ................................ ............................  6 
7 Preparations for sampling  ................................ ................................ ................................ ....................  7 
7.1 Sampling devices and sample bottles  ................................ ................................ ................................  7 
7.2 Sampling preparation ................................ ................................ ................................ ............................  8 
8 Monitoring the properties of pesticide packages  ................................ ................................ ..............  9 
9 Sampling for testing physical and chemical properties  ................................ ................................ .. 10 
9.1 Technical active ingredients  ................................ ................................ ................................ ..............  10 
9.2 Formulations  ................................ ................................ ................................ ................................ ........  10 
9.2.1  Liquid formulations (solutions, emulsifiable concentrates, suspension concentrates, 
emulsions)  ................................ ................................ ................................ ................................ ............  11 
9.2.2  Particulate solids (dusts, dispersible powders, water dispersible granules, granular 
formulations)  ................................ ................................ ................................ ................................ ........  12 
10 Shipping and transporting samples  ................................ ................................ ................................ .. 13 
Annex  A (normative)  Sampling of water dispersible granules  ................................ ................................ ... 14 
A.1 Scope  ................................ ................................ ................................ ................................ ....................  14 
A.2 Outline of method  ................................ ................................ ................................ ................................  14 
A.3 Apparatus  ................................ ................................ ................................ ................................ .............  14 
A.4 Procedure  ................................ ................................ ................................ ................................ .............  14 
Annex  B (normative)  Dust content and apparent density of granular pesticide formulations  ...............  16 
B.1 Sampling  ................................ ................................ ................................ ................................ ..............  16 
B.1.1  Apparatus  ................................ ................................ ................................ ................................ .............  16 
B.1.2  Procedure  ................................ ................................ ................................ ................................ .............  16 
B.2 Preparation of sample  ................................ ................................ ................................ .........................  16 
B.3 Apparent density after compaction without pressure  ................................ ................................ ..... 18 
B.3.1  Apparatus  ................................ ................................ ................................ ................................ .............  18 
Annex  C (Informative)  Supply and certificat ion of reference substances of pesticide active 
ingredients  ................................ ................................ ................................ ................................ ...........  21 
C.1 Introduction  ................................ ................................ ................................ ................................ ..........  21 
C.2 Supply of reference substances  ................................ ................................ ................................ ........  21 
C.3 Supply by the manufacturer  ................................ ................................ ................................ ...............  21 
C.4 Certification  ................................ ................................ ................................ ................................ ..........  22 
Annex  D (Informative)  Model sampling report  ................................ ................................ .............................  23 DRS 405: 2019  
©RSB 2019  - All rights reserved                  iv 
  DRS 405: 2019  
v                ©RSB 2019  - All rights reserved  
 Foreword   
Rwanda Standard s 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 S tandards 
adopted by Technical committ ees are ratifie d by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS 405 was prepared by Technical Committee RSB/TC 024, Chemicals and Consumer Products . 
In the preparation of this standard, reference was made to the following sta ndard:  
ES 694 : Pesticides – Methods of sampling  
The assistance de rived from the above source is hereby acknowledged with thanks.  
Committee membership  
The following organizations were represented on the Technical Committee on Chemicals and Consumer 
Products (RSB/TC 024) in the preparation of this standard.  
Star Construction and Consultancy (SCC) Ltd  
University of Rwanda/College of Science and Technology (UR/CST)  
HORIZON/SOPYRWA Ltd  
University of Rwanda/College of Education  
AGRO PY Ltd  
Rwanda  Standards Board  (RSB) – Secretariat  
  DRS 405: 2019  
1                ©RSB 2019  - All rights reserved  
 Pesticides  — Methods of sampling  
1 Scope   
This Draft Rwanda Standard prescribes the methods of sampling of representative test samples of liquid and 
solid agricultural pesticides  
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.  
DRS xxx, Pesticides  — Terminology  
RS ISO 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes 
of openings  
 
3 Terms and definitions   
For the purposes of this standard, the terms and definitions given in DRS 406 and the following apply.  
3.1 
analytical  portion  
a portion of a suitably prepared and appropriately homogenized laboratory sample  (see 3.11)  which is 
analyzed or tested; also known as a test portion  
3.2 
bulk sample  
the combined total of the primary samples taken from the batch. The bulk sample should be mixed thoroughly 
before dividing it into (at least three) equal laboratory samples. The bulk sample should not be  less than 300 g 
or 300 ml for technical materials, 6 00 ml for liquid formulations and 1800 g for solid formulations. These 
requirements may be increased, depending upon the tests required. Where the bulk sample is comprised of 
small packages (e.g. sachets), each containing less than these quantities: either  the packaged should be 
opened and the contents thoroughly, but carefully, mixed before subdivision into the laboratory samples; or 
the intact packages should be d ivided equally and randomly  between the laboratory samples but, in the case, 
each laboratory sample must consist of at least three individual containers. Where a batch of a formulation is 
stored or transported in si ngle bulk container, the bulk sample should consist of samples taken from a number 
of points in the batch .  
©RSB 2019  - All rights reserved                  2 
 3.3 
consignment  
a quantity of one or more materials delivered at one time. A consignment of pesticides may consist of one or 
more batches or parts of batches . 
3.4 
distribution  
the process by which pesticides are supplied through trade channels to local or international markets  
3.5 
end - user  
the persons or organizations using the pesticide for its intended purpose  
3.6 
IATA  
International Air Transport Association  
3.7 
ICAO  
International Civil Aviation Organization  
3.8 
IMO 
International Maritime Organization  
3.9 
Inspector ( Sampling Offi cer) 
a person who has been properly trained in reliable and safe sampling, and who is authorized by the 
responsible authority to examine pesticides and take samples for controlling the quality of pesticides and their 
packaging  
NOTE  The inspector should carry an appropriate identification or authorization document.  DRS 405: 2019  
3                ©RSB 2019  - All rights reserved  
 3.10 
label  
the written or graphic information on, or attached to, the immediate container of the pesticide and its external 
packaging, if any  
3.11 
laboratory sample  
the portion of material whic h is obtained by the specified sampling procedure, and which is sent to the 
laboratory for testing  
NOTE  The laboratory sample should not be less than 100 g or 100 ml for technical materials, 200 ml for liquid 
formulations and 600  for solid formulations. Th ese requirements may be increased, depending upon the tests required. 
Where the laboratory sample is comprised of more than one intact container of a formulation, each container shall be 
analyzed individually, if practicable. In this case, each container s hall meet the specification and, in case of dispute, the 
containers comprising the replicate laboratory samples shall also be analyzed separately.  
3.12 
packaging  
the container together with the protective wrapping used to transport pesticides, via wholesal e or retail 
distribution, to end u sers 
3.13 
packaging unit  
an individual container containing pesticide, and/or a retail package containing a number of smaller packages 
or containers, each usually less than 2L or 2 Kg, of pesticide  
3.14 
primary sample  
a qu antity of material, loose or packaged, taken, with or without a sampling tool, from a single sampling 
position in a container or batch  
NOTE  Where a formulation is packaged for the end user in quantities larger than that required for the bulk sample, 
the pr imary sample and the bulk sample may be indistinguishable as the corresponding laboratory samples are withdrawn 
from a single container . For small packages containing less material than the minimum amount required for the sample, 
the next larger packaging unit (e.g.: a box containing a sufficient number of small packages ) may be opened to take 
randomly the necessary number of small packages (i.e. primary samples) to prepare the bulk sample.  
3.15 
RID 
International Regulation concerning the Carriage of Danger ous Goods by Rail   
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 3.16 
random sampling  
a sampling procedure in which each package or portion of material has an equal chance of being chosen  
3.17 
referee analysis  
an analysis performed in an independent laboratory staffed by suitably experienced personnel,  agreed by the 
parties to a dispute, in order to certify the quality of a disputed sample  
3.18 
registration certificate  
a document issued by the responsible government organization which sets out specification for a formulated 
pesticides  
3.19 
responsible a uthority  
the government agency or agencies responsible for regulating the manufacture, distribution and/or use of 
pesticides, and more generally for implementing registration  
3.20 
sampling assistant  
a person allocated to help the inspector in handling cont ainers, sampling equipment etc.  
NOTE  A sampling assistant can only take samples under supervision from the inspector  
3.21 
sampling report  
the standard report from completed one to be attached to each laboratory sample and one to be retained by 
the inspecto r for his/her own record.  
NOTE  At least four copies are required, one to be attached to each laboratory sample and one to be retained by the 
inspector for his/her own record  
3.22 
testing laboratory  
a laboratory which is authorized by the responsible authority to test pesticides for their compliance with quality 
specifications.  DRS 405: 2019  
5                ©RSB 2019  - All rights reserved  
 4 Objective  
The objective of this sampling procedure is to provide sufficient representative material for testing the 
packaging and physical and chemical properties of pesticides, to ensure that pesticides moving in trade meet 
their minimum quality specifications, and that their physical state and chemical composition are suitable for 
safe and efficient use.  
The procedure has been established harmonization to ensure that samples are collected safely and at an 
appropriate stage, are representative, and will arrive at their destination intact. The procedure may be used for 
commercial or official regulatory purpo ses. 
5 Safety precautions  
Pesticides are toxic chemicals, which can poison if handled improperly. These sampling guidelines are not 
intended to provide detailed safety instructions and therefore sampling inspectors should be informed of, and 
comply with, the  safety precautions required for specific pesticides and should wear appropriate protective 
clothing as indicated by labels or pictograms. The general precautions to be taken include the following.  
 Take great care to avoid contamination of the eye, skin or  clothing, ingestion of pesticides, or 
inhalation of dusts and vapours. Take similar care to avoid contamination of personal belongings and 
the local environment. Do not keep food in the immediate vicinity. If practicable, sample pesticides only 
in a well -ventilated environment.  
 Take care to avoid spillage or splashing of liquids or spreading of dusts. Take particular care in 
handling leaking containers or those with a build up of material around the opening.  
 Before sampling make sure washing facilities are  available, in case of accidental spillage and for 
adequate washing after sampling is completed.  
 Do not eat, smoke or drink during sampling or before removing protective clothing and washing 
thoroughly.  
 Attach labels to sample containers before starting th e sampling. As far as practicable, ensure that the 
outsides of sample containers are not contaminated with the sample material.  
 Ensure the safe and proper cleaning of equipment and the safe disposal of contaminated materials 
such as personal protective clo thing and equipment, tissue paper, etc.   
6 General principles of sampling  
Sampling and subsequent analysis of the sample taken constitute the most effective way to monitor 
compliance with quality specifications. Although sampling should preferably be done by  removing material 
from positions in a batch which are chosen in a statistically random manner, in practice the positions may be 
limited by accessibility and safety. If random sampling is not practicable, the method of selecting primary 
samples  should be n oted in the Sampling Report under Remarks.   
©RSB 2019  - All rights reserved                  6 
 6.1 Sampling protocol for on -site examination of packaging  
The general sampling protocol for on -site examination of packaging is as follows:  
 
Figure 1 – General sampling protocol for on -site examination  
6.2 Sampling prot ocol for laboratory testing  
6.2.1  The general sampling protocol for laboratory testing is as follows:  
 
DRS 405: 2019  
7                ©RSB 2019  - All rights reserved  
 Figure 2 – General sampling protocol for laboratory testing  
6.2.2  Where applicable, the samples for laboratory testing may be taken from packaging units, which have 
been selected for on -site examination.  
6.2.3  Sampling may be carried out at any point in the distribution of pesticides, from the factory to the retail 
outlet.  
6.2.4  The role of the inspector in collecting samples and forwarding them to t he testing laboratory is crucial 
to the success of the testing carried out. The inspector must be well trained in sampling procedures. In all 
cases the sampling technique used must ensure that the samples taken enable the analyst to provide results 
which a re representative of the material sampled. The inspector must therefore follow established procedures 
for sampling, handling and packaging.  
6.2.5  The basic principles of sampling of technical active ingredients  and formulations differ because of 
their subs equent uses. Technical active ingredients are processed into formulations. During this procedure the 
raw material is likely to be mixed thoroughly and consequently its average properties should be determined 
from composite samples representing the batch. O n the other hand, each container of a formulation should 
meet the quality specification. Consequently the material removed from each package should be analyzed 
separately.  
6.2.6  The quality of technical active ingredients should be tested at manufacturing or formulating plants, 
etc., before formulation.  
6.2.7  Formulated pesticides may be checked before distribution at manufacturing, formulati on and 
packaging plants o r, in the case of imported formulations, at central depots or stores. If practicable, sample s 
should be taken from retail outlets before the beginning of the normal season of use for the pesticide, so that 
effective corrective action can be taken, if required.  
6.2.8  The bulk sample should be thoroughly mixed and divided into three equal laborator y samples. The 
three laboratory samples are provided for the testing laboratory; the organization agreed by both parties to 
retain referee samples; and the person designated responsible for the batch at time of sampling. A Sampling 
Report should be complet ed in a minimum of four copies. One copy of the sampling report should accompany  
each laboratory sample and the last copy should be retained by the Inspector.  
6.2.9  The recommended form of sampling report is shown in annex D . In the remarks section of the report, 
the Inspector should record his/her observations of the suitability of the storage conditions; whether the 
pesticide was exposed to frost, water, prolonged sunshine or high temperature; whether opened containers 
were present; the apparent homogenei ty of the batch; whether segregated fractions of the formulation were 
sampled separately and how many such samples were taken from the batch.  
7 Preparations for sampling  
7.1 Sampling devices and sample bottles  
7.1.1  Appropriate, clean equipment and containers mu st be used to take and retain samples, to avoid 
contamination from outside sources , to ensure that contamination of the sampling officer is minimized and to 
enable the analyst to analyze the submitted material satisfactorily.   
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 7.1.2  Bottles, their seals and  sampling equipment must be approved by the testing laboratory. Bottles 
should be made of glass but solvent -resistant plastic may be satisfactory in certain cases.  
7.2 Sampling preparation  
a) Collect information on:  
 The toxicity of, and handling instructions for,  the pesticides to be sampled;  
 The amount of laboratory sample required for the tests;  
 The nature and identify of pesticide materials to be sampled and the number and sizes of packaging 
units involved.  
b) Select appropriate:  
 Sampling apparatus, e.g. 50 – 100 mL pipettes; 3 -way pipette fillers; siphon -and-lift hand pumps 
(possibly with interchangeable non -drip discharge tubes suitable for hydrocarbons); dip tubes; sample 
triers, scoops, etc.; sample bottles (pre ferably glass containers with caps that can be tig htly closed); 
plastic bags (without ventilation holes); plastic sheets; tools for opening pesticide containers; 
containers for pesticides where the original containers are to be emptied;  
 Portable balance(s) with a suitable weighing range;  
 Labels which can be firmly glued or otherwise attached to the sample containers;  
 Sealing tape and wax seal, or official printed tape to certify the authorized opening of containers and to 
indicate the amount taken as sample (only where national legislation permits selling resealed 
containers);  
 Personal safety devices, e. g. appropriate gloves (suitable for handling d rums, cans packages, 
sampling devices and sample containers), aprons, dust masks, an effective respirator where 
necessary, safety goggles, tissue paper, first ai d kit, soap, towel and a supply of water for washing;  
 Case for sampling equipment and sample containers which enables them to be carried and 
transported safely;  
 Absorbent material (e.g. sawdust, vermiculite or similar material) for filling the space around  sample 
containers.  
Note  Newspaper, polystyrene granules or wood are not satisfactory absorbents.  
c) Check the availability of:  
 A sufficient number of sampling report sheets;  DRS 405: 2019  
9                ©RSB 2019  - All rights reserved  
  Writing and marking pens;  
 A valid identification document or authorization of the Inspector (Sampling Officer);  
 Sampling Assistants;  
 Vehicle for carrying sampling personnel, equipment and samples; and  
 Transportation for the samples of the laboratory.  
d) Notify  
 The individual responsible for the site in advance of the sampling date to ensure the availability of 
responsible personnel to handle pesticide containers during the sampling operations; and  
 The laboratories of the types and numbers of samples likely to be sent to analysis.  
Note  Merchants or retailers who are re -packing pesticide  formulations for sale in small quantities should not be 
notified in advance.  
8 Monitoring the properties of pesticide packages  
The quality of packaging is assessed by external examination of original intact containers or packages. The 
number of packaging un it to be selected from randomly chosen positions depends on the size of the batch, as 
follows: up to 5 units, each unit; for 6 – 100 units, 5 units; for more than 100 units, 1 for every 20 units. Each 
selected packaging unit shall meet the quality specific ation.  
NOTE 1  The packaging is acceptable if all containers selected randomly as samples are intact, their contents do not 
leak during shaking or turning, there is no observable sign of pesticide contamination on the surface of the containers, and 
the mate rial and size of tha packaging comply with the Registration Certificate. Deformation of containers is unacceptable 
if the contents are thereby pressurized or if the containers are rendered more difficult or hazardous to store, to transport or 
to use.  
NOTE 2 The permanent label and any attached documents are acceptable if they are clearly legible, intelligible and 
give the information which is specified in the Registration Certificate. Secondary packaging, if any, of the pesticide 
containers is acceptable if  it indicates clearly the nature of the contents and the hazard involved.  
NOTE 3  Where the nominal gross mass (or the nominal mass of the container) is specified, the mass of the contents of 
pesticide containers should be checked by weighing the intact con tainers with their contents.  
Where only the net mass or volume is specified, the mass of the contents of pesticide containers should be checked by 
weighing  the intact containers complete with contents. The mass of the container (and of the contents where t he volume is 
specified) must then be determined. Where applicable, the following procedure should be performed in the laboratory but if 
not suitable alternative containers are required on site and the Inspector must take due care in transferring the pestic ide. 
The measurements should be made on a minimum of 3 containers. Carefully and completely remove the entire contents 
into a suitable alternative container. Where the net volume is specified, calculate the nominal net mass either from the 
measured  specifi c gravity or from the specific gravity, quoted in the pesticide specification. Sum the mean mass of the 
empty containers with the nominal mass content to obtain the estimated nominal gross mass. Compare the measured 
gross masses of the selected containers with the estimated nominal gross mass and, where the deviation exceeds the 
specified value 9or that permitted by national legislation), determine the net masses or volumes by removal of the  
©RSB 2019  - All rights reserved                  10 
 contents. Where the same pesticide, in identical containers, is to  be checked on a number of occasions, the nominal gross 
mass estimated for the first batch might be used to check subsequent batches.  
The accuracy of the mass or volume measurements should be equal to or better than 1/4th of the acceptable deviation 
from t he nominal mass or volume, in the quality specification. For example, if the nominal gross mass is 550 g and the 
permitted deviation is ± 2% then its mass equiv alent is 11 g. consequently the accuracy of the weighing should be ±2.5 g 
or better (and the res olution of the balance should be ±1 g). 
NOTE 4  The inspector should pay attention to the general condition of the packages during sampling. If any deficiency 
(deformation, leakage, loose labels, etc.) is observed, the packages in the remainder of the batch  should be examined 
individually and the defective ones removed. Their further use should be determined on a case -by-case basis depending 
on national legislation and the corrective actions, which are practicable.  
9 Sampling for testing physical and chemical properties  
9.1 Technical active ingredients  
9.1.1  In the case of packaged pesticides the number of primary  samples to be taken and aggregated into a 
bulk sample is as follows: up to 5 packaging units, 1 primary sample from each unit; 6 – 100 units, 1 primary 
sample from 5 units; over 100 units, 1 primary sample per 20 units.  
9.1.2  Where the technical active ingredient is transported or stored in a single, large bulk, 15 primary 
samples should be taken from randomly selected parts of the batch.  
9.1.3  The minimum  mass of the bulk sample should be 300 g and 3 equal laboratory samples should be 
withdrawn from it. After mixing one is to be sent to the testing laboratory, the second to be retained by the 
supplier of the pesticide and the third to be kept for referee a nalysis in case of dispute. The referee sample 
should be retained by an organization agreed by both parties.  
NOTE  Bulk samples and laboratory samples of technical active ingredients must be made homogeneous,  as far as is 
practicable, before subdivision. In order to facilitate homogenization of laboratory samples, liquid pesticides may be 
carefully warmed to a maximum of 40 ºC, in the laboratory. Warning of bulk samples in the field should not be attempted.  
9.2 Formulations  
In an acceptable batch of formulated pesticide, the material in each individual container should meet the 
specification. Therefore each bulk sample taken for testing should normally be obtained from a single 
packaging unit and may consist of one or more primary samples taken from that packaging unit. The 
packaging unit and the corresponding method for obtaining primary/bulk samples should be identified as 
follows.  
i. For end -user containers which each holds sufficient formulation to be subdivided  into three laboratory 
samples (i.e. holding 600 ml or more for liquid formulations and 1800 g or more for solid formulations), 
the bulk sample is obtained from a sin gle container and no primary sampling is required. The contents 
should be well mixed befor e opening the container and removal of the three laboratory samples. In 
the case of large containers, each laboratory sample should consist of material removed from the top, 
middle and bottom of the container, as far as is practicable.  
ii. For end -user contain ers which each hold less than is required for three laboratory samples (i.e. 
holding less than 600 ml for liquid formulations or less than 1800 g for solid formulations).  DRS 405: 2019  
11                ©RSB 2019  - All rights reserved  
 The bulk sample should be taken from a single packaging unit consisting of multiple s mall containers 
(the primary samples) which, when aggregated, will provide sufficient formulation to be subdivided 
into three laboratory samples. If individual containers are not packaged into larger units at the time of 
sampling, the bulk sample should be  aggregated from sufficient containers taken at one point in the 
batch.  
 
The individual containers of the bulk sample should normally be opened, their contents should be 
mixed thoroughly (taking special care with granules and water -dispersible formulations ) and 
subdivided into three laboratory samples. Alternatively, if required (where the containers are also to 
be tested by the laboratory, for example), the individual containers may remain intact but each 
laboratory sample should then consist of a minimum of three containers and each should be analyzed 
separately.  
 
iii. Bulk tankers or wagons should be sampled by taking three primary samples, each a minimum of 200 
ml (of liquid formulations) or 600 g (of solid formulations), from different depths of the tank or at the 
beginning, middle and end of discharging. The primary samples should be aggregated into bulk 
sample, well mixed and subdivided into three laboratory samples.  
One of the laboratory samples should be sent to the testing laboratory, the second should b e retained 
by the supplier of the pesticide, and the third should be kept for referee analysis in cas e of dispute. 
The referee sample should be retained by an organization agreed by both parties.  
Where an identifiable batch of end -user packaged formulation  cannot be presumed uniform (e.g. 
where there are no data from previously satisfactory similar batches, etc.), separate bulk samples 
should be taken from the number of sampling positions indicated in table 1 . These bulk samples must 
not be aggregated but s hould be identified and analyzed separately. If a batch  may be presumed 
uniform, bulk samples may be taken from fewer positions (a minimum of one) in the batch. Batches of 
solid formulations, particularly granular formulations, are less easily judged to be  uniform than are 
liquid formulations and should normal ly be sampled in accordance with the requirements of table 1 . 
Table 1 – Number of bulk samples to be selected randomly for testing physical and chemical 
properties of formulated pesticides  
Number of pa ckaging units in the batch  Number of packaging units form which 
primary/bulk samples are to be taken  
Up to 10  1 
11 – 20 2 
21 – 40 3 
˃ 40 3 plus 1 for every additional 20 units up to 
a maximum of 15 sampled units  
 
The sampling report should indicate whether the storage conditions could have been unsatisfactory for 
formulations, which must be protected from frost, extreme heat or moisture.  
In national legislation permits, the net content of open containers may be restored (where samples have been 
taken  from several containers) by combining their contents if the samples removed represent more than 10% 
of the net contents. In this case, reseal the containers with official tape to indicate that they have been 
sampled.  
9.2.1  Liquid formulations (solutions, emulsi fiable concentrates, suspension concentrates, 
emulsions)  
Using appropriate care, containers which are to be opened for sampling should be shaken, rolled, tumbled or 
otherwise agitated (using methods which could be adopted by end users) before sampling, to try to achi eve 
physical homogeneity. Before taking samples, the contents of containers of liquid pesticides should be visually 
checked, where practicable, for any physical heterogeneity, such as crystallization, precipitation,  
©RSB 2019  - All rights reserved                  12 
 sedimentation or separation. A rod may be used to check for the presence of dense sediment. After complete 
or partial emptying, inspect containers again for sediment, which was not re -suspended.  
Where the separated components of formulations cannot be re -dissolved by methods which can  also be used 
in the field before application of the formulation, this must be recorded in the sampling report.  
NOTE  Such a formulation is not su itable for use and separate samples should be taken from the segregated portions 
as evidence of the deteriorate d condition. Subsequent analysis may be omitted. An estimate should be made of the 
amount or depth of any sediment or separated layers remaining.  
The samples from containers, which are to be opened, should be collected, using appropriate apparatus such 
as a pump or pipette, into glass bottles or other containers that can be tightly closed.  
9.2.2  Particulate solids (dusts, dispersible powders, water dispersible granules, granular 
formulations)  
Particulate solid formulations are not usually sensitive to frost, although they are frequently affected by high 
temperatures and moisture, a batch that has been stored in an exposed state (e.g. in inadequately sealed 
bags) must be regarded as non -uniform and the number of bulk samples taken should be in accordance with 
table 1 . 
Granular formulations (especially those such as GR, WG, SG, etc.) may undergo mechanical segregation of 
the different particle sizes during transport and when being transferred to o ther containers. At the initial 
sampling and when samples are subdivide for preparing the laboratory sample and analytical portions, the 
utmost c are must be exercised to obtain a representative portion of the material.  
Where applicable, annex A and annex B  should be used for sampling solids. Otherwise, bags may be 
sampled through a top corner. The primary samples from a single bag should be collected with an appropriate 
dip tube, trier, sampling probe or s coop and aggregated, to form bulk sample, in a glass  bottle, plastic bag or 
other container that can be tightly closed. The dip tube, etc., should be inserted through the opening 
diagonally across the bag and should be long enough to reach the bottom. Using a long -handled scoop, the 
bag may be tilted so that primary samples can be taken from the top, middle and bottom parts of the bag. 
Other types of container should be opened appropriately and sampled in a similar way to bags.  
The bulk sample from each bag, or other container of the pesticide, should be divided into 3 equal laboratory 
samples, preferably using a mechanical sample divider. If a mechanical divider is not available, laboratory 
samples should be prepared by manual division, paying the utmost attention to avoiding contamination of the 
working environment, as follows.  
 Transfer the bulk sample into a polyethylene bag large enough to be about one third full.  
 Mix the contents by inverting the securely closed bag at least 10 times, put the bag on a flat surface 
and spread the material within it over  as large an area as possible. (The sample layer should be 
approximately 1 cm deep).  
 Divide the spread material into 6 approximately equal portions and combine pairs of p ortions to form 
each laboratory sample (e.g. 1st and 4th; 2nd and 5th; 3rd and 6th). DRS 405: 2019  
13                ©RSB 2019  - All rights reserved  
 Where a formulation in water -soluble bags is to be sampled, intact bags must be taken complete with 
contents, preferably from freshly opened commercial packs. The individual bags must not be opened but 
dispatched for testing as quickly as possible.  
10 Shipping  and transporting samples  
Care must be taken to avoid spillage, leakage or deterioration of samples during packaging and transport. 
Pesticide samples, which are packaged improperly and broken during transport, can endanger the health of 
both transport hand lers and laboratory staff.  
The following example procedure may be adopted when packaging and shipping pesticide samples.  
a) Place each sealed sample container, clearly labelled with a sample number which corres ponds to that on 
the accompanying sampling report , in a plastic bag and seal with tape.  
b) Line a robust container of about 4 L capacity (e.g. a plastic or metal can with a securely fitting lid) with a 
suitably large plastic bag.  
c) Half-fill the plastic -lined container with absorbent material to immobilize th e sample bottles and to absorb 
any leakage from broken bottles.  
d) Place the sampling reports in a separate plastic bag, seal it and place it in the container. Fill the remainder 
of the container with absorbent material.  
e) Close the container and seal its lid. Attach securely labels showing:  
i) The address of the testing laboratory, and the name of the contact unit or person;  
ii) The appropriate hazard classification of the pesticide;  
iii) Arrow(s) indicating the “up” position of the samples.  
When pesticide samples are tran sported, the regulations of ICAO, IMO, RID or IATA must be met as 
applicable . 
  
©RSB 2019  - All rights reserved                  14 
 Annex  A 
(normative)  
 
Sampling of water dispersible granules  
A.1 Scope  
The method is suitable for preparing samples of water dispersible granules for the determination of the 
amount of active ingredient content or the physical properties of the formulation.  
A.2 Outline of method  
Water dispersible granules (WG) may have a relatively broad particle size spectrum so that segregation into 
different particle sizes may occur during transportation or handling of the products.  
It is, therefore, essential to divide samples with great care. This may be achieved by using a dividing 
apparatus or by standardized manual dividing.  
A.3 Apparatus  
A.3.1  Mechanical sample divider  
A.3.2  Polyethylene bag size about 3 0 cm square  
A.3.3  Laboratory spoon -spatula  
A.4 Procedure  
A.4.1  With the dividing apparatus  
Mechanical sample division is most suitable for taking representative individual samples. Fir the handling of 
the apparatus, refer to the instructions of the manufacture r. 
A.4.2  Manual  
Put a representative sample -of about 200 g  of the WG into a sufficiently large polyethylene bag, filling this by 
at least one third.  
NOTE  If the original sample is bigger than 200 g, start the manual sampling procedure carefully. Spread out the 
contents of the entire container and take sub samples by spoon from 20 – 25 different positions per kg to get a 
representative sample of 200 g.  DRS 405: 2019  
15                ©RSB 2019  - All rights reserved  
 Mix the contents by turning the closed bag end over at least 10 times. Put the polyethylene bag on a fla t 
surface and spread the granules within the bag over as large an area as possible. The sample layer should be 
approximately 1 cm thick.  
Take the required sub sample from a minimum of five positions from the sample layer.  
For samples taken from large conta iner, a mechanical sample divider is preferred.  
   
©RSB 2019  - All rights reserved                  16 
 Annex  B 
(normative)  
 
Dust content and apparent density of granular pesticide formulations  
B.1 Sampling  
B.1.1  Apparatus  
Metal or plastic boxes 10 x 10 x 3.5 cm, with well -fitting lids  
B.1.2  Procedure  
Gently rotate the bulk containers for at least 10 full cycles and then allow standing for 2 min to allow any dust 
to settle before the package is opened.  
Take at least three samples (350 ml x 3) of which one must be from the top, one from  the middle and one from 
the bottom of co ntainer. For ease of sampling, tilt the container and fill the sampling boxes to the brim by 
using them as scoops. Leave a small air space (5 ml) in each box, secure the lids and label “for sieve 
analysis”. Take a fourth sample (100 ml), secure the lid and  label “for density determination”.  
Take care not to disperse dust into the air when sampling from bulk containers. Do not pour the material into 
the sampling boxes.  
B.2 Preparation of sample  
Remove the lids from the sample boxes, and dry at 18 ºC to constant weight in an evacuated desiccators, 
using phosphorus (V) oxide as the desiccant.  
B.2.1  Apparatus  
B.2.1.1  Test sieves  
RS ISO 565  or equivalent, 200 µm diameter, nominal aperture sizes µm: 150, 250, 355, 420, 500, 710, 850.  
B.2.1.2  Lid and a receiver pan for  the sieves  
B.2.1.3  Soft brush (2.5 cm flat) for cleaning the finer mesh sieves  
B.2.1.4  Stiff brush for cleaning the coarser mesh sieves  
B.2.1.5  Balance sensitive to 0.1 g, with a precision of ± 0.05 g  DRS 405: 2019  
17                ©RSB 2019  - All rights reserved  
 B.2.1.6  Beakers 10 to 300 ml  
B.2.1.7  Sheets of glazed paper not less than 38 cm square  
B.2.1.8  Incline test sieve shaker  
Model No 1, 8 -inch (about 20 cm) platform. The table of the incline sieve shaker, on which the platform rests, 
is inclined to the axis of the unit at an angle of 4.5 degrees and its movement is like an inclined disc rolling 
around its perimeter, the speed of rotation being normally 2.5 rpm. A few models have been marketed with 
rotational speeds of approximately 2.1 rpm but the manufacturer can rapidly modify them. This gyrator 
simultaneously vibrates up and down through 4 mm, at a frequen cy of about 300 vibrations per minute. The 
rotary and vibratory movements are governed by the same mechanism; hence it is sufficient to measure the 
speed of rotation of the fraction inclined table to check the characteristics of a particular machine. The period 
allowed for s ieving is 45 min at 2.5 ± 0.04 rpm. If it is outside this range, the granular material collected or 
machine is unsuitable.  
B.2.2  Procedure  
Assemble the nest of sieves in the correct order above the receiver pan.  
Weigh a sample box and its contents. Empty t he contents carefully on the coarsest sieve (850 µm) and brush 
out any residue into the sieve. Weigh the empty sample box and record the mass of sample transferred to 
sieve. Fit the lid to the nest of sieves and amount in the shaking machine. Shake for a p eriod of 45 min.  
The volume of sample should be between 300 and 350 ml and the approximate mass of samples of different 
apparent densities should be as follows:  
Apparent density (g/ml)  Mass of sample (g)  
1.0 300 
Between 0.7 and 1.0  210 to 300  
Between 0.4 and 0.7  120 to 210  
Remove the nest of sieves from the machine after allowing time for suspended dust to settle (about 2 min). 
Carefully remove the lid and invert each sieve over separate sheets of paper, tap the side of the sieve frame 
and carefully b rush the uppermost surface. Invert the sieve and brush out any loose particles remaining, 
inside the sieve. Add the brushings to the bulk of the material taken from each sieve. Follow this procedure for 
the 850 µm to 250 µm sieves inclusive and record the mass to the nearest 0.1 g. also record the mass (to the 
nearest 0.1 g) of the material collected on the 150 µm sieve and in the receiver pan.  
B.2.2.1  Loss of dust during sieving  
The mass collected on the sieves, together with the mass of material collected  in the receiver pan, are added 
together and subtracted from the mass of the sample taken. This gives the loss during sieving which should 
be less than 0.25% of the sample mass. If not, repeat the test.  
 Add the mass of sample lost on sieving (less than 0. 25% of the total mass) to that of the fraction passing the 
150 µm sieve. Express the mass of each sieved fraction fraction as a percentage of the sample mass, to the 
nearest 0.1%.  
B.2.2.2  A typical result   
©RSB 2019  - All rights reserved                  18 
 Fraction  Mass percent distribution  
Granular material collected on 850 µm test 
sieves (inclusive)  96.2 
Dust fraction through 250 µm and retained 
on 150 µm test sieve  3.1 
Dust fraction through 150 µm test sieve in 
receiver pan (including loss during sieving)  0.7 
 
Total 100.0  
 
Calculate the cumulative percentage by mass of the sample passing through the 250 µm sieve, by adding the 
calculated percentage retained on the 150 µm sieve to that passing through it into the receiver pan. In the 
above example, this would be 3.8% of the s ample mass.  
B.2.2.3  Inter pretation of results  
In the United Kingdom, legislation that the more toxic pesticides in granular form shall have no more than four 
percent by mass (cumulative percentage) passing the 250 µm sieve, and not more than one percent pa ssing 
the 150 µm sieve. Otherwise appropriate protective clothing must be worn. The accuracy of the sieving 
procedure in determining this percentage distribution of the dust fractions (particles less than 250 µm 
diameter) in normally no more than 10% of th e specified limits. Hence, a product found to have 4.4% by mass 
passing the 250 µm mesh sieve and 1.1% passing the 150 µm mesh sieve just complies with the 
specification.  
B.3 Apparent density after compaction without pressure  
B.3.1  Apparatus  
B.3.1.1  Dropping box  
Firmly scre wed to a rigid table or bench (figure 1).  
B.3.1.2  Measuring cylinder  
Glass cylinder without spout and fitted with a rubber bung; the base of the cylinder shall be ground flat, and 
the weight of the cylinder and rubber bung shall be 250 ± 2 mm, i.e. the total lift of the cylinder shall be 
adjusted to 25 ± 2 mm by the application of suitable packaging to the under side of the shelf.  
B.3.1.3  Rubber base pad  
The rubber base pad shall have a BS hardness of 35 to 50.  
B.3.1.4  Timing device to indicate seconds  
B.3.1.5  Balance or scales  
A type providing easy access to the pans, the pans being at least 10 cm in diameter. It is necessary that the 
pointer should show a significant deflection for a change of load of 0.25 g.  DRS 405: 2019  
19                ©RSB 2019  - All rights reserved  
 B.3.1.6  Sampling paper black glazed  
B.3.1.7  Finger stalls or g loves smooth rubber  
B.3.1.8  Test sieve 500 µm 
B.3.2  Procedure  
Weigh 40 g of sample into a beaker, pour gently into the cylinder and fit the rubber bung into the cylinder 
without jolting. Put it carefully in the dropping box and start the timing device.  
With the thumb and forefinger of one hand gently hold the upper part of the cylinder and, during 1 sec, lift it to 
the full extent of its travel. Avoid any undue impact against the upper stop so that no jar is given to the sample. 
At the beginning of the next second, smartly release the cylinder by quickly and completely withdrawing the 
thumb and forefinger. Continue the process of lifting and dropping until 50 counted drops are completed, the 
cylinder falling once every 2 sec. rotation of the  cylinder through  an arc of about 1 0 degrees should be given 
during the lifting which precedes each drop, since this will help to impart a level surface to the sample for the 
final volume reading.  
Immediately the 50 drops are completed, remove the cylinder from the dropping box and note the volume to 
the nearest 1 ml (V). Any further drop in the level after standing should be ignored.  
 
Figure B1 – Tap density apparatus  
 
©RSB 2019  - All rights reserved                  20 
 B.3.3  Calculation of results  
Calculate the apparent density, D after compaction of the sample to two significant figures.  
D=40
𝑉𝑔/𝑚𝑙 
B.3.4  Interpretation of results  
The statutory specification for pesticides in granular form requires the apparent density by compaction without 
press ure to be not less than 0.4 g/ml.  DRS 405: 2019  
21                ©RSB 2019  - All rights reserved  
 Annex  C 
(Informative)  
 
Supply and certification of reference substances of pesticide active 
ingredients  
C.1 Introduction  
Reference substances of known content are often essential for the quantitative determination of pesticide 
active  ingredients in different types of samples and at various concentration levels. They are available from 
various sources. It is important that the active ingredient content is declared and certified.  
C.2 Supply of reference substances  
There are two sources for the supply of certified reference substances:  
a) The manufacturer of the active ingredient in question;  
b) National Standards Bodies or companies selling substances  
C.3 Supply by the manufacturer  
The manufacturer of a pesticide technical grade active ingredient, or its formulations, is obliged to supply a 
certified reference substance in the following cases:  
C.3.1  Trade relations between customer and manufacturer  
The customer, or an independent laboratory, might want to check  the active ingredient content of material  
delivered by the manufacturer. This is to be done on the basis of the specification and using the analytical 
method stated therein. The manufacturer’s certified reference substances should be made available to the 
customer so as to avoid any discrepancy i n the analytical results, which could be made available to the 
customer so as to avoid any discrepancy in the analytical results, which could otherwise be derived from 
differences in the purity of the reference substances used by the two parties.  
C.3.2  Relations between manufacturer and registration authorities  
Each company (not only the inventor company) applying for the registration of a pesticide (new a.i. or 
formulation) must supply its own certified reference substance, if required by the registration authorities.  
C.3.3  Supply by reference substances producers or suppliers  
There are various standards institutions and commercial companies, which offer reference substances. They 
should normally be approached if reference substances are required in situations different from those 
mentioned above. On request manufacturers may, at their discretion, also supply reference substances in 
such cases.   
©RSB 2019  - All rights reserved                  22 
 C.4 Certification  
A certificate of identity and determined content, together with the corresponding measurement uncertainty and 
a reference to the method(s) of analysis used, must always accompany each sample of a certified reference 
substance. Descriptions such as “greater than …%” are unacceptable. The recommended storage conditions 
and an expiry date shall be sta ted. DRS 405: 2019  
23                ©RSB 2019  - All rights reserved  
 Annex  D 
(Informative)  
 
Model sampling report  
Name and address of store or plant: 
………………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………………  
Name of pesticide: ………………………………… …………………………………………………………………….  
Manufacturer/supplier: …………………………………………………………………………………………………..  
Batch No.: …………………………………………………………………………………………………………………  
Batch total quantity (kg, l or pieces): …………………………………………………………………………………..  
Date of manufacture: ……………………………………… …………………………………………………………..  
External tests  
Number of packaging units selected: ……………………………………………………………………………….  
Minimum and maximum measured gross masses of containers: ………………………………………………..  
Mean measured mass of empty containers (if applicable): …………………………………… ………………….  
Estimated nominal gross mass of containers (if applicable): ……………………………………………………..  
Quality of packaging: …………………………………………………………………………………………………..  
Quality of label: …………………………………………………………………………………………………………  
Sampling for laboratory tests  
Number of pac kaging units sampled: ……………………………………………………………………………….  
Amount and number of primary samples taken for bulk sample: ………………………………………………..  
Location of the reference sample and name of responsible person: ……………………………………………   
©RSB 2019  - All rights reserved                  24 
 Remarks : 
…………………………………………………………………………… …………………………………………………
………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………….  
Date: ……………………………….  
……………………………………………..       ………………………………………………….  
Name and signature of Inspector        Name and signature of owner or  
              Representative of store/plant  
 
 DRS 405: 2019  
ICS 65.100.01  
 
 
©RSB 2019  - All right s reserved