PUBLIC REVIEW DRAFT DRAFT UGANDA STANDARD  
  DUS DEAS 933 
First  Edition  
2018-mm-dd 
 
 Reference number  
DUS DEAS 933: 2018 
© UNBS 2018 
   
Paper and board intended to come into contact with foodstuffs 
—Determination of formaldehyde in an aqueous extract  
 
 PUBLIC REVIEW DRAFTDUS DEAS 933: 2018  
ii                © UNBS  2018 - 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 2018 
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 
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Uganda 
Tel: +256 417 333 250/1/2 
Fax: +256 414 286 123 
E-mail: info@unbs.go.ug  
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 PUBLIC REVIEW DRAFTDUS DEAS 933: 2018  
© UNBS  2018 - All rights reserved                iii National 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) a nd  
(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. 
This Draft Uganda Standard, DUS DEAS 933:2018, Paper and board intended to come into contact with 
foodstuffs —Determination of formaldehyde in an aqueous extract , is identical with and has been reproduced 
from an East African Standard, EAS 933:2018, Paper and board intended to come into contact with foodstuffs 
—Determination of formaldehyde in an aqueous extract , and is being proposed for adoption as a Uganda 
Standard. 
The committee responsible for this document is Technical Committee UNBS/TC 19, Packaging . 
Wherever the words, “ East African Standard " appear, they should be replaced by "Uganda Standard." PUBLIC REVIEW DRAFT
 DEAS 933: 2018  
ICS 55.120  
 
© EAC 2018                                                                                                                              First Edition 2018 
 DRAFT EAST AFRICAN STANDARD 
Paper and board intended to come into contact with foodstuffs —
Determination of formaldehyde in an aqueous extract 
EAST AFRICAN COMMUNITY PUBLIC REVIEW DRAFTPUBLIC REVIEW DRAFTDEAS 933: 2018 
© EAC 2018 – All rights reserved  ii 
 Copyright notice 
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Violators may be prosecuted. PUBLIC REVIEW DRAFTDEAS 933: 2018 
© EAC 2018 – All rights reserved  iii 
 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 African 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.  
The Community has established an East African Standards Committee (EASC) mandated to develop and 
issue East African Standards (EAS).The Committee is composed of representatives of the National Standards 
Bodies in Partner States, together with the representatives from the public and private sector organizations in 
the community .  
East African Standards are developed through Technical Committees that are representative of key 
stakeholders including government, academia, consumer groups, private sector and other interested parties. 
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 Principles and procedures for development of East African Standards.  
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.  
The committee responsible for this document is Technical Committee EASC/TC 066, Packaging. 
Attention is drawn to the possibility that some of the elements of this document may be subject of patent 
rights. EAC shall not be held responsible for identifying any or all such patent rights. 
During the preparation of this Standard, reference was made to the following document: 
EN 1541, Paper and board intended to come into contact with foodstuffs — Determination of formaldehyde in 
an aqueous extract  
Acknowledgment is hereby made for the assistance derived from this source. 
 PUBLIC REVIEW DRAFTPUBLIC REVIEW DRAFTDRAFT EAST AFRICAN STANDARD  DEAS 933: 2018  
 
© EAC 2018 – All rights reserved  1 
 Paper and board intended to come into contact with foodstuffs 
— Determination of formaldehyde in an aqueous extract  
1 Scope 
This Draft East African Standard specifies the determination of formaldehyde in aqueous extracts prepared 
from paper and board intended to come in contact with foodstuffs. The limit of determination is 1 mg/kg. 
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. 
ISO 6588- 1, Paper, board and pulps — Determination of pH of aqueous extracts — Part 1: Cold extraction  
ISO 6588-2, Paper, board and pulps — Determination of pH of aqueous extracts — Part 2: Hot extraction  
3 Terms and definitions 
For the purposes of this standard, the following terms and definitions apply. 
3.1 
cold water extract 
water solution obtained as a result of cold extraction ISO 6588-1 
3.2 
hot water extract 
water solution obtained as a result of hot extraction ISO 6588-1 
4 Principle 
Formaldehyde reacts with pentane-2, 4-dione (acetyl acetone) in the presence of ammonium acetate to form 
3, 5-diacetyl-1 , 4-dihydrolutidine. The absorbance of the extract is measured at a wavelength of 410 nm. 
NOTE The extract should also be scanned by ultraviolet (UV) spectroscopy for confirmation where the level of 
formaldehyde exceeds specified limits (see clause 10). 
5 Reagents 
All reagents shall be of analytical grade and the water shall be distilled or of equivalent purity. 
5.1 Anhydrous ammonium acetate 
5.2 Acetic acid 99 % (d = 1.05)  
5.3 Pentane-2.4-dione 
5.4 Hydrochloric acid, 1 mol/l  
5.5 Sodium hydroxide solution, 1 mol/l  PUBLIC REVIEW DRAFTDEAS 933: 2018 
2 © EAC 2018 – All rights reserved  
 5.6 Starch solution freshly prepared, 2 g/l 
5.7 Formaldehyde solution, 370 g/l to 400 g/l  
5.8 Standard iodine solution , 0.05 mol/l  
5.9 Standard sodium thiosulphate solution, 0.1 mol/l  
5.10 Pentane- 2, 4-dione reagent  
In a 100.0-ml volumetric flask dissolve: 
a) 15.0 g anhydrous ammonium acetate (see 5.1); 
b) 0.2 ml pentane-2, 4-dione (see 5.3); 
c) 0.3 ml acetic acid (see 5.2); 
d) 25 ml of water. 
Make up to 100.0 ml with water. This reagent shall be freshly prepared. 
5.11 Reagent  (see 5.10) without pentane-2 , 4-dione 
5.12 Formaldehyde-standard: Stock solution 
5.12.1  Measure 5.0 ml formaldehyde solution (see 5.7) into a 1000 ml volumetric flask and make up to 1000 
ml with water. 
5.12. 2 Just before use determine the concentration of this solution as follows. 
Transfer 10.0 ml of the stock solution into a conical flask, add 25.0 ml of a standard iodine solution (see 5.8) 
and 10.0 ml of sodium hydroxide solution (see 5.5). Allow to stand for 5 min. Acidify with 11.0 ml of 
hydrochloric acid (see 5.4) and determine the excess iodine by titration with a standard sodium thiosulphate 
solution (see 5.9), using 0.1 ml of the starch solution (see 5.6) as indicator. 
NOTE Add the starch solution when the solution being titrated has become a pale straw colour. Theoretically, 1.0 ml 
of 0.05 mol/l iodine consumed is equivalent to 1.5 mg formaldehyde. 
5.13 Formaldehyde-standard: Dilute solution 
Dilute an aliquot of the formaldehyde stock solution (see 5.12) to 20 times its volume with water, and then 
furtherdilute an aliquot of this second solution to 100 times its volume so that 1.0 ml of the final solution 
contains about 0.001 mg of formaldehyde. Use pipettes and volumetric flasks. Calculate the actual 
formaldehyde content. This solution shall be freshly prepared. 
6 Apparatus 
6.1 Ordinary laboratory apparatus  
6.2 Spectro photo meter for use at the wavelength of 410 nm , with cells of an optical path length of 10 
mm. 
6.3 Scanning ultraviolet (UV) spectrophotometer in the range of 300 nm to 500 nm (Only for the 
confirmation steps). 
6.4 Thermostatic water-bath capable of maintaining a temperature of (60 °C ± 2 °C). PUBLIC REVIEW DRAFTDEAS 933: 2018 
© EAC 2018 – All rights reserved  3 
 7 Preparation of sample 
Sampling, sample preparation and extraction shall be carried out according to the methods for the preparation 
of cold water (ISO 6588-1) or hot water extracts (ISO 6588-2).Two parallel extractions shall be carried out. 
The test shall be performed not longer than 24 h after extraction. 
8 Procedure 
8.1 For each extract at least two parallel determinations shall be carried out 
Att room temperature the cold water extract is applied while for paper and board materials intended for boiling 
and hot filtering purposes the hot water extract is applied 
8.2 Sample solution 
Into a 50-ml conical flask add: 
- 25.0 ml extract (V1) (see 8.1); 
- 5.0 ml pentane-2.4-dione reagent (see 5.10). 
8.3 Reference solution 
Possible interference due to coloured substances in the aqueous extract is eliminated by the use of this 
reference solution. 
Into a 50-ml conical flask add 
- 25.0 ml extract (see 8.1); 
- 5.0 ml reagent without pentane - 2.4-dione (see 5.11). 
8.4 Blank test 
This is performed in order to construct the calibration curve. 
Into a 50-ml conical flask add 
- 25.0 ml water; 
- 5.0 ml pentane - 2.4-dione reagent (see 5.10). 
8.5 Determination 
8.5.1  Shake the solutions 8.2, 8.3 and 8.4 for about 15 s. Immerse the conical flasks in a thermostatic 
waterbath (see 6.4) at (60 °C ± 2 °C) for 10 min ± 10 s. Allow to cool for at least 2 min in a bath of iced water. 
8.5.2  Bring the solutions into the measuring cells (see 6.2). Measure the absorbance at 410 nm of the 
sample solution (see 8.2) with the reference solution (see 8.3) in the reference cell (A1). 
8.5.3  Measure the absorbance of the blank test (see 8.4) with water in the reference cell (A2). 
8.5.4  The absorbance measurements shall be made between 35 min and 60 min from the time when the 
conical flasks were placed in the water bath at 60 °C. 
8.5.5  If the value of formaldehyde obtained exceeds the range covered by the calibration solutions, the 
measurement shall be repeated with a more dilute sample solution and using an equally diluted reference 
solution. PUBLIC REVIEW DRAFTDEAS 933: 2018 
4 © EAC 2018 – All rights reserved  
 8.6 Calibration curve 
8.6.1  Into a 50-ml conical flask add: 
- 1.0 ml of the formaldehyde diluted standard solution (see 5.13); 
- 5.0 ml of the pentane – 2.4-dione reagent (see 5.10); 
- make up with water to 30.0 ml. 
8.6.2 Continue as described in 8.5 and measure the absorbance with water (see 8.5) in the reference cell. 
8.6.3 Repeat the procedure with 5.0 ml; 10.0 ml; 15.0 ml; 20.0 ml and 25.0 ml of the formaldehyde diluted 
standard solution (see 5.13).Construct the calibration curve after subtraction of the blank test value (see 8.5) 
from each of the absorbance obtained. 
9 Calculation and expression of results 
9.1 Subtract A2 from A1 and read off from the calibration curve (see 8.6) the amount C in mg of 
formaldehyde in the sample solution (see 8.2). 
9.2 Calculate the formaldehyde content of the sample (Cs ) or (Cm ) as follows: 
C2-C x  
   x  
    x  
  1 
Cm-C x  
  x  
  x    
      x 100 2 
where, 
Cs amount of formaldehyde soluble of the sample in mg/dm²; 
Cm amount of formaldehyde soluble of the sample in mg/kg; 
C amount of formaldehyde read from the calibration graph, in mg; 
V0 otal volume of extract (250 ml), in ml; 
V1 volume taken for the test (25.0 ml), in ml; 
B grammage, in g/m²; 
G mass, in grams, of the sample taken under the same condition as grammage; 
F moisture content of the sample, in %. 
Report the result with two significant figures. 
10 Confirmation 
10.1 Requirement for confirmation 
Where the level of formaldehyde in the water extract under test (see clause 7) exceeds any specified limit, the 
determination shall be confirmed by scanning ultraviolet (UV) spectroscopy (see 6.3). PUBLIC REVIEW DRAFTDEAS 933: 2018 
© EAC 2018 – All rights reserved  5 
 10.2 Standard spectrum 
Whilst preparing the formaldehyde derivative (see 8.5), scan the intermediate standard (10.0 ml standard from 
8.6) from 300 nm to 500 nm. Record the position and absorbance value at the peak maximum and calculate 
the ratio of the measurements of the absorbance measured at 20 nm increments either side of the maximum. 
The spectrum shall satisfy the following conditions: 
a) the maximum shall be in the range from 408 nm to 411 nm; 
b) the spectrum shall tend to zero absorbance, that is less than 0.02 absorbance units, below 320 nm. 
Examples of the absorbance ratios to be expected are listed in Table 1. 
Maximum absorbance: 410 nm 
Table 1 — Examples of absorbance ratios at corresponding wavelengths 
Wavelength pair in nm  Ratio  
370 / 410  0.520 ± 0 .02 
390 / 410  0.843 ± 0 .01 
430 / 410  0.802 ± 0 .01 
450 / 410 0.386 ± 0 .02 
 
12 Test report 
The test report shall refer to this East African Standard and state: 
a) extraction method; 
b) nature, origin and designation of the sample; 
c) date of sampling; 
d) date of test; 
e) mean result; 
f) whether confirmation test has been carried out and if so, its result; 
g) any deviations from this East African Standard. PUBLIC REVIEW DRAFTDEAS 933: 2018 
6 © EAC 2018 – All rights reserved  
 Bibliography 
Kenyan std  
 
 
 PUBLIC REVIEW DRAFTDEAS 933: 2018   
 
© EAC 201 8 – All rights reserved