DEAS 9 10:2018  
 
© EAS 2018                                                                                                               First Edition 201 8 
 
 
DRAFT EAST AFRICAN STANDARD  
Fertilizer — Urea —Specification  
EAST AFRICAN COMMUNITY     
 
 
  
 Foreword  
Development of the East African Standards has been necessitated by the need for harmonizing requirements 
governing quality of products and services in the East A frican Community. It is envisaged that through 
harmonized standardization, trade barriers that are encountered when goods and services are exchanged 
within the Community will be removed.  
In order to achieve this objective, the Community established an Eas t African Standards Committee mandated 
to develop and issue East African Standards.  
The Committee is composed of representatives of the National Standards Bodies in Partner States, together 
with the representatives from the private sectors and consumer or ganizations. Draft East African Standards 
are circulated to stakeholders through the National Standards Bodies in the Partner States. The comments 
received are discussed and incorporated before finalization of standards, in accordance with the procedures 
of the Community.  
East African Standards are subject to review, to keep pace with technological advances. Users of the East 
African Standards are therefore expected to ensure that they always have the latest versions of the standards 
they are implementing .   
© EAC 2018 – All rights reserved  Fertilizer — Urea — Specification  
1 Scope  
This Draft East African  Standard specifies  the requirements, methods of test and sampling  for urea fertilizer.  
2 Normative references  
The following referenced documents are indispensable for the application of t his document. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies  
ISO 8157 , Fertilizers and Soil Conditioners – Vocabulary  
DEAS 913 , Fertilizers - Methods of Sampling   
ISO 17318 , Fertilizers and soil conditioners -- Determination of arsenic, cadmium, chromium, lead and 
mercury contents  
ISO 8397 , Solid Fertilizers and Soil Conditioners – Test sieving   
ISO 53 15, Fertilizers – Determination of Total Nitro gen Content – Titrimetric method after distillation   
3 Terms and definitions  
For the purpose of this standard, terms and definitions given in ISO 8157  shall apply . 
4 Requirements  
4.1 Physical  
Fertilizer shall be in the form of a free -flowing granules  or prills, free from foreign matter and impurities. The 
colour of the fertilizer shall be uniform. When tested by ISO 8397 , not less than 90 percent by weight of the 
material shall be of particles in the size range of 1 mm to 4 mm for prills and 2mm to 5mm for  granules.  
4.2 Chemical  
The fertilizer shall comply with the requirements specified in Table 1  
Table 1 - Chemical requirements for urea fertilizer  
Characteristic  Requirement  Method of test  
Total nitrogen, % by  
mass, min.  46 ISO 5315  
Biuret, % by mas s, max. 1.5 Annex A  
Moisture, % by mass,  
Max. 1.0 Annex B   
  5 Heavy metal contaminants  
Heavy metal contaminants in the fertilizers shall  conform to the limits given in Table 2 when tested with the 
method specified therein.  
Table 2 — Requirements for heavy  metal contaminants  
Heavy metal  Requirement  Method of test  
Arsenic , mg/kg, max  20 
ISO 17318  Cadmium , mg/kg, max.  7 
Mercury , mg/kg, max  0.1 
Lead , mg/kg, max.  30 
Chromium , mg/kg, max.  500 
6.0 Sampling   
Sampling of fertilizer shall be  carried out a s prescribed in DEAS 913.  
7.0 Packaging and labelling  
7.1  Packaging  
The fertilizer shall be packaged in materials that are clean and non -defective that protect the product from 
physical, chemical and moisture contamination and  withstand multiple stages o f handlin g (transportation and 
storage ). 
7.2 Labelling  
Each package shall be indelibly labeled in  English and/or any other language with the following  information : 
a) name of the fertilizer i.e. "urea fertilizer;  
b) name and address of the manufacturer and impor ter; 
c) nutrient content;  
d) net content by mass in kg;  
e) handling instructions – including the words “Use No hooks”;  
f) production date and expiry date;  
g) country of origin  
h) batch number  
i) storage conditions    
© EAC 2018 – All rights reserved  Annex A 
(normative)  
 
Determination of biuret  
A.1 Reagents  
A.1.1 Alkaline tartarate solution  – Dissolve 40 g of NaOH in 500 ml of H 2O, add 50 g potassium sodium 
tartrate (NaKC 4 H4 O6 .4H 2O), and dilute to 1 litre. Let the solution stand for a day before use.  
A.1.2  Copper sulphate solution (CuSO 4) – Dissolve 15 g CuSO 4.5H 2O in carbon dioxide (CO 2) free water 
(H2O), and dilute to 1 litre.  
A.1.3  Biuret  – To recrystallize, weigh approximately 10 g reagent grade biuret, transfer to 1 litre beaker, 
add 1l absolute alcohol, and dissolve. Concentrate by gentle heating to appr oximately 250 ml. Cool at 5 ºC 
and filter through fritted glass funnel. Repeat crystallization and dry final product for 1 hour at 105 °C – 110 ºC 
in an oven. Remove from oven, place in desiccator and cool to room temperature.  
A.1.4  Biuret standard solutio n – 1 mg / ml - Dissolve 1. 0000 g recrystallized biuret in carbon dioxide 
(CO 2) free water and dilute to 1 litre.  
A.2 Preparation of the standard curve  
Transfer series of aliquots, 2 ml –  50 ml of standard biuret solution to 100 ml volumetric flasks. Adj ust volume 
to approximately 50 ml with CO 2 free H 2O. Add 1 drop methyl red, and neutralize with 0.05 M H 2SO 4 to pink 
colour. Add, with swirling 20 ml alkaline tartrate solution and then 20 ml CuSO 4 solution. Dilute to volume, 
shake for 10 s, and place in H 2O bath for 15 minutes at 30 °C ± 5 ºC. Also, prepare reagent blank. Determine 
the absorbance A of each solution against blank at 555 nm (instrument with 500nm to 570 nm filter is also 
satisfactory) with 1 cm -  5cm cell. Plot the standard curve.  
A.3 Proc edure  
Continuously, stir approximately 10g of the sample containing 30 mg to 125 mg biuret in 150 ml of water at 50  ºC for 30 
minutes. Filter and wash into 250 ml volumetric flask, and dilute to volume. Transfer 50 ml aliquot to 100 ml volumetric 
flask and  proceed as in A.2 above. Calculate biuret concentration using standard curve.   
  Annex B  
(normative)  
 
Determination of moisture content  
B.1 Oven dry method  
B.1.1  General  
The method does not apply to fertilizers that yield volatile substances other than water  at drying temperature.  
B.1.2 Procedure  
B.1.2.1 Weigh accurately 2 g of the prepared sample in a pre -weighed, clean and dry weighing bottle or 
petridish.  
B.1.2.2 Heat in an oven for about 5 hours at 1050C + 2 C to constant weight. Cool in a desiccator and 
weigh. For urea, heat at 700C + 50C for five hours to constant weight.  
B.1.3 Calculation  
Moisture per cent by weight  (%) = 
ABCB

100  
where, 
A is the weight in gram of the empty bottle ; 
B is the weight of the bottle plus the material in gram, before drying ; 
C is the weight of the bottle plus the material in gram, after drying  
B.2 Vacuum desiccator method  
B.2.1 General  
The method is applicable to Ammonium Chloride, Calcium Ammonium Nitrate (CAN), Di -Ammonium 
Phosphate (DAP) and all types of comp lex and mixtures of NPK fertilizers.  
B.2.2 Procedure  
Weigh accurately in duplicate 5g of prepared sample in a weighed shallow porcelain dish. Put the sample in a 
desiccator over concentrated sulphuric acid, close and introduce vacuum for about 10 minutes, then stop the 
vacuum pump and leave the sample for 24 hours, then release vacuum, remove the sample from the 
desiccator and weigh.  
B.2.3 Calculation  
Moisture per cent by weight = 
) () (
100
1 23 2
W WW W

   
© EAC 2018 – All rights reserved  where,  
W1 is the  weight in gram of empty porcelain di sh; 
W2 is the weight in gram of porcelain dish with sample before putting the sample for 24 hours in the 
desiccator ; 
W3 is the weight in gram of porcelain dish with sample after putting the sample for 24 hours in the 
desiccator . 
B.3 Karl Fischer method  
B.3.1 General This method is applicable to fertilizers like CAN, Urea and urea based complexes. This 
method is not suitable for phosphate rock based fertilizers and fertilizers containing monocalcium phosphate, 
calcium sulphate, alkali carbonates as well as al dehydes and ketone groups.  
B.3.2 Apparatus  
Karl Fischer titrator  
B.3.3 Reagents  
B.3.3.1 Karl Fischer reagent(KF)  – Karl Fischer solution (pyridine free) (single solution)  
B.3.3.2 Di-sodium tartarate dihydrate  (Na 2C4O62H2O) analytical grade  
B.3.3.3 Methano l-KF grade/spectroscopy grade containing less than 0.05 % water   
B.3.4 Procedure  
B.3.4.1 Standardization of KF reagent  
B.3.4.1.1 Set up the instrument as per manufacturer’s manual.  
B.3.4.1.2 Add methanol to the titration vessel until the electrodes are d ipped and titrate with Karl -Fischer 
reagent to a pre -set end point persists for 30 seconds.  
B.3.4.1.3Add 100mg of the disodium tartarate dehydrate to the titration vessel carefully and titrate with Karl 
Fischer reagent to a pre -set end point (the pre -set e nd point should persist for 30 seconds). Note the volume 
of KF reagent used as V 1 mL. 
B.3.4.2 Determination of moisture of sample  
B.3.4.2.1 Weigh accurately 1 g of the prepared sample and transfer to the titration vessel carefully and stir 
until dispersed.  
B.3.4.2.2 Titrate with KF reagent to the same pre -set end point as above and note the volume of KF 
reagent used as V 2 mL. 
B.3.5 Calculation  
Factor (F)(mgH 2O/1 ml of KF reagent ) = 
1added dihy drate tartarate sodiumofmg 0.1566
V  
Moisture per cent by weight = 
0001 (gram) sampleof Weight100 2
VF