DRAFT UGANDA STANDARD  
  DUS 2475  
First Edition  
yyyy -mm-dd 
 
 
 Reference number  
DUS 2475 :2023 
© UNBS 202 3  
  
Refined pyrethrum concentrate — Specification  
 DUS  2475: 2023 
ii © UNBS 2023 – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its co rrect application  
© UNBS 2023. 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photocopying and microfilm, without prior written 
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: +256 41 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 2475 :2023 
© UNBS 202 3 – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................  v 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4  Requirements  ................................ ................................ ................................ ................................ ........  1 
4.1  General requirements  ................................ ................................ ................................ ..........................  1 
4.2  Active ingredients  ................................ ................................ ................................ ................................  2 
4.3  Specific requirements  ................................ ................................ ................................ ..........................  2 
5  Packaging  ................................ ................................ ................................ ................................ ..............  2 
6  Labelling  ................................ ................................ ................................ ................................ .................  3 
7  Sampling  ................................ ................................ ................................ ................................ ................  3 
Annex A  (normative)   Determination of total pyrethrins  ................................ ................................ ..............  4 
A.1  General  ................................ ................................ ................................ ................................ ...................  4 
A.2  Reagents  ................................ ................................ ................................ ................................ ...............  4 
A.3  Apparatus  ................................ ................................ ................................ ................................ ...............  4 
A.4  Operating conditions  ................................ ................................ ................................ ...........................  4 
A.5  Preparation of the standard  ................................ ................................ ................................ ................  4 
A.6  Sample preparation  ................................ ................................ ................................ ...............................  5 
A.7  Procedure  ................................ ................................ ................................ ................................ ..............  5 
A.8  Calculation of the % total pyrethrins (active ingredient) ................................ ................................ ... 5 
Annex B  (normative)   Determination of moisture content  ................................ ................................ ...........  6 
B.1  General  ................................ ................................ ................................ ................................ ..................  6 
B.2  Apparatus  ................................ ................................ ................................ ................................ ...............  6 
B.3  Reagents  ................................ ................................ ................................ ................................ ...............  7 
B.4  Sampling, preparation and calibration of the apparatus  ................................ ................................ ... 7 
B.4.1  Sampling:  ................................ ................................ ................................ ................................ ...............  7 
B.4.2  Preparation of the apparatus:  ................................ ................................ ................................ ..............  7 
B.4.3  Calibration of the instrument:  ................................ ................................ ................................ ..............  8 
B.5  Procedure  ................................ ................................ ................................ ................................ ..............  8 
B.6  Calculation of Results  ................................ ................................ ................................ ...........................  8 
Annex C  (normative)   Determination of flash point  ................................ ................................ ......................  9 
C.1  General  ................................ ................................ ................................ ................................ ..................  9 
C.2  Apparatus  ................................ ................................ ................................ ................................ ..............  9 
C.3  Reagents  ................................ ................................ ................................ ................................ ...............  9 
C.4  Procedure  ................................ ................................ ................................ ................................ .............  10 
C.5  Results  ................................ ................................ ................................ ................................ ..................  11 
Annex D  (normative)   Determination of specific gravity  ................................ ................................ ............  12 
D.1  General  ................................ ................................ ................................ ................................ ................  12 
D.2  Apparatus  ................................ ................................ ................................ ................................ ............  12 
D.3  Reagents  ................................ ................................ ................................ ................................ ..............  12 
D.4  Procedure  ................................ ................................ ................................ ................................ .............  12 
D.5  Calculation of result  ................................ ................................ ................................ ...........................  13 
Annex E (normative)   Determination of optical density  ................................ ................................ ..............  14 
E.1  General  ................................ ................................ ................................ ................................ .................  14 
E.2  Apparatus  ................................ ................................ ................................ ................................ ............  14 
E.3  Reagents  ................................ ................................ ................................ ................................ ..............  14 DUS  2475: 2023 
iv © UNBS 2023 – All rights reserved  
 E.4  Procedure  ................................ ................................ ................................ ................................ ............  14 
Annex F  (normative)   Determination of pH  ................................ ................................ ................................ . 15 
F.1  Apparatus  ................................ ................................ ................................ ................................ ...........  15 
F.2  Reagents  ................................ ................................ ................................ ................................ .............  15 
F.3  Procedure  ................................ ................................ ................................ ................................ ...........  15 
Annex G  (normative)   Determination of Butylated Hydroxy Toluene (BHT)  ................................ ............  16 
G.1  General  ................................ ................................ ................................ ................................ .................  16 
G.2  Reagents  ................................ ................................ ................................ ................................ ..............  16 
G.3  Apparatus  ................................ ................................ ................................ ................................ ...........  16 
G.4  Operating conditions  ................................ ................................ ................................ ..........................  16 
G.5  Preparation of the standard  ................................ ................................ ................................ ..............  16 
G.6 Sample preparation  ................................ ................................ ................................ ............................  17 
G.7 Procedure  ................................ ................................ ................................ ................................ ............  17 
G.8  Calculation of the % BHT  ................................ ................................ ................................ ..................  17 
Annex H  (normative )   Determination of Taraxasterol  ................................ ................................ ................  18 
H.1  General  ................................ ................................ ................................ ................................ ................  18 
H.2 Reagents  ................................ ................................ ................................ ................................ ....................  18 
H.3  Apparatus  ................................ ................................ ................................ ................................ ...........  18 
H.4  Operating conditions  ................................ ................................ ................................ .........................  18 
H.4.1   Preparation of the column  ................................ ................................ ................................ ................  18 
H.5  Preparation of the standard  ................................ ................................ ................................ ...............  19 
H.6  Sample preparation  ................................ ................................ ................................ ............................  19 
H.7  Procedure  ................................ ................................ ................................ ................................ ...........  19 
H.8  Calculation of the % Taraxasterol  ................................ ................................ ................................ .... 20 
Annex I  (normative)   Determination of matters insoluble in dichlorodifluoromethane  ..........................  21 
I.1  General  ................................ ................................ ................................ ................................ .................  21 
I.2  Reagents  ................................ ................................ ................................ ................................ .............  21 
I.3  Apparatus  ................................ ................................ ................................ ................................ ............  21 
I.4  Procedure  ................................ ................................ ................................ ................................ ...........  21 
I.5  Calculation of the % matters Insoluble  ................................ ................................ ............................  21 
Bibliography  ................................ ................................ ................................ ................................ .....................  22 
 
  
 DUS 2475 :2023 
© UNBS 202 3 – All rights reserved  v 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperatives established under Cap 327 , of the Laws of Uganda , as amended .  UNBS is mandated to co -
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS /TC 301, Chemis try. 
  DUS  2475: 2023 
vi © UNBS 2023 – All rights reserved  
 Introduction  
Pyrethrum is a naturally occurring mixture of chemicals found in ce rtain chrysanthemum flowers. Pyrethrum 
was first recognized as having insecticidal properties around 1800 in Asia and was used to kill ticks and 
various insects such as fleas and mosquitos. Six individual chemicals have active insecticidal properties in th e 
pyrethrum extract, and these compounds are called pyrethrins.  
They comprise esters of the natural sterioisomers of Chrysanthemic acid commonly known as Pyrethrins 
1(pyrethrin 1, cinerin 1 and jasmolin 1) and the corresponding esters of pyrethric acid co mmonly known as 
Pyrethrins 2 (pyrethrin 2, cinerin 2 and jasmolin 2). The ratio of Pyrethrins 1/Pyrethrins 2 is commonly within 
the range 0.95 -1.15 and most commercial refined pyrethrum extracts contain 20 -50 % pyrethrins.  
Pyrethrum is tan -colored dust -like when in ground flower form and syrup liquid -like when in crude extract form.  
Pyrethrins are only slightly soluble in water, but they dissolve in organic solvents like alcohol, chlorinated 
hydrocarbons, and kerosene. Pyrethrins  are often used in househol d insecticides and products to control 
insects on pets or livestock. Pyrethrins break down quickly in the environment, especially when exposed to 
natural sunlight.  
Pyrethrum, a natural insecticide, is derived from the dried flowers of the "pyrethrum daisy" . The outstanding 
properties of pyrethrum are:  
 Rapid Action (contact insecticide attacking the nervous system of insects almost immediately and 
causing knockdown and flushing out effects followed by kill)  
 Low Mammalian Toxicity (proven safety towards human s and other warm blooded animals)  
 Lack of Insect Immunity (insect resistance is not a practical concern)  
 Broad Spectrum of Activity (consist of a group of insecticidal compounds and has activity against a 
wide spectrum insect species)  
 Lack of persistence ( degraded by UV in sunlight and other light sources)  
 Repellency (very effective insect repellant)  
 It is by far the most widely used natural insecticide  
The term pyrethrins  is used collectively for the six insecticidal constituents present in extracts of the  flowers 
Tanacetum  cinerariifolium.   
  
  
 
 DRAFT UGANDA STANDARD  DUS 2475:2 023 
 
© UNBS 2023 – All rights reserved  1 
 Refined pyrethrum concentrate — Specification  
1 Scope   
This Draft Uganda Standard specifies the requirements, sampling and test methods for refined pyrethrum 
concentrate . 
2 Normative references  
There are no norm ative references in this document.   
3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online br owsing platform: available at http://www.iso.org/obp  
3.1  
pyrethrum  
aromatic plant of the daisy family, typically having feathery foliage  whose brightly coloured 
aromatic  flower  heads contain  pyrethrins as the active  compounds.  
3.2  
pyrethrum concentrate  
extract f rom mature and open  flowers  of Chrysanthemum cinerariaefolium  plant  
3.3  
pyrethrins  
six naturally occurring isomers found in the flower of Chrysanthemum cinerariifolium  as esters of pyrethric acid 
(pyrethri n-II, cinerin -II, and jasmolin -II) and chrysanthemic  acid (pyrethrin -I, cinerin -1 and jasmolin -I) that have 
insecticidal property  
4  Requirements  
4.1  General requirements  
4.1.1  Refined pyrethr um concentrate shall consist of the extract of the flowers o f the plant, Chrysanthemum  
cinerariaefolium , together with related manufacturing impurities, in the form of viscous liquid.  
4.1.2  Refined pyrethrum concentrate shall be greenish yellow in colour and possess the characteristic 
odour of the commercial pyre thrum flowers.  
4.1.3  Refined pyrethrum concentrate shall not contain traces of the solvent (such as hexane) used during 
extraction.   
2 © UNBS 202 3 – All rights reserved  
 4.1.4  Refined pyrethrum concentrate shall be insoluble in water but soluble in organic solvents, free from 
visible extraneo us matter and added modifying agents of synergizing agents except for the diluents and 
stabilizer, if required.  
4.1.5 Known common anti -oxidants  without synergist  may be used  in refined pyrethrum concentrate.  
4.2  Active ingredients  
4.2.1   The extract sh all consist of a mixture of three closely related insecticidal esters of chrysanthemic acid 
(cinerin I, jasmolin I and pyrethrin I) and three closely related insecticidal esters of pyrethric acid (cinerin II, 
jasmolin II and pyrethrin II).  
4.2.2   The thre e esters of chrysanthemic acid and the three esters of pyrethric acid shall be known as 
Pyrethrins I and Pyrethrins II respectively and shall constitute the only active ingredients in the extract.  
4.2.3   The synthetic pyrethroids shall not form part of th e composition of the material.  
4.3  Specific requirements  
4.3.1  Refined pyrethrum concentrate  shall comply with  the specific requirement s given in table 1 when 
tested in accordance to the methods described therein.  
 Table 1 — Specific requirements for refined pyrethrum concentrate  
S/N Parameters  Requirements  Test methods  
1 Active ingredients (as total Pyrethrins I 
& II), % w/w  48 - 52 Annex A 
2 Moisture content, % w/w, max  0.5 Annex B  
3 Flash point, ºC, min  60 Annex C 
4 Density at 20 ºC, g/mL  0.940 – 0.980  Annex D 
5 Optical density, max.  0.900  Annex  E 
6 pH (1% w/ v solution)  4 – 7 Annex F 
7 Butylated Hydroxy Toluene ( BHT), % 
w/w 3 – 5 Annex G 
8 Taraxasterol, % w/w, max.  3.5 Annex H 
9 Matters insoluble in 
dichlorodifluoromethane, % w/w, max.  1.5 Annex I 
 
4.3.2  The total Pyrethrins content (Pyrethrins I&II) in refined pyrethrum concentrate shall not differ by more 
than 0.5 % (within +/- 0.5% ) of the declared active ingredients.  
 
5  Packaging   
Refined pyrethrum concentrate shall be packaged in sui table well -sealed containers that shall protect the 
contents during transportation, handling and storage and shall not cause any contamination or react with the 
product.   
 DUS  2475 :2023 
© UNBS 2023 – All rights reserved  3 
 6  Labelling  
6.1 The container shall be durably and legibly marked with the followi ng information:  
a)  name of the product as “Refined Pyrethrum Concentrate”  
b)  guaranteed  actual minimum amount of the Active Ingredient as total Pyrethrins;  
c)  name and physical address of the manufacturer;  
d)  date of manufactur e 
e)  expiry date;  
e) net weight of the content (the choice of the unit of weight may be agreed between the purchaser and the 
supplier);  
f)  batch number;  
6.2 The following shall be indelibly and prominently displayed on the label (Other internationally accepted 
labelling p ractices in complement to the requirement of this clause are accepted and encouraged):  
i.  instruction on Handling and Storage (It shall also be indicated that the product should not be stored 
at temperatures exceeding 40 ºC;  
ii.  hazards to humans and a nimals;  
iii . safety precautions together with first aid measures;  
iv.  information regarding applicable measures for the disposal of wastes and empty containers; and  
v . information regarding applicable measures if spilling occurs.  
7  Sampling    
7.1  Refined pyrethrum concentrate shall be sampled using appropriate equipment (e.g. a personal 
sampling pump with flexible connecting tubing) and in such a way that the sampling equipment, sampling 
method, and sample handling shall not affect the characterist ics and nature of the sample.  
7.2 Refined pyrethrum concentrate shall be representative of the lot; to this end, the content of the 
container shall be thoroughly mixed (preferably with an agitator) prior to sampling and individual samples shall 
also be th oroughly mixed to constitute the test sample.  
7.3   Refined pyrethrum concentrate  shall be stored in opaque, airtight containers which do not affect or are 
affected by the sample and it shall be tested as quickly as possible  
   
4 © UNBS 202 3 – All rights reserved  
  Annex A  
(normative)  
 
 Determination of total pyrethrins  
A.1  General  
The active ingredients in pyrethrum extract may be determined using a HPLC system first by injecting a 
solution of the analyte into the chromatograph, followed by the separation and comparison of peaks areas of  
the analytes in the sample with that of an external standard containing a known amount of the analytes. The 
peaks are eluted in the following order: Cinerin II, Pyrethrin II, Jasmolin II (total Pyrethrins II) and Cinerin I, 
Pyrethrin I, Jasmolin I (total Pyrethrins I).  
A.2  Reagents  
A.2.1  Pyrethrins reference standards , 50 %  w/w 
A.2.2  Acetonitrile, HPLC grade  
A.2.3  Water, HPLC grade  
A.3  Apparatus  
A liquid chromatography System equipped with an auto -sampler, a Variable Wavelength Detector (or 
equivale nt) and a Column {Phenomenex, 250 x 4.6 mm Luna Phenyl -Hexyl 5  μm Reverse Phase (or 
equivalent)}.  
A.4  Operating conditions  
A.4.1  Flow rate: 1.5 ml/min  
A.4.2  Composition: 40:60 (% v/v water/acetonitrile)  
A.4.3  Elution: Isocratic  
A.4.4  Oven temperature: 40 ºC  
A.4.5  Wavelength: 240 nm  
A.4.6  Injection Volume: 15 µl  
A.4.7  Stop time: 22 min  
A.4.8  Post time: 1 min  
A.5  Preparation of the standard  
Weigh 20 mg of the pyrethr in reference standard to the nearest 0.0001 g in a 100 mL volumetric flask and 
dissolve in Acetonitrile and dilute to volume . Transfer a small po rtion to a sample vial and label it accordingly.  DUS  2475 :2023 
© UNBS 2023 – All rights reserved  5 
 A.6  Sample preparation  
In a 100 ml volumetric flask, weigh 20 mg to the nearest 0.0001 g of the sample to be analyzed and dissolve 
in Acetonitrile and dilute to volume . Sample this solution using a vial a nd label it accordingly.  
A.7  Procedure  
After the chromatograph is stable, make a minimum of three injections for the standard solution as well as for 
the analyte and average the area counts. The relative Standard Deviation between injections should be wi thin 
2 %. 
A.8  Calculation of the % total pyrethrins (active ingredient)  
The % Total Pyrethrins is calculated as follow:  
% 𝑎𝑐𝑡𝑖𝑣𝑒  𝑖𝑛𝑔𝑟𝑒𝑑𝑖𝑒𝑛𝑡𝑠  = (𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑠𝑎𝑚𝑝𝑙𝑒  𝑎𝑟𝑒𝑎  𝑋 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑋 𝑃𝑢𝑟𝑖𝑡𝑦  𝑜𝑓 𝑡ℎ𝑒 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  (𝑖𝑛 %)) ÷ 
(𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑎𝑟𝑒𝑎 𝑋 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒 .)  
6 © UNBS 202 3 – All rights reserved  
 Annex B  
(normative)  
 
 Determination of moisture content  
B.1  General  
Using an automated coulometric titration procedure the test method is based on the Karl Fischer reaction for 
determining water — the reduction of iodine by sulphur dioxide in the presence of wat er to form Sulphur 
trioxide and Hydroiodic acid.  
The coulombs of electricity required to generate the reagent are converted to micrograms of water, which is 
obtained as a direct digital readout. The reaction becomes quantitative only when pyridine or othe r organic 
base and methanol or other alcohols are present.  
B.2  Apparatus  
B.2.1   Automatic Titrator: consisting of a control unit, titration vessel, dual platinum sensing electrode, 
generator assembly, and magnetic stirrer. The instrument is designed to coulometrically generate iodine that 
reacts stoichiometrically with the water present in the sample solution.  
B.2.2   Syringe, 50 mL, fitted with a 115 mm hypodermic needle for removing excess solution from the 
titration chamber.  
NOTE   Rinse all glass syr inges and needles with anhydrous acetone after cleaning, then dry in an oven at 100 ºC for 
at least 1 h and store in a desiccator. Plastic syringes shall be disposed of after use.  
B.2.3   Syringe, 20 mL, fitted with a 115 mm hypodermic needle for introduct ion of neutralizing solution into 
the titration chamber.  
B.2.4   Syringes, 1 mL and 5 mL, fitted with a 115 mm hypodermic needles for introduction of samples into 
titration chamber.  
B.2.5   Syringe, 5 µL, fitted with a 115 mm hypodermic needle for standard ization of instrument.  
B.2.6   Fluorocarbon Sealing Grease or TFE -Fluorocarbon, to seal the titration chamber against atmospheric 
moisture.  
B.2.7   Septa, to seal sample port but allow introduction of samples by a needle with a minimum of moisture 
contamin ation. Replace serum caps and septa as required to prevent air leakage as indicated by instrument 
drift.  
B.2.8   Serum Bottles.  
B.2.9   Oven, temperature 100 ± 5 ºC.  
B.2.10   Desiccator, a standard laboratory type with colour change indicator.  
B.2.11   Analytical balance, capable of weighing to ± 0.0001 g.  DUS  2475 :2023 
© UNBS 2023 – All rights reserved  7 
 B.3  Reagents  
B.3.1   Karl Fischer Reagents – commercial coulometric Karl Fischer reagents and reagent systems and the 
use of pyridine -free reagents is recommended whenever possible.  
B.3.2   Generator Tit rant Solution (Catholyte) – Containing iodine, sulphur dioxide, pyridine or other organic 
base and methanol or other alcohol to provide iodine in the reaction mixture.  
B.3.3   Solvent Titration Solution (Anolyte) – Prepared as per instrument specifications .  
B.3.4   Neutralizing Solution – methanol containing approximately 20 mg H 2O/mL.  
NOTE   The water and the reagents shall be of analytical grade and of sufficiently high purity to guarantee its use 
does not lessen the accuracy of the analytical results.  
B.4  Sampling, preparation and calibration of the apparatus  
B.4.1  Sampling:  
 Because of the low concentration of water to be measured, maximum care must be exercised at all times to 
avoid contaminating the sample with moisture from the sample container, th e atmosphere, or transfer 
equipment.  
Dry the sample bottles and caps overnight in an oven at 100°C b efore using. Allow to cool in a desiccator 
before filling and sealing. Fill the sample bottle as rapidly as possible to within 25 mm of the top and 
immedia tely seal.  
Remove the test specimens for analysis from the sample bottle with a dry hypodermic syringe. Inject dry 
nitrogen into the sample bottle with the syringe to displace the sample that is removed.  
B.4.2  Preparation of the apparatus:  
Clean, dry, an d assemble the titration chamber. Use fluorocarbon grease or TFE -fluorocarbon to seal the 
upper and lower sections of the chamber from atmospheric moisture. Connect the leads from the sensing and 
generator electrodes to the titrator.  
Prepare the titration  solution (Anolyte) and fill the instrument reservoir. Add the generator solution (Catholyte) 
to the generator assembly and replace the cover cap. The surface of the generator solution must be below the 
level of the titration solution to prevent backflow c ontamination of the titration solution. The generator solution 
may have to be removed periodically to maintain the lower level.  
Agitate the titration solution by gently swirling the titration chamber to remove any residual moisture from the 
walls. Allow t he solution to stir for at least 20 min to dry and stabilize the inner atmosphere.  
NOTE  There are some automatic moisture analyzers which do not require the steps above.  
Attach an 11.5 cm hypodermic needle to the 20 mL syringe and withdraw about 15 mL of  neutralizing solution. 
Insert the needle through the sample port septum and lower it until the tip is just below the surface of the 
titration solution.  
Slowly inject the neutralizing solution into the titration solution until the colour changes from brow n to light red. 
This indicates that the end point is near. Continue the addition very slowly until the ON light comes on, 
indicating an excess of water is present, then carefully withdraw the syringe and needle. The total volume of 
neutralizing solution re quired will range from 5 to 15 mL. Allow the system to stabilize for 1 h.   
8 © UNBS 202 3 – All rights reserved  
 B.4.3  Calibration of the instrument:  
Calibrate the instrument in accordance to the manufacturer’s instructions but verify the calibration with a 
standard solution that approximates  the same range of water expected to be in the samples. It is also 
recommended that a control chart measuring a Quality Control standard sample be established and 
maintained.  
Measure the control sample each time a test sample(s) is tested. If the measured  value exceeds ± 5 % of the 
known amount, take appropriate action before proceeding with the sample test; this may require even 
replacing or regenerating the reagent solutions.  
B.5  Procedure  
Assemble a dry syringe and needle and attach a small piece of rubber septum to the needle tip. Withdraw 1 to 
2 mL of the sample into the syringe and discard the contents. Withdraw 0.5 mL of test sample into the syringe 
and seal with the rubber septum. Obtain a tare weight to ± 0.1 mg.  
With the analyzer stabilized, c arefully insert the needle of the sample syringe through the septum and below 
the level of solution in the titration chamber. Inject the sample slowly into the titration solution and begin 
titration. Withdraw the syringe needle, seal and again weigh to the  nearest ± 0.1 mg to determine the exact 
sample mass. Allow the titration to proceed until the end -point is indicated. Record the micrograms of water 
determined.  
B.6  Calculation of Results  
Calculate the water content of the sample to the nearest 0.001% mass as follows:  
𝑊𝑎𝑡𝑒𝑟  𝑐𝑜𝑛𝑡𝑒𝑛𝑡 , % (𝑚𝑎𝑠𝑠 ) = 𝜇𝑔 𝑊𝑎𝑡𝑒𝑟  𝑓𝑜𝑢𝑛𝑑  ÷ (𝑔 𝑆𝑎𝑚𝑝𝑙𝑒  𝑋 10,000 ) 
  
Report the percentage of water to the nearest 0.001%  DUS  2475 :2023 
© UNBS 2023 – All rights reserved  9 
 Annex C  
(normative)  
 
 Determination of flash point  
C.1  General  
This test method is similar to the Continuously Closed Cup Flash Point Test method. It utilizes a closed but 
unsealed cup with air injected into the test chamber.  
C.2  Apparatus  
The Continuously Closed Cup Flash Point tester shall essentially consist of:  
C.2.1   A lid of  solid brass: The temperature of which is controlled electrically. Two temperature sensors for 
the specimen and the lid temperatures, respectively, two electrically insulated pins for a high voltage arc, and 
a connecting tube for the pressure monitoring.  
C.2.2   Sample Cup: Made of nickel -plated aluminium with an overall volume of 4 mL and capable of 
containing 1± 0.1 mL of sample.  
C.2.3   Test Chamber: Formed by sample cup and the temperature controlled lid and shall have an overall 
volume of 4 ± 0.2 mL  
C.2.4  Specimen Temperature Sensor: A thermocouple (Ni -Cr-Ni or similar) in stainless steel of 1 mm 
diameter with a response time of t(90) = 3 sec. It shall be immersed to a depth of at least 2 mm into the 
specimen. It shall have a resolution of 0.1 °C and a minimum accuracy of ± 0.2 °C, with a digital readout.  
C.2.5   Magnetic Stirring: A rotating magnet outside the sample cup that can drive a small stirring magnet, 
which is inserted into the sample cup after sample introduction. It should have a diameter o f 3 ± 0.2 mm and a 
length of 12 ± 1 mm. The rotation speed of the driving magnet shall be between 250 and 270 
revolution/minute.  
C.2.6   Air Introduction Provision: For introduction of 1.5 ± 0.5 mL of air immediately after each test. The air 
shall be intro duced by a short air pulse from a small membrane compressor by means of a T -inlet in the 
connecting tube to the pressure transducer.  
C.2.7   Arrangement Electrical heating and thermoelectric cooling of the lid: used to regulate the temperature 
of the test chamber during the test. The temperature regulation shall have a minimum accuracy of ± 0.2°C.  
C.2.8   A high voltage electric arc: Used for the ignition of the flammable vapour. The energy of the arc 
should be 3± 0.5 mJ per arc and it shall be applied with in 43 ± 3 ms.  
C.2.9   The pressure transducer (for flash point detection): connected to the connecting tube in the lid; 
should have a minimum operational range from 80 to 177 kPa with a minimum resolution of 0.1 kPa and a 
minimum accuracy of ± 0.5 kPa. It s hall be capable of detecting an instantaneous pressure increase above 
barometric pressure of a minimum of 20 kPa within 100 ms.  
C.3  Reagents  
The reagents should be of analytical quality and of sufficient purity to guarantee the accuracy of the test 
results.   
10 © UNBS 202 3 – All rights reserved  
 C.3.1  Anisole  
C.3.2  Dodecane  
C.3.3  Acetone (or toluene)  
C.4  Procedure  
C.4.1   Thoroughly clean and dry the lid together with the arc pins and the sample cup before starting the 
test. Remove any solvent used to clean the apparatus. If the expected  flash point of a sample is more than 15 
°C higher than the flash point of the previous sample, heat the lid together with an empty, dry sample cup to a 
temperature 30 °C higher than the expected flash point of the new sample.  
C.4.2   Set the initial tempe rature to at least 18 °C below the expected flash point. Set the final temperature to 
a value beyond the expected flash point.  
C.4.3   Set the pressure threshold for the flash detection to 20 kPa.  
C.4.4   Initiate the test procedure to regulate the lid to the initial temperature. When the initial temperature is 
reached as indicated by the instrument, prepare to introduce 1± 0.1 mL specimen of the sample.  
C.4.5   Ensure that the sealed sample and the sample cup are at least 18 °C below the expected flash poi nt 
temperature, cool if necessary. Shake the sample thoroughly before opening the sample container. Extract 1 
mL of sample with a pipette or syringe, and close the container. Transfer 1± 0.1 mL of the sample to be tested 
into the sample cup.  
C.4.6   Insert  a stirring magnet into the sample cup to ensure a consistent sample mixing. Put the sample 
cup onto the sample cup support of the tester, and start the procedure. Raise and press the sample cup onto 
the lid, which is at the initial temperature and thus at  a higher temperature than the sample cup.  
C.4.7   While the temperature of the sample cup and the lid are equalizing, apply a precautionary arc at 10 
°C intervals. If a flash is detected at one of these precautionary arcs, discontinue the test, and discar d the 
result. Repeat the test with a fresh specimen and with a lower initial temperature of at least 18 °C below the 
temperature at which the flash was detected.  
C.4.8   After the temperature between the temperatures regulated lid and the specimen have equ alized to 
within 1 °C, start the actual test for the flash point. Heat the lid with the programmed heating rate, and apply 
the arc ignition in equidistant temperature steps of 1 °C. Monitor the instantaneous pressure increase within  
100 ms after the arc. S top the test when a flash is detected or when the final temperature is reached in the 
case of no flash point. The flash point temperature is the specimen temperature at which the instantaneous 
pressure increase, due to the presence of the flash, exceeds 20  kPa.  
C.4.9   When a flash is detected at a temperature that is higher than 26 °C above the initial temperature, or 
when a flash is detected at a temperature that is less than 10 °C above the initial temperature, consider the 
result approximate and repeat the test with a fresh test specimen. Adjust the expected flash point for this next 
test to the temperature of the approximate result. The initial temperature for this fresh test specimen shall be 
18 °C below the temperature of the previous approximate resu lt.  
C.4.10   Record the specimen temperature reading at the detected flash point as the uncorrected flash point 
temperature. If no flash point was detected within the tested temperature range, record “flash point is 
higherthan the final temperature”.  
C.4.11  At the conclusion of the test, cool the sample cup below 50 °C to withdraw it safely.  DUS  2475 :2023 
© UNBS 2023 – All rights reserved  11 
 C.5  Results  
C.5.1  Observe and record the ambient barometric pressure at the time of the test; when the pressure differs 
from 101.3 kPa, correct the flash point as follows:  
 Corrected flash point = C + 0.25 (101.3 – p)  
where,  
 C = observed flash point in ºC  
 p = ambient barometric pressure in kPa  
Round up the corrected value to the nearest 0.5 ºC.  
C.5.2   The barometric pressure used in this calculation must be the absolute ambient pressure for the 
laboratory at the time of the test. Aneroid barometers, such as those used at weather stations and airports, 
are corrected to give sea level readings; these shall not be used.   
12 © UNBS 202 3 – All rights reserved  
 Annex D  
 (normative)   
 
Determination of s pecific gravity  
D.1  General  
A tared Pycnometer  is filled with freshly boiled water that has been cooled to the specified test temperature 
and weighed to determine the weight of water in the filled Pycnometer. The same Pycnometer  is filled with the 
sampl e at the test temperature and weighed. The ratio of the weight of sample to water in air is the specific 
gravity, apparent.  
D.2  Apparatus  
D.2.1   Pycnometer — A Pycnometer of 25 mL capacity with a ground -glass stopper having a capillary 
opening, a chamber  to provide for expansion up to room temperature, and a cap to prevent evaporation.  
D.2.2   Water bath — A water bath capable of maintaining the test temperature at ± 0.05 °C during the test.  
D.2.3   Thermometer — A 76-mm immersion thermometer which covers from 0 to 30 °C in 0.1 °C graduations.  
D.2.4   Analytical balance — A balance capable of weighing 150 g with a precision of 0.1 mg.  
D.2.5   Analytical weights — Class S weights or equivalent weights, if required by the balance.  
D.3  Reagents  
Water — shall be of quality and purity that guarantee accurate result.  
D.4  Procedure  
D.4.1   Clean the Pycnometer by filling it with a saturated solution of Chromic Acid in Sulphuric Acid 
(H2SO4), sp gr 1.84), allowing it to stand for a few hours, emptying, and rins ing well with water.  
D.4.2   Fill the Pycnometer with freshly boiled water that has been cooled to about 2 °C below the test 
temperature; place it in the water bath maintained at the test temperature ± 0.05 °C until the Pycnometer and 
its contents are at a  constant volume at the test temperature. After immersion in the bath for at least 30 min, 
adjust the level of liquid to the proper point on the Pycnometer, put the stopper in place, remove from the bath, 
wipe dry, and weigh.  
D.4.3   Empty the Pycnometer, rinse successively with alcohol and ether, remove the ether vapour, immerse 
in the bath, and bring to the test temperature as was done before. After immersion at the test temperature for 
at least 30 min, put the stopper in place, remove from the bath, wipe  dry, and weigh.  
D.4.4   Subtract the weight of the empty Pycnometer from the weight when filled with water in order to get the 
weight of the contained water at the test temperature in air. Call this difference W.  
D.4.5   Cool the sample about 2 °C below th e test temperature, fill the Pycnometer with it, immerse in the 
bath, and bring to the test temperature as was done before. After immersion at the test temperature for at 
least 30 min, adjust the liquid level, put the stopper in place, remove from the bath , wipe dry, and weigh.  DUS  2475 :2023 
© UNBS 2023 – All rights reserved  13 
 D.4.6   Subtract the weight of the empty Pycnometer from the weight when filled with sample in order to 
obtain the weight  of the contained sample at the test temperature. Call this difference S.  
NOTE  The test temperature of both th e sample and water is 20 ºC.  
D.5  Calculation of result  
Calculate specific gravity of the sample at 20 ºC (in air) as follows:  
 Specific gravity at x/y ºC = S/W  
where,  
 x = temperature of the sample, ºC  
 y = temperature of the water, ºC.  
The density  of the test substance at the test temperature is the ratio of its mass to its volume   
14 © UNBS 202 3 – All rights reserved  
 Annex E  
(normative)  
 
 Determination of optical density  
E.1  General  
The natural colouring matter content of pyrethrum extract is extracted with mineral turpentine oil. The 
absorbance of the solution obtained is measured by using a UV -Visible Spectrometer at a wavelength of 435 
nm.  
E.2  Apparatus  
E.2.1  A UC -visible Spectrophotometer suitable for measuring at a wavelength of 435 nm and having a band 
width of 2 nm.  
E.2.2  A 20 mL volumetric flask  
E.2.3  Measuring Cylinder  
E.2.4  A pair of cuvettes  
E.3  Reagents  
Mineral turpentine oil of known purity.  
E.4  Procedure  
Measure and transfer exactly 1 mL of the pyrethrum extract in the 20 mL volumetric flask. Add to it miner al 
turpentine oil and make up the volume up to the mark. Shake the flask to mix the content thoroughly.  
Take a pair of clean cuvettes. Switch on the Spectrophotometer and set the wavelength at 435 nm. In one 
cuvette take the solvent and place this cuvette  in the reference cell of the spectrophotometer. Take the diluted 
sample from the volumetric flask in the other cuvette and place the cuvette in the sample cell of the 
spectrophotometer. Close the chamber and measure the absorbance at 435 nm.  DUS  2475 :2023 
© UNBS 2023 – All rights reserved  15 
 Annex F  
(normative)  
 
 Determination of pH  
F.1  Apparatus  
A pH Electrode System such as a single or dual glass electrode system conditioned and maintained according 
to the manufacturer’s instructions.  
F.2  Reagents  
Freshly distilled/deionized water free from accumu lation of CO2 from the atmosphere.  
F.3  Procedure  
Prepare a 1 % solution of the extract by weighing 1.0 g of sample into a mixing cylinder containing 50 mL 
reagent water. Add reagent water to 100 mL, stopper and shake vigorously until the formulation is completely 
mixed or dispersed.  
Prior to pH measurement, calibrate the pH -meter using a standard buffer but ensure that the temperature of 
the solution does not differ from the reference solutions used for calibration. Rinse the cell several times with a 
small amount of the solution.   
Immerse the electrode into the solution and measure the pH without stirring. Record the pH value after 1 
minute. If the pH value changes more than 0.1 pH unit during this equilibration time, record the pH ten minutes 
after th e immersion of the electrode.   
16 © UNBS 202 3 – All rights reserved  
 Annex G  
(normative)  
 
 Determination of Butylated Hydroxy Toluene (BHT)  
G.1  General  
The Butylated Hydroxy -toluene (BHT) in refined pyrethrum extract is determined using a HPLC system by 
injecting a solution of the extract i nto the chromatograph, followed by the separation and comparison of peaks 
areas of the analyte sample with that of a standard containing a known amount of the analytes (BHT).  
G.2  Reagents  
G.2.1  Butylated HydroxyToluene Standard; 99 % w/w 
G.2.2  Hexane, H PLC grade  
G.2.3  Diethyl Ether, HPLC grade  
G.3  Apparatus  
A liquid chromatography System equipped with an auto -sampler, a Variable Wavelength Detector (or 
equivalent) and a Colum n {Phenomenex, 250 x 4.6 mm Luna 5μ m Normal  Phase (or equivalent)}  
G.4  Operating conditions  
G.4.1  Flow rate; 2 ml/min  
G.4.2  Composition: 99:1 (% v/v, hexane: diethyl ether)  
G.4.3  Elution: Isocratic  
G.4.4  Oven temperature: 40 ºC  
G.4.5  Wavelength: 270 nm  
G.4.6  Injection volume: 15 µl  
G.4.7  Stop time: 8 min  
G.4.8  Post time: 1 min  
G.5  Preparation of the standard  
Weigh 8 mg of the BHT standard to the nearest 0.0001g in a 100 mL volumetric flask and di ssolved in Hexane 
and diluted to the mark. Transfe r a small portion to a sample vial and label it accordingly.  DUS  2475 :2023 
© UNBS 2023 – All rights reserved  17 
 G.6 Sample preparation  
In a 100 ml volumetric flask, weigh 300 mg to the nearest 0.0001 g of the sample to be analyzed and dilute to 
volume with Hexane. Sample this solution using a vial and la bel it accordingly.  
G.7 Procedure  
After the chromatograph is stable, make a minimum of two injections for the standard solution as well as for 
the analyte and average the area counts. The relative Standard Deviation between injections should be within 
2 %.  
G.8  Calculation of the % BHT  
The % of BHT is calculated as follow:  
% 𝐵𝐻𝑇 =(𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑆𝑎𝑚𝑝𝑙𝑒  𝑎𝑟𝑒𝑎 𝑋 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑋 𝑃𝑢𝑟𝑖𝑡𝑦  𝑜𝑓 𝑡ℎ𝑒 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  (𝑖𝑛 %)) ÷(𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑  
𝑎𝑟𝑒𝑎 𝑋 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒 )  
18 © UNBS 202 3 – All rights reserved  
 Annex H  
(normative)  
 
 Determination of Ta raxasterol  
H.1  General  
Taraxasterol  in refined pyrethrum concentrate is determined using a Gas Liquid Chromatography (GLC) 
system by injecting a solution of the refined pyrethrum concentrate   into the GLC, followed by comparison of 
peaks areas of the an alytes in the sample with that of an external reference standard containing a known 
amount of the analyte.  
H.2 Reagents  
H.2.1  Taraxasterol standard; ˃ 97 %  w/w  
H.2.2  Butanol  
H.2.3  Chloroform  
H.2.4  Hexane  
H.2.5  OV-17 GC Columns  
H.2.6  Chromosorb W AW DMCS 100/120  
H.3  Apparatus  
A Gas Liquid Chromatography (GLC) System equipped with a integrator, a syringe, Z -folder paper, Bubble 
Flow meter  (or equivalent) and a Packed Glass Column – 15 OV -17 in 1.5 mx 4mm ID (or equivalent).  
H.4  Operating conditions  
H.4.1   Preparation of the column  
H.4.1.1   Weigh 0.1 g of OV -17; add to 9.9 g of Chromosorb W 100/120.  
H.4.1.2   Mix thoroughly in a Petri d ish adding chloroform until mixture is fully covered and ensure uniform 
covering of Chromosorb W with a thin layer of OV -17.  
H.4.1.3   Place the Petri dish on the top of oven set at 100 ºC and evaporate chloroform to dryness all the 
time continuously tritu rating the mixture.  
H.4.1.4   Wash the empty (1.5m x 4mm ID) glass column with chloroform and allow drying.  
H.4.1.5   Plug the outlet of the column with a piece of wool , and connect the outlet of the column to a 
vacuum pump and start suction.  
H.4.1.6   Using a funnel assembly at the inlet of the glass column, introduce the dry mixture into the 
column, gently tapping to ensure even packing.  DUS  2475 :2023 
© UNBS 2023 – All rights reserved  19 
 H.4.1.7   Continue introducing the mixture until the packing is 2 inches from the inlet.  
H.4.1.8   Plug the inlet with g lass wool.  
H.4.2   Conditioning of the column   
H.4.2.1   Switch on the instrument.  
H.4.2.2   Open the GLC oven and connect the inlet of column to the injection port.  
H.4.2.3  Connect the flow meter to the outlet of the column and measure a flow rate of 20~3 0 mL/min.  
H.4.2.4   Do not connect column outlet to detector base.  
H.4.2.5   Close the oven and set the oven, the injector and the column temperature to 300 ºC.  
H.4.2.6   Condition the column for at least 12 hours.  
H.4.2.7   Switch off the instrument to co ol.  
H.4.3   Bubble flow meter  
H.4.3.1   Connect the flow meter to the adaptor tube.  
H.4.3.2   Fill the rubber reservoir with soap solution and connect to the flow meter. Test for bubbles by 
squeezing the rubber bulb.  
H.4.3.3   Use the in -built stop and set  the flow to 10 mL.  
H.4.3.4   Open the control knob for Nitrogen and squeeze the bulb on flow meter to create bubbles  
H.4.3.5   Maintain the flow at 10mL and adjust the flow for all gases to the required level in the order of 
Nitrogen, Hydrogen and Air.  
H.5  Preparation of the standard  
Weigh 0.015 g of the Taraxasterol Reference Standard to the nearest 0.0001 g in a 100 mL volumetric flask  
and dissolve in Butanol and dilute to the mark . Transfer a syringe for the injection of 2 mL   
H.6  Sample preparation   
In a 100 mL volumetric flask, weigh 0.5 g to the nearest 0.0001 g of the sample to be analyzed and dilute to 
volume with Butanol. Sample this solution using a syringe.  
H.7  Procedure  
H.7.1   After the instrument is stable, make a minimum of two injectio ns of the Reference Standard solution 
as well as of the sample and average the area counts.  
H.7.2   Make injections of the standard, the sample and the standard, cleaning the syringe thoroughly before 
next injection.  
H.7.3   Where peak areas differ signifi cantly, dilute either the sample or the Reference Standard.   
20 © UNBS 202 3 – All rights reserved  
 H.8  Calculation of the % Taraxasterol  
The % of Taraxasterol is calculated as follow:  
% Taraxasterol = ( 𝐴𝑣𝑒𝑟𝑎𝑔𝑒  𝑆𝑎𝑚𝑝𝑙𝑒  𝑎𝑟𝑒𝑎  𝑋 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑋 𝑃𝑢𝑟𝑖𝑡𝑦  𝑜𝑓 𝑡ℎ𝑒 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑  (𝑖𝑛 %))÷ (𝐴𝑣𝑒𝑟𝑎𝑔𝑒  
𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑  𝑎𝑟𝑒𝑎  𝑋 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒 ) DUS  2475 :2023 
© UNBS 2023 – All rights reserved  21 
 Annex I  
(normative)   
 
Determination of matters ins oluble in dichlorodifluoromethane  
I.1  General  
The insoluble matters are determined by allowing a known amount of the sample to dissolve in 
dichlorodifluoromethane for a given period of time then , drying and weighing the insoluble residue.  
I.2  Reagents   
Dichlorofluoromethane  
I.3  Apparatus  
I.3.1 A 500 mL bottle  
I.3.2 Petri dish  
I.3.3 Vacuum oven  
I.4  Procedure  
I.4.1  Introduce 2 g of the sample into a 500 mL bottle fixed in a protective frame.  
I.4.2   Evacuate air from the bottle and fill it with about 150 mL Dichlorodifluoromethane.  
I.4.3   Store the bottle and contents overnight in a slanted position.  
I.4.4  Invert the bottle and allow the propellant to escape through a cotton filter plug. Wash the  bottle and 
the filter plug with chloroform.  
I.4.5  Transfer the washing to a Petri dish whose weight is known and evaporate the washing on the Petri 
dish to a constant weight at 80oC in a vacuum oven.  
I.5  Calculation of the % matters Insoluble  
The % m atters insoluble in Dichlorofluoromethane  
% 𝑀𝑎𝑡𝑡𝑒𝑟𝑠  𝐼𝑛𝑠𝑜𝑙𝑢𝑏𝑙𝑒  = (𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑖𝑛𝑠𝑜𝑙𝑢𝑏𝑙𝑒𝑠  ÷ 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑠𝑎𝑚𝑝𝑙𝑒 ) 𝑋 100 
  
22 © UNBS 202 3 – All rights reserved  
 Bibliography  
[1] RS 191: 2019 , Refined pyrethrum concentrate — Specification . 
 DUS 2 475:2023 
© UNBS 2023 – All rights reserved  23 
 Certifica tion marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations  made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relati on to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked product s are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 2 475:2023   
 
ICS 65.100 .10 
Price based on nn pages  
© UNBS 202 3– All rights reserved