UGANDA STANDARD  
     US ISO 5985
First Edition
   2009 -09-04
 
Reference numbe r 
US ISO 5985:2002
 © UNBS 200 9 
  
Animal feeding stuffs — Determination of ash insoluble in 
hydrochloric acid 
 US ISO 5985:2002  
 
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A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2009  
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  US ISO 5985:2002  
© UNBS  2009 - All rights reserved National foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established by the Act of Parliament of 198 3, of the Laws of Uganda.  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 A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements 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 gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee 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. 
This Uganda Standard, US ISO 5985:2002,  Animal feeding stuffs — Determination of ash insoluble in
hydrochloric acid, is identical with and  has been reproduced from an International Standard ISO 5985:2002,
Animal feeding stuffs — Determination of ash insoluble in hydrochloric acid, and has been adopted as 
a Uganda Standard . 
Wherever the words, "International Standard" a ppear, they should be replaced by "Uganda Standard."    
 Reference numbe r
ISO 5985:2002(E)
© ISO 2002
  
 INTERNATIONAL 
STANDARD  ISO
5985
Second edition
2002-11-15
Animal feeding stuffs — Determination 
of ash insoluble in hydrochloric acid 
Aliments des animaux — Détermination des cendres insolubles dans 
l'acide chlorhydrique 
 ISO 5985:2002(E) 
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ii © ISO 2002 — All rights reserved
  ISO 5985:2002(E) 
© ISO 2002 — All rights reserved  iii
 Foreword 
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO 
member bodies). The work of preparing International Standards is normally carried out through ISO technical 
committees. Each member body interested in a subject for which a technical committee has been established has 
the right to be represented on that committee. International organizations, governmental and non-governmental, in 
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical 
Commission (IEC) on all matters of electrotechnical standardization. 
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of technical committees is to prepare International Standards. Draft International Standards adopted 
by the technical committees are circulated to the member bodies for voting. Publication as an International 
Standard requires approval by at least 75 % of the member bodies casting a vote. 
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of 
patent rights. ISO shall not be held responsible for identiying any or all such patent rights. 
ISO 5985 was prepared by Technical Committee ISO/TC 34, Food products , Subcommittee SC 10, Animal feeding 
stuffs . 
This second edition cancels and replaces the first edition (ISO 5985:1978), of which it constitutes a minor revision. 
Annex A of this International Standard is for information only.  INTERNATIONAL STANDARD ISO 5985:2002(E)
 
© ISO 2002 — All rights reserved  1
 Animal feeding stuffs — Determination of ash insoluble 
in hydrochloric acid 
1 Scope 
This International Standard specifies two procedures for animal feeding stuffs for the determination of the ash 
which is insoluble in hydrochloric acid. 
The applicable procedure depends on the nature of the sample. 
a) Procedure A is applicable to simple organic animal feeding stuffs and to compound feeding stuffs (except 
those mentioned under procedure B). 
b) Procedure B is applicable to minerals, mineral mixtures and compound feeding stuffs of which the ash 
insoluble in hydrochloric acid exceeds 1 % (mass fraction), as determined by procedure A. 
2 Normative reference 
The following normative document contains provisions which, through reference in this text, constitute provisions of 
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these 
publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For 
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC 
maintain registers of currently valid International Standards. 
ISO 6498, Animal feeding stuffs — Preparation of test samples  
3 Term and definition 
For the purposes of this International Standard, the following term and definition applies. 
3.1 
ash insoluble in hydrochloric acid 
that part of the ash which is insoluble in dilute hydrochloric acid under the conditions specified in this International 
Standard 
NOTE It is expressed as a mass fraction of the sample in percent. 
4 Principle 
4.1 Procedure A 
The organic matter in a test portion is decomposed by incineration. 
The ash obtained is treated with hydrochloric acid. The mixture is filtered, followed by drying, incineration and 
weighing of the residue. ISO 5985:2002(E) 
2 © ISO 2002 — All rights reserved
 4.2 Procedure B 
A test portion is treated with hydrochloric acid. The mixture is filtered, followed by drying and incineration. 
The ash is treated as in 4.1. 
5 Reagents 
Use only reagents of analytical quality, and distilled or demineralized water or water of at least equivalent purity. 5.1 Dilute hydrochloric acid , 3 mol/l. 
5.2 Trichloroacetic acid solution , 200 g/l. 
5.3 Trichloroacetic acid solution , 10 g/l. 
6 Apparatus 
Usual laboratory apparatus and, in particular, the following. 
6.1 Analytical  balance , capable of weighing to the nearest 0,001 g. 
6.2 Muffle  furnace , electrically heated, thermostatically controlled, and provided with a pyrometer. 
The furnace, when set at 550 °C, shall be capable of being controlled in such a way that the temperature in the 
places where the incineration dishes will be placed will not differ by more than 20 °C from this set temperature. 
6.3 Drying oven , capable of being controlled at (103 ± 2) °C. 
6.4 Hot-plate  or gas burner  
6.5 Boiling water bath 
6.6 Incineration  dishes , of platinum or platinum-gold alloy (e.g. 10 % Pt, 90 % Au) or of other material 
unaffected by the conditions of the test, preferably rectangular, with a surface area of about 20 cm2 and a height of 
about 2,5 cm. 
For samples which are inclined to swell on carbonization, use dishes with a surface area of about 30 cm2 and a 
height of about 3 cm. 6.7 Desiccator , provided with an effective desiccant. 
7 Sampling 
It is important that the laboratory receive a sample which is truly representative and has not been damaged or 
changed during transport or storage. 
Store the sample in such a way that deterioration and change in composition are prevented. Sampling is not part of the method specified in this International Standard. A recommended sampling method is 
given in ISO 6497. ISO 5985:2002(E) 
© ISO 2002 — All rights reserved  3
 8 Procedures 
8.1 Preparation of test sample 
Prepare the test sample in acordance with ISO 6498. 
8.2 Procedure A 
8.2.1 Test portion 
Weigh, to the nearest 0,001 g, about 5 g of the test sample (8.1) into an incineration dish (6.6).  
8.2.2 Determination 
8.2.2.1 Place the incineration dish containing the test portion (8.2.1) on a hot plate or over a gas burner (6.4) 
and heat progressively until the test portion has carbonized. Transfer the dish to the muffle furnace (6.2), previously 
set at 550 °C, and leave it for 3 h. Inspect visually whether the ash is free from carbonaceous particles. If it is not, replace the dish in the furnace and heat for another 1 h. If carbonaceous particles are still visible, or if there is doubt as to whether they are present, allow the ash to cool, moisten with distilled water, evaporate carefully to 
dryness in the oven (6.3), set at 103 °C. Then replace the dish in the furnace and heat for another 1 h. Allow the 
dish to cool to room temperature in the desiccator (6.7). 
NOTE The ash obtained at this point corresponds to that obtained by the procedure specified in ISO 5984. 
8.2.2.2 Transfer the ash with 75 ml of the dilute hydrochloric acid (5.1) to a 250 ml to 400 ml beaker. Heat 
carefully to boiling on the hot plate or gas burner (6.4) and boil for 15 min. Filter the hot solution through an ash-free filter paper and wash the filter paper and residue with hot water until the washings are free from acid. 
Transfer the filter paper with the residue to an incineration dish (6.6), previously heated for at least 30 min in the 
muffle furnace (6.2) set at 550 °C, cooled in the desiccator (6.7) and weighed to the nearest 0,001 g. Dry the dish and its contents for 2 h in the oven (6.3), set at 103 °C, then ignite for 30 min in the muffle furnace (6.2), set at 550 °C. Cool the dish to room temperature in the desiccator (6.7) then weigh rapidly to the nearest 0,001 g. 
8.2.2.3 Carry out two determinations on test portions from the same test sample. 
8.3 Procedure B 
8.3.1 Test portion 
Weigh, to the nearest 0,001 g, about 5 g of the test sample (8.1) into a 250 ml to 400 ml beaker. 
8.3.2 Determination 
8.3.2.1 Add successively to the beaker containing the test portion (8.3.1), 25 ml of water and 25 ml of the 
dilute hydrochloric acid (5.1). Mix and allow to stand until foaming has ceased. Add 50 ml of the hydrochloric acid 
and wait again, if necessary, until foaming has practically ceased. Heat the beaker over the boiling water bath (6.5) for 30 min or longer until all starch present has been completely hydrolysed. 
Filter the hot solution through an ash-free filter paper and wash the filter paper and residue with 50 ml of hot water. 
8.3.2.2 If the solution is difficult to filter, repeat the determination using a new test portion but adding 50 ml of 
the trichloroacetic acid solution (5.2) instead of 50 ml of the hydrochloric acid, and wash the filter paper and residue 
with hot trichloroacetic acid solution (5.3) before washing with hot water. 
8.3.2.3 Transfer the filter paper with the residue to an incineration dish (6.6). Dry for 2 h in the oven (6.3), set 
at 103 °C, then ignite in the muffle furnace (6.2) set at 550 °C for 3 h. Allow the dish to cool to room temperature in 
the desiccator (6.7). ISO 5985:2002(E) 
4 © ISO 2002 — All rights reserved
 8.3.2.4 Continue as described in 8.2.2.2. 
8.3.2.5 Carry out two determinations on test portions from the same test sample. 
9 Expression of results 
The ash insoluble in hydrochloric acid, w, expressed as a mass fraction of the test sample in percent, is equal to: 
20
10100 %mmwmm−=×− 
where 
m0 is the mass, in grams, of the empty dish (8.2.2.2); 
m1 is the mass, in grams, of the dish containing the test portion (8.2.1 or 8.3.1); 
m2 is the mass, in grams, of the dish and the ash insoluble in hydrochloric acid. 
Take as the result the arithmetic mean of the two determinations, provided that the requirement for repeatability 
(see 10.2) is satisfied. Report the result to the nearest 0,1 % (mass fraction). 
10 Precision 
10.1 Interlaboratory tests 
Details of interlaboratory tests on the precision of the method are given in annex A. The values derived from these 
tests may not be applicable to concentration ranges and matrices other than those given. 
10.2 Repeatability 
The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same operator using the same equipment, will in not more than 5 % of 
cases exceed the repeatability limit ( r) given in Table 1. 
Table 1 — Repeatability limit (r) and reproducibility limit (R) 
Values in grams per kilogram 
Sample Crude ash insoluble in HCl r R 
Fishmeal 8,2 0,8 2,3 
Tapioca 34,6 2,8 5,2 
Meat meal 8,6 0,8 1,9 
Piglet feed 2,6 0,3 1,0 
Broiler feed 1,7 0,3 1,0 
Barley 2,6 0,5 1,7 
Palm kernel expellers 6,0 0,8 1,2 
 ISO 5985:2002(E) 
© ISO 2002 — All rights reserved  5
 10.3 Reproducibility 
The absolute difference between two single test results, obtained using the same method on identical test material 
in different laboratories by different operators using different equipment, will in not more than 5 % of cases exceed the reproducibility limit ( R) given in Table 1. 
11 Test report 
The test report shall specify: 
a) all information required for the complete identification of the sample; b) the sampling method used, if known; c) the test method used (procedure A or B), with reference to this International Standard; d) all operating details not specified in this International Standard, or regarded as optional, together with details of 
any incident which may have influenced the result(s); 
e) the test result(s) obtained; 
f) if the repeatability has been checked the final quoted results obtained.  ISO 5985:2002(E) 
6 © ISO 2002 — All rights reserved
 Annex A  
(informative) 
 
Results of interlaboratory tests 
The precision of the method was established by interlaboratory tests carried out in accordance with ISO 5725-1 
and ISO 5725-2, in which the Dixon test is replaced by the Grubbs test in case of outliers. In the tests, 20 to 30 
laboratories participated and samples were investigated of fishmeal, tapioca, meat meal, piglet feed, broiler feed, 
barley, palm kernel expellers. The results of the interlaboratory tests are given in Table A.1. 
Table A.1 — Statistical results of interlaboratory tests 
Samplea 
Parameter 
1 2 3 4 5 6 7 
Number of laboratories 29 30 23 22 20 24 25 
Number of individual results 29 30 23 22 20 24 25 
Number of accepted results 28 29 22 20 19 23 23 
Mean crude ash insoluble in HCl, g/kg 8,2 34,6 8,6 2,6 1,7 2,6 6,0 
Repeatability standard deviation ( sr), g/kg 0,3 1,0 0,3 0,1 0,1 0,2 0,3 
Repeatability coefficient of variation, % 9,5 8,0 8,9 12,2 17,6 18,3 13,3 
Repeatability limit ( r), g/kg 0,8 2,8 0,8 0,3 0,3 0,5 0,8 
Reproducibility standard deviation ( sR), g/kg 0,8 1,7 0,7 0,3 0,3 0,6 0,4 
Reproducibility coefficient of variation, % 28,1 14,9 22,5 39,1 56,9 64,7 20,7 
Reproducibility limit ( R), g/kg 2,3 5,2 1,9 1,0 1,0 1,7 1,2 
a 1: fishmeal; 
 2: tapioca; 
 3: meat meal; 
 4: piglet feed; 5: broiler feed; 
6: barley; 7: palm kernel expellers. 
 ISO 5985:2002(E) 
© ISO 2002 — All rights reserved  7
 Bibliography 
[1] ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General 
principles and definitions  
[2] ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic 
method for the determination of repeatability and reproducibility of a standard measurement method  
[3] ISO 5984, Animal feeding stuffs — Determination of crude ash  
[4] ISO 6497, Animal feeding stuffs — Sampling  ISO 5985:2002(E) 
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