DRAFT UGANDA STANDARD  
 
  DUS 659  
Secon d Edition  
2021 
 
 
 Reference number  
DUS 659:20 21 
© UNBS 20 21  
  
Leather — Determination of m atter extractable by petroleum 
ether  
 DUS 659:20 21 
ii © UNBS 20 21 – 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 correct application  
© UNBS 20 21  
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 DUS 659:202 1 
© UNBS 20 21 – All rights reserved  iii 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade, Industry and 
Cooperatives established under C ap 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 Sta ndards, 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 f ield 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 pub lic 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 7, Textiles, Leather, Paper 
and related products , Subcommittee SC 2, Leather  and related products . 
This second edition cancels and replaces the first ed ition (US 659 :2006), which has been technically revised:  
The title was modified to “Leather — Determination of Matter extractable by petroleum ether”  
The scope was modified to “t his draft Uganda Standard specifies a method for the determination of matter 
extractable from leather using petroleum ether”  
Normative references: US ISO 2419 replaced US 655 and US 656  
 DRAFT UGANDA STANDARD  DUS 659:20 21 
 
© UNBS 20 21 – All rights  reserved                  1 
 Leather — Determination of Matter extractable by petroleum 
ether  
1 Scope  
This draft Uganda Standard specifies a method for the determination of matter extractable from leather using  
petroleum ether.  
2 Normative references  
The following referenced documen ts 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.  
US ISO 2419 , Leather — Physical and mechanical tests — Sample preparation and conditioning  
4 Terms and definitions  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online brow sing platform: available at http://www.iso.org/obp  
No terms and definitions are listed in this document.  
4 Principle  
Soluble matter is continuously extracted with petroleum ether from a prepared leather sample taken in 
accordance with US ISO 2419 . After re duction of the solvent, the extract is dried at 95 °C ± 5 °C and weighed.  
5 Reagents  
For this analysis, use only reagents of recognized analytical grade.  
5.1 Petroleum ether,  boiling range 60 °C to 80 °C 
Warning - Petroleum ether is highly flammable, has t oxic properties and should be used with caution.  
5.2 Acetone  
6 Apparatus  
6.1 Soxhlet extraction apparatus  including an extraction flask of suitable capacity, a suitable heating 
mantle and a condenser   
2 © UNBS 20 21 – All rights reserved  
 6.2 Filter paper (Whatman No. 11, medium fast)  
6.3 Dryin g oven  capable of being maintained at 95 °C ± 5 °C 
6.4 Steam bath  capable of boiling water  
6.5 Desiccator  large enough to take the extraction flask (see 6 .1) 
7 Procedure  
7.1 Prepare the leather samples as specified in US ISO 2419  
7.2 Clean the extraction f lask (see 6 .1) and dry it by heating at 95 °C ± 5 °C for at lea st 30 min (see 6 .3). 
Place three clean, dry glass beads in the flask, to prevent bumping during boiling. Allow to cool in the 
desiccator and determine the mass of the flask with the beads to wi thin ± 0.001 g.  
7.3 Weigh 10 g ±1 g of the final sample and record the mass to the nearest 0.001 g. Place the sample (in a 
folded filter paper cup) in the extraction apparatus and close.  
7.4 Begin the continuous extraction with the petroleum ether. Once th e extraction is complete, reduce the 
solvent from the residue on a steam bath.  
NOTE  Boiling (at a rate that causes siphoning every 10 min) for a period of 5 h will usually extract at the extractable 
matter, but in doubtful cases a further extraction of the  specimen should be carried out, using a clean flask and fresh 
petroleum ether.  
Add ± 5 mL of acetone to the residue and swirl the flask to facilitate mixing. Place the flask on the steam bath until it is 
solvent free. Dry the residue in the flask for at l east 3 h in the drying oven maintained at 95 °C ± 5 °C. Allow the flask and 
residue to cool in the desiccator. Determine and record, to the nearest ± 0.001 g, the mass of both flask and residue.  
7 Results  
Calculate the extractable matter content (X) as fol lows:  
100abx
 
where  
a is the mass, in grams, of the test sample;  
b is the mass, in grams, of the residue in the flask; and  
x is the extractable matter content, as percentage.  
NOTE  To express the result on a 14 % leather moisture basis, mult iply this value for the extractable matter by the 
factor 
c10086 , where c is the actual percentage moisture content, determined as in US 657.   
© UNBS 20 21 – All rights reserved  3 
 Bibliography  
US 659:2006,  Leather — Matter extractable by petroleum ether  
 
  
4 © UNBS 20 21 – All rights reserved  
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Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
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The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
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certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continu ally 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.  
 
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